diff options
Diffstat (limited to 'fs/btrfs/relocation.c')
| -rw-r--r-- | fs/btrfs/relocation.c | 3118 |
1 files changed, 1390 insertions, 1728 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 995d4b8b1cfd..666a37a0ee89 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -9,6 +9,7 @@ #include <linux/blkdev.h> #include <linux/rbtree.h> #include <linux/slab.h> +#include <linux/error-injection.h> #include "ctree.h" #include "disk-io.h" #include "transaction.h" @@ -17,106 +18,72 @@ #include "btrfs_inode.h" #include "async-thread.h" #include "free-space-cache.h" -#include "inode-map.h" #include "qgroup.h" #include "print-tree.h" #include "delalloc-space.h" #include "block-group.h" +#include "backref.h" +#include "misc.h" +#include "subpage.h" +#include "zoned.h" +#include "inode-item.h" /* - * backref_node, mapping_node and tree_block start with this - */ -struct tree_entry { - struct rb_node rb_node; - u64 bytenr; -}; - -/* - * present a tree block in the backref cache - */ -struct backref_node { - struct rb_node rb_node; - u64 bytenr; - - u64 new_bytenr; - /* objectid of tree block owner, can be not uptodate */ - u64 owner; - /* link to pending, changed or detached list */ - struct list_head list; - /* list of upper level blocks reference this block */ - struct list_head upper; - /* list of child blocks in the cache */ - struct list_head lower; - /* NULL if this node is not tree root */ - struct btrfs_root *root; - /* extent buffer got by COW the block */ - struct extent_buffer *eb; - /* level of tree block */ - unsigned int level:8; - /* is the block in non-reference counted tree */ - unsigned int cowonly:1; - /* 1 if no child node in the cache */ - unsigned int lowest:1; - /* is the extent buffer locked */ - unsigned int locked:1; - /* has the block been processed */ - unsigned int processed:1; - /* have backrefs of this block been checked */ - unsigned int checked:1; - /* - * 1 if corresponding block has been cowed but some upper - * level block pointers may not point to the new location - */ - unsigned int pending:1; - /* - * 1 if the backref node isn't connected to any other - * backref node. - */ - unsigned int detached:1; -}; - -/* - * present a block pointer in the backref cache + * Relocation overview + * + * [What does relocation do] + * + * The objective of relocation is to relocate all extents of the target block + * group to other block groups. + * This is utilized by resize (shrink only), profile converting, compacting + * space, or balance routine to spread chunks over devices. + * + * Before | After + * ------------------------------------------------------------------ + * BG A: 10 data extents | BG A: deleted + * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated) + * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated) + * + * [How does relocation work] + * + * 1. Mark the target block group read-only + * New extents won't be allocated from the target block group. + * + * 2.1 Record each extent in the target block group + * To build a proper map of extents to be relocated. + * + * 2.2 Build data reloc tree and reloc trees + * Data reloc tree will contain an inode, recording all newly relocated + * data extents. + * There will be only one data reloc tree for one data block group. + * + * Reloc tree will be a special snapshot of its source tree, containing + * relocated tree blocks. + * Each tree referring to a tree block in target block group will get its + * reloc tree built. + * + * 2.3 Swap source tree with its corresponding reloc tree + * Each involved tree only refers to new extents after swap. + * + * 3. Cleanup reloc trees and data reloc tree. + * As old extents in the target block group are still referenced by reloc + * trees, we need to clean them up before really freeing the target block + * group. + * + * The main complexity is in steps 2.2 and 2.3. + * + * The entry point of relocation is relocate_block_group() function. */ -struct backref_edge { - struct list_head list[2]; - struct backref_node *node[2]; -}; -#define LOWER 0 -#define UPPER 1 #define RELOCATION_RESERVED_NODES 256 - -struct backref_cache { - /* red black tree of all backref nodes in the cache */ - struct rb_root rb_root; - /* for passing backref nodes to btrfs_reloc_cow_block */ - struct backref_node *path[BTRFS_MAX_LEVEL]; - /* - * list of blocks that have been cowed but some block - * pointers in upper level blocks may not reflect the - * new location - */ - struct list_head pending[BTRFS_MAX_LEVEL]; - /* list of backref nodes with no child node */ - struct list_head leaves; - /* list of blocks that have been cowed in current transaction */ - struct list_head changed; - /* list of detached backref node. */ - struct list_head detached; - - u64 last_trans; - - int nr_nodes; - int nr_edges; -}; - /* * map address of tree root to tree */ struct mapping_node { - struct rb_node rb_node; - u64 bytenr; + struct { + struct rb_node rb_node; + u64 bytenr; + }; /* Use rb_simle_node for search/insert */ void *data; }; @@ -129,8 +96,11 @@ struct mapping_tree { * present a tree block to process */ struct tree_block { - struct rb_node rb_node; - u64 bytenr; + struct { + struct rb_node rb_node; + u64 bytenr; + }; /* Use rb_simple_node for search/insert */ + u64 owner; struct btrfs_key key; unsigned int level:8; unsigned int key_ready:1; @@ -155,7 +125,7 @@ struct reloc_control { struct btrfs_block_rsv *block_rsv; - struct backref_cache backref_cache; + struct btrfs_backref_cache backref_cache; struct file_extent_cluster cluster; /* tree blocks have been processed */ @@ -186,167 +156,41 @@ struct reloc_control { #define MOVE_DATA_EXTENTS 0 #define UPDATE_DATA_PTRS 1 -static void remove_backref_node(struct backref_cache *cache, - struct backref_node *node); -static void __mark_block_processed(struct reloc_control *rc, - struct backref_node *node); - -static void mapping_tree_init(struct mapping_tree *tree) -{ - tree->rb_root = RB_ROOT; - spin_lock_init(&tree->lock); -} - -static void backref_cache_init(struct backref_cache *cache) -{ - int i; - cache->rb_root = RB_ROOT; - for (i = 0; i < BTRFS_MAX_LEVEL; i++) - INIT_LIST_HEAD(&cache->pending[i]); - INIT_LIST_HEAD(&cache->changed); - INIT_LIST_HEAD(&cache->detached); - INIT_LIST_HEAD(&cache->leaves); -} - -static void backref_cache_cleanup(struct backref_cache *cache) -{ - struct backref_node *node; - int i; - - while (!list_empty(&cache->detached)) { - node = list_entry(cache->detached.next, - struct backref_node, list); - remove_backref_node(cache, node); - } - - while (!list_empty(&cache->leaves)) { - node = list_entry(cache->leaves.next, - struct backref_node, lower); - remove_backref_node(cache, node); - } - - cache->last_trans = 0; - - for (i = 0; i < BTRFS_MAX_LEVEL; i++) - ASSERT(list_empty(&cache->pending[i])); - ASSERT(list_empty(&cache->changed)); - ASSERT(list_empty(&cache->detached)); - ASSERT(RB_EMPTY_ROOT(&cache->rb_root)); - ASSERT(!cache->nr_nodes); - ASSERT(!cache->nr_edges); -} - -static struct backref_node *alloc_backref_node(struct backref_cache *cache) -{ - struct backref_node *node; - - node = kzalloc(sizeof(*node), GFP_NOFS); - if (node) { - INIT_LIST_HEAD(&node->list); - INIT_LIST_HEAD(&node->upper); - INIT_LIST_HEAD(&node->lower); - RB_CLEAR_NODE(&node->rb_node); - cache->nr_nodes++; - } - return node; -} - -static void free_backref_node(struct backref_cache *cache, - struct backref_node *node) -{ - if (node) { - cache->nr_nodes--; - kfree(node); - } -} - -static struct backref_edge *alloc_backref_edge(struct backref_cache *cache) -{ - struct backref_edge *edge; - - edge = kzalloc(sizeof(*edge), GFP_NOFS); - if (edge) - cache->nr_edges++; - return edge; -} - -static void free_backref_edge(struct backref_cache *cache, - struct backref_edge *edge) +static void mark_block_processed(struct reloc_control *rc, + struct btrfs_backref_node *node) { - if (edge) { - cache->nr_edges--; - kfree(edge); - } -} + u32 blocksize; -static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr, - struct rb_node *node) -{ - struct rb_node **p = &root->rb_node; - struct rb_node *parent = NULL; - struct tree_entry *entry; - - while (*p) { - parent = *p; - entry = rb_entry(parent, struct tree_entry, rb_node); - - if (bytenr < entry->bytenr) - p = &(*p)->rb_left; - else if (bytenr > entry->bytenr) - p = &(*p)->rb_right; - else - return parent; + if (node->level == 0 || + in_range(node->bytenr, rc->block_group->start, + rc->block_group->length)) { + blocksize = rc->extent_root->fs_info->nodesize; + set_extent_bits(&rc->processed_blocks, node->bytenr, + node->bytenr + blocksize - 1, EXTENT_DIRTY); } - - rb_link_node(node, parent, p); - rb_insert_color(node, root); - return NULL; + node->processed = 1; } -static struct rb_node *tree_search(struct rb_root *root, u64 bytenr) -{ - struct rb_node *n = root->rb_node; - struct tree_entry *entry; - - while (n) { - entry = rb_entry(n, struct tree_entry, rb_node); - - if (bytenr < entry->bytenr) - n = n->rb_left; - else if (bytenr > entry->bytenr) - n = n->rb_right; - else - return n; - } - return NULL; -} -static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr) +static void mapping_tree_init(struct mapping_tree *tree) { - - struct btrfs_fs_info *fs_info = NULL; - struct backref_node *bnode = rb_entry(rb_node, struct backref_node, - rb_node); - if (bnode->root) - fs_info = bnode->root->fs_info; - btrfs_panic(fs_info, errno, - "Inconsistency in backref cache found at offset %llu", - bytenr); + tree->rb_root = RB_ROOT; + spin_lock_init(&tree->lock); } /* * walk up backref nodes until reach node presents tree root */ -static struct backref_node *walk_up_backref(struct backref_node *node, - struct backref_edge *edges[], - int *index) +static struct btrfs_backref_node *walk_up_backref( + struct btrfs_backref_node *node, + struct btrfs_backref_edge *edges[], int *index) { - struct backref_edge *edge; + struct btrfs_backref_edge *edge; int idx = *index; while (!list_empty(&node->upper)) { edge = list_entry(node->upper.next, - struct backref_edge, list[LOWER]); + struct btrfs_backref_edge, list[LOWER]); edges[idx++] = edge; node = edge->node[UPPER]; } @@ -358,11 +202,11 @@ static struct backref_node *walk_up_backref(struct backref_node *node, /* * walk down backref nodes to find start of next reference path */ -static struct backref_node *walk_down_backref(struct backref_edge *edges[], - int *index) +static struct btrfs_backref_node *walk_down_backref( + struct btrfs_backref_edge *edges[], int *index) { - struct backref_edge *edge; - struct backref_node *lower; + struct btrfs_backref_edge *edge; + struct btrfs_backref_node *lower; int idx = *index; while (idx > 0) { @@ -373,7 +217,7 @@ static struct backref_node *walk_down_backref(struct backref_edge *edges[], continue; } edge = list_entry(edge->list[LOWER].next, - struct backref_edge, list[LOWER]); + struct btrfs_backref_edge, list[LOWER]); edges[idx - 1] = edge; *index = idx; return edge->node[UPPER]; @@ -382,95 +226,24 @@ static struct backref_node *walk_down_backref(struct backref_edge *edges[], return NULL; } -static void unlock_node_buffer(struct backref_node *node) -{ - if (node->locked) { - btrfs_tree_unlock(node->eb); - node->locked = 0; - } -} - -static void drop_node_buffer(struct backref_node *node) -{ - if (node->eb) { - unlock_node_buffer(node); - free_extent_buffer(node->eb); - node->eb = NULL; - } -} - -static void drop_backref_node(struct backref_cache *tree, - struct backref_node *node) -{ - BUG_ON(!list_empty(&node->upper)); - - drop_node_buffer(node); - list_del(&node->list); - list_del(&node->lower); - if (!RB_EMPTY_NODE(&node->rb_node)) - rb_erase(&node->rb_node, &tree->rb_root); - free_backref_node(tree, node); -} - -/* - * remove a backref node from the backref cache - */ -static void remove_backref_node(struct backref_cache *cache, - struct backref_node *node) -{ - struct backref_node *upper; - struct backref_edge *edge; - - if (!node) - return; - - BUG_ON(!node->lowest && !node->detached); - while (!list_empty(&node->upper)) { - edge = list_entry(node->upper.next, struct backref_edge, - list[LOWER]); - upper = edge->node[UPPER]; - list_del(&edge->list[LOWER]); - list_del(&edge->list[UPPER]); - free_backref_edge(cache, edge); - - if (RB_EMPTY_NODE(&upper->rb_node)) { - BUG_ON(!list_empty(&node->upper)); - drop_backref_node(cache, node); - node = upper; - node->lowest = 1; - continue; - } - /* - * add the node to leaf node list if no other - * child block cached. - */ - if (list_empty(&upper->lower)) { - list_add_tail(&upper->lower, &cache->leaves); - upper->lowest = 1; - } - } - - drop_backref_node(cache, node); -} - -static void update_backref_node(struct backref_cache *cache, - struct backref_node *node, u64 bytenr) +static void update_backref_node(struct btrfs_backref_cache *cache, + struct btrfs_backref_node *node, u64 bytenr) { struct rb_node *rb_node; rb_erase(&node->rb_node, &cache->rb_root); node->bytenr = bytenr; - rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node); + rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node); if (rb_node) - backref_tree_panic(rb_node, -EEXIST, bytenr); + btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST); } /* * update backref cache after a transaction commit */ static int update_backref_cache(struct btrfs_trans_handle *trans, - struct backref_cache *cache) + struct btrfs_backref_cache *cache) { - struct backref_node *node; + struct btrfs_backref_node *node; int level = 0; if (cache->last_trans == 0) { @@ -488,13 +261,13 @@ static int update_backref_cache(struct btrfs_trans_handle *trans, */ while (!list_empty(&cache->detached)) { node = list_entry(cache->detached.next, - struct backref_node, list); - remove_backref_node(cache, node); + struct btrfs_backref_node, list); + btrfs_backref_cleanup_node(cache, node); } while (!list_empty(&cache->changed)) { node = list_entry(cache->changed.next, - struct backref_node, list); + struct btrfs_backref_node, list); list_del_init(&node->list); BUG_ON(node->pending); update_backref_node(cache, node, node->new_bytenr); @@ -535,7 +308,8 @@ static bool reloc_root_is_dead(struct btrfs_root *root) * * Reloc tree after swap is considered dead, thus not considered as valid. * This is enough for most callers, as they don't distinguish dead reloc root - * from no reloc root. But should_ignore_root() below is a special case. + * from no reloc root. But btrfs_should_ignore_reloc_root() below is a + * special case. */ static bool have_reloc_root(struct btrfs_root *root) { @@ -546,11 +320,11 @@ static bool have_reloc_root(struct btrfs_root *root) return true; } -static int should_ignore_root(struct btrfs_root *root) +int btrfs_should_ignore_reloc_root(struct btrfs_root *root) { struct btrfs_root *reloc_root; - if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) + if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) return 0; /* This root has been merged with its reloc tree, we can ignore it */ @@ -561,8 +335,8 @@ static int should_ignore_root(struct btrfs_root *root) if (!reloc_root) return 0; - if (btrfs_root_last_snapshot(&reloc_root->root_item) == - root->fs_info->running_transaction->transid - 1) + if (btrfs_header_generation(reloc_root->commit_root) == + root->fs_info->running_transaction->transid) return 0; /* * if there is reloc tree and it was created in previous @@ -572,624 +346,187 @@ static int should_ignore_root(struct btrfs_root *root) */ return 1; } + /* * find reloc tree by address of tree root */ -static struct btrfs_root *find_reloc_root(struct reloc_control *rc, - u64 bytenr) +struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr) { + struct reloc_control *rc = fs_info->reloc_ctl; struct rb_node *rb_node; struct mapping_node *node; struct btrfs_root *root = NULL; + ASSERT(rc); spin_lock(&rc->reloc_root_tree.lock); - rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr); + rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr); if (rb_node) { node = rb_entry(rb_node, struct mapping_node, rb_node); - root = (struct btrfs_root *)node->data; + root = node->data; } spin_unlock(&rc->reloc_root_tree.lock); - return root; + return btrfs_grab_root(root); } -static int is_cowonly_root(u64 root_objectid) +/* + * For useless nodes, do two major clean ups: + * + * - Cleanup the children edges and nodes + * If child node is also orphan (no parent) during cleanup, then the child + * node will also be cleaned up. + * + * - Freeing up leaves (level 0), keeps nodes detached + * For nodes, the node is still cached as "detached" + * + * Return false if @node is not in the @useless_nodes list. + * Return true if @node is in the @useless_nodes list. + */ +static bool handle_useless_nodes(struct reloc_control *rc, + struct btrfs_backref_node *node) { - if (root_objectid == BTRFS_ROOT_TREE_OBJECTID || - root_objectid == BTRFS_EXTENT_TREE_OBJECTID || - root_objectid == BTRFS_CHUNK_TREE_OBJECTID || - root_objectid == BTRFS_DEV_TREE_OBJECTID || - root_objectid == BTRFS_TREE_LOG_OBJECTID || - root_objectid == BTRFS_CSUM_TREE_OBJECTID || - root_objectid == BTRFS_UUID_TREE_OBJECTID || - root_objectid == BTRFS_QUOTA_TREE_OBJECTID || - root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID) - return 1; - return 0; -} + struct btrfs_backref_cache *cache = &rc->backref_cache; + struct list_head *useless_node = &cache->useless_node; + bool ret = false; -static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info, - u64 root_objectid) -{ - struct btrfs_key key; + while (!list_empty(useless_node)) { + struct btrfs_backref_node *cur; - key.objectid = root_objectid; - key.type = BTRFS_ROOT_ITEM_KEY; - if (is_cowonly_root(root_objectid)) - key.offset = 0; - else - key.offset = (u64)-1; + cur = list_first_entry(useless_node, struct btrfs_backref_node, + list); + list_del_init(&cur->list); - return btrfs_get_fs_root(fs_info, &key, false); -} + /* Only tree root nodes can be added to @useless_nodes */ + ASSERT(list_empty(&cur->upper)); -static noinline_for_stack -int find_inline_backref(struct extent_buffer *leaf, int slot, - unsigned long *ptr, unsigned long *end) -{ - struct btrfs_key key; - struct btrfs_extent_item *ei; - struct btrfs_tree_block_info *bi; - u32 item_size; + if (cur == node) + ret = true; - btrfs_item_key_to_cpu(leaf, &key, slot); + /* The node is the lowest node */ + if (cur->lowest) { + list_del_init(&cur->lower); + cur->lowest = 0; + } - item_size = btrfs_item_size_nr(leaf, slot); - if (item_size < sizeof(*ei)) { - btrfs_print_v0_err(leaf->fs_info); - btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL); - return 1; - } - ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); - WARN_ON(!(btrfs_extent_flags(leaf, ei) & - BTRFS_EXTENT_FLAG_TREE_BLOCK)); + /* Cleanup the lower edges */ + while (!list_empty(&cur->lower)) { + struct btrfs_backref_edge *edge; + struct btrfs_backref_node *lower; - if (key.type == BTRFS_EXTENT_ITEM_KEY && - item_size <= sizeof(*ei) + sizeof(*bi)) { - WARN_ON(item_size < sizeof(*ei) + sizeof(*bi)); - return 1; - } - if (key.type == BTRFS_METADATA_ITEM_KEY && - item_size <= sizeof(*ei)) { - WARN_ON(item_size < sizeof(*ei)); - return 1; - } + edge = list_entry(cur->lower.next, + struct btrfs_backref_edge, list[UPPER]); + list_del(&edge->list[UPPER]); + list_del(&edge->list[LOWER]); + lower = edge->node[LOWER]; + btrfs_backref_free_edge(cache, edge); - if (key.type == BTRFS_EXTENT_ITEM_KEY) { - bi = (struct btrfs_tree_block_info *)(ei + 1); - *ptr = (unsigned long)(bi + 1); - } else { - *ptr = (unsigned long)(ei + 1); + /* Child node is also orphan, queue for cleanup */ + if (list_empty(&lower->upper)) + list_add(&lower->list, useless_node); + } + /* Mark this block processed for relocation */ + mark_block_processed(rc, cur); + + /* + * Backref nodes for tree leaves are deleted from the cache. + * Backref nodes for upper level tree blocks are left in the + * cache to avoid unnecessary backref lookup. + */ + if (cur->level > 0) { + list_add(&cur->list, &cache->detached); + cur->detached = 1; + } else { + rb_erase(&cur->rb_node, &cache->rb_root); + btrfs_backref_free_node(cache, cur); + } } - *end = (unsigned long)ei + item_size; - return 0; + return ret; } /* - * build backref tree for a given tree block. root of the backref tree - * corresponds the tree block, leaves of the backref tree correspond - * roots of b-trees that reference the tree block. + * Build backref tree for a given tree block. Root of the backref tree + * corresponds the tree block, leaves of the backref tree correspond roots of + * b-trees that reference the tree block. * - * the basic idea of this function is check backrefs of a given block - * to find upper level blocks that reference the block, and then check - * backrefs of these upper level blocks recursively. the recursion stop - * when tree root is reached or backrefs for the block is cached. + * The basic idea of this function is check backrefs of a given block to find + * upper level blocks that reference the block, and then check backrefs of + * these upper level blocks recursively. The recursion stops when tree root is + * reached or backrefs for the block is cached. * - * NOTE: if we find backrefs for a block are cached, we know backrefs - * for all upper level blocks that directly/indirectly reference the - * block are also cached. + * NOTE: if we find that backrefs for a block are cached, we know backrefs for + * all upper level blocks that directly/indirectly reference the block are also + * cached. */ -static noinline_for_stack -struct backref_node *build_backref_tree(struct reloc_control *rc, - struct btrfs_key *node_key, - int level, u64 bytenr) +static noinline_for_stack struct btrfs_backref_node *build_backref_tree( + struct reloc_control *rc, struct btrfs_key *node_key, + int level, u64 bytenr) { - struct backref_cache *cache = &rc->backref_cache; - struct btrfs_path *path1; /* For searching extent root */ - struct btrfs_path *path2; /* For searching parent of TREE_BLOCK_REF */ - struct extent_buffer *eb; - struct btrfs_root *root; - struct backref_node *cur; - struct backref_node *upper; - struct backref_node *lower; - struct backref_node *node = NULL; - struct backref_node *exist = NULL; - struct backref_edge *edge; - struct rb_node *rb_node; - struct btrfs_key key; - unsigned long end; - unsigned long ptr; - LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */ - LIST_HEAD(useless); - int cowonly; + struct btrfs_backref_iter *iter; + struct btrfs_backref_cache *cache = &rc->backref_cache; + /* For searching parent of TREE_BLOCK_REF */ + struct btrfs_path *path; + struct btrfs_backref_node *cur; + struct btrfs_backref_node *node = NULL; + struct btrfs_backref_edge *edge; int ret; int err = 0; - bool need_check = true; - path1 = btrfs_alloc_path(); - path2 = btrfs_alloc_path(); - if (!path1 || !path2) { + iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info, GFP_NOFS); + if (!iter) + return ERR_PTR(-ENOMEM); + path = btrfs_alloc_path(); + if (!path) { err = -ENOMEM; goto out; } - path1->reada = READA_FORWARD; - path2->reada = READA_FORWARD; - node = alloc_backref_node(cache); + node = btrfs_backref_alloc_node(cache, bytenr, level); if (!node) { err = -ENOMEM; goto out; } - node->bytenr = bytenr; - node->level = level; node->lowest = 1; cur = node; -again: - end = 0; - ptr = 0; - key.objectid = cur->bytenr; - key.type = BTRFS_METADATA_ITEM_KEY; - key.offset = (u64)-1; - - path1->search_commit_root = 1; - path1->skip_locking = 1; - ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1, - 0, 0); - if (ret < 0) { - err = ret; - goto out; - } - ASSERT(ret); - ASSERT(path1->slots[0]); - - path1->slots[0]--; - - WARN_ON(cur->checked); - if (!list_empty(&cur->upper)) { - /* - * the backref was added previously when processing - * backref of type BTRFS_TREE_BLOCK_REF_KEY - */ - ASSERT(list_is_singular(&cur->upper)); - edge = list_entry(cur->upper.next, struct backref_edge, - list[LOWER]); - ASSERT(list_empty(&edge->list[UPPER])); - exist = edge->node[UPPER]; - /* - * add the upper level block to pending list if we need - * check its backrefs - */ - if (!exist->checked) - list_add_tail(&edge->list[UPPER], &list); - } else { - exist = NULL; - } - - while (1) { - cond_resched(); - eb = path1->nodes[0]; - - if (ptr >= end) { - if (path1->slots[0] >= btrfs_header_nritems(eb)) { - ret = btrfs_next_leaf(rc->extent_root, path1); - if (ret < 0) { - err = ret; - goto out; - } - if (ret > 0) - break; - eb = path1->nodes[0]; - } - - btrfs_item_key_to_cpu(eb, &key, path1->slots[0]); - if (key.objectid != cur->bytenr) { - WARN_ON(exist); - break; - } - - if (key.type == BTRFS_EXTENT_ITEM_KEY || - key.type == BTRFS_METADATA_ITEM_KEY) { - ret = find_inline_backref(eb, path1->slots[0], - &ptr, &end); - if (ret) - goto next; - } - } - - if (ptr < end) { - /* update key for inline back ref */ - struct btrfs_extent_inline_ref *iref; - int type; - iref = (struct btrfs_extent_inline_ref *)ptr; - type = btrfs_get_extent_inline_ref_type(eb, iref, - BTRFS_REF_TYPE_BLOCK); - if (type == BTRFS_REF_TYPE_INVALID) { - err = -EUCLEAN; - goto out; - } - key.type = type; - key.offset = btrfs_extent_inline_ref_offset(eb, iref); - - WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY && - key.type != BTRFS_SHARED_BLOCK_REF_KEY); - } - - /* - * Parent node found and matches current inline ref, no need to - * rebuild this node for this inline ref. - */ - if (exist && - ((key.type == BTRFS_TREE_BLOCK_REF_KEY && - exist->owner == key.offset) || - (key.type == BTRFS_SHARED_BLOCK_REF_KEY && - exist->bytenr == key.offset))) { - exist = NULL; - goto next; - } - - /* SHARED_BLOCK_REF means key.offset is the parent bytenr */ - if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) { - if (key.objectid == key.offset) { - /* - * Only root blocks of reloc trees use backref - * pointing to itself. - */ - root = find_reloc_root(rc, cur->bytenr); - ASSERT(root); - cur->root = root; - break; - } - - edge = alloc_backref_edge(cache); - if (!edge) { - err = -ENOMEM; - goto out; - } - rb_node = tree_search(&cache->rb_root, key.offset); - if (!rb_node) { - upper = alloc_backref_node(cache); - if (!upper) { - free_backref_edge(cache, edge); - err = -ENOMEM; - goto out; - } - upper->bytenr = key.offset; - upper->level = cur->level + 1; - /* - * backrefs for the upper level block isn't - * cached, add the block to pending list - */ - list_add_tail(&edge->list[UPPER], &list); - } else { - upper = rb_entry(rb_node, struct backref_node, - rb_node); - ASSERT(upper->checked); - INIT_LIST_HEAD(&edge->list[UPPER]); - } - list_add_tail(&edge->list[LOWER], &cur->upper); - edge->node[LOWER] = cur; - edge->node[UPPER] = upper; - - goto next; - } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) { - err = -EINVAL; - btrfs_print_v0_err(rc->extent_root->fs_info); - btrfs_handle_fs_error(rc->extent_root->fs_info, err, - NULL); - goto out; - } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) { - goto next; - } - - /* - * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset - * means the root objectid. We need to search the tree to get - * its parent bytenr. - */ - root = read_fs_root(rc->extent_root->fs_info, key.offset); - if (IS_ERR(root)) { - err = PTR_ERR(root); - goto out; - } - - if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) - cur->cowonly = 1; - - if (btrfs_root_level(&root->root_item) == cur->level) { - /* tree root */ - ASSERT(btrfs_root_bytenr(&root->root_item) == - cur->bytenr); - if (should_ignore_root(root)) - list_add(&cur->list, &useless); - else - cur->root = root; - break; - } - - level = cur->level + 1; - /* Search the tree to find parent blocks referring the block. */ - path2->search_commit_root = 1; - path2->skip_locking = 1; - path2->lowest_level = level; - ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0); - path2->lowest_level = 0; + /* Breadth-first search to build backref cache */ + do { + ret = btrfs_backref_add_tree_node(cache, path, iter, node_key, + cur); if (ret < 0) { err = ret; goto out; } - if (ret > 0 && path2->slots[level] > 0) - path2->slots[level]--; - - eb = path2->nodes[level]; - if (btrfs_node_blockptr(eb, path2->slots[level]) != - cur->bytenr) { - btrfs_err(root->fs_info, - "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)", - cur->bytenr, level - 1, - root->root_key.objectid, - node_key->objectid, node_key->type, - node_key->offset); - err = -ENOENT; - goto out; - } - lower = cur; - need_check = true; - - /* Add all nodes and edges in the path */ - for (; level < BTRFS_MAX_LEVEL; level++) { - if (!path2->nodes[level]) { - ASSERT(btrfs_root_bytenr(&root->root_item) == - lower->bytenr); - if (should_ignore_root(root)) - list_add(&lower->list, &useless); - else - lower->root = root; - break; - } - - edge = alloc_backref_edge(cache); - if (!edge) { - err = -ENOMEM; - goto out; - } - - eb = path2->nodes[level]; - rb_node = tree_search(&cache->rb_root, eb->start); - if (!rb_node) { - upper = alloc_backref_node(cache); - if (!upper) { - free_backref_edge(cache, edge); - err = -ENOMEM; - goto out; - } - upper->bytenr = eb->start; - upper->owner = btrfs_header_owner(eb); - upper->level = lower->level + 1; - if (!test_bit(BTRFS_ROOT_REF_COWS, - &root->state)) - upper->cowonly = 1; - - /* - * if we know the block isn't shared - * we can void checking its backrefs. - */ - if (btrfs_block_can_be_shared(root, eb)) - upper->checked = 0; - else - upper->checked = 1; - - /* - * add the block to pending list if we - * need check its backrefs, we only do this once - * while walking up a tree as we will catch - * anything else later on. - */ - if (!upper->checked && need_check) { - need_check = false; - list_add_tail(&edge->list[UPPER], - &list); - } else { - if (upper->checked) - need_check = true; - INIT_LIST_HEAD(&edge->list[UPPER]); - } - } else { - upper = rb_entry(rb_node, struct backref_node, - rb_node); - ASSERT(upper->checked); - INIT_LIST_HEAD(&edge->list[UPPER]); - if (!upper->owner) - upper->owner = btrfs_header_owner(eb); - } - list_add_tail(&edge->list[LOWER], &lower->upper); - edge->node[LOWER] = lower; - edge->node[UPPER] = upper; - - if (rb_node) - break; - lower = upper; - upper = NULL; - } - btrfs_release_path(path2); -next: - if (ptr < end) { - ptr += btrfs_extent_inline_ref_size(key.type); - if (ptr >= end) { - WARN_ON(ptr > end); - ptr = 0; - end = 0; - } + edge = list_first_entry_or_null(&cache->pending_edge, + struct btrfs_backref_edge, list[UPPER]); + /* + * The pending list isn't empty, take the first block to + * process + */ + if (edge) { + list_del_init(&edge->list[UPPER]); + cur = edge->node[UPPER]; } - if (ptr >= end) - path1->slots[0]++; - } - btrfs_release_path(path1); - - cur->checked = 1; - WARN_ON(exist); - - /* the pending list isn't empty, take the first block to process */ - if (!list_empty(&list)) { - edge = list_entry(list.next, struct backref_edge, list[UPPER]); - list_del_init(&edge->list[UPPER]); - cur = edge->node[UPPER]; - goto again; - } + } while (edge); - /* - * everything goes well, connect backref nodes and insert backref nodes - * into the cache. - */ - ASSERT(node->checked); - cowonly = node->cowonly; - if (!cowonly) { - rb_node = tree_insert(&cache->rb_root, node->bytenr, - &node->rb_node); - if (rb_node) - backref_tree_panic(rb_node, -EEXIST, node->bytenr); - list_add_tail(&node->lower, &cache->leaves); + /* Finish the upper linkage of newly added edges/nodes */ + ret = btrfs_backref_finish_upper_links(cache, node); + if (ret < 0) { + err = ret; + goto out; } - list_for_each_entry(edge, &node->upper, list[LOWER]) - list_add_tail(&edge->list[UPPER], &list); - - while (!list_empty(&list)) { - edge = list_entry(list.next, struct backref_edge, list[UPPER]); - list_del_init(&edge->list[UPPER]); - upper = edge->node[UPPER]; - if (upper->detached) { - list_del(&edge->list[LOWER]); - lower = edge->node[LOWER]; - free_backref_edge(cache, edge); - if (list_empty(&lower->upper)) - list_add(&lower->list, &useless); - continue; - } - - if (!RB_EMPTY_NODE(&upper->rb_node)) { - if (upper->lowest) { - list_del_init(&upper->lower); - upper->lowest = 0; - } - - list_add_tail(&edge->list[UPPER], &upper->lower); - continue; - } - - if (!upper->checked) { - /* - * Still want to blow up for developers since this is a - * logic bug. - */ - ASSERT(0); - err = -EINVAL; - goto out; - } - if (cowonly != upper->cowonly) { - ASSERT(0); - err = -EINVAL; - goto out; - } - - if (!cowonly) { - rb_node = tree_insert(&cache->rb_root, upper->bytenr, - &upper->rb_node); - if (rb_node) - backref_tree_panic(rb_node, -EEXIST, - upper->bytenr); - } - - list_add_tail(&edge->list[UPPER], &upper->lower); - - list_for_each_entry(edge, &upper->upper, list[LOWER]) - list_add_tail(&edge->list[UPPER], &list); - } - /* - * process useless backref nodes. backref nodes for tree leaves - * are deleted from the cache. backref nodes for upper level - * tree blocks are left in the cache to avoid unnecessary backref - * lookup. - */ - while (!list_empty(&useless)) { - upper = list_entry(useless.next, struct backref_node, list); - list_del_init(&upper->list); - ASSERT(list_empty(&upper->upper)); - if (upper == node) - node = NULL; - if (upper->lowest) { - list_del_init(&upper->lower); - upper->lowest = 0; - } - while (!list_empty(&upper->lower)) { - edge = list_entry(upper->lower.next, - struct backref_edge, list[UPPER]); - list_del(&edge->list[UPPER]); - list_del(&edge->list[LOWER]); - lower = edge->node[LOWER]; - free_backref_edge(cache, edge); - - if (list_empty(&lower->upper)) - list_add(&lower->list, &useless); - } - __mark_block_processed(rc, upper); - if (upper->level > 0) { - list_add(&upper->list, &cache->detached); - upper->detached = 1; - } else { - rb_erase(&upper->rb_node, &cache->rb_root); - free_backref_node(cache, upper); - } - } + if (handle_useless_nodes(rc, node)) + node = NULL; out: - btrfs_free_path(path1); - btrfs_free_path(path2); + btrfs_backref_iter_free(iter); + btrfs_free_path(path); if (err) { - while (!list_empty(&useless)) { - lower = list_entry(useless.next, - struct backref_node, list); - list_del_init(&lower->list); - } - while (!list_empty(&list)) { - edge = list_first_entry(&list, struct backref_edge, - list[UPPER]); - list_del(&edge->list[UPPER]); - list_del(&edge->list[LOWER]); - lower = edge->node[LOWER]; - upper = edge->node[UPPER]; - free_backref_edge(cache, edge); - - /* - * Lower is no longer linked to any upper backref nodes - * and isn't in the cache, we can free it ourselves. - */ - if (list_empty(&lower->upper) && - RB_EMPTY_NODE(&lower->rb_node)) - list_add(&lower->list, &useless); - - if (!RB_EMPTY_NODE(&upper->rb_node)) - continue; - - /* Add this guy's upper edges to the list to process */ - list_for_each_entry(edge, &upper->upper, list[LOWER]) - list_add_tail(&edge->list[UPPER], &list); - if (list_empty(&upper->upper)) - list_add(&upper->list, &useless); - } - - while (!list_empty(&useless)) { - lower = list_entry(useless.next, - struct backref_node, list); - list_del_init(&lower->list); - if (lower == node) - node = NULL; - free_backref_node(cache, lower); - } - - free_backref_node(cache, node); + btrfs_backref_error_cleanup(cache, node); return ERR_PTR(err); } ASSERT(!node || !node->detached); + ASSERT(list_empty(&cache->useless_node) && + list_empty(&cache->pending_edge)); return node; } @@ -1204,19 +541,19 @@ static int clone_backref_node(struct btrfs_trans_handle *trans, struct btrfs_root *dest) { struct btrfs_root *reloc_root = src->reloc_root; - struct backref_cache *cache = &rc->backref_cache; - struct backref_node *node = NULL; - struct backref_node *new_node; - struct backref_edge *edge; - struct backref_edge *new_edge; + struct btrfs_backref_cache *cache = &rc->backref_cache; + struct btrfs_backref_node *node = NULL; + struct btrfs_backref_node *new_node; + struct btrfs_backref_edge *edge; + struct btrfs_backref_edge *new_edge; struct rb_node *rb_node; if (cache->last_trans > 0) update_backref_cache(trans, cache); - rb_node = tree_search(&cache->rb_root, src->commit_root->start); + rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start); if (rb_node) { - node = rb_entry(rb_node, struct backref_node, rb_node); + node = rb_entry(rb_node, struct btrfs_backref_node, rb_node); if (node->detached) node = NULL; else @@ -1224,10 +561,10 @@ static int clone_backref_node(struct btrfs_trans_handle *trans, } if (!node) { - rb_node = tree_search(&cache->rb_root, - reloc_root->commit_root->start); + rb_node = rb_simple_search(&cache->rb_root, + reloc_root->commit_root->start); if (rb_node) { - node = rb_entry(rb_node, struct backref_node, + node = rb_entry(rb_node, struct btrfs_backref_node, rb_node); BUG_ON(node->detached); } @@ -1236,35 +573,33 @@ static int clone_backref_node(struct btrfs_trans_handle *trans, if (!node) return 0; - new_node = alloc_backref_node(cache); + new_node = btrfs_backref_alloc_node(cache, dest->node->start, + node->level); if (!new_node) return -ENOMEM; - new_node->bytenr = dest->node->start; - new_node->level = node->level; new_node->lowest = node->lowest; new_node->checked = 1; - new_node->root = dest; + new_node->root = btrfs_grab_root(dest); + ASSERT(new_node->root); if (!node->lowest) { list_for_each_entry(edge, &node->lower, list[UPPER]) { - new_edge = alloc_backref_edge(cache); + new_edge = btrfs_backref_alloc_edge(cache); if (!new_edge) goto fail; - new_edge->node[UPPER] = new_node; - new_edge->node[LOWER] = edge->node[LOWER]; - list_add_tail(&new_edge->list[UPPER], - &new_node->lower); + btrfs_backref_link_edge(new_edge, edge->node[LOWER], + new_node, LINK_UPPER); } } else { list_add_tail(&new_node->lower, &cache->leaves); } - rb_node = tree_insert(&cache->rb_root, new_node->bytenr, - &new_node->rb_node); + rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr, + &new_node->rb_node); if (rb_node) - backref_tree_panic(rb_node, -EEXIST, new_node->bytenr); + btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST); if (!new_node->lowest) { list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) { @@ -1276,11 +611,11 @@ static int clone_backref_node(struct btrfs_trans_handle *trans, fail: while (!list_empty(&new_node->lower)) { new_edge = list_entry(new_node->lower.next, - struct backref_edge, list[UPPER]); + struct btrfs_backref_edge, list[UPPER]); list_del(&new_edge->list[UPPER]); - free_backref_edge(cache, new_edge); + btrfs_backref_free_edge(cache, new_edge); } - free_backref_node(cache, new_node); + btrfs_backref_free_node(cache, new_node); return -ENOMEM; } @@ -1298,17 +633,18 @@ static int __must_check __add_reloc_root(struct btrfs_root *root) if (!node) return -ENOMEM; - node->bytenr = root->node->start; + node->bytenr = root->commit_root->start; node->data = root; spin_lock(&rc->reloc_root_tree.lock); - rb_node = tree_insert(&rc->reloc_root_tree.rb_root, - node->bytenr, &node->rb_node); + rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root, + node->bytenr, &node->rb_node); spin_unlock(&rc->reloc_root_tree.lock); if (rb_node) { - btrfs_panic(fs_info, -EEXIST, + btrfs_err(fs_info, "Duplicate root found for start=%llu while inserting into relocation tree", node->bytenr); + return -EEXIST; } list_add_tail(&root->root_list, &rc->reloc_roots); @@ -1325,24 +661,37 @@ static void __del_reloc_root(struct btrfs_root *root) struct rb_node *rb_node; struct mapping_node *node = NULL; struct reloc_control *rc = fs_info->reloc_ctl; + bool put_ref = false; if (rc && root->node) { spin_lock(&rc->reloc_root_tree.lock); - rb_node = tree_search(&rc->reloc_root_tree.rb_root, - root->node->start); + rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, + root->commit_root->start); if (rb_node) { node = rb_entry(rb_node, struct mapping_node, rb_node); rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root); + RB_CLEAR_NODE(&node->rb_node); } spin_unlock(&rc->reloc_root_tree.lock); - if (!node) - return; - BUG_ON((struct btrfs_root *)node->data != root); + ASSERT(!node || (struct btrfs_root *)node->data == root); } + /* + * We only put the reloc root here if it's on the list. There's a lot + * of places where the pattern is to splice the rc->reloc_roots, process + * the reloc roots, and then add the reloc root back onto + * rc->reloc_roots. If we call __del_reloc_root while it's off of the + * list we don't want the reference being dropped, because the guy + * messing with the list is in charge of the reference. + */ spin_lock(&fs_info->trans_lock); - list_del_init(&root->root_list); + if (!list_empty(&root->root_list)) { + put_ref = true; + list_del_init(&root->root_list); + } spin_unlock(&fs_info->trans_lock); + if (put_ref) + btrfs_put_root(root); kfree(node); } @@ -1350,7 +699,7 @@ static void __del_reloc_root(struct btrfs_root *root) * helper to update the 'address of tree root -> reloc tree' * mapping */ -static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr) +static int __update_reloc_root(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct rb_node *rb_node; @@ -1358,8 +707,8 @@ static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr) struct reloc_control *rc = fs_info->reloc_ctl; spin_lock(&rc->reloc_root_tree.lock); - rb_node = tree_search(&rc->reloc_root_tree.rb_root, - root->node->start); + rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, + root->commit_root->start); if (rb_node) { node = rb_entry(rb_node, struct mapping_node, rb_node); rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root); @@ -1371,12 +720,12 @@ static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr) BUG_ON((struct btrfs_root *)node->data != root); spin_lock(&rc->reloc_root_tree.lock); - node->bytenr = new_bytenr; - rb_node = tree_insert(&rc->reloc_root_tree.rb_root, - node->bytenr, &node->rb_node); + node->bytenr = root->node->start; + rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root, + node->bytenr, &node->rb_node); spin_unlock(&rc->reloc_root_tree.lock); if (rb_node) - backref_tree_panic(rb_node, -EEXIST, node->bytenr); + btrfs_backref_panic(fs_info, node->bytenr, -EEXIST); return 0; } @@ -1388,10 +737,12 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, struct extent_buffer *eb; struct btrfs_root_item *root_item; struct btrfs_key root_key; - int ret; + int ret = 0; + bool must_abort = false; root_item = kmalloc(sizeof(*root_item), GFP_NOFS); - BUG_ON(!root_item); + if (!root_item) + return ERR_PTR(-ENOMEM); root_key.objectid = BTRFS_TREE_RELOC_OBJECTID; root_key.type = BTRFS_ROOT_ITEM_KEY; @@ -1403,7 +754,9 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, /* called by btrfs_init_reloc_root */ ret = btrfs_copy_root(trans, root, root->commit_root, &eb, BTRFS_TREE_RELOC_OBJECTID); - BUG_ON(ret); + if (ret) + goto fail; + /* * Set the last_snapshot field to the generation of the commit * root - like this ctree.c:btrfs_block_can_be_shared() behaves @@ -1424,9 +777,16 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, */ ret = btrfs_copy_root(trans, root, root->node, &eb, BTRFS_TREE_RELOC_OBJECTID); - BUG_ON(ret); + if (ret) + goto fail; } + /* + * We have changed references at this point, we must abort the + * transaction if anything fails. + */ + must_abort = true; + memcpy(root_item, &root->root_item, sizeof(*root_item)); btrfs_set_root_bytenr(root_item, eb->start); btrfs_set_root_level(root_item, btrfs_header_level(eb)); @@ -1436,7 +796,7 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, btrfs_set_root_refs(root_item, 0); memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key)); - root_item->drop_level = 0; + btrfs_set_root_drop_level(root_item, 0); } btrfs_tree_unlock(eb); @@ -1444,18 +804,33 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, ret = btrfs_insert_root(trans, fs_info->tree_root, &root_key, root_item); - BUG_ON(ret); + if (ret) + goto fail; + kfree(root_item); - reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key); - BUG_ON(IS_ERR(reloc_root)); + reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key); + if (IS_ERR(reloc_root)) { + ret = PTR_ERR(reloc_root); + goto abort; + } + set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state); reloc_root->last_trans = trans->transid; return reloc_root; +fail: + kfree(root_item); +abort: + if (must_abort) + btrfs_abort_transaction(trans, ret); + return ERR_PTR(ret); } /* * create reloc tree for a given fs tree. reloc tree is just a * snapshot of the fs tree with special root objectid. + * + * The reloc_root comes out of here with two references, one for + * root->reloc_root, and another for being on the rc->reloc_roots list. */ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, struct btrfs_root *root) @@ -1467,6 +842,9 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, int clear_rsv = 0; int ret; + if (!rc) + return 0; + /* * The subvolume has reloc tree but the swap is finished, no need to * create/update the dead reloc tree @@ -1474,13 +852,25 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, if (reloc_root_is_dead(root)) return 0; + /* + * This is subtle but important. We do not do + * record_root_in_transaction for reloc roots, instead we record their + * corresponding fs root, and then here we update the last trans for the + * reloc root. This means that we have to do this for the entire life + * of the reloc root, regardless of which stage of the relocation we are + * in. + */ if (root->reloc_root) { reloc_root = root->reloc_root; reloc_root->last_trans = trans->transid; return 0; } - if (!rc || !rc->create_reloc_tree || + /* + * We are merging reloc roots, we do not need new reloc trees. Also + * reloc trees never need their own reloc tree. + */ + if (!rc->create_reloc_tree || root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) return 0; @@ -1492,10 +882,17 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, reloc_root = create_reloc_root(trans, root, root->root_key.objectid); if (clear_rsv) trans->block_rsv = rsv; + if (IS_ERR(reloc_root)) + return PTR_ERR(reloc_root); ret = __add_reloc_root(reloc_root); - BUG_ON(ret < 0); - root->reloc_root = reloc_root; + ASSERT(ret != -EEXIST); + if (ret) { + /* Pairs with create_reloc_root */ + btrfs_put_root(reloc_root); + return ret; + } + root->reloc_root = btrfs_grab_root(reloc_root); return 0; } @@ -1511,11 +908,18 @@ int btrfs_update_reloc_root(struct btrfs_trans_handle *trans, int ret; if (!have_reloc_root(root)) - goto out; + return 0; reloc_root = root->reloc_root; root_item = &reloc_root->root_item; + /* + * We are probably ok here, but __del_reloc_root() will drop its ref of + * the root. We have the ref for root->reloc_root, but just in case + * hold it while we update the reloc root. + */ + btrfs_grab_root(reloc_root); + /* root->reloc_root will stay until current relocation finished */ if (fs_info->reloc_ctl->merge_reloc_tree && btrfs_root_refs(root_item) == 0) { @@ -1529,6 +933,7 @@ int btrfs_update_reloc_root(struct btrfs_trans_handle *trans, } if (reloc_root->commit_root != reloc_root->node) { + __update_reloc_root(reloc_root); btrfs_set_root_node(root_item, reloc_root->node); free_extent_buffer(reloc_root->commit_root); reloc_root->commit_root = btrfs_root_node(reloc_root); @@ -1536,10 +941,8 @@ int btrfs_update_reloc_root(struct btrfs_trans_handle *trans, ret = btrfs_update_root(trans, fs_info->tree_root, &reloc_root->root_key, root_item); - BUG_ON(ret); - -out: - return 0; + btrfs_put_root(reloc_root); + return ret; } /* @@ -1596,14 +999,6 @@ again: return NULL; } -static int in_block_group(u64 bytenr, struct btrfs_block_group *block_group) -{ - if (bytenr >= block_group->start && - bytenr < block_group->start + block_group->length) - return 1; - return 0; -} - /* * get new location of data */ @@ -1701,11 +1096,12 @@ int replace_file_extents(struct btrfs_trans_handle *trans, num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); if (bytenr == 0) continue; - if (!in_block_group(bytenr, rc->block_group)) + if (!in_range(bytenr, rc->block_group->start, + rc->block_group->length)) continue; /* - * if we are modifying block in fs tree, wait for readpage + * if we are modifying block in fs tree, wait for read_folio * to complete and drop the extent cache */ if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) { @@ -1728,10 +1124,10 @@ int replace_file_extents(struct btrfs_trans_handle *trans, if (!ret) continue; - btrfs_drop_extent_cache(BTRFS_I(inode), - key.offset, end, 1); + btrfs_drop_extent_map_range(BTRFS_I(inode), + key.offset, end, true); unlock_extent(&BTRFS_I(inode)->io_tree, - key.offset, end); + key.offset, end, NULL); } } @@ -1751,9 +1147,9 @@ int replace_file_extents(struct btrfs_trans_handle *trans, key.offset -= btrfs_file_extent_offset(leaf, fi); btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr, num_bytes, parent); - ref.real_root = root->root_key.objectid; btrfs_init_data_ref(&ref, btrfs_header_owner(leaf), - key.objectid, key.offset); + key.objectid, key.offset, + root->root_key.objectid, false); ret = btrfs_inc_extent_ref(trans, &ref); if (ret) { btrfs_abort_transaction(trans, ret); @@ -1762,9 +1158,9 @@ int replace_file_extents(struct btrfs_trans_handle *trans, btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr, num_bytes, parent); - ref.real_root = root->root_key.objectid; btrfs_init_data_ref(&ref, btrfs_header_owner(leaf), - key.objectid, key.offset); + key.objectid, key.offset, + root->root_key.objectid, false); ret = btrfs_free_extent(trans, &ref); if (ret) { btrfs_abort_transaction(trans, ret); @@ -1820,8 +1216,8 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc, int ret; int slot; - BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); - BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID); + ASSERT(src->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID); + ASSERT(dest->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); last_snapshot = btrfs_root_last_snapshot(&src->root_item); again: @@ -1829,7 +1225,6 @@ again: btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot); eb = btrfs_lock_root_node(dest); - btrfs_set_lock_blocking_write(eb); level = btrfs_header_level(eb); if (level < lowest_level) { @@ -1839,10 +1234,14 @@ again: } if (cow) { - ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb); - BUG_ON(ret); + ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb, + BTRFS_NESTING_COW); + if (ret) { + btrfs_tree_unlock(eb); + free_extent_buffer(eb); + return ret; + } } - btrfs_set_lock_blocking_write(eb); if (next_key) { next_key->objectid = (u64)-1; @@ -1852,12 +1251,10 @@ again: parent = eb; while (1) { - struct btrfs_key first_key; - level = btrfs_header_level(parent); - BUG_ON(level < lowest_level); + ASSERT(level >= lowest_level); - ret = btrfs_bin_search(parent, &key, level, &slot); + ret = btrfs_bin_search(parent, &key, &slot); if (ret < 0) break; if (ret && slot > 0) @@ -1869,7 +1266,6 @@ again: old_bytenr = btrfs_node_blockptr(parent, slot); blocksize = fs_info->nodesize; old_ptr_gen = btrfs_node_ptr_generation(parent, slot); - btrfs_node_key_to_cpu(parent, &first_key, slot); if (level <= max_level) { eb = path->nodes[level]; @@ -1894,23 +1290,22 @@ again: break; } - eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen, - level - 1, &first_key); + eb = btrfs_read_node_slot(parent, slot); if (IS_ERR(eb)) { ret = PTR_ERR(eb); break; - } else if (!extent_buffer_uptodate(eb)) { - ret = -EIO; - free_extent_buffer(eb); - break; } btrfs_tree_lock(eb); if (cow) { ret = btrfs_cow_block(trans, dest, eb, parent, - slot, &eb); - BUG_ON(ret); + slot, &eb, + BTRFS_NESTING_COW); + if (ret) { + btrfs_tree_unlock(eb); + free_extent_buffer(eb); + break; + } } - btrfs_set_lock_blocking_write(eb); btrfs_tree_unlock(parent); free_extent_buffer(parent); @@ -1931,9 +1326,15 @@ again: btrfs_release_path(path); path->lowest_level = level; + set_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state); ret = btrfs_search_slot(trans, src, &key, path, 0, 1); + clear_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state); path->lowest_level = 0; - BUG_ON(ret); + if (ret) { + if (ret > 0) + ret = -ENOENT; + break; + } /* * Info qgroup to trace both subtrees. @@ -1970,30 +1371,42 @@ again: btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr, blocksize, path->nodes[level]->start); - ref.skip_qgroup = true; - btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid); + btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid, + 0, true); ret = btrfs_inc_extent_ref(trans, &ref); - BUG_ON(ret); + if (ret) { + btrfs_abort_transaction(trans, ret); + break; + } btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr, blocksize, 0); - ref.skip_qgroup = true; - btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid); + btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, 0, + true); ret = btrfs_inc_extent_ref(trans, &ref); - BUG_ON(ret); + if (ret) { + btrfs_abort_transaction(trans, ret); + break; + } btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr, blocksize, path->nodes[level]->start); - btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid); - ref.skip_qgroup = true; + btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid, + 0, true); ret = btrfs_free_extent(trans, &ref); - BUG_ON(ret); + if (ret) { + btrfs_abort_transaction(trans, ret); + break; + } btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr, blocksize, 0); - btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid); - ref.skip_qgroup = true; + btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, + 0, true); ret = btrfs_free_extent(trans, &ref); - BUG_ON(ret); + if (ret) { + btrfs_abort_transaction(trans, ret); + break; + } btrfs_unlock_up_safe(path, 0); @@ -2049,10 +1462,8 @@ static noinline_for_stack int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, int *level) { - struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *eb = NULL; int i; - u64 bytenr; u64 ptr_gen = 0; u64 last_snapshot; u32 nritems; @@ -2060,8 +1471,6 @@ int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, last_snapshot = btrfs_root_last_snapshot(&root->root_item); for (i = *level; i > 0; i--) { - struct btrfs_key first_key; - eb = path->nodes[i]; nritems = btrfs_header_nritems(eb); while (path->slots[i] < nritems) { @@ -2081,16 +1490,9 @@ int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, return 0; } - bytenr = btrfs_node_blockptr(eb, path->slots[i]); - btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]); - eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1, - &first_key); - if (IS_ERR(eb)) { + eb = btrfs_read_node_slot(eb, path->slots[i]); + if (IS_ERR(eb)) return PTR_ERR(eb); - } else if (!extent_buffer_uptodate(eb)) { - free_extent_buffer(eb); - return -EIO; - } BUG_ON(btrfs_header_level(eb) != i - 1); path->nodes[i - 1] = eb; path->slots[i - 1] = 0; @@ -2163,10 +1565,10 @@ static int invalidate_extent_cache(struct btrfs_root *root, end = (u64)-1; } - /* the lock_extent waits for readpage to complete */ - lock_extent(&BTRFS_I(inode)->io_tree, start, end); - btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1); - unlock_extent(&BTRFS_I(inode)->io_tree, start, end); + /* the lock_extent waits for read_folio to complete */ + lock_extent(&BTRFS_I(inode)->io_tree, start, end, NULL); + btrfs_drop_extent_map_range(BTRFS_I(inode), start, end, true); + unlock_extent(&BTRFS_I(inode)->io_tree, start, end, NULL); } return 0; } @@ -2192,12 +1594,13 @@ static int find_next_key(struct btrfs_path *path, int level, /* * Insert current subvolume into reloc_control::dirty_subvol_roots */ -static void insert_dirty_subvol(struct btrfs_trans_handle *trans, - struct reloc_control *rc, - struct btrfs_root *root) +static int insert_dirty_subvol(struct btrfs_trans_handle *trans, + struct reloc_control *rc, + struct btrfs_root *root) { struct btrfs_root *reloc_root = root->reloc_root; struct btrfs_root_item *reloc_root_item; + int ret; /* @root must be a subvolume tree root with a valid reloc tree */ ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); @@ -2206,14 +1609,18 @@ static void insert_dirty_subvol(struct btrfs_trans_handle *trans, reloc_root_item = &reloc_root->root_item; memset(&reloc_root_item->drop_progress, 0, sizeof(reloc_root_item->drop_progress)); - reloc_root_item->drop_level = 0; + btrfs_set_root_drop_level(reloc_root_item, 0); btrfs_set_root_refs(reloc_root_item, 0); - btrfs_update_reloc_root(trans, root); + ret = btrfs_update_reloc_root(trans, root); + if (ret) + return ret; if (list_empty(&root->reloc_dirty_list)) { - btrfs_grab_fs_root(root); + btrfs_grab_root(root); list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots); } + + return 0; } static int clean_dirty_subvols(struct reloc_control *rc) @@ -2231,24 +1638,34 @@ static int clean_dirty_subvols(struct reloc_control *rc) list_del_init(&root->reloc_dirty_list); root->reloc_root = NULL; - if (reloc_root) { - - ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1); - if (ret2 < 0 && !ret) - ret = ret2; - } /* * Need barrier to ensure clear_bit() only happens after * root->reloc_root = NULL. Pairs with have_reloc_root. */ smp_wmb(); clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state); - btrfs_put_fs_root(root); + if (reloc_root) { + /* + * btrfs_drop_snapshot drops our ref we hold for + * ->reloc_root. If it fails however we must + * drop the ref ourselves. + */ + ret2 = btrfs_drop_snapshot(reloc_root, 0, 1); + if (ret2 < 0) { + btrfs_put_root(reloc_root); + if (!ret) + ret = ret2; + } + } + btrfs_put_root(root); } else { /* Orphan reloc tree, just clean it up */ - ret2 = btrfs_drop_snapshot(root, NULL, 0, 1); - if (ret2 < 0 && !ret) - ret = ret2; + ret2 = btrfs_drop_snapshot(root, 0, 1); + if (ret2 < 0) { + btrfs_put_root(root); + if (!ret) + ret = ret2; + } } } return ret; @@ -2269,11 +1686,11 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, struct btrfs_root_item *root_item; struct btrfs_path *path; struct extent_buffer *leaf; + int reserve_level; int level; int max_level; int replaced = 0; - int ret; - int err = 0; + int ret = 0; u32 min_reserved; path = btrfs_alloc_path(); @@ -2292,7 +1709,7 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, } else { btrfs_disk_key_to_cpu(&key, &root_item->drop_progress); - level = root_item->drop_level; + level = btrfs_root_drop_level(root_item); BUG_ON(level == 0); path->lowest_level = level; ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0); @@ -2309,32 +1726,50 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, btrfs_unlock_up_safe(path, 0); } - min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2; + /* + * In merge_reloc_root(), we modify the upper level pointer to swap the + * tree blocks between reloc tree and subvolume tree. Thus for tree + * block COW, we COW at most from level 1 to root level for each tree. + * + * Thus the needed metadata size is at most root_level * nodesize, + * and * 2 since we have two trees to COW. + */ + reserve_level = max_t(int, 1, btrfs_root_level(root_item)); + min_reserved = fs_info->nodesize * reserve_level * 2; memset(&next_key, 0, sizeof(next_key)); while (1) { - ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved, - BTRFS_RESERVE_FLUSH_ALL); - if (ret) { - err = ret; + ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, + min_reserved, + BTRFS_RESERVE_FLUSH_LIMIT); + if (ret) goto out; - } trans = btrfs_start_transaction(root, 0); if (IS_ERR(trans)) { - err = PTR_ERR(trans); + ret = PTR_ERR(trans); trans = NULL; goto out; } + + /* + * At this point we no longer have a reloc_control, so we can't + * depend on btrfs_init_reloc_root to update our last_trans. + * + * But that's ok, we started the trans handle on our + * corresponding fs_root, which means it's been added to the + * dirty list. At commit time we'll still call + * btrfs_update_reloc_root() and update our root item + * appropriately. + */ + reloc_root->last_trans = trans->transid; trans->block_rsv = rc->block_rsv; replaced = 0; max_level = level; ret = walk_down_reloc_tree(reloc_root, path, &level); - if (ret < 0) { - err = ret; + if (ret < 0) goto out; - } if (ret > 0) break; @@ -2345,11 +1780,8 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, ret = replace_path(trans, rc, root, reloc_root, path, &next_key, level, max_level); } - if (ret < 0) { - err = ret; + if (ret < 0) goto out; - } - if (ret > 0) { level = ret; btrfs_node_key_to_cpu(path->nodes[level], &key, @@ -2368,7 +1800,7 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, */ btrfs_node_key(path->nodes[level], &root_item->drop_progress, path->slots[level]); - root_item->drop_level = level; + btrfs_set_root_drop_level(root_item, level); btrfs_end_transaction_throttle(trans); trans = NULL; @@ -2384,16 +1816,18 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, * relocated and the block is tree root. */ leaf = btrfs_lock_root_node(root); - ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf); + ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf, + BTRFS_NESTING_COW); btrfs_tree_unlock(leaf); free_extent_buffer(leaf); - if (ret < 0) - err = ret; out: btrfs_free_path(path); - if (err == 0) - insert_dirty_subvol(trans, rc, root); + if (ret == 0) { + ret = insert_dirty_subvol(trans, rc, root); + if (ret) + btrfs_abort_transaction(trans, ret); + } if (trans) btrfs_end_transaction_throttle(trans); @@ -2403,7 +1837,7 @@ out: if (replaced && rc->stage == UPDATE_DATA_PTRS) invalidate_extent_cache(root, &key, &next_key); - return err; + return ret; } static noinline_for_stack @@ -2425,7 +1859,7 @@ int prepare_to_merge(struct reloc_control *rc, int err) again: if (!err) { num_bytes = rc->merging_rsv_size; - ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes, + ret = btrfs_block_rsv_add(fs_info, rc->block_rsv, num_bytes, BTRFS_RESERVE_FLUSH_ALL); if (ret) err = ret; @@ -2435,7 +1869,7 @@ again: if (IS_ERR(trans)) { if (!err) btrfs_block_rsv_release(fs_info, rc->block_rsv, - num_bytes); + num_bytes, NULL); return PTR_ERR(trans); } @@ -2443,7 +1877,7 @@ again: if (num_bytes != rc->merging_rsv_size) { btrfs_end_transaction(trans); btrfs_block_rsv_release(fs_info, rc->block_rsv, - num_bytes); + num_bytes, NULL); goto again; } } @@ -2455,9 +1889,20 @@ again: struct btrfs_root, root_list); list_del_init(&reloc_root->root_list); - root = read_fs_root(fs_info, reloc_root->root_key.offset); - BUG_ON(IS_ERR(root)); - BUG_ON(root->reloc_root != reloc_root); + root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, + false); + if (IS_ERR(root)) { + /* + * Even if we have an error we need this reloc root + * back on our list so we can clean up properly. + */ + list_add(&reloc_root->root_list, &reloc_roots); + btrfs_abort_transaction(trans, (int)PTR_ERR(root)); + if (!err) + err = PTR_ERR(root); + break; + } + ASSERT(root->reloc_root == reloc_root); /* * set reference count to 1, so btrfs_recover_relocation @@ -2465,15 +1910,27 @@ again: */ if (!err) btrfs_set_root_refs(&reloc_root->root_item, 1); - btrfs_update_reloc_root(trans, root); + ret = btrfs_update_reloc_root(trans, root); + /* + * Even if we have an error we need this reloc root back on our + * list so we can clean up properly. + */ list_add(&reloc_root->root_list, &reloc_roots); + btrfs_put_root(root); + + if (ret) { + btrfs_abort_transaction(trans, ret); + if (!err) + err = ret; + break; + } } list_splice(&reloc_roots, &rc->reloc_roots); if (!err) - btrfs_commit_transaction(trans); + err = btrfs_commit_transaction(trans); else btrfs_end_transaction(trans); return err; @@ -2482,17 +1939,10 @@ again: static noinline_for_stack void free_reloc_roots(struct list_head *list) { - struct btrfs_root *reloc_root; + struct btrfs_root *reloc_root, *tmp; - while (!list_empty(list)) { - reloc_root = list_entry(list->next, struct btrfs_root, - root_list); + list_for_each_entry_safe(reloc_root, tmp, list, root_list) __del_reloc_root(reloc_root); - free_extent_buffer(reloc_root->node); - free_extent_buffer(reloc_root->commit_root); - reloc_root->node = NULL; - reloc_root->commit_root = NULL; - } } static noinline_for_stack @@ -2522,13 +1972,34 @@ again: reloc_root = list_entry(reloc_roots.next, struct btrfs_root, root_list); + root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, + false); if (btrfs_root_refs(&reloc_root->root_item) > 0) { - root = read_fs_root(fs_info, - reloc_root->root_key.offset); - BUG_ON(IS_ERR(root)); - BUG_ON(root->reloc_root != reloc_root); - + if (IS_ERR(root)) { + /* + * For recovery we read the fs roots on mount, + * and if we didn't find the root then we marked + * the reloc root as a garbage root. For normal + * relocation obviously the root should exist in + * memory. However there's no reason we can't + * handle the error properly here just in case. + */ + ASSERT(0); + ret = PTR_ERR(root); + goto out; + } + if (root->reloc_root != reloc_root) { + /* + * This is actually impossible without something + * going really wrong (like weird race condition + * or cosmic rays). + */ + ASSERT(0); + ret = -EINVAL; + goto out; + } ret = merge_reloc_root(rc, root); + btrfs_put_root(root); if (ret) { if (list_empty(&reloc_root->root_list)) list_add_tail(&reloc_root->root_list, @@ -2536,6 +2007,16 @@ again: goto out; } } else { + if (!IS_ERR(root)) { + if (root->reloc_root == reloc_root) { + root->reloc_root = NULL; + btrfs_put_root(reloc_root); + } + clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, + &root->state); + btrfs_put_root(root); + } + list_del_init(&reloc_root->root_list); /* Don't forget to queue this reloc root for cleanup */ list_add_tail(&reloc_root->reloc_dirty_list, @@ -2550,18 +2031,30 @@ again: out: if (ret) { btrfs_handle_fs_error(fs_info, ret, NULL); - if (!list_empty(&reloc_roots)) - free_reloc_roots(&reloc_roots); + free_reloc_roots(&reloc_roots); /* new reloc root may be added */ mutex_lock(&fs_info->reloc_mutex); list_splice_init(&rc->reloc_roots, &reloc_roots); mutex_unlock(&fs_info->reloc_mutex); - if (!list_empty(&reloc_roots)) - free_reloc_roots(&reloc_roots); + free_reloc_roots(&reloc_roots); } - BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root)); + /* + * We used to have + * + * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root)); + * + * here, but it's wrong. If we fail to start the transaction in + * prepare_to_merge() we will have only 0 ref reloc roots, none of which + * have actually been removed from the reloc_root_tree rb tree. This is + * fine because we're bailing here, and we hold a reference on the root + * for the list that holds it, so these roots will be cleaned up when we + * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root + * will be cleaned up on unmount. + * + * The remaining nodes will be cleaned up by free_reloc_control. + */ } static void free_block_list(struct rb_root *blocks) @@ -2580,51 +2073,126 @@ static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans, { struct btrfs_fs_info *fs_info = reloc_root->fs_info; struct btrfs_root *root; + int ret; if (reloc_root->last_trans == trans->transid) return 0; - root = read_fs_root(fs_info, reloc_root->root_key.offset); - BUG_ON(IS_ERR(root)); - BUG_ON(root->reloc_root != reloc_root); + root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false); - return btrfs_record_root_in_trans(trans, root); + /* + * This should succeed, since we can't have a reloc root without having + * already looked up the actual root and created the reloc root for this + * root. + * + * However if there's some sort of corruption where we have a ref to a + * reloc root without a corresponding root this could return ENOENT. + */ + if (IS_ERR(root)) { + ASSERT(0); + return PTR_ERR(root); + } + if (root->reloc_root != reloc_root) { + ASSERT(0); + btrfs_err(fs_info, + "root %llu has two reloc roots associated with it", + reloc_root->root_key.offset); + btrfs_put_root(root); + return -EUCLEAN; + } + ret = btrfs_record_root_in_trans(trans, root); + btrfs_put_root(root); + + return ret; } static noinline_for_stack struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, struct reloc_control *rc, - struct backref_node *node, - struct backref_edge *edges[]) + struct btrfs_backref_node *node, + struct btrfs_backref_edge *edges[]) { - struct backref_node *next; + struct btrfs_backref_node *next; struct btrfs_root *root; int index = 0; + int ret; next = node; while (1) { cond_resched(); next = walk_up_backref(next, edges, &index); root = next->root; - BUG_ON(!root); - BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state)); + + /* + * If there is no root, then our references for this block are + * incomplete, as we should be able to walk all the way up to a + * block that is owned by a root. + * + * This path is only for SHAREABLE roots, so if we come upon a + * non-SHAREABLE root then we have backrefs that resolve + * improperly. + * + * Both of these cases indicate file system corruption, or a bug + * in the backref walking code. + */ + if (!root) { + ASSERT(0); + btrfs_err(trans->fs_info, + "bytenr %llu doesn't have a backref path ending in a root", + node->bytenr); + return ERR_PTR(-EUCLEAN); + } + if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { + ASSERT(0); + btrfs_err(trans->fs_info, + "bytenr %llu has multiple refs with one ending in a non-shareable root", + node->bytenr); + return ERR_PTR(-EUCLEAN); + } if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { - record_reloc_root_in_trans(trans, root); + ret = record_reloc_root_in_trans(trans, root); + if (ret) + return ERR_PTR(ret); break; } - btrfs_record_root_in_trans(trans, root); + ret = btrfs_record_root_in_trans(trans, root); + if (ret) + return ERR_PTR(ret); root = root->reloc_root; + /* + * We could have raced with another thread which failed, so + * root->reloc_root may not be set, return ENOENT in this case. + */ + if (!root) + return ERR_PTR(-ENOENT); + if (next->new_bytenr != root->node->start) { - BUG_ON(next->new_bytenr); - BUG_ON(!list_empty(&next->list)); + /* + * We just created the reloc root, so we shouldn't have + * ->new_bytenr set and this shouldn't be in the changed + * list. If it is then we have multiple roots pointing + * at the same bytenr which indicates corruption, or + * we've made a mistake in the backref walking code. + */ + ASSERT(next->new_bytenr == 0); + ASSERT(list_empty(&next->list)); + if (next->new_bytenr || !list_empty(&next->list)) { + btrfs_err(trans->fs_info, + "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu", + node->bytenr, next->bytenr); + return ERR_PTR(-EUCLEAN); + } + next->new_bytenr = root->node->start; - next->root = root; + btrfs_put_root(next->root); + next->root = btrfs_grab_root(root); + ASSERT(next->root); list_add_tail(&next->list, &rc->backref_cache.changed); - __mark_block_processed(rc, next); + mark_block_processed(rc, next); break; } @@ -2634,8 +2202,14 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, if (!next || next->level <= node->level) break; } - if (!root) - return NULL; + if (!root) { + /* + * This can happen if there's fs corruption or if there's a bug + * in the backref lookup code. + */ + ASSERT(0); + return ERR_PTR(-ENOENT); + } next = node; /* setup backref node path for btrfs_reloc_cow_block */ @@ -2649,18 +2223,21 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, } /* - * select a tree root for relocation. return NULL if the block - * is reference counted. we should use do_relocation() in this - * case. return a tree root pointer if the block isn't reference - * counted. return -ENOENT if the block is root of reloc tree. + * Select a tree root for relocation. + * + * Return NULL if the block is not shareable. We should use do_relocation() in + * this case. + * + * Return a tree root pointer if the block is shareable. + * Return -ENOENT if the block is root of reloc tree. */ static noinline_for_stack -struct btrfs_root *select_one_root(struct backref_node *node) +struct btrfs_root *select_one_root(struct btrfs_backref_node *node) { - struct backref_node *next; + struct btrfs_backref_node *next; struct btrfs_root *root; struct btrfs_root *fs_root = NULL; - struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; + struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1]; int index = 0; next = node; @@ -2668,10 +2245,16 @@ struct btrfs_root *select_one_root(struct backref_node *node) cond_resched(); next = walk_up_backref(next, edges, &index); root = next->root; - BUG_ON(!root); - /* no other choice for non-references counted tree */ - if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) + /* + * This can occur if we have incomplete extent refs leading all + * the way up a particular path, in this case return -EUCLEAN. + */ + if (!root) + return ERR_PTR(-EUCLEAN); + + /* No other choice for non-shareable tree */ + if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) return root; if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) @@ -2692,12 +2275,12 @@ struct btrfs_root *select_one_root(struct backref_node *node) static noinline_for_stack u64 calcu_metadata_size(struct reloc_control *rc, - struct backref_node *node, int reserve) + struct btrfs_backref_node *node, int reserve) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; - struct backref_node *next = node; - struct backref_edge *edge; - struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; + struct btrfs_backref_node *next = node; + struct btrfs_backref_edge *edge; + struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1]; u64 num_bytes = 0; int index = 0; @@ -2715,7 +2298,7 @@ u64 calcu_metadata_size(struct reloc_control *rc, break; edge = list_entry(next->upper.next, - struct backref_edge, list[LOWER]); + struct btrfs_backref_edge, list[LOWER]); edges[index++] = edge; next = edge->node[UPPER]; } @@ -2726,7 +2309,7 @@ u64 calcu_metadata_size(struct reloc_control *rc, static int reserve_metadata_space(struct btrfs_trans_handle *trans, struct reloc_control *rc, - struct backref_node *node) + struct btrfs_backref_node *node) { struct btrfs_root *root = rc->extent_root; struct btrfs_fs_info *fs_info = root->fs_info; @@ -2744,8 +2327,8 @@ static int reserve_metadata_space(struct btrfs_trans_handle *trans, * If we get an enospc just kick back -EAGAIN so we know to drop the * transaction and try to refill when we can flush all the things. */ - ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes, - BTRFS_RESERVE_FLUSH_LIMIT); + ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, num_bytes, + BTRFS_RESERVE_FLUSH_LIMIT); if (ret) { tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES; while (tmp <= rc->reserved_bytes) @@ -2774,60 +2357,58 @@ static int reserve_metadata_space(struct btrfs_trans_handle *trans, */ static int do_relocation(struct btrfs_trans_handle *trans, struct reloc_control *rc, - struct backref_node *node, + struct btrfs_backref_node *node, struct btrfs_key *key, struct btrfs_path *path, int lowest) { - struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; - struct backref_node *upper; - struct backref_edge *edge; - struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; + struct btrfs_backref_node *upper; + struct btrfs_backref_edge *edge; + struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1]; struct btrfs_root *root; struct extent_buffer *eb; u32 blocksize; u64 bytenr; - u64 generation; int slot; - int ret; - int err = 0; + int ret = 0; - BUG_ON(lowest && node->eb); + /* + * If we are lowest then this is the first time we're processing this + * block, and thus shouldn't have an eb associated with it yet. + */ + ASSERT(!lowest || !node->eb); path->lowest_level = node->level + 1; rc->backref_cache.path[node->level] = node; list_for_each_entry(edge, &node->upper, list[LOWER]) { - struct btrfs_key first_key; struct btrfs_ref ref = { 0 }; cond_resched(); upper = edge->node[UPPER]; root = select_reloc_root(trans, rc, upper, edges); - BUG_ON(!root); + if (IS_ERR(root)) { + ret = PTR_ERR(root); + goto next; + } if (upper->eb && !upper->locked) { if (!lowest) { - ret = btrfs_bin_search(upper->eb, key, - upper->level, &slot); - if (ret < 0) { - err = ret; + ret = btrfs_bin_search(upper->eb, key, &slot); + if (ret < 0) goto next; - } BUG_ON(ret); bytenr = btrfs_node_blockptr(upper->eb, slot); if (node->eb->start == bytenr) goto next; } - drop_node_buffer(upper); + btrfs_backref_drop_node_buffer(upper); } if (!upper->eb) { ret = btrfs_search_slot(trans, root, key, path, 0, 1); if (ret) { - if (ret < 0) - err = ret; - else - err = -ENOENT; + if (ret > 0) + ret = -ENOENT; btrfs_release_path(path); break; @@ -2846,12 +2427,9 @@ static int do_relocation(struct btrfs_trans_handle *trans, slot = path->slots[upper->level]; btrfs_release_path(path); } else { - ret = btrfs_bin_search(upper->eb, key, upper->level, - &slot); - if (ret < 0) { - err = ret; + ret = btrfs_bin_search(upper->eb, key, &slot); + if (ret < 0) goto next; - } BUG_ON(ret); } @@ -2862,7 +2440,7 @@ static int do_relocation(struct btrfs_trans_handle *trans, "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu", bytenr, node->bytenr, slot, upper->eb->start); - err = -EIO; + ret = -EIO; goto next; } } else { @@ -2871,31 +2449,25 @@ static int do_relocation(struct btrfs_trans_handle *trans, } blocksize = root->fs_info->nodesize; - generation = btrfs_node_ptr_generation(upper->eb, slot); - btrfs_node_key_to_cpu(upper->eb, &first_key, slot); - eb = read_tree_block(fs_info, bytenr, generation, - upper->level - 1, &first_key); + eb = btrfs_read_node_slot(upper->eb, slot); if (IS_ERR(eb)) { - err = PTR_ERR(eb); - goto next; - } else if (!extent_buffer_uptodate(eb)) { - free_extent_buffer(eb); - err = -EIO; + ret = PTR_ERR(eb); goto next; } btrfs_tree_lock(eb); - btrfs_set_lock_blocking_write(eb); if (!node->eb) { ret = btrfs_cow_block(trans, root, eb, upper->eb, - slot, &eb); + slot, &eb, BTRFS_NESTING_COW); btrfs_tree_unlock(eb); free_extent_buffer(eb); - if (ret < 0) { - err = ret; + if (ret < 0) goto next; - } - BUG_ON(node->eb != eb); + /* + * We've just COWed this block, it should have updated + * the correct backref node entry. + */ + ASSERT(node->eb == eb); } else { btrfs_set_node_blockptr(upper->eb, slot, node->eb->start); @@ -2906,38 +2478,44 @@ static int do_relocation(struct btrfs_trans_handle *trans, btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, node->eb->start, blocksize, upper->eb->start); - ref.real_root = root->root_key.objectid; btrfs_init_tree_ref(&ref, node->level, - btrfs_header_owner(upper->eb)); + btrfs_header_owner(upper->eb), + root->root_key.objectid, false); ret = btrfs_inc_extent_ref(trans, &ref); - BUG_ON(ret); - - ret = btrfs_drop_subtree(trans, root, eb, upper->eb); - BUG_ON(ret); + if (!ret) + ret = btrfs_drop_subtree(trans, root, eb, + upper->eb); + if (ret) + btrfs_abort_transaction(trans, ret); } next: if (!upper->pending) - drop_node_buffer(upper); + btrfs_backref_drop_node_buffer(upper); else - unlock_node_buffer(upper); - if (err) + btrfs_backref_unlock_node_buffer(upper); + if (ret) break; } - if (!err && node->pending) { - drop_node_buffer(node); + if (!ret && node->pending) { + btrfs_backref_drop_node_buffer(node); list_move_tail(&node->list, &rc->backref_cache.changed); node->pending = 0; } path->lowest_level = 0; - BUG_ON(err == -ENOSPC); - return err; + + /* + * We should have allocated all of our space in the block rsv and thus + * shouldn't ENOSPC. + */ + ASSERT(ret != -ENOSPC); + return ret; } static int link_to_upper(struct btrfs_trans_handle *trans, struct reloc_control *rc, - struct backref_node *node, + struct btrfs_backref_node *node, struct btrfs_path *path) { struct btrfs_key key; @@ -2951,15 +2529,15 @@ static int finish_pending_nodes(struct btrfs_trans_handle *trans, struct btrfs_path *path, int err) { LIST_HEAD(list); - struct backref_cache *cache = &rc->backref_cache; - struct backref_node *node; + struct btrfs_backref_cache *cache = &rc->backref_cache; + struct btrfs_backref_node *node; int level; int ret; for (level = 0; level < BTRFS_MAX_LEVEL; level++) { while (!list_empty(&cache->pending[level])) { node = list_entry(cache->pending[level].next, - struct backref_node, list); + struct btrfs_backref_node, list); list_move_tail(&node->list, &list); BUG_ON(!node->pending); @@ -2974,35 +2552,16 @@ static int finish_pending_nodes(struct btrfs_trans_handle *trans, return err; } -static void mark_block_processed(struct reloc_control *rc, - u64 bytenr, u32 blocksize) -{ - set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1, - EXTENT_DIRTY); -} - -static void __mark_block_processed(struct reloc_control *rc, - struct backref_node *node) -{ - u32 blocksize; - if (node->level == 0 || - in_block_group(node->bytenr, rc->block_group)) { - blocksize = rc->extent_root->fs_info->nodesize; - mark_block_processed(rc, node->bytenr, blocksize); - } - node->processed = 1; -} - /* * mark a block and all blocks directly/indirectly reference the block * as processed. */ static void update_processed_blocks(struct reloc_control *rc, - struct backref_node *node) + struct btrfs_backref_node *node) { - struct backref_node *next = node; - struct backref_edge *edge; - struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; + struct btrfs_backref_node *next = node; + struct btrfs_backref_edge *edge; + struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1]; int index = 0; while (next) { @@ -3011,13 +2570,13 @@ static void update_processed_blocks(struct reloc_control *rc, if (next->processed) break; - __mark_block_processed(rc, next); + mark_block_processed(rc, next); if (list_empty(&next->upper)) break; edge = list_entry(next->upper.next, - struct backref_edge, list[LOWER]); + struct btrfs_backref_edge, list[LOWER]); edges[index++] = edge; next = edge->node[UPPER]; } @@ -3040,12 +2599,11 @@ static int get_tree_block_key(struct btrfs_fs_info *fs_info, { struct extent_buffer *eb; - BUG_ON(block->key_ready); - eb = read_tree_block(fs_info, block->bytenr, block->key.offset, - block->level, NULL); - if (IS_ERR(eb)) { + eb = read_tree_block(fs_info, block->bytenr, block->owner, + block->key.offset, block->level, NULL); + if (IS_ERR(eb)) return PTR_ERR(eb); - } else if (!extent_buffer_uptodate(eb)) { + if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); return -EIO; } @@ -3063,7 +2621,7 @@ static int get_tree_block_key(struct btrfs_fs_info *fs_info, */ static int relocate_tree_block(struct btrfs_trans_handle *trans, struct reloc_control *rc, - struct backref_node *node, + struct btrfs_backref_node *node, struct btrfs_key *key, struct btrfs_path *path) { @@ -3073,32 +2631,77 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans, if (!node) return 0; + /* + * If we fail here we want to drop our backref_node because we are going + * to start over and regenerate the tree for it. + */ + ret = reserve_metadata_space(trans, rc, node); + if (ret) + goto out; + BUG_ON(node->processed); root = select_one_root(node); - if (root == ERR_PTR(-ENOENT)) { - update_processed_blocks(rc, node); - goto out; - } + if (IS_ERR(root)) { + ret = PTR_ERR(root); - if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) { - ret = reserve_metadata_space(trans, rc, node); - if (ret) - goto out; + /* See explanation in select_one_root for the -EUCLEAN case. */ + ASSERT(ret == -ENOENT); + if (ret == -ENOENT) { + ret = 0; + update_processed_blocks(rc, node); + } + goto out; } if (root) { - if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) { - BUG_ON(node->new_bytenr); - BUG_ON(!list_empty(&node->list)); - btrfs_record_root_in_trans(trans, root); + if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { + /* + * This block was the root block of a root, and this is + * the first time we're processing the block and thus it + * should not have had the ->new_bytenr modified and + * should have not been included on the changed list. + * + * However in the case of corruption we could have + * multiple refs pointing to the same block improperly, + * and thus we would trip over these checks. ASSERT() + * for the developer case, because it could indicate a + * bug in the backref code, however error out for a + * normal user in the case of corruption. + */ + ASSERT(node->new_bytenr == 0); + ASSERT(list_empty(&node->list)); + if (node->new_bytenr || !list_empty(&node->list)) { + btrfs_err(root->fs_info, + "bytenr %llu has improper references to it", + node->bytenr); + ret = -EUCLEAN; + goto out; + } + ret = btrfs_record_root_in_trans(trans, root); + if (ret) + goto out; + /* + * Another thread could have failed, need to check if we + * have reloc_root actually set. + */ + if (!root->reloc_root) { + ret = -ENOENT; + goto out; + } root = root->reloc_root; node->new_bytenr = root->node->start; - node->root = root; + btrfs_put_root(node->root); + node->root = btrfs_grab_root(root); + ASSERT(node->root); list_add_tail(&node->list, &rc->backref_cache.changed); } else { path->lowest_level = node->level; + if (root == root->fs_info->chunk_root) + btrfs_reserve_chunk_metadata(trans, false); ret = btrfs_search_slot(trans, root, key, path, 0, 1); btrfs_release_path(path); + if (root == root->fs_info->chunk_root) + btrfs_trans_release_chunk_metadata(trans); if (ret > 0) ret = 0; } @@ -3109,7 +2712,7 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans, } out: if (ret || node->level == 0 || node->cowonly) - remove_backref_node(&rc->backref_cache, node); + btrfs_backref_cleanup_node(&rc->backref_cache, node); return ret; } @@ -3121,7 +2724,7 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct rb_root *blocks) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; - struct backref_node *node; + struct btrfs_backref_node *node; struct btrfs_path *path; struct tree_block *block; struct tree_block *next; @@ -3137,7 +2740,9 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans, /* Kick in readahead for tree blocks with missing keys */ rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) { if (!block->key_ready) - readahead_tree_block(fs_info, block->bytenr); + btrfs_readahead_tree_block(fs_info, block->bytenr, + block->owner, 0, + block->level); } /* Get first keys */ @@ -3161,9 +2766,8 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans, ret = relocate_tree_block(trans, rc, node, &block->key, path); if (ret < 0) { - if (ret != -EAGAIN || &block->rb_node == rb_first(blocks)) - err = ret; - goto out; + err = ret; + break; } } out: @@ -3176,66 +2780,116 @@ out_free_blocks: return err; } -static noinline_for_stack -int prealloc_file_extent_cluster(struct inode *inode, - struct file_extent_cluster *cluster) +static noinline_for_stack int prealloc_file_extent_cluster( + struct btrfs_inode *inode, + struct file_extent_cluster *cluster) { u64 alloc_hint = 0; u64 start; u64 end; - u64 offset = BTRFS_I(inode)->index_cnt; + u64 offset = inode->index_cnt; u64 num_bytes; - int nr = 0; + int nr; int ret = 0; + u64 i_size = i_size_read(&inode->vfs_inode); u64 prealloc_start = cluster->start - offset; u64 prealloc_end = cluster->end - offset; - u64 cur_offset; - struct extent_changeset *data_reserved = NULL; + u64 cur_offset = prealloc_start; - BUG_ON(cluster->start != cluster->boundary[0]); - inode_lock(inode); + /* + * For subpage case, previous i_size may not be aligned to PAGE_SIZE. + * This means the range [i_size, PAGE_END + 1) is filled with zeros by + * btrfs_do_readpage() call of previously relocated file cluster. + * + * If the current cluster starts in the above range, btrfs_do_readpage() + * will skip the read, and relocate_one_page() will later writeback + * the padding zeros as new data, causing data corruption. + * + * Here we have to manually invalidate the range (i_size, PAGE_END + 1). + */ + if (!IS_ALIGNED(i_size, PAGE_SIZE)) { + struct address_space *mapping = inode->vfs_inode.i_mapping; + struct btrfs_fs_info *fs_info = inode->root->fs_info; + const u32 sectorsize = fs_info->sectorsize; + struct page *page; + + ASSERT(sectorsize < PAGE_SIZE); + ASSERT(IS_ALIGNED(i_size, sectorsize)); + + /* + * Subpage can't handle page with DIRTY but without UPTODATE + * bit as it can lead to the following deadlock: + * + * btrfs_read_folio() + * | Page already *locked* + * |- btrfs_lock_and_flush_ordered_range() + * |- btrfs_start_ordered_extent() + * |- extent_write_cache_pages() + * |- lock_page() + * We try to lock the page we already hold. + * + * Here we just writeback the whole data reloc inode, so that + * we will be ensured to have no dirty range in the page, and + * are safe to clear the uptodate bits. + * + * This shouldn't cause too much overhead, as we need to write + * the data back anyway. + */ + ret = filemap_write_and_wait(mapping); + if (ret < 0) + return ret; - ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start, - prealloc_end + 1 - prealloc_start); + clear_extent_bits(&inode->io_tree, i_size, + round_up(i_size, PAGE_SIZE) - 1, + EXTENT_UPTODATE); + page = find_lock_page(mapping, i_size >> PAGE_SHIFT); + /* + * If page is freed we don't need to do anything then, as we + * will re-read the whole page anyway. + */ + if (page) { + btrfs_subpage_clear_uptodate(fs_info, page, i_size, + round_up(i_size, PAGE_SIZE) - i_size); + unlock_page(page); + put_page(page); + } + } + + BUG_ON(cluster->start != cluster->boundary[0]); + ret = btrfs_alloc_data_chunk_ondemand(inode, + prealloc_end + 1 - prealloc_start); if (ret) - goto out; + return ret; - cur_offset = prealloc_start; - while (nr < cluster->nr) { + btrfs_inode_lock(&inode->vfs_inode, 0); + for (nr = 0; nr < cluster->nr; nr++) { start = cluster->boundary[nr] - offset; if (nr + 1 < cluster->nr) end = cluster->boundary[nr + 1] - 1 - offset; else end = cluster->end - offset; - lock_extent(&BTRFS_I(inode)->io_tree, start, end); + lock_extent(&inode->io_tree, start, end, NULL); num_bytes = end + 1 - start; - if (cur_offset < start) - btrfs_free_reserved_data_space(inode, data_reserved, - cur_offset, start - cur_offset); - ret = btrfs_prealloc_file_range(inode, 0, start, + ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start, num_bytes, num_bytes, end + 1, &alloc_hint); cur_offset = end + 1; - unlock_extent(&BTRFS_I(inode)->io_tree, start, end); + unlock_extent(&inode->io_tree, start, end, NULL); if (ret) break; - nr++; } + btrfs_inode_unlock(&inode->vfs_inode, 0); + if (cur_offset < prealloc_end) - btrfs_free_reserved_data_space(inode, data_reserved, - cur_offset, prealloc_end + 1 - cur_offset); -out: - inode_unlock(inode); - extent_changeset_free(data_reserved); + btrfs_free_reserved_data_space_noquota(inode->root->fs_info, + prealloc_end + 1 - cur_offset); return ret; } -static noinline_for_stack -int setup_extent_mapping(struct inode *inode, u64 start, u64 end, - u64 block_start) +static noinline_for_stack int setup_relocation_extent_mapping(struct inode *inode, + u64 start, u64 end, u64 block_start) { - struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; struct extent_map *em; int ret = 0; @@ -3249,34 +2903,169 @@ int setup_extent_mapping(struct inode *inode, u64 start, u64 end, em->block_start = block_start; set_bit(EXTENT_FLAG_PINNED, &em->flags); - lock_extent(&BTRFS_I(inode)->io_tree, start, end); - while (1) { - write_lock(&em_tree->lock); - ret = add_extent_mapping(em_tree, em, 0); - write_unlock(&em_tree->lock); - if (ret != -EEXIST) { - free_extent_map(em); - break; + lock_extent(&BTRFS_I(inode)->io_tree, start, end, NULL); + ret = btrfs_replace_extent_map_range(BTRFS_I(inode), em, false); + unlock_extent(&BTRFS_I(inode)->io_tree, start, end, NULL); + free_extent_map(em); + + return ret; +} + +/* + * Allow error injection to test balance/relocation cancellation + */ +noinline int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info) +{ + return atomic_read(&fs_info->balance_cancel_req) || + atomic_read(&fs_info->reloc_cancel_req) || + fatal_signal_pending(current); +} +ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE); + +static u64 get_cluster_boundary_end(struct file_extent_cluster *cluster, + int cluster_nr) +{ + /* Last extent, use cluster end directly */ + if (cluster_nr >= cluster->nr - 1) + return cluster->end; + + /* Use next boundary start*/ + return cluster->boundary[cluster_nr + 1] - 1; +} + +static int relocate_one_page(struct inode *inode, struct file_ra_state *ra, + struct file_extent_cluster *cluster, + int *cluster_nr, unsigned long page_index) +{ + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + u64 offset = BTRFS_I(inode)->index_cnt; + const unsigned long last_index = (cluster->end - offset) >> PAGE_SHIFT; + gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping); + struct page *page; + u64 page_start; + u64 page_end; + u64 cur; + int ret; + + ASSERT(page_index <= last_index); + page = find_lock_page(inode->i_mapping, page_index); + if (!page) { + page_cache_sync_readahead(inode->i_mapping, ra, NULL, + page_index, last_index + 1 - page_index); + page = find_or_create_page(inode->i_mapping, page_index, mask); + if (!page) + return -ENOMEM; + } + ret = set_page_extent_mapped(page); + if (ret < 0) + goto release_page; + + if (PageReadahead(page)) + page_cache_async_readahead(inode->i_mapping, ra, NULL, + page_folio(page), page_index, + last_index + 1 - page_index); + + if (!PageUptodate(page)) { + btrfs_read_folio(NULL, page_folio(page)); + lock_page(page); + if (!PageUptodate(page)) { + ret = -EIO; + goto release_page; + } + } + + page_start = page_offset(page); + page_end = page_start + PAGE_SIZE - 1; + + /* + * Start from the cluster, as for subpage case, the cluster can start + * inside the page. + */ + cur = max(page_start, cluster->boundary[*cluster_nr] - offset); + while (cur <= page_end) { + u64 extent_start = cluster->boundary[*cluster_nr] - offset; + u64 extent_end = get_cluster_boundary_end(cluster, + *cluster_nr) - offset; + u64 clamped_start = max(page_start, extent_start); + u64 clamped_end = min(page_end, extent_end); + u32 clamped_len = clamped_end + 1 - clamped_start; + + /* Reserve metadata for this range */ + ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), + clamped_len, clamped_len, + false); + if (ret) + goto release_page; + + /* Mark the range delalloc and dirty for later writeback */ + lock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end, NULL); + ret = btrfs_set_extent_delalloc(BTRFS_I(inode), clamped_start, + clamped_end, 0, NULL); + if (ret) { + clear_extent_bits(&BTRFS_I(inode)->io_tree, + clamped_start, clamped_end, + EXTENT_LOCKED | EXTENT_BOUNDARY); + btrfs_delalloc_release_metadata(BTRFS_I(inode), + clamped_len, true); + btrfs_delalloc_release_extents(BTRFS_I(inode), + clamped_len); + goto release_page; + } + btrfs_page_set_dirty(fs_info, page, clamped_start, clamped_len); + + /* + * Set the boundary if it's inside the page. + * Data relocation requires the destination extents to have the + * same size as the source. + * EXTENT_BOUNDARY bit prevents current extent from being merged + * with previous extent. + */ + if (in_range(cluster->boundary[*cluster_nr] - offset, + page_start, PAGE_SIZE)) { + u64 boundary_start = cluster->boundary[*cluster_nr] - + offset; + u64 boundary_end = boundary_start + + fs_info->sectorsize - 1; + + set_extent_bits(&BTRFS_I(inode)->io_tree, + boundary_start, boundary_end, + EXTENT_BOUNDARY); + } + unlock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end, NULL); + btrfs_delalloc_release_extents(BTRFS_I(inode), clamped_len); + cur += clamped_len; + + /* Crossed extent end, go to next extent */ + if (cur >= extent_end) { + (*cluster_nr)++; + /* Just finished the last extent of the cluster, exit. */ + if (*cluster_nr >= cluster->nr) + break; } - btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0); } - unlock_extent(&BTRFS_I(inode)->io_tree, start, end); + unlock_page(page); + put_page(page); + + balance_dirty_pages_ratelimited(inode->i_mapping); + btrfs_throttle(fs_info); + if (btrfs_should_cancel_balance(fs_info)) + ret = -ECANCELED; + return ret; + +release_page: + unlock_page(page); + put_page(page); return ret; } static int relocate_file_extent_cluster(struct inode *inode, struct file_extent_cluster *cluster) { - struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); - u64 page_start; - u64 page_end; u64 offset = BTRFS_I(inode)->index_cnt; unsigned long index; unsigned long last_index; - struct page *page; struct file_ra_state *ra; - gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping); - int nr = 0; + int cluster_nr = 0; int ret = 0; if (!cluster->nr) @@ -3286,107 +3075,23 @@ static int relocate_file_extent_cluster(struct inode *inode, if (!ra) return -ENOMEM; - ret = prealloc_file_extent_cluster(inode, cluster); + ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster); if (ret) goto out; file_ra_state_init(ra, inode->i_mapping); - ret = setup_extent_mapping(inode, cluster->start - offset, + ret = setup_relocation_extent_mapping(inode, cluster->start - offset, cluster->end - offset, cluster->start); if (ret) goto out; - index = (cluster->start - offset) >> PAGE_SHIFT; last_index = (cluster->end - offset) >> PAGE_SHIFT; - while (index <= last_index) { - ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), - PAGE_SIZE); - if (ret) - goto out; - - page = find_lock_page(inode->i_mapping, index); - if (!page) { - page_cache_sync_readahead(inode->i_mapping, - ra, NULL, index, - last_index + 1 - index); - page = find_or_create_page(inode->i_mapping, index, - mask); - if (!page) { - btrfs_delalloc_release_metadata(BTRFS_I(inode), - PAGE_SIZE, true); - btrfs_delalloc_release_extents(BTRFS_I(inode), - PAGE_SIZE); - ret = -ENOMEM; - goto out; - } - } - - if (PageReadahead(page)) { - page_cache_async_readahead(inode->i_mapping, - ra, NULL, page, index, - last_index + 1 - index); - } - - if (!PageUptodate(page)) { - btrfs_readpage(NULL, page); - lock_page(page); - if (!PageUptodate(page)) { - unlock_page(page); - put_page(page); - btrfs_delalloc_release_metadata(BTRFS_I(inode), - PAGE_SIZE, true); - btrfs_delalloc_release_extents(BTRFS_I(inode), - PAGE_SIZE); - ret = -EIO; - goto out; - } - } - - page_start = page_offset(page); - page_end = page_start + PAGE_SIZE - 1; - - lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end); - - set_page_extent_mapped(page); - - if (nr < cluster->nr && - page_start + offset == cluster->boundary[nr]) { - set_extent_bits(&BTRFS_I(inode)->io_tree, - page_start, page_end, - EXTENT_BOUNDARY); - nr++; - } - - ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0, - NULL); - if (ret) { - unlock_page(page); - put_page(page); - btrfs_delalloc_release_metadata(BTRFS_I(inode), - PAGE_SIZE, true); - btrfs_delalloc_release_extents(BTRFS_I(inode), - PAGE_SIZE); - - clear_extent_bits(&BTRFS_I(inode)->io_tree, - page_start, page_end, - EXTENT_LOCKED | EXTENT_BOUNDARY); - goto out; - - } - set_page_dirty(page); - - unlock_extent(&BTRFS_I(inode)->io_tree, - page_start, page_end); - unlock_page(page); - put_page(page); - - index++; - btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE); - balance_dirty_pages_ratelimited(inode->i_mapping); - btrfs_throttle(fs_info); - } - WARN_ON(nr != cluster->nr); + for (index = (cluster->start - offset) >> PAGE_SHIFT; + index <= last_index && !ret; index++) + ret = relocate_one_page(inode, ra, cluster, &cluster_nr, index); + if (ret == 0) + WARN_ON(cluster_nr != cluster->nr); out: kfree(ra); return ret; @@ -3439,21 +3144,58 @@ static int add_tree_block(struct reloc_control *rc, u32 item_size; int level = -1; u64 generation; + u64 owner = 0; eb = path->nodes[0]; - item_size = btrfs_item_size_nr(eb, path->slots[0]); + item_size = btrfs_item_size(eb, path->slots[0]); if (extent_key->type == BTRFS_METADATA_ITEM_KEY || item_size >= sizeof(*ei) + sizeof(*bi)) { + unsigned long ptr = 0, end; + ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); + end = (unsigned long)ei + item_size; if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) { bi = (struct btrfs_tree_block_info *)(ei + 1); level = btrfs_tree_block_level(eb, bi); + ptr = (unsigned long)(bi + 1); } else { level = (int)extent_key->offset; + ptr = (unsigned long)(ei + 1); } generation = btrfs_extent_generation(eb, ei); + + /* + * We're reading random blocks without knowing their owner ahead + * of time. This is ok most of the time, as all reloc roots and + * fs roots have the same lock type. However normal trees do + * not, and the only way to know ahead of time is to read the + * inline ref offset. We know it's an fs root if + * + * 1. There's more than one ref. + * 2. There's a SHARED_DATA_REF_KEY set. + * 3. FULL_BACKREF is set on the flags. + * + * Otherwise it's safe to assume that the ref offset == the + * owner of this block, so we can use that when calling + * read_tree_block. + */ + if (btrfs_extent_refs(eb, ei) == 1 && + !(btrfs_extent_flags(eb, ei) & + BTRFS_BLOCK_FLAG_FULL_BACKREF) && + ptr < end) { + struct btrfs_extent_inline_ref *iref; + int type; + + iref = (struct btrfs_extent_inline_ref *)ptr; + type = btrfs_get_extent_inline_ref_type(eb, iref, + BTRFS_REF_TYPE_BLOCK); + if (type == BTRFS_REF_TYPE_INVALID) + return -EINVAL; + if (type == BTRFS_TREE_BLOCK_REF_KEY) + owner = btrfs_extent_inline_ref_offset(eb, iref); + } } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) { btrfs_print_v0_err(eb->fs_info); btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL); @@ -3475,10 +3217,12 @@ static int add_tree_block(struct reloc_control *rc, block->key.offset = generation; block->level = level; block->key_ready = 0; + block->owner = owner; - rb_node = tree_insert(blocks, block->bytenr, &block->rb_node); + rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node); if (rb_node) - backref_tree_panic(rb_node, -EEXIST, block->bytenr); + btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr, + -EEXIST); return 0; } @@ -3499,7 +3243,7 @@ static int __add_tree_block(struct reloc_control *rc, if (tree_block_processed(bytenr, rc)) return 0; - if (tree_search(blocks, bytenr)) + if (rb_simple_search(blocks, bytenr)) return 0; path = btrfs_alloc_path(); @@ -3556,37 +3300,11 @@ out: return ret; } -/* - * helper to check if the block use full backrefs for pointers in it - */ -static int block_use_full_backref(struct reloc_control *rc, - struct extent_buffer *eb) -{ - u64 flags; - int ret; - - if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) || - btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV) - return 1; - - ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info, - eb->start, btrfs_header_level(eb), 1, - NULL, &flags); - BUG_ON(ret); - - if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) - ret = 1; - else - ret = 0; - return ret; -} - static int delete_block_group_cache(struct btrfs_fs_info *fs_info, struct btrfs_block_group *block_group, struct inode *inode, u64 ino) { - struct btrfs_key key; struct btrfs_root *root = fs_info->tree_root; struct btrfs_trans_handle *trans; int ret = 0; @@ -3594,11 +3312,7 @@ static int delete_block_group_cache(struct btrfs_fs_info *fs_info, if (inode) goto truncate; - key.objectid = ino; - key.type = BTRFS_INODE_ITEM_KEY; - key.offset = 0; - - inode = btrfs_iget(fs_info->sb, &key, root); + inode = btrfs_iget(fs_info->sb, ino, root); if (IS_ERR(inode)) return -ENOENT; @@ -3624,172 +3338,45 @@ out: } /* - * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY - * this function scans fs tree to find blocks reference the data extent + * Locate the free space cache EXTENT_DATA in root tree leaf and delete the + * cache inode, to avoid free space cache data extent blocking data relocation. */ -static int find_data_references(struct reloc_control *rc, - struct btrfs_key *extent_key, - struct extent_buffer *leaf, - struct btrfs_extent_data_ref *ref, - struct rb_root *blocks) +static int delete_v1_space_cache(struct extent_buffer *leaf, + struct btrfs_block_group *block_group, + u64 data_bytenr) { - struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; - struct btrfs_path *path; - struct tree_block *block; - struct btrfs_root *root; - struct btrfs_file_extent_item *fi; - struct rb_node *rb_node; + u64 space_cache_ino; + struct btrfs_file_extent_item *ei; struct btrfs_key key; - u64 ref_root; - u64 ref_objectid; - u64 ref_offset; - u32 ref_count; - u32 nritems; - int err = 0; - int added = 0; - int counted; + bool found = false; + int i; int ret; - ref_root = btrfs_extent_data_ref_root(leaf, ref); - ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref); - ref_offset = btrfs_extent_data_ref_offset(leaf, ref); - ref_count = btrfs_extent_data_ref_count(leaf, ref); - - /* - * This is an extent belonging to the free space cache, lets just delete - * it and redo the search. - */ - if (ref_root == BTRFS_ROOT_TREE_OBJECTID) { - ret = delete_block_group_cache(fs_info, rc->block_group, - NULL, ref_objectid); - if (ret != -ENOENT) - return ret; - ret = 0; - } - - path = btrfs_alloc_path(); - if (!path) - return -ENOMEM; - path->reada = READA_FORWARD; - - root = read_fs_root(fs_info, ref_root); - if (IS_ERR(root)) { - err = PTR_ERR(root); - goto out; - } - - key.objectid = ref_objectid; - key.type = BTRFS_EXTENT_DATA_KEY; - if (ref_offset > ((u64)-1 << 32)) - key.offset = 0; - else - key.offset = ref_offset; - - path->search_commit_root = 1; - path->skip_locking = 1; - ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); - if (ret < 0) { - err = ret; - goto out; - } - - leaf = path->nodes[0]; - nritems = btrfs_header_nritems(leaf); - /* - * the references in tree blocks that use full backrefs - * are not counted in - */ - if (block_use_full_backref(rc, leaf)) - counted = 0; - else - counted = 1; - rb_node = tree_search(blocks, leaf->start); - if (rb_node) { - if (counted) - added = 1; - else - path->slots[0] = nritems; - } - - while (ref_count > 0) { - while (path->slots[0] >= nritems) { - ret = btrfs_next_leaf(root, path); - if (ret < 0) { - err = ret; - goto out; - } - if (WARN_ON(ret > 0)) - goto out; - - leaf = path->nodes[0]; - nritems = btrfs_header_nritems(leaf); - added = 0; + if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID) + return 0; - if (block_use_full_backref(rc, leaf)) - counted = 0; - else - counted = 1; - rb_node = tree_search(blocks, leaf->start); - if (rb_node) { - if (counted) - added = 1; - else - path->slots[0] = nritems; - } - } + for (i = 0; i < btrfs_header_nritems(leaf); i++) { + u8 type; - btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); - if (WARN_ON(key.objectid != ref_objectid || - key.type != BTRFS_EXTENT_DATA_KEY)) + btrfs_item_key_to_cpu(leaf, &key, i); + if (key.type != BTRFS_EXTENT_DATA_KEY) + continue; + ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item); + type = btrfs_file_extent_type(leaf, ei); + + if ((type == BTRFS_FILE_EXTENT_REG || + type == BTRFS_FILE_EXTENT_PREALLOC) && + btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) { + found = true; + space_cache_ino = key.objectid; break; - - fi = btrfs_item_ptr(leaf, path->slots[0], - struct btrfs_file_extent_item); - - if (btrfs_file_extent_type(leaf, fi) == - BTRFS_FILE_EXTENT_INLINE) - goto next; - - if (btrfs_file_extent_disk_bytenr(leaf, fi) != - extent_key->objectid) - goto next; - - key.offset -= btrfs_file_extent_offset(leaf, fi); - if (key.offset != ref_offset) - goto next; - - if (counted) - ref_count--; - if (added) - goto next; - - if (!tree_block_processed(leaf->start, rc)) { - block = kmalloc(sizeof(*block), GFP_NOFS); - if (!block) { - err = -ENOMEM; - break; - } - block->bytenr = leaf->start; - btrfs_item_key_to_cpu(leaf, &block->key, 0); - block->level = 0; - block->key_ready = 1; - rb_node = tree_insert(blocks, block->bytenr, - &block->rb_node); - if (rb_node) - backref_tree_panic(rb_node, -EEXIST, - block->bytenr); } - if (counted) - added = 1; - else - path->slots[0] = nritems; -next: - path->slots[0]++; - } -out: - btrfs_free_path(path); - return err; + if (!found) + return -ENOENT; + ret = delete_block_group_cache(leaf->fs_info, block_group, NULL, + space_cache_ino); + return ret; } /* @@ -3801,91 +3388,41 @@ int add_data_references(struct reloc_control *rc, struct btrfs_path *path, struct rb_root *blocks) { - struct btrfs_key key; - struct extent_buffer *eb; - struct btrfs_extent_data_ref *dref; - struct btrfs_extent_inline_ref *iref; - unsigned long ptr; - unsigned long end; - u32 blocksize = rc->extent_root->fs_info->nodesize; + struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; + struct ulist *leaves = NULL; + struct ulist_iterator leaf_uiter; + struct ulist_node *ref_node = NULL; + const u32 blocksize = fs_info->nodesize; int ret = 0; - int err = 0; - eb = path->nodes[0]; - ptr = btrfs_item_ptr_offset(eb, path->slots[0]); - end = ptr + btrfs_item_size_nr(eb, path->slots[0]); - ptr += sizeof(struct btrfs_extent_item); - - while (ptr < end) { - iref = (struct btrfs_extent_inline_ref *)ptr; - key.type = btrfs_get_extent_inline_ref_type(eb, iref, - BTRFS_REF_TYPE_DATA); - if (key.type == BTRFS_SHARED_DATA_REF_KEY) { - key.offset = btrfs_extent_inline_ref_offset(eb, iref); - ret = __add_tree_block(rc, key.offset, blocksize, - blocks); - } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { - dref = (struct btrfs_extent_data_ref *)(&iref->offset); - ret = find_data_references(rc, extent_key, - eb, dref, blocks); - } else { - ret = -EUCLEAN; - btrfs_err(rc->extent_root->fs_info, - "extent %llu slot %d has an invalid inline ref type", - eb->start, path->slots[0]); - } - if (ret) { - err = ret; - goto out; - } - ptr += btrfs_extent_inline_ref_size(key.type); - } - WARN_ON(ptr > end); + btrfs_release_path(path); + ret = btrfs_find_all_leafs(NULL, fs_info, extent_key->objectid, + 0, &leaves, NULL, true); + if (ret < 0) + return ret; - while (1) { - cond_resched(); - eb = path->nodes[0]; - if (path->slots[0] >= btrfs_header_nritems(eb)) { - ret = btrfs_next_leaf(rc->extent_root, path); - if (ret < 0) { - err = ret; - break; - } - if (ret > 0) - break; - eb = path->nodes[0]; - } + ULIST_ITER_INIT(&leaf_uiter); + while ((ref_node = ulist_next(leaves, &leaf_uiter))) { + struct extent_buffer *eb; - btrfs_item_key_to_cpu(eb, &key, path->slots[0]); - if (key.objectid != extent_key->objectid) + eb = read_tree_block(fs_info, ref_node->val, 0, 0, 0, NULL); + if (IS_ERR(eb)) { + ret = PTR_ERR(eb); break; - - if (key.type == BTRFS_SHARED_DATA_REF_KEY) { - ret = __add_tree_block(rc, key.offset, blocksize, - blocks); - } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { - dref = btrfs_item_ptr(eb, path->slots[0], - struct btrfs_extent_data_ref); - ret = find_data_references(rc, extent_key, - eb, dref, blocks); - } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) { - btrfs_print_v0_err(eb->fs_info); - btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL); - ret = -EINVAL; - } else { - ret = 0; } - if (ret) { - err = ret; + ret = delete_v1_space_cache(eb, rc->block_group, + extent_key->objectid); + free_extent_buffer(eb); + if (ret < 0) + break; + ret = __add_tree_block(rc, ref_node->val, blocksize, blocks); + if (ret < 0) break; - } - path->slots[0]++; } -out: - btrfs_release_path(path); - if (err) + if (ret < 0) free_block_list(blocks); - return err; + ulist_free(leaves); + return ret; } /* @@ -3992,20 +3529,6 @@ static void unset_reloc_control(struct reloc_control *rc) mutex_unlock(&fs_info->reloc_mutex); } -static int check_extent_flags(u64 flags) -{ - if ((flags & BTRFS_EXTENT_FLAG_DATA) && - (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) - return 1; - if (!(flags & BTRFS_EXTENT_FLAG_DATA) && - !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) - return 1; - if ((flags & BTRFS_EXTENT_FLAG_DATA) && - (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) - return 1; - return 0; -} - static noinline_for_stack int prepare_to_relocate(struct reloc_control *rc) { @@ -4025,7 +3548,7 @@ int prepare_to_relocate(struct reloc_control *rc) rc->reserved_bytes = 0; rc->block_rsv->size = rc->extent_root->fs_info->nodesize * RELOCATION_RESERVED_NODES; - ret = btrfs_block_rsv_refill(rc->extent_root, + ret = btrfs_block_rsv_refill(rc->extent_root->fs_info, rc->block_rsv, rc->block_rsv->size, BTRFS_RESERVE_FLUSH_ALL); if (ret) @@ -4044,8 +3567,12 @@ int prepare_to_relocate(struct reloc_control *rc) */ return PTR_ERR(trans); } - btrfs_commit_transaction(trans); - return 0; + + ret = btrfs_commit_transaction(trans); + if (ret) + unset_reloc_control(rc); + + return ret; } static noinline_for_stack int relocate_block_group(struct reloc_control *rc) @@ -4057,7 +3584,6 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) struct btrfs_path *path; struct btrfs_extent_item *ei; u64 flags; - u32 item_size; int ret; int err = 0; int progress = 0; @@ -4075,9 +3601,9 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) while (1) { rc->reserved_bytes = 0; - ret = btrfs_block_rsv_refill(rc->extent_root, - rc->block_rsv, rc->block_rsv->size, - BTRFS_RESERVE_FLUSH_ALL); + ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, + rc->block_rsv->size, + BTRFS_RESERVE_FLUSH_ALL); if (ret) { err = ret; break; @@ -4106,19 +3632,7 @@ restart: ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_extent_item); - item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]); - if (item_size >= sizeof(*ei)) { - flags = btrfs_extent_flags(path->nodes[0], ei); - ret = check_extent_flags(flags); - BUG_ON(ret); - } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) { - err = -EINVAL; - btrfs_print_v0_err(trans->fs_info); - btrfs_abort_transaction(trans, err); - break; - } else { - BUG(); - } + flags = btrfs_extent_flags(path->nodes[0], ei); if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { ret = add_tree_block(rc, &key, path, &blocks); @@ -4137,12 +3651,6 @@ restart: if (!RB_EMPTY_ROOT(&blocks)) { ret = relocate_tree_blocks(trans, rc, &blocks); if (ret < 0) { - /* - * if we fail to relocate tree blocks, force to update - * backref cache when committing transaction. - */ - rc->backref_cache.last_trans = trans->transid - 1; - if (ret != -EAGAIN) { err = ret; break; @@ -4166,6 +3674,10 @@ restart: break; } } + if (btrfs_should_cancel_balance(fs_info)) { + err = -ECANCELED; + break; + } } if (trans && progress && err == -ENOSPC) { ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags); @@ -4194,16 +3706,24 @@ restart: rc->create_reloc_tree = 0; set_reloc_control(rc); - backref_cache_cleanup(&rc->backref_cache); - btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1); + btrfs_backref_release_cache(&rc->backref_cache); + btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL); + /* + * Even in the case when the relocation is cancelled, we should all go + * through prepare_to_merge() and merge_reloc_roots(). + * + * For error (including cancelled balance), prepare_to_merge() will + * mark all reloc trees orphan, then queue them for cleanup in + * merge_reloc_roots() + */ err = prepare_to_merge(rc, err); merge_reloc_roots(rc); rc->merge_reloc_tree = 0; unset_reloc_control(rc); - btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1); + btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL); /* get rid of pinned extents */ trans = btrfs_join_transaction(rc->extent_root); @@ -4211,11 +3731,13 @@ restart: err = PTR_ERR(trans); goto out_free; } - btrfs_commit_transaction(trans); + ret = btrfs_commit_transaction(trans); + if (ret && !err) + err = ret; +out_free: ret = clean_dirty_subvols(rc); if (ret < 0 && !err) err = ret; -out_free: btrfs_free_block_rsv(fs_info, rc->block_rsv); btrfs_free_path(path); return err; @@ -4251,6 +3773,35 @@ out: return ret; } +static void delete_orphan_inode(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 objectid) +{ + struct btrfs_path *path; + struct btrfs_key key; + int ret = 0; + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + key.objectid = objectid; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret) { + if (ret > 0) + ret = -ENOENT; + goto out; + } + ret = btrfs_del_item(trans, root, path); +out: + if (ret) + btrfs_abort_transaction(trans, ret); + btrfs_free_path(path); +} + /* * helper to create inode for data relocation. * the inode is in data relocation tree and its link count is 0 @@ -4262,44 +3813,86 @@ struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info, struct inode *inode = NULL; struct btrfs_trans_handle *trans; struct btrfs_root *root; - struct btrfs_key key; u64 objectid; int err = 0; - root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID); - if (IS_ERR(root)) - return ERR_CAST(root); - + root = btrfs_grab_root(fs_info->data_reloc_root); trans = btrfs_start_transaction(root, 6); - if (IS_ERR(trans)) + if (IS_ERR(trans)) { + btrfs_put_root(root); return ERR_CAST(trans); + } - err = btrfs_find_free_objectid(root, &objectid); + err = btrfs_get_free_objectid(root, &objectid); if (err) goto out; err = __insert_orphan_inode(trans, root, objectid); - BUG_ON(err); + if (err) + goto out; - key.objectid = objectid; - key.type = BTRFS_INODE_ITEM_KEY; - key.offset = 0; - inode = btrfs_iget(fs_info->sb, &key, root); - BUG_ON(IS_ERR(inode)); + inode = btrfs_iget(fs_info->sb, objectid, root); + if (IS_ERR(inode)) { + delete_orphan_inode(trans, root, objectid); + err = PTR_ERR(inode); + inode = NULL; + goto out; + } BTRFS_I(inode)->index_cnt = group->start; err = btrfs_orphan_add(trans, BTRFS_I(inode)); out: + btrfs_put_root(root); btrfs_end_transaction(trans); btrfs_btree_balance_dirty(fs_info); if (err) { - if (inode) - iput(inode); + iput(inode); inode = ERR_PTR(err); } return inode; } +/* + * Mark start of chunk relocation that is cancellable. Check if the cancellation + * has been requested meanwhile and don't start in that case. + * + * Return: + * 0 success + * -EINPROGRESS operation is already in progress, that's probably a bug + * -ECANCELED cancellation request was set before the operation started + */ +static int reloc_chunk_start(struct btrfs_fs_info *fs_info) +{ + if (test_and_set_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) { + /* This should not happen */ + btrfs_err(fs_info, "reloc already running, cannot start"); + return -EINPROGRESS; + } + + if (atomic_read(&fs_info->reloc_cancel_req) > 0) { + btrfs_info(fs_info, "chunk relocation canceled on start"); + /* + * On cancel, clear all requests but let the caller mark + * the end after cleanup operations. + */ + atomic_set(&fs_info->reloc_cancel_req, 0); + return -ECANCELED; + } + return 0; +} + +/* + * Mark end of chunk relocation that is cancellable and wake any waiters. + */ +static void reloc_chunk_end(struct btrfs_fs_info *fs_info) +{ + /* Requested after start, clear bit first so any waiters can continue */ + if (atomic_read(&fs_info->reloc_cancel_req) > 0) + btrfs_info(fs_info, "chunk relocation canceled during operation"); + clear_and_wake_up_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags); + atomic_set(&fs_info->reloc_cancel_req, 0); +} + static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info) { struct reloc_control *rc; @@ -4310,13 +3903,25 @@ static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info) INIT_LIST_HEAD(&rc->reloc_roots); INIT_LIST_HEAD(&rc->dirty_subvol_roots); - backref_cache_init(&rc->backref_cache); + btrfs_backref_init_cache(fs_info, &rc->backref_cache, 1); mapping_tree_init(&rc->reloc_root_tree); extent_io_tree_init(fs_info, &rc->processed_blocks, IO_TREE_RELOC_BLOCKS, NULL); return rc; } +static void free_reloc_control(struct reloc_control *rc) +{ + struct mapping_node *node, *tmp; + + free_reloc_roots(&rc->reloc_roots); + rbtree_postorder_for_each_entry_safe(node, tmp, + &rc->reloc_root_tree.rb_root, rb_node) + kfree(node); + + kfree(rc); +} + /* * Print the block group being relocated */ @@ -4347,7 +3952,7 @@ static const char *stage_to_string(int stage) int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start) { struct btrfs_block_group *bg; - struct btrfs_root *extent_root = fs_info->extent_root; + struct btrfs_root *extent_root = btrfs_extent_root(fs_info, group_start); struct reloc_control *rc; struct inode *inode; struct btrfs_path *path; @@ -4355,10 +3960,34 @@ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start) int rw = 0; int err = 0; + /* + * This only gets set if we had a half-deleted snapshot on mount. We + * cannot allow relocation to start while we're still trying to clean up + * these pending deletions. + */ + ret = wait_on_bit(&fs_info->flags, BTRFS_FS_UNFINISHED_DROPS, TASK_INTERRUPTIBLE); + if (ret) + return ret; + + /* We may have been woken up by close_ctree, so bail if we're closing. */ + if (btrfs_fs_closing(fs_info)) + return -EINTR; + bg = btrfs_lookup_block_group(fs_info, group_start); if (!bg) return -ENOENT; + /* + * Relocation of a data block group creates ordered extents. Without + * sb_start_write(), we can freeze the filesystem while unfinished + * ordered extents are left. Such ordered extents can cause a deadlock + * e.g. when syncfs() is waiting for their completion but they can't + * finish because they block when joining a transaction, due to the + * fact that the freeze locks are being held in write mode. + */ + if (bg->flags & BTRFS_BLOCK_GROUP_DATA) + ASSERT(sb_write_started(fs_info->sb)); + if (btrfs_pinned_by_swapfile(fs_info, bg)) { btrfs_put_block_group(bg); return -ETXTBSY; @@ -4370,6 +3999,12 @@ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start) return -ENOMEM; } + ret = reloc_chunk_start(fs_info); + if (ret < 0) { + err = ret; + goto out_put_bg; + } + rc->extent_root = extent_root; rc->block_group = bg; @@ -4414,6 +4049,9 @@ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start) rc->block_group->start, rc->block_group->length); + ret = btrfs_zone_finish(rc->block_group); + WARN_ON(ret && ret != -EAGAIN); + while (1) { int finishes_stage; @@ -4460,8 +4098,10 @@ out: if (err && rw) btrfs_dec_block_group_ro(rc->block_group); iput(rc->data_inode); - btrfs_put_block_group(rc->block_group); - kfree(rc); +out_put_bg: + btrfs_put_block_group(bg); + reloc_chunk_end(fs_info); + free_reloc_control(rc); return err; } @@ -4477,7 +4117,7 @@ static noinline_for_stack int mark_garbage_root(struct btrfs_root *root) memset(&root->root_item.drop_progress, 0, sizeof(root->root_item.drop_progress)); - root->root_item.drop_level = 0; + btrfs_set_root_drop_level(&root->root_item, 0); btrfs_set_root_refs(&root->root_item, 0); ret = btrfs_update_root(trans, fs_info->tree_root, &root->root_key, &root->root_item); @@ -4494,9 +4134,8 @@ static noinline_for_stack int mark_garbage_root(struct btrfs_root *root) * this function resumes merging reloc trees with corresponding fs trees. * this is important for keeping the sharing of tree blocks */ -int btrfs_recover_relocation(struct btrfs_root *root) +int btrfs_recover_relocation(struct btrfs_fs_info *fs_info) { - struct btrfs_fs_info *fs_info = root->fs_info; LIST_HEAD(reloc_roots); struct btrfs_key key; struct btrfs_root *fs_root; @@ -4537,17 +4176,18 @@ int btrfs_recover_relocation(struct btrfs_root *root) key.type != BTRFS_ROOT_ITEM_KEY) break; - reloc_root = btrfs_read_fs_root(root, &key); + reloc_root = btrfs_read_tree_root(fs_info->tree_root, &key); if (IS_ERR(reloc_root)) { err = PTR_ERR(reloc_root); goto out; } + set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state); list_add(&reloc_root->root_list, &reloc_roots); if (btrfs_root_refs(&reloc_root->root_item) > 0) { - fs_root = read_fs_root(fs_info, - reloc_root->root_key.offset); + fs_root = btrfs_get_fs_root(fs_info, + reloc_root->root_key.offset, false); if (IS_ERR(fs_root)) { ret = PTR_ERR(fs_root); if (ret != -ENOENT) { @@ -4559,6 +4199,8 @@ int btrfs_recover_relocation(struct btrfs_root *root) err = ret; goto out; } + } else { + btrfs_put_root(fs_root); } } @@ -4578,15 +4220,20 @@ int btrfs_recover_relocation(struct btrfs_root *root) goto out; } - rc->extent_root = fs_info->extent_root; + ret = reloc_chunk_start(fs_info); + if (ret < 0) { + err = ret; + goto out_end; + } + + rc->extent_root = btrfs_extent_root(fs_info, 0); set_reloc_control(rc); trans = btrfs_join_transaction(rc->extent_root); if (IS_ERR(trans)) { - unset_reloc_control(rc); err = PTR_ERR(trans); - goto out_free; + goto out_unset; } rc->merge_reloc_tree = 1; @@ -4602,21 +4249,30 @@ int btrfs_recover_relocation(struct btrfs_root *root) continue; } - fs_root = read_fs_root(fs_info, reloc_root->root_key.offset); + fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, + false); if (IS_ERR(fs_root)) { err = PTR_ERR(fs_root); list_add_tail(&reloc_root->root_list, &reloc_roots); - goto out_free; + btrfs_end_transaction(trans); + goto out_unset; } err = __add_reloc_root(reloc_root); - BUG_ON(err < 0); /* -ENOMEM or logic error */ - fs_root->reloc_root = reloc_root; + ASSERT(err != -EEXIST); + if (err) { + list_add_tail(&reloc_root->root_list, &reloc_roots); + btrfs_put_root(fs_root); + btrfs_end_transaction(trans); + goto out_unset; + } + fs_root->reloc_root = btrfs_grab_root(reloc_root); + btrfs_put_root(fs_root); } err = btrfs_commit_transaction(trans); if (err) - goto out_free; + goto out_unset; merge_reloc_roots(rc); @@ -4625,28 +4281,29 @@ int btrfs_recover_relocation(struct btrfs_root *root) trans = btrfs_join_transaction(rc->extent_root); if (IS_ERR(trans)) { err = PTR_ERR(trans); - goto out_free; + goto out_clean; } err = btrfs_commit_transaction(trans); - +out_clean: ret = clean_dirty_subvols(rc); if (ret < 0 && !err) err = ret; -out_free: - kfree(rc); +out_unset: + unset_reloc_control(rc); +out_end: + reloc_chunk_end(fs_info); + free_reloc_control(rc); out: - if (!list_empty(&reloc_roots)) - free_reloc_roots(&reloc_roots); + free_reloc_roots(&reloc_roots); btrfs_free_path(path); if (err == 0) { /* cleanup orphan inode in data relocation tree */ - fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID); - if (IS_ERR(fs_root)) - err = PTR_ERR(fs_root); - else - err = btrfs_orphan_cleanup(fs_root); + fs_root = btrfs_grab_root(fs_info->data_reloc_root); + ASSERT(fs_root); + err = btrfs_orphan_cleanup(fs_root); + btrfs_put_root(fs_root); } return err; } @@ -4657,9 +4314,10 @@ out: * cloning checksum properly handles the nodatasum extents. * it also saves CPU time to re-calculate the checksum. */ -int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len) +int btrfs_reloc_clone_csums(struct btrfs_inode *inode, u64 file_pos, u64 len) { - struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct btrfs_root *csum_root; struct btrfs_ordered_sum *sums; struct btrfs_ordered_extent *ordered; int ret; @@ -4670,9 +4328,10 @@ int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len) ordered = btrfs_lookup_ordered_extent(inode, file_pos); BUG_ON(ordered->file_offset != file_pos || ordered->num_bytes != len); - disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt; - ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr, - disk_bytenr + len - 1, &list, 0); + disk_bytenr = file_pos + inode->index_cnt; + csum_root = btrfs_csum_root(fs_info, disk_bytenr); + ret = btrfs_lookup_csums_range(csum_root, disk_bytenr, + disk_bytenr + len - 1, &list, 0, false); if (ret) goto out; @@ -4708,7 +4367,7 @@ int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans, { struct btrfs_fs_info *fs_info = root->fs_info; struct reloc_control *rc; - struct backref_node *node; + struct btrfs_backref_node *node; int first_cow = 0; int level; int ret = 0; @@ -4717,13 +4376,7 @@ int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans, if (!rc) return 0; - BUG_ON(rc->stage == UPDATE_DATA_PTRS && - root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID); - - if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { - if (buf == root->node) - __update_reloc_root(root, cow->start); - } + BUG_ON(rc->stage == UPDATE_DATA_PTRS && btrfs_is_data_reloc_root(root)); level = btrfs_header_level(buf); if (btrfs_header_generation(buf) <= @@ -4738,7 +4391,7 @@ int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans, BUG_ON(node->bytenr != buf->start && node->new_bytenr != buf->start); - drop_node_buffer(node); + btrfs_backref_drop_node_buffer(node); atomic_inc(&cow->refs); node->eb = cow; node->new_bytenr = cow->start; @@ -4750,7 +4403,7 @@ int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans, } if (first_cow) - __mark_block_processed(rc, node); + mark_block_processed(rc, node); if (first_cow && level > 0) rc->nodes_relocated += buf->len; @@ -4795,6 +4448,10 @@ void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending, /* * called after snapshot is created. migrate block reservation * and create reloc root for the newly created snapshot + * + * This is similar to btrfs_init_reloc_root(), we come out of here with two + * references held on the reloc_root, one for root->reloc_root and one for + * rc->reloc_roots. */ int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans, struct btrfs_pending_snapshot *pending) @@ -4826,8 +4483,13 @@ int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans, return PTR_ERR(reloc_root); ret = __add_reloc_root(reloc_root); - BUG_ON(ret < 0); - new_root->reloc_root = reloc_root; + ASSERT(ret != -EEXIST); + if (ret) { + /* Pairs with create_reloc_root */ + btrfs_put_root(reloc_root); + return ret; + } + new_root->reloc_root = btrfs_grab_root(reloc_root); if (rc->create_reloc_tree) ret = clone_backref_node(trans, rc, root, reloc_root); |