diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/btrfs/send.c | 417 |
1 files changed, 331 insertions, 86 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 040324d71118..d8ccb62aa7d2 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -24,6 +24,7 @@ #include "transaction.h" #include "compression.h" #include "xattr.h" +#include "print-tree.h" /* * Maximum number of references an extent can have in order for us to attempt to @@ -98,6 +99,15 @@ struct send_ctx { struct btrfs_key *cmp_key; /* + * Keep track of the generation of the last transaction that was used + * for relocating a block group. This is periodically checked in order + * to detect if a relocation happened since the last check, so that we + * don't operate on stale extent buffers for nodes (level >= 1) or on + * stale disk_bytenr values of file extent items. + */ + u64 last_reloc_trans; + + /* * infos of the currently processed inode. In case of deleted inodes, * these are the values from the deleted inode. */ @@ -898,7 +908,6 @@ static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path, iterate_inode_ref_t iterate, void *ctx) { struct extent_buffer *eb = path->nodes[0]; - struct btrfs_item *item; struct btrfs_inode_ref *iref; struct btrfs_inode_extref *extref; struct btrfs_path *tmp_path; @@ -930,12 +939,11 @@ static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path, if (found_key->type == BTRFS_INODE_REF_KEY) { ptr = (unsigned long)btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); - item = btrfs_item_nr(slot); - total = btrfs_item_size(eb, item); + total = btrfs_item_size(eb, slot); elem_size = sizeof(*iref); } else { ptr = btrfs_item_ptr_offset(eb, slot); - total = btrfs_item_size_nr(eb, slot); + total = btrfs_item_size(eb, slot); elem_size = sizeof(*extref); } @@ -1004,7 +1012,7 @@ out: typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, - u8 type, void *ctx); + void *ctx); /* * Helper function to iterate the entries in ONE btrfs_dir_item. @@ -1018,7 +1026,6 @@ static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path, { int ret = 0; struct extent_buffer *eb; - struct btrfs_item *item; struct btrfs_dir_item *di; struct btrfs_key di_key; char *buf = NULL; @@ -1030,7 +1037,6 @@ static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path, u32 total; int slot; int num; - u8 type; /* * Start with a small buffer (1 page). If later we end up needing more @@ -1047,20 +1053,18 @@ static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path, eb = path->nodes[0]; slot = path->slots[0]; - item = btrfs_item_nr(slot); di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item); cur = 0; len = 0; - total = btrfs_item_size(eb, item); + total = btrfs_item_size(eb, slot); num = 0; while (cur < total) { name_len = btrfs_dir_name_len(eb, di); data_len = btrfs_dir_data_len(eb, di); - type = btrfs_dir_type(eb, di); btrfs_dir_item_key_to_cpu(eb, di, &di_key); - if (type == BTRFS_FT_XATTR) { + if (btrfs_dir_type(eb, di) == BTRFS_FT_XATTR) { if (name_len > XATTR_NAME_MAX) { ret = -ENAMETOOLONG; goto out; @@ -1110,7 +1114,7 @@ static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path, cur += len; ret = iterate(num, &di_key, buf, name_len, buf + name_len, - data_len, type, ctx); + data_len, ctx); if (ret < 0) goto out; if (ret) { @@ -1427,6 +1431,26 @@ static int find_extent_clone(struct send_ctx *sctx, if (ret < 0) goto out; + down_read(&fs_info->commit_root_sem); + if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { + /* + * A transaction commit for a transaction in which block group + * relocation was done just happened. + * The disk_bytenr of the file extent item we processed is + * possibly stale, referring to the extent's location before + * relocation. So act as if we haven't found any clone sources + * and fallback to write commands, which will read the correct + * data from the new extent location. Otherwise we will fail + * below because we haven't found our own back reference or we + * could be getting incorrect sources in case the old extent + * was already reallocated after the relocation. + */ + up_read(&fs_info->commit_root_sem); + ret = -ENOENT; + goto out; + } + up_read(&fs_info->commit_root_sem); + if (!backref_ctx.found_itself) { /* found a bug in backref code? */ ret = -EIO; @@ -1692,8 +1716,7 @@ out: */ static int lookup_dir_item_inode(struct btrfs_root *root, u64 dir, const char *name, int name_len, - u64 *found_inode, - u8 *found_type) + u64 *found_inode) { int ret = 0; struct btrfs_dir_item *di; @@ -1716,7 +1739,6 @@ static int lookup_dir_item_inode(struct btrfs_root *root, goto out; } *found_inode = key.objectid; - *found_type = btrfs_dir_type(path->nodes[0], di); out: btrfs_free_path(path); @@ -1839,7 +1861,6 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen, int ret = 0; u64 gen; u64 other_inode = 0; - u8 other_type = 0; if (!sctx->parent_root) goto out; @@ -1867,7 +1888,7 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen, } ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len, - &other_inode, &other_type); + &other_inode); if (ret < 0 && ret != -ENOENT) goto out; if (ret) { @@ -1912,7 +1933,6 @@ static int did_overwrite_ref(struct send_ctx *sctx, int ret = 0; u64 gen; u64 ow_inode; - u8 other_type; if (!sctx->parent_root) goto out; @@ -1936,7 +1956,7 @@ static int did_overwrite_ref(struct send_ctx *sctx, /* check if the ref was overwritten by another ref */ ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len, - &ow_inode, &other_type); + &ow_inode); if (ret < 0 && ret != -ENOENT) goto out; if (ret) { @@ -3622,7 +3642,7 @@ static int is_ancestor(struct btrfs_root *root, key.type != BTRFS_INODE_EXTREF_KEY) break; - item_size = btrfs_item_size_nr(leaf, slot); + item_size = btrfs_item_size(leaf, slot); while (cur_offset < item_size) { u64 parent; u64 parent_gen; @@ -4651,9 +4671,8 @@ out: } static int __process_new_xattr(int num, struct btrfs_key *di_key, - const char *name, int name_len, - const char *data, int data_len, - u8 type, void *ctx) + const char *name, int name_len, const char *data, + int data_len, void *ctx) { int ret; struct send_ctx *sctx = ctx; @@ -4697,8 +4716,7 @@ out: static int __process_deleted_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, - const char *data, int data_len, - u8 type, void *ctx) + const char *data, int data_len, void *ctx) { int ret; struct send_ctx *sctx = ctx; @@ -4743,10 +4761,8 @@ struct find_xattr_ctx { int found_data_len; }; -static int __find_xattr(int num, struct btrfs_key *di_key, - const char *name, int name_len, - const char *data, int data_len, - u8 type, void *vctx) +static int __find_xattr(int num, struct btrfs_key *di_key, const char *name, + int name_len, const char *data, int data_len, void *vctx) { struct find_xattr_ctx *ctx = vctx; @@ -4796,7 +4812,7 @@ static int find_xattr(struct btrfs_root *root, static int __process_changed_new_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, - u8 type, void *ctx) + void *ctx) { int ret; struct send_ctx *sctx = ctx; @@ -4808,12 +4824,12 @@ static int __process_changed_new_xattr(int num, struct btrfs_key *di_key, &found_data_len); if (ret == -ENOENT) { ret = __process_new_xattr(num, di_key, name, name_len, data, - data_len, type, ctx); + data_len, ctx); } else if (ret >= 0) { if (data_len != found_data_len || memcmp(data, found_data, data_len)) { ret = __process_new_xattr(num, di_key, name, name_len, - data, data_len, type, ctx); + data, data_len, ctx); } else { ret = 0; } @@ -4826,7 +4842,7 @@ static int __process_changed_new_xattr(int num, struct btrfs_key *di_key, static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, - u8 type, void *ctx) + void *ctx) { int ret; struct send_ctx *sctx = ctx; @@ -4835,7 +4851,7 @@ static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key, name, name_len, NULL, NULL); if (ret == -ENOENT) ret = __process_deleted_xattr(num, di_key, name, name_len, data, - data_len, type, ctx); + data_len, ctx); else if (ret >= 0) ret = 0; @@ -6566,7 +6582,7 @@ static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path, } leaf = path->nodes[0]; - item_size = btrfs_item_size_nr(leaf, path->slots[0]); + item_size = btrfs_item_size(leaf, path->slots[0]); ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); while (cur_offset < item_size) { extref = (struct btrfs_inode_extref *)(ptr + @@ -6597,6 +6613,50 @@ static int changed_cb(struct btrfs_path *left_path, { int ret = 0; + /* + * We can not hold the commit root semaphore here. This is because in + * the case of sending and receiving to the same filesystem, using a + * pipe, could result in a deadlock: + * + * 1) The task running send blocks on the pipe because it's full; + * + * 2) The task running receive, which is the only consumer of the pipe, + * is waiting for a transaction commit (for example due to a space + * reservation when doing a write or triggering a transaction commit + * when creating a subvolume); + * + * 3) The transaction is waiting to write lock the commit root semaphore, + * but can not acquire it since it's being held at 1). + * + * Down this call chain we write to the pipe through kernel_write(). + * The same type of problem can also happen when sending to a file that + * is stored in the same filesystem - when reserving space for a write + * into the file, we can trigger a transaction commit. + * + * Our caller has supplied us with clones of leaves from the send and + * parent roots, so we're safe here from a concurrent relocation and + * further reallocation of metadata extents while we are here. Below we + * also assert that the leaves are clones. + */ + lockdep_assert_not_held(&sctx->send_root->fs_info->commit_root_sem); + + /* + * We always have a send root, so left_path is never NULL. We will not + * have a leaf when we have reached the end of the send root but have + * not yet reached the end of the parent root. + */ + if (left_path->nodes[0]) + ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED, + &left_path->nodes[0]->bflags)); + /* + * When doing a full send we don't have a parent root, so right_path is + * NULL. When doing an incremental send, we may have reached the end of + * the parent root already, so we don't have a leaf at right_path. + */ + if (right_path && right_path->nodes[0]) + ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED, + &right_path->nodes[0]->bflags)); + if (result == BTRFS_COMPARE_TREE_SAME) { if (key->type == BTRFS_INODE_REF_KEY || key->type == BTRFS_INODE_EXTREF_KEY) { @@ -6643,14 +6703,46 @@ out: return ret; } +static int search_key_again(const struct send_ctx *sctx, + struct btrfs_root *root, + struct btrfs_path *path, + const struct btrfs_key *key) +{ + int ret; + + if (!path->need_commit_sem) + lockdep_assert_held_read(&root->fs_info->commit_root_sem); + + /* + * Roots used for send operations are readonly and no one can add, + * update or remove keys from them, so we should be able to find our + * key again. The only exception is deduplication, which can operate on + * readonly roots and add, update or remove keys to/from them - but at + * the moment we don't allow it to run in parallel with send. + */ + ret = btrfs_search_slot(NULL, root, key, path, 0, 0); + ASSERT(ret <= 0); + if (ret > 0) { + btrfs_print_tree(path->nodes[path->lowest_level], false); + btrfs_err(root->fs_info, +"send: key (%llu %u %llu) not found in %s root %llu, lowest_level %d, slot %d", + key->objectid, key->type, key->offset, + (root == sctx->parent_root ? "parent" : "send"), + root->root_key.objectid, path->lowest_level, + path->slots[path->lowest_level]); + return -EUCLEAN; + } + + return ret; +} + static int full_send_tree(struct send_ctx *sctx) { int ret; struct btrfs_root *send_root = sctx->send_root; struct btrfs_key key; + struct btrfs_fs_info *fs_info = send_root->fs_info; struct btrfs_path *path; - struct extent_buffer *eb; - int slot; path = alloc_path_for_send(); if (!path) @@ -6661,6 +6753,10 @@ static int full_send_tree(struct send_ctx *sctx) key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; + down_read(&fs_info->commit_root_sem); + sctx->last_reloc_trans = fs_info->last_reloc_trans; + up_read(&fs_info->commit_root_sem); + ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0); if (ret < 0) goto out; @@ -6668,15 +6764,35 @@ static int full_send_tree(struct send_ctx *sctx) goto out_finish; while (1) { - eb = path->nodes[0]; - slot = path->slots[0]; - btrfs_item_key_to_cpu(eb, &key, slot); + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); ret = changed_cb(path, NULL, &key, BTRFS_COMPARE_TREE_NEW, sctx); if (ret < 0) goto out; + down_read(&fs_info->commit_root_sem); + if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { + sctx->last_reloc_trans = fs_info->last_reloc_trans; + up_read(&fs_info->commit_root_sem); + /* + * A transaction used for relocating a block group was + * committed or is about to finish its commit. Release + * our path (leaf) and restart the search, so that we + * avoid operating on any file extent items that are + * stale, with a disk_bytenr that reflects a pre + * relocation value. This way we avoid as much as + * possible to fallback to regular writes when checking + * if we can clone file ranges. + */ + btrfs_release_path(path); + ret = search_key_again(sctx, send_root, path, &key); + if (ret < 0) + goto out; + } else { + up_read(&fs_info->commit_root_sem); + } + ret = btrfs_next_item(send_root, path); if (ret < 0) goto out; @@ -6694,6 +6810,20 @@ out: return ret; } +static int replace_node_with_clone(struct btrfs_path *path, int level) +{ + struct extent_buffer *clone; + + clone = btrfs_clone_extent_buffer(path->nodes[level]); + if (!clone) + return -ENOMEM; + + free_extent_buffer(path->nodes[level]); + path->nodes[level] = clone; + + return 0; +} + static int tree_move_down(struct btrfs_path *path, int *level, u64 reada_min_gen) { struct extent_buffer *eb; @@ -6703,6 +6833,8 @@ static int tree_move_down(struct btrfs_path *path, int *level, u64 reada_min_gen u64 reada_max; u64 reada_done = 0; + lockdep_assert_held_read(&parent->fs_info->commit_root_sem); + BUG_ON(*level == 0); eb = btrfs_read_node_slot(parent, slot); if (IS_ERR(eb)) @@ -6726,6 +6858,10 @@ static int tree_move_down(struct btrfs_path *path, int *level, u64 reada_min_gen path->nodes[*level - 1] = eb; path->slots[*level - 1] = 0; (*level)--; + + if (*level == 0) + return replace_node_with_clone(path, 0); + return 0; } @@ -6739,8 +6875,10 @@ static int tree_move_next_or_upnext(struct btrfs_path *path, path->slots[*level]++; while (path->slots[*level] >= nritems) { - if (*level == root_level) + if (*level == root_level) { + path->slots[*level] = nritems - 1; return -1; + } /* move upnext */ path->slots[*level] = 0; @@ -6772,14 +6910,20 @@ static int tree_advance(struct btrfs_path *path, } else { ret = tree_move_down(path, level, reada_min_gen); } - if (ret >= 0) { - if (*level == 0) - btrfs_item_key_to_cpu(path->nodes[*level], key, - path->slots[*level]); - else - btrfs_node_key_to_cpu(path->nodes[*level], key, - path->slots[*level]); - } + + /* + * Even if we have reached the end of a tree, ret is -1, update the key + * anyway, so that in case we need to restart due to a block group + * relocation, we can assert that the last key of the root node still + * exists in the tree. + */ + if (*level == 0) + btrfs_item_key_to_cpu(path->nodes[*level], key, + path->slots[*level]); + else + btrfs_node_key_to_cpu(path->nodes[*level], key, + path->slots[*level]); + return ret; } @@ -6791,8 +6935,8 @@ static int tree_compare_item(struct btrfs_path *left_path, int len1, len2; unsigned long off1, off2; - len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]); - len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]); + len1 = btrfs_item_size(left_path->nodes[0], left_path->slots[0]); + len2 = btrfs_item_size(right_path->nodes[0], right_path->slots[0]); if (len1 != len2) return 1; @@ -6809,6 +6953,97 @@ static int tree_compare_item(struct btrfs_path *left_path, } /* + * A transaction used for relocating a block group was committed or is about to + * finish its commit. Release our paths and restart the search, so that we are + * not using stale extent buffers: + * + * 1) For levels > 0, we are only holding references of extent buffers, without + * any locks on them, which does not prevent them from having been relocated + * and reallocated after the last time we released the commit root semaphore. + * The exception are the root nodes, for which we always have a clone, see + * the comment at btrfs_compare_trees(); + * + * 2) For leaves, level 0, we are holding copies (clones) of extent buffers, so + * we are safe from the concurrent relocation and reallocation. However they + * can have file extent items with a pre relocation disk_bytenr value, so we + * restart the start from the current commit roots and clone the new leaves so + * that we get the post relocation disk_bytenr values. Not doing so, could + * make us clone the wrong data in case there are new extents using the old + * disk_bytenr that happen to be shared. + */ +static int restart_after_relocation(struct btrfs_path *left_path, + struct btrfs_path *right_path, + const struct btrfs_key *left_key, + const struct btrfs_key *right_key, + int left_level, + int right_level, + const struct send_ctx *sctx) +{ + int root_level; + int ret; + + lockdep_assert_held_read(&sctx->send_root->fs_info->commit_root_sem); + + btrfs_release_path(left_path); + btrfs_release_path(right_path); + + /* + * Since keys can not be added or removed to/from our roots because they + * are readonly and we do not allow deduplication to run in parallel + * (which can add, remove or change keys), the layout of the trees should + * not change. + */ + left_path->lowest_level = left_level; + ret = search_key_again(sctx, sctx->send_root, left_path, left_key); + if (ret < 0) + return ret; + + right_path->lowest_level = right_level; + ret = search_key_again(sctx, sctx->parent_root, right_path, right_key); + if (ret < 0) + return ret; + + /* + * If the lowest level nodes are leaves, clone them so that they can be + * safely used by changed_cb() while not under the protection of the + * commit root semaphore, even if relocation and reallocation happens in + * parallel. + */ + if (left_level == 0) { + ret = replace_node_with_clone(left_path, 0); + if (ret < 0) + return ret; + } + + if (right_level == 0) { + ret = replace_node_with_clone(right_path, 0); + if (ret < 0) + return ret; + } + + /* + * Now clone the root nodes (unless they happen to be the leaves we have + * already cloned). This is to protect against concurrent snapshotting of + * the send and parent roots (see the comment at btrfs_compare_trees()). + */ + root_level = btrfs_header_level(sctx->send_root->commit_root); + if (root_level > 0) { + ret = replace_node_with_clone(left_path, root_level); + if (ret < 0) + return ret; + } + + root_level = btrfs_header_level(sctx->parent_root->commit_root); + if (root_level > 0) { + ret = replace_node_with_clone(right_path, root_level); + if (ret < 0) + return ret; + } + + return 0; +} + +/* * This function compares two trees and calls the provided callback for * every changed/new/deleted item it finds. * If shared tree blocks are encountered, whole subtrees are skipped, making @@ -6836,10 +7071,10 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, int right_root_level; int left_level; int right_level; - int left_end_reached; - int right_end_reached; - int advance_left; - int advance_right; + int left_end_reached = 0; + int right_end_reached = 0; + int advance_left = 0; + int advance_right = 0; u64 left_blockptr; u64 right_blockptr; u64 left_gen; @@ -6907,12 +7142,18 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, down_read(&fs_info->commit_root_sem); left_level = btrfs_header_level(left_root->commit_root); left_root_level = left_level; + /* + * We clone the root node of the send and parent roots to prevent races + * with snapshot creation of these roots. Snapshot creation COWs the + * root node of a tree, so after the transaction is committed the old + * extent can be reallocated while this send operation is still ongoing. + * So we clone them, under the commit root semaphore, to be race free. + */ left_path->nodes[left_level] = btrfs_clone_extent_buffer(left_root->commit_root); if (!left_path->nodes[left_level]) { - up_read(&fs_info->commit_root_sem); ret = -ENOMEM; - goto out; + goto out_unlock; } right_level = btrfs_header_level(right_root->commit_root); @@ -6920,9 +7161,8 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, right_path->nodes[right_level] = btrfs_clone_extent_buffer(right_root->commit_root); if (!right_path->nodes[right_level]) { - up_read(&fs_info->commit_root_sem); ret = -ENOMEM; - goto out; + goto out_unlock; } /* * Our right root is the parent root, while the left root is the "send" @@ -6932,7 +7172,6 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, * will need to read them at some point. */ reada_min_gen = btrfs_header_generation(right_root->commit_root); - up_read(&fs_info->commit_root_sem); if (left_level == 0) btrfs_item_key_to_cpu(left_path->nodes[left_level], @@ -6947,11 +7186,26 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, btrfs_node_key_to_cpu(right_path->nodes[right_level], &right_key, right_path->slots[right_level]); - left_end_reached = right_end_reached = 0; - advance_left = advance_right = 0; + sctx->last_reloc_trans = fs_info->last_reloc_trans; while (1) { - cond_resched(); + if (need_resched() || + rwsem_is_contended(&fs_info->commit_root_sem)) { + up_read(&fs_info->commit_root_sem); + cond_resched(); + down_read(&fs_info->commit_root_sem); + } + + if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { + ret = restart_after_relocation(left_path, right_path, + &left_key, &right_key, + left_level, right_level, + sctx); + if (ret < 0) + goto out_unlock; + sctx->last_reloc_trans = fs_info->last_reloc_trans; + } + if (advance_left && !left_end_reached) { ret = tree_advance(left_path, &left_level, left_root_level, @@ -6960,7 +7214,7 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, if (ret == -1) left_end_reached = ADVANCE; else if (ret < 0) - goto out; + goto out_unlock; advance_left = 0; } if (advance_right && !right_end_reached) { @@ -6971,54 +7225,55 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, if (ret == -1) right_end_reached = ADVANCE; else if (ret < 0) - goto out; + goto out_unlock; advance_right = 0; } if (left_end_reached && right_end_reached) { ret = 0; - goto out; + goto out_unlock; } else if (left_end_reached) { if (right_level == 0) { + up_read(&fs_info->commit_root_sem); ret = changed_cb(left_path, right_path, &right_key, BTRFS_COMPARE_TREE_DELETED, sctx); if (ret < 0) goto out; + down_read(&fs_info->commit_root_sem); } advance_right = ADVANCE; continue; } else if (right_end_reached) { if (left_level == 0) { + up_read(&fs_info->commit_root_sem); ret = changed_cb(left_path, right_path, &left_key, BTRFS_COMPARE_TREE_NEW, sctx); if (ret < 0) goto out; + down_read(&fs_info->commit_root_sem); } advance_left = ADVANCE; continue; } if (left_level == 0 && right_level == 0) { + up_read(&fs_info->commit_root_sem); cmp = btrfs_comp_cpu_keys(&left_key, &right_key); if (cmp < 0) { ret = changed_cb(left_path, right_path, &left_key, BTRFS_COMPARE_TREE_NEW, sctx); - if (ret < 0) - goto out; advance_left = ADVANCE; } else if (cmp > 0) { ret = changed_cb(left_path, right_path, &right_key, BTRFS_COMPARE_TREE_DELETED, sctx); - if (ret < 0) - goto out; advance_right = ADVANCE; } else { enum btrfs_compare_tree_result result; @@ -7032,11 +7287,13 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, result = BTRFS_COMPARE_TREE_SAME; ret = changed_cb(left_path, right_path, &left_key, result, sctx); - if (ret < 0) - goto out; advance_left = ADVANCE; advance_right = ADVANCE; } + + if (ret < 0) + goto out; + down_read(&fs_info->commit_root_sem); } else if (left_level == right_level) { cmp = btrfs_comp_cpu_keys(&left_key, &right_key); if (cmp < 0) { @@ -7076,6 +7333,8 @@ static int btrfs_compare_trees(struct btrfs_root *left_root, } } +out_unlock: + up_read(&fs_info->commit_root_sem); out: btrfs_free_path(left_path); btrfs_free_path(right_path); @@ -7425,21 +7684,7 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg) if (ret) goto out; - spin_lock(&fs_info->send_reloc_lock); - if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) { - spin_unlock(&fs_info->send_reloc_lock); - btrfs_warn_rl(fs_info, - "cannot run send because a relocation operation is in progress"); - ret = -EAGAIN; - goto out; - } - fs_info->send_in_progress++; - spin_unlock(&fs_info->send_reloc_lock); - ret = send_subvol(sctx); - spin_lock(&fs_info->send_reloc_lock); - fs_info->send_in_progress--; - spin_unlock(&fs_info->send_reloc_lock); if (ret < 0) goto out; |