1 files changed, 166 insertions, 47 deletions

diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c
index d07bd41a7c1e..ec96285357e0 100644
--- a/fs/btrfs/block-rsv.c
+++ b/fs/btrfs/block-rsv.c
@@ -5,6 +5,100 @@
 #include "block-rsv.h"
 #include "space-info.h"
 #include "transaction.h"
+#include "block-group.h"
+#include "disk-io.h"
+
+/*
+ * HOW DO BLOCK RESERVES WORK
+ *
+ *   Think of block_rsv's as buckets for logically grouped metadata
+ *   reservations.  Each block_rsv has a ->size and a ->reserved.  ->size is
+ *   how large we want our block rsv to be, ->reserved is how much space is
+ *   currently reserved for this block reserve.
+ *
+ *   ->failfast exists for the truncate case, and is described below.
+ *
+ * NORMAL OPERATION
+ *
+ *   -> Reserve
+ *     Entrance: btrfs_block_rsv_add, btrfs_block_rsv_refill
+ *
+ *     We call into btrfs_reserve_metadata_bytes() with our bytes, which is
+ *     accounted for in space_info->bytes_may_use, and then add the bytes to
+ *     ->reserved, and ->size in the case of btrfs_block_rsv_add.
+ *
+ *     ->size is an over-estimation of how much we may use for a particular
+ *     operation.
+ *
+ *   -> Use
+ *     Entrance: btrfs_use_block_rsv
+ *
+ *     When we do a btrfs_alloc_tree_block() we call into btrfs_use_block_rsv()
+ *     to determine the appropriate block_rsv to use, and then verify that
+ *     ->reserved has enough space for our tree block allocation.  Once
+ *     successful we subtract fs_info->nodesize from ->reserved.
+ *
+ *   -> Finish
+ *     Entrance: btrfs_block_rsv_release
+ *
+ *     We are finished with our operation, subtract our individual reservation
+ *     from ->size, and then subtract ->size from ->reserved and free up the
+ *     excess if there is any.
+ *
+ *     There is some logic here to refill the delayed refs rsv or the global rsv
+ *     as needed, otherwise the excess is subtracted from
+ *     space_info->bytes_may_use.
+ *
+ * TYPES OF BLOCK RESERVES
+ *
+ * BLOCK_RSV_TRANS, BLOCK_RSV_DELOPS, BLOCK_RSV_CHUNK
+ *   These behave normally, as described above, just within the confines of the
+ *   lifetime of their particular operation (transaction for the whole trans
+ *   handle lifetime, for example).
+ *
+ * BLOCK_RSV_GLOBAL
+ *   It is impossible to properly account for all the space that may be required
+ *   to make our extent tree updates.  This block reserve acts as an overflow
+ *   buffer in case our delayed refs reserve does not reserve enough space to
+ *   update the extent tree.
+ *
+ *   We can steal from this in some cases as well, notably on evict() or
+ *   truncate() in order to help users recover from ENOSPC conditions.
+ *
+ * BLOCK_RSV_DELALLOC
+ *   The individual item sizes are determined by the per-inode size
+ *   calculations, which are described with the delalloc code.  This is pretty
+ *   straightforward, it's just the calculation of ->size encodes a lot of
+ *   different items, and thus it gets used when updating inodes, inserting file
+ *   extents, and inserting checksums.
+ *
+ * BLOCK_RSV_DELREFS
+ *   We keep a running tally of how many delayed refs we have on the system.
+ *   We assume each one of these delayed refs are going to use a full
+ *   reservation.  We use the transaction items and pre-reserve space for every
+ *   operation, and use this reservation to refill any gap between ->size and
+ *   ->reserved that may exist.
+ *
+ *   From there it's straightforward, removing a delayed ref means we remove its
+ *   count from ->size and free up reservations as necessary.  Since this is
+ *   the most dynamic block reserve in the system, we will try to refill this
+ *   block reserve first with any excess returned by any other block reserve.
+ *
+ * BLOCK_RSV_EMPTY
+ *   This is the fallback block reserve to make us try to reserve space if we
+ *   don't have a specific bucket for this allocation.  It is mostly used for
+ *   updating the device tree and such, since that is a separate pool we're
+ *   content to just reserve space from the space_info on demand.
+ *
+ * BLOCK_RSV_TEMP
+ *   This is used by things like truncate and iput.  We will temporarily
+ *   allocate a block reserve, set it to some size, and then truncate bytes
+ *   until we have no space left.  With ->failfast set we'll simply return
+ *   ENOSPC from btrfs_use_block_rsv() to signal that we need to unwind and try
+ *   to make a new reservation.  This is because these operations are
+ *   unbounded, so we want to do as much work as we can, and then back off and
+ *   re-reserve.
+ */
 
 static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
 				    struct btrfs_block_rsv *block_rsv,
@@ -24,7 +118,7 @@ static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
 	if (block_rsv->reserved >= block_rsv->size) {
 		num_bytes = block_rsv->reserved - block_rsv->size;
 		block_rsv->reserved = block_rsv->size;
-		block_rsv->full = 1;
+		block_rsv->full = true;
 	} else {
 		num_bytes = 0;
 	}
@@ -48,7 +142,7 @@ static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
 				bytes_to_add = min(num_bytes, bytes_to_add);
 				dest->reserved += bytes_to_add;
 				if (dest->reserved >= dest->size)
-					dest->full = 1;
+					dest->full = true;
 				num_bytes -= bytes_to_add;
 			}
 			spin_unlock(&dest->lock);
@@ -77,7 +171,7 @@ int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
 	return 0;
 }
 
-void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
+void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, enum btrfs_rsv_type type)
 {
 	memset(rsv, 0, sizeof(*rsv));
 	spin_lock_init(&rsv->lock);
@@ -86,7 +180,7 @@ void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
 
 void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
 				   struct btrfs_block_rsv *rsv,
-				   unsigned short type)
+				   enum btrfs_rsv_type type)
 {
 	btrfs_init_block_rsv(rsv, type);
 	rsv->space_info = btrfs_find_space_info(fs_info,
@@ -94,7 +188,7 @@ void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
 }
 
 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
-					      unsigned short type)
+					      enum btrfs_rsv_type type)
 {
 	struct btrfs_block_rsv *block_rsv;
 
@@ -111,11 +205,11 @@ void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
 {
 	if (!rsv)
 		return;
-	btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
+	btrfs_block_rsv_release(fs_info, rsv, (u64)-1, NULL);
 	kfree(rsv);
 }
 
-int btrfs_block_rsv_add(struct btrfs_root *root,
+int btrfs_block_rsv_add(struct btrfs_fs_info *fs_info,
 			struct btrfs_block_rsv *block_rsv, u64 num_bytes,
 			enum btrfs_reserve_flush_enum flush)
 {
@@ -124,7 +218,7 @@ int btrfs_block_rsv_add(struct btrfs_root *root,
 	if (num_bytes == 0)
 		return 0;
 
-	ret = btrfs_reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
+	ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, num_bytes, flush);
 	if (!ret)
 		btrfs_block_rsv_add_bytes(block_rsv, num_bytes, true);
 
@@ -148,7 +242,7 @@ int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
 	return ret;
 }
 
-int btrfs_block_rsv_refill(struct btrfs_root *root,
+int btrfs_block_rsv_refill(struct btrfs_fs_info *fs_info,
 			   struct btrfs_block_rsv *block_rsv, u64 min_reserved,
 			   enum btrfs_reserve_flush_enum flush)
 {
@@ -169,7 +263,7 @@ int btrfs_block_rsv_refill(struct btrfs_root *root,
 	if (!ret)
 		return 0;
 
-	ret = btrfs_reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
+	ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, num_bytes, flush);
 	if (!ret) {
 		btrfs_block_rsv_add_bytes(block_rsv, num_bytes, false);
 		return 0;
@@ -178,9 +272,9 @@ int btrfs_block_rsv_refill(struct btrfs_root *root,
 	return ret;
 }
 
-u64 __btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
-			      struct btrfs_block_rsv *block_rsv,
-			      u64 num_bytes, u64 *qgroup_to_release)
+u64 btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
+			    struct btrfs_block_rsv *block_rsv, u64 num_bytes,
+			    u64 *qgroup_to_release)
 {
 	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
 	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
@@ -192,7 +286,7 @@ u64 __btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
 	 */
 	if (block_rsv == delayed_rsv)
 		target = global_rsv;
-	else if (block_rsv != global_rsv && !delayed_rsv->full)
+	else if (block_rsv != global_rsv && !btrfs_block_rsv_full(delayed_rsv))
 		target = delayed_rsv;
 
 	if (target && block_rsv->space_info != target->space_info)
@@ -210,7 +304,7 @@ int btrfs_block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv, u64 num_bytes)
 	if (block_rsv->reserved >= num_bytes) {
 		block_rsv->reserved -= num_bytes;
 		if (block_rsv->reserved < block_rsv->size)
-			block_rsv->full = 0;
+			block_rsv->full = false;
 		ret = 0;
 	}
 	spin_unlock(&block_rsv->lock);
@@ -225,7 +319,7 @@ void btrfs_block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
 	if (update_size)
 		block_rsv->size += num_bytes;
 	else if (block_rsv->reserved >= block_rsv->size)
-		block_rsv->full = 1;
+		block_rsv->full = true;
 	spin_unlock(&block_rsv->lock);
 }
 
@@ -247,7 +341,7 @@ int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
 	}
 	global_rsv->reserved -= num_bytes;
 	if (global_rsv->reserved < global_rsv->size)
-		global_rsv->full = 0;
+		global_rsv->full = false;
 	spin_unlock(&global_rsv->lock);
 
 	btrfs_block_rsv_add_bytes(dest, num_bytes, true);
@@ -258,23 +352,29 @@ void btrfs_update_global_block_rsv(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
 	struct btrfs_space_info *sinfo = block_rsv->space_info;
-	u64 num_bytes;
-	unsigned min_items;
+	struct btrfs_root *root, *tmp;
+	u64 num_bytes = btrfs_root_used(&fs_info->tree_root->root_item);
+	unsigned int min_items = 1;
 
 	/*
 	 * The global block rsv is based on the size of the extent tree, the
 	 * checksum tree and the root tree.  If the fs is empty we want to set
 	 * it to a minimal amount for safety.
+	 *
+	 * We also are going to need to modify the minimum of the tree root and
+	 * any global roots we could touch.
 	 */
-	num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
-		btrfs_root_used(&fs_info->csum_root->root_item) +
-		btrfs_root_used(&fs_info->tree_root->root_item);
-
-	/*
-	 * We at a minimum are going to modify the csum root, the tree root, and
-	 * the extent root.
-	 */
-	min_items = 3;
+	read_lock(&fs_info->global_root_lock);
+	rbtree_postorder_for_each_entry_safe(root, tmp, &fs_info->global_root_tree,
+					     rb_node) {
+		if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID ||
+		    root->root_key.objectid == BTRFS_CSUM_TREE_OBJECTID ||
+		    root->root_key.objectid == BTRFS_FREE_SPACE_TREE_OBJECTID) {
+			num_bytes += btrfs_root_used(&root->root_item);
+			min_items++;
+		}
+	}
+	read_unlock(&fs_info->global_root_lock);
 
 	/*
 	 * But we also want to reserve enough space so we can do the fallback
@@ -297,9 +397,9 @@ void btrfs_update_global_block_rsv(struct btrfs_fs_info *fs_info)
 
 	if (block_rsv->reserved < block_rsv->size) {
 		num_bytes = block_rsv->size - block_rsv->reserved;
-		block_rsv->reserved += num_bytes;
 		btrfs_space_info_update_bytes_may_use(fs_info, sinfo,
 						      num_bytes);
+		block_rsv->reserved = block_rsv->size;
 	} else if (block_rsv->reserved > block_rsv->size) {
 		num_bytes = block_rsv->reserved - block_rsv->size;
 		btrfs_space_info_update_bytes_may_use(fs_info, sinfo,
@@ -308,15 +408,39 @@ void btrfs_update_global_block_rsv(struct btrfs_fs_info *fs_info)
 		btrfs_try_granting_tickets(fs_info, sinfo);
 	}
 
-	if (block_rsv->reserved == block_rsv->size)
-		block_rsv->full = 1;
-	else
-		block_rsv->full = 0;
+	block_rsv->full = (block_rsv->reserved == block_rsv->size);
 
+	if (block_rsv->size >= sinfo->total_bytes)
+		sinfo->force_alloc = CHUNK_ALLOC_FORCE;
 	spin_unlock(&block_rsv->lock);
 	spin_unlock(&sinfo->lock);
 }
 
+void btrfs_init_root_block_rsv(struct btrfs_root *root)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+
+	switch (root->root_key.objectid) {
+	case BTRFS_CSUM_TREE_OBJECTID:
+	case BTRFS_EXTENT_TREE_OBJECTID:
+	case BTRFS_FREE_SPACE_TREE_OBJECTID:
+	case BTRFS_BLOCK_GROUP_TREE_OBJECTID:
+		root->block_rsv = &fs_info->delayed_refs_rsv;
+		break;
+	case BTRFS_ROOT_TREE_OBJECTID:
+	case BTRFS_DEV_TREE_OBJECTID:
+	case BTRFS_QUOTA_TREE_OBJECTID:
+		root->block_rsv = &fs_info->global_block_rsv;
+		break;
+	case BTRFS_CHUNK_TREE_OBJECTID:
+		root->block_rsv = &fs_info->chunk_block_rsv;
+		break;
+	default:
+		root->block_rsv = NULL;
+		break;
+	}
+}
+
 void btrfs_init_global_block_rsv(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_space_info *space_info;
@@ -331,20 +455,13 @@ void btrfs_init_global_block_rsv(struct btrfs_fs_info *fs_info)
 	fs_info->delayed_block_rsv.space_info = space_info;
 	fs_info->delayed_refs_rsv.space_info = space_info;
 
-	fs_info->extent_root->block_rsv = &fs_info->delayed_refs_rsv;
-	fs_info->csum_root->block_rsv = &fs_info->delayed_refs_rsv;
-	fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
-	fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
-	if (fs_info->quota_root)
-		fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
-	fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
-
 	btrfs_update_global_block_rsv(fs_info);
 }
 
 void btrfs_release_global_block_rsv(struct btrfs_fs_info *fs_info)
 {
-	btrfs_block_rsv_release(fs_info, &fs_info->global_block_rsv, (u64)-1);
+	btrfs_block_rsv_release(fs_info, &fs_info->global_block_rsv, (u64)-1,
+				NULL);
 	WARN_ON(fs_info->trans_block_rsv.size > 0);
 	WARN_ON(fs_info->trans_block_rsv.reserved > 0);
 	WARN_ON(fs_info->chunk_block_rsv.size > 0);
@@ -362,9 +479,10 @@ static struct btrfs_block_rsv *get_block_rsv(
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_block_rsv *block_rsv = NULL;
 
-	if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
-	    (root == fs_info->csum_root && trans->adding_csums) ||
-	    (root == fs_info->uuid_root))
+	if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
+	    (root == fs_info->uuid_root) ||
+	    (trans->adding_csums &&
+	     root->root_key.objectid == BTRFS_CSUM_TREE_OBJECTID))
 		block_rsv = trans->block_rsv;
 
 	if (!block_rsv)
@@ -415,10 +533,11 @@ again:
 				/*DEFAULT_RATELIMIT_BURST*/ 1);
 		if (__ratelimit(&_rs))
 			WARN(1, KERN_DEBUG
-				"BTRFS: block rsv returned %d\n", ret);
+				"BTRFS: block rsv %d returned %d\n",
+				block_rsv->type, ret);
 	}
 try_reserve:
-	ret = btrfs_reserve_metadata_bytes(root, block_rsv, blocksize,
+	ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, blocksize,
 					   BTRFS_RESERVE_NO_FLUSH);
 	if (!ret)
 		return block_rsv;