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btrfs: handle ENOMEM in btrfs_alloc_tree_block

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This is one of the first places to give out when memory is tight. Handle
it properly rather than with a BUG_ON.

Also fix the comment about the return value, which is an ERR_PTR, not
NULL, on error.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Omar Sandoval 2015-02-24 02:47:04 -08:00 committed by Chris Mason
parent 1b98450816
commit 67b7859e9b
1 changed files with 28 additions and 13 deletions
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41
fs/btrfs/extent-tree.c
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@ -7546,7 +7546,7 @@ static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
* returns the key for the extent through ins, and a tree buffer for
* the first block of the extent through buf.
*
* returns the tree buffer or NULL.
* returns the tree buffer or an ERR_PTR on error.
*/
struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
@ -7557,6 +7557,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_key ins;
struct btrfs_block_rsv *block_rsv;
struct extent_buffer *buf;
struct btrfs_delayed_extent_op *extent_op;
u64 flags = 0;
int ret;
u32 blocksize = root->nodesize;
@ -7577,13 +7578,14 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
ret = btrfs_reserve_extent(root, blocksize, blocksize,
empty_size, hint, &ins, 0, 0);
if (ret) {
unuse_block_rsv(root->fs_info, block_rsv, blocksize);
return ERR_PTR(ret);
}
if (ret)
goto out_unuse;
buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
BUG_ON(IS_ERR(buf)); /* -ENOMEM */
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto out_free_reserved;
}
if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
if (parent == 0)
@ -7593,9 +7595,11 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
BUG_ON(parent > 0);
if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
struct btrfs_delayed_extent_op *extent_op;
extent_op = btrfs_alloc_delayed_extent_op();
BUG_ON(!extent_op); /* -ENOMEM */
if (!extent_op) {
ret = -ENOMEM;
goto out_free_buf;
}
if (key)
memcpy(&extent_op->key, key, sizeof(extent_op->key));
else
@ -7610,13 +7614,24 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
extent_op->level = level;
ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
ins.objectid,
ins.offset, parent, root_objectid,
level, BTRFS_ADD_DELAYED_EXTENT,
extent_op, 0);
BUG_ON(ret); /* -ENOMEM */
ins.objectid, ins.offset,
parent, root_objectid, level,
BTRFS_ADD_DELAYED_EXTENT,
extent_op, 0);
if (ret)
goto out_free_delayed;
}
return buf;
out_free_delayed:
btrfs_free_delayed_extent_op(extent_op);
out_free_buf:
free_extent_buffer(buf);
out_free_reserved:
btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
out_unuse:
unuse_block_rsv(root->fs_info, block_rsv, blocksize);
return ERR_PTR(ret);
}
struct walk_control {