I recently did some ENOSPC testing that involved filling the disk
while create and removing snapshots in a loop. During the test cycle,
I ran into an ENOSPC when trying to remove a snapshot, leaving the fs
stuck in ENOSPC even after a umount/mount cycle.
This patch allow subvolume removal to fall back onto the global
block reservation in order to succeed when it would have failed
otherwise.
Signed-off-by: Jeff Mahoney <je...@suse.com>
---
fs/btrfs/ctree.h | 2 +-
fs/btrfs/extent-tree.c | 8 +++++++-
fs/btrfs/ioctl.c | 7 ++++---
3 files changed, 12 insertions(+), 5 deletions(-)
--- a/fs/btrfs/ctree.h 2013-07-09 13:29:35.396801859 -0400
+++ b/fs/btrfs/ctree.h 2013-07-09 14:38:04.132071707 -0400
@@ -3186,7 +3186,7 @@ void btrfs_orphan_release_metadata(struc
int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
struct btrfs_block_rsv *rsv,
int nitems,
- u64 *qgroup_reserved);
+ u64 *qgroup_reserved, bool use_global_rsv);
void btrfs_subvolume_release_metadata(struct btrfs_root *root,
struct btrfs_block_rsv *rsv,
u64 qgroup_reserved);
--- a/fs/btrfs/extent-tree.c 2013-07-09 13:45:53.226342333 -0400
+++ b/fs/btrfs/extent-tree.c 2013-07-09 15:24:09.639950458 -0400
@@ -4735,10 +4735,12 @@ void btrfs_orphan_release_metadata(struc
int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
struct btrfs_block_rsv *rsv,
int items,
- u64 *qgroup_reserved)
+ u64 *qgroup_reserved,
+ bool use_global_rsv)
{
u64 num_bytes;
int ret;
+ struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
if (root->fs_info->quota_enabled) {
/* One for parent inode, two for dir entries */
@@ -4757,6 +4759,10 @@ int btrfs_subvolume_reserve_metadata(str
BTRFS_BLOCK_GROUP_METADATA);
ret = btrfs_block_rsv_add(root, rsv, num_bytes,
BTRFS_RESERVE_FLUSH_ALL);
+
+ if (ret == -ENOSPC && use_global_rsv)
+ ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
+
if (ret) {
if (*qgroup_reserved)
btrfs_qgroup_free(root, *qgroup_reserved);
--- a/fs/btrfs/ioctl.c 2013-07-09 14:37:25.828624893 -0400
+++ b/fs/btrfs/ioctl.c 2013-07-09 14:37:45.868335492 -0400
@@ -396,7 +396,7 @@ static noinline int create_subvol(struct
* of create_snapshot().
*/
ret = btrfs_subvolume_reserve_metadata(root, &block_rsv,
- 7, &qgroup_reserved);
+ 7, &qgroup_reserved, false);
if (ret)
return ret;
@@ -576,7 +576,8 @@ static int create_snapshot(struct btrfs_
*/
ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root,
&pending_snapshot->block_rsv, 7,
- &pending_snapshot->qgroup_reserved);
+ &pending_snapshot->qgroup_reserved,
+ false);
if (ret)
goto out;
@@ -2174,7 +2175,7 @@ static noinline int btrfs_ioctl_snap_des
* ref/backref.
*/
err = btrfs_subvolume_reserve_metadata(root, &block_rsv,
- 5, &qgroup_reserved);
+ 5, &qgroup_reserved, true);
if (err)
goto out_up_write;
--
Jeff Mahoney
SUSE Labs
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