diff options
| author | Filipe Manana <fdmanana@suse.com> | 2023-06-13 19:07:54 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2023-06-19 14:59:39 +0300 |
| commit | 6822b3f708608d74820cd69e76de16d42899a230 (patch) | |
| tree | a3f2289eba32fae1b402de60a05d50fa22ba1225 /fs/btrfs | |
| parent | df9f278239046719c91aeb59ec0afb1a99ee8b2b (diff) | |
| download | linux-6822b3f708608d74820cd69e76de16d42899a230.tar.xz | |
btrfs: do not BUG_ON after failure to migrate space during truncation
During truncation we reserve 2 metadata units when starting a transaction
(reserved space goes to fs_info->trans_block_rsv) and then attempt to
migrate 1 unit (min_size bytes) from fs_info->trans_block_rsv into the
local block reserve. If we ever fail we trigger a BUG_ON(), which should
never happen, because we reserved 2 units. However if we happen to fail
for some reason, we don't need to be so dire and hit a BUG_ON(), we can
just error out the truncation and, since this is highly unexpected,
surround the error check with WARN_ON(), to get an informative stack
trace and tag the branh as 'unlikely'. Also make the 'min_size' variable
const, since it's not supposed to ever change and any accidental change
could possibly make the space migration not so unlikely to fail.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/inode.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index b92c814cec97..dbbb67293e34 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8344,7 +8344,7 @@ static int btrfs_truncate(struct btrfs_inode *inode, bool skip_writeback) int ret; struct btrfs_trans_handle *trans; u64 mask = fs_info->sectorsize - 1; - u64 min_size = btrfs_calc_metadata_size(fs_info, 1); + const u64 min_size = btrfs_calc_metadata_size(fs_info, 1); if (!skip_writeback) { ret = btrfs_wait_ordered_range(&inode->vfs_inode, @@ -8401,7 +8401,15 @@ static int btrfs_truncate(struct btrfs_inode *inode, bool skip_writeback) /* Migrate the slack space for the truncate to our reserve */ ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv, min_size, false); - BUG_ON(ret); + /* + * We have reserved 2 metadata units when we started the transaction and + * min_size matches 1 unit, so this should never fail, but if it does, + * it's not critical we just fail truncation. + */ + if (WARN_ON(ret)) { + btrfs_end_transaction(trans); + goto out; + } trans->block_rsv = rsv; @@ -8449,7 +8457,14 @@ static int btrfs_truncate(struct btrfs_inode *inode, bool skip_writeback) btrfs_block_rsv_release(fs_info, rsv, -1, NULL); ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv, min_size, false); - BUG_ON(ret); /* shouldn't happen */ + /* + * We have reserved 2 metadata units when we started the + * transaction and min_size matches 1 unit, so this should never + * fail, but if it does, it's not critical we just fail truncation. + */ + if (WARN_ON(ret)) + break; + trans->block_rsv = rsv; } |