diff options
Diffstat (limited to 'fs/btrfs/scrub.c')
| -rw-r--r-- | fs/btrfs/scrub.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index e2c87220600f..bd3f2266c5f4 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -3559,7 +3559,26 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx, * -> btrfs_scrub_pause() */ scrub_pause_on(fs_info); - ret = btrfs_inc_block_group_ro(cache); + + /* + * Don't do chunk preallocation for scrub. + * + * This is especially important for SYSTEM bgs, or we can hit + * -EFBIG from btrfs_finish_chunk_alloc() like: + * 1. The only SYSTEM bg is marked RO. + * Since SYSTEM bg is small, that's pretty common. + * 2. New SYSTEM bg will be allocated + * Due to regular version will allocate new chunk. + * 3. New SYSTEM bg is empty and will get cleaned up + * Before cleanup really happens, it's marked RO again. + * 4. Empty SYSTEM bg get scrubbed + * We go back to 2. + * + * This can easily boost the amount of SYSTEM chunks if cleaner + * thread can't be triggered fast enough, and use up all space + * of btrfs_super_block::sys_chunk_array + */ + ret = btrfs_inc_block_group_ro(cache, false); if (!ret && sctx->is_dev_replace) { /* * If we are doing a device replace wait for any tasks |