diff options
Diffstat (limited to 'fs/xfs/xfs_iomap.c')
| -rw-r--r-- | fs/xfs/xfs_iomap.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 344557eef928..9072794e3a42 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -389,8 +389,15 @@ xfs_iomap_prealloc_size( if (!alloc_blocks) goto check_writeio; - alloc_blocks = XFS_FILEOFF_MIN(MAXEXTLEN, - rounddown_pow_of_two(alloc_blocks)); + /* + * MAXEXTLEN is not a power of two value but we round the prealloc down + * to the nearest power of two value after throttling. To prevent the + * round down from unconditionally reducing the maximum supported prealloc + * size, we round up first, apply appropriate throttling, round down and + * cap the value to MAXEXTLEN. + */ + alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(MAXEXTLEN), + alloc_blocks); xfs_icsb_sync_counters(mp, XFS_ICSB_LAZY_COUNT); freesp = mp->m_sb.sb_fdblocks; @@ -407,6 +414,14 @@ xfs_iomap_prealloc_size( } if (shift) alloc_blocks >>= shift; + /* + * rounddown_pow_of_two() returns an undefined result if we pass in + * alloc_blocks = 0. + */ + if (alloc_blocks) + alloc_blocks = rounddown_pow_of_two(alloc_blocks); + if (alloc_blocks > MAXEXTLEN) + alloc_blocks = MAXEXTLEN; /* * If we are still trying to allocate more space than is |