diff options
| author | Brian Foster <bfoster@redhat.com> | 2013-03-18 10:51:44 -0400 |
|---|---|---|
| committer | Ben Myers <bpm@sgi.com> | 2013-03-22 16:05:00 -0500 |
| commit | c9bdbdc0741d90908f492415c890b630f43f17f8 (patch) | |
| tree | cf8bf3498ad3b724adcd3b609947e8d88cfed0f7 /fs/xfs/xfs_iomap.c | |
| parent | 3c58b5f809eda8ae8d891b7a87d0a235ab0f9bf5 (diff) | |
xfs: push rounddown_pow_of_two() to after prealloc throttle
The round down occurs towards the beginning of the function. Push
it down after throttling has occurred. This is to support adding
further transformations to 'alloc_blocks' that might not preserve
power-of-two alignment (and thus could lead to rounding down
multiple times).
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
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 344557eef92..9072794e3a4 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 |