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| author | Dave Chinner <dchinner@redhat.com> | 2010-11-30 05:16:02 +0100 |
|---|---|---|
| committer | Alex Elder <aelder@sgi.com> | 2010-12-01 14:40:20 +0100 |
| commit | 309c848002052edbec650075a1eb098b17c17f35 (patch) | |
| tree | 7e3e38c9ebcfa539716298c0f8a0000b45cffd8e | |
| parent | xfs: push stale, pinned buffers on trylock failures (diff) | |
| download | linux-309c848002052edbec650075a1eb098b17c17f35.tar.xz linux-309c848002052edbec650075a1eb098b17c17f35.zip | |
xfs: delayed alloc blocks beyond EOF are valid after writeback
There is an assumption in the parts of XFS that flushing a dirty
file will make all the delayed allocation blocks disappear from an
inode. That is, that after calling xfs_flush_pages() then
ip->i_delayed_blks will be zero.
This is an invalid assumption as we may have specualtive
preallocation beyond EOF and they are recorded in
ip->i_delayed_blks. A flush of the dirty pages of an inode will not
change the state of these blocks beyond EOF, so a non-zero
deeelalloc block count after a flush is valid.
The bmap code has an invalid ASSERT() that needs to be removed, and
the swapext code has a bug in that while it swaps the data forks
around, it fails to swap the i_delayed_blks counter associated with
the fork and hence can get the block accounting wrong.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | fs/xfs/xfs_bmap.c | 9 | ||||
| -rw-r--r-- | fs/xfs/xfs_dfrag.c | 13 |
2 files changed, 20 insertions, 2 deletions
diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c index 08b179fa9e8f..4111cd3966c7 100644 --- a/fs/xfs/xfs_bmap.c +++ b/fs/xfs/xfs_bmap.c @@ -5471,8 +5471,13 @@ xfs_getbmap( if (error) goto out_unlock_iolock; } - - ASSERT(ip->i_delayed_blks == 0); + /* + * even after flushing the inode, there can still be delalloc + * blocks on the inode beyond EOF due to speculative + * preallocation. These are not removed until the release + * function is called or the inode is inactivated. Hence we + * cannot assert here that ip->i_delayed_blks == 0. + */ } lock = xfs_ilock_map_shared(ip); diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c index 3b9582c60a22..e60490bc00a6 100644 --- a/fs/xfs/xfs_dfrag.c +++ b/fs/xfs/xfs_dfrag.c @@ -377,6 +377,19 @@ xfs_swap_extents( ip->i_d.di_format = tip->i_d.di_format; tip->i_d.di_format = tmp; + /* + * The extents in the source inode could still contain speculative + * preallocation beyond EOF (e.g. the file is open but not modified + * while defrag is in progress). In that case, we need to copy over the + * number of delalloc blocks the data fork in the source inode is + * tracking beyond EOF so that when the fork is truncated away when the + * temporary inode is unlinked we don't underrun the i_delayed_blks + * counter on that inode. + */ + ASSERT(tip->i_delayed_blks == 0); + tip->i_delayed_blks = ip->i_delayed_blks; + ip->i_delayed_blks = 0; + ilf_fields = XFS_ILOG_CORE; switch(ip->i_d.di_format) { |