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authorBrian Foster <bfoster@redhat.com>2014-07-24 19:49:28 +1000
committerDave Chinner <david@fromorbit.com>2014-07-24 19:49:28 +1000
commitdc06f398f00059707236d456d954a3a9d2a829db (patch)
treeb7d0f9a2d9a109a32e6b72af3909b9465b406c23 /fs/xfs/xfs_icache.h
parentf4526397928fff052f795713748f376a2bba1b5e (diff)
downloadlinux-dc06f398f00059707236d456d954a3a9d2a829db.tar.bz2
xfs: run an eofblocks scan on ENOSPC/EDQUOT
From: Brian Foster <bfoster@redhat.com> Speculative preallocation and and the associated throttling metrics assume we're working with large files on large filesystems. Users have reported inefficiencies in these mechanisms when we happen to be dealing with large files on smaller filesystems. This can occur because while prealloc throttling is aggressive under low free space conditions, it is not active until we reach 5% free space or less. For example, a 40GB filesystem has enough space for several files large enough to have multi-GB preallocations at any given time. If those files are slow growing, they might reserve preallocation for long periods of time as well as avoid the background scanner due to frequent modification. If a new file is written under these conditions, said file has no access to this already reserved space and premature ENOSPC is imminent. To handle this scenario, modify the buffered write ENOSPC handling and retry sequence to invoke an eofblocks scan. In the smaller filesystem scenario, the eofblocks scan resets the usage of preallocation such that when the 5% free space threshold is met, throttling effectively takes over to provide fair and efficient preallocation until legitimate ENOSPC. The eofblocks scan is selective based on the nature of the failure. For example, an EDQUOT failure in a particular quota will use a filtered scan for that quota. Because we don't know which quota might have caused an allocation failure at any given time, we include each applicable quota determined to be under low free space conditions in the scan. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/xfs_icache.h')
-rw-r--r--fs/xfs/xfs_icache.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/xfs/xfs_icache.h b/fs/xfs/xfs_icache.h
index 98687af6a99d..46748b86b12f 100644
--- a/fs/xfs/xfs_icache.h
+++ b/fs/xfs/xfs_icache.h
@@ -58,6 +58,7 @@ void xfs_inode_set_reclaim_tag(struct xfs_inode *ip);
void xfs_inode_set_eofblocks_tag(struct xfs_inode *ip);
void xfs_inode_clear_eofblocks_tag(struct xfs_inode *ip);
int xfs_icache_free_eofblocks(struct xfs_mount *, struct xfs_eofblocks *);
+int xfs_inode_free_quota_eofblocks(struct xfs_inode *ip);
void xfs_eofblocks_worker(struct work_struct *);
int xfs_inode_ag_iterator(struct xfs_mount *mp,