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xfs: update fork seq counter on data fork changes 

The sequence counter in the xfs_ifork structure is only updated on
COW forks. This is because the counter is currently only used to
optimize out repetitive COW fork checks at writeback time.

Tweak the extent code to update the seq counter regardless of the
fork type in preparation for using this counter on data forks as
well.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Brian Foster 2019-02-01 09:14:22 -08:00 committed by Darrick J. Wong
parent d519da41e2
commit 9f9bc034b8
2 changed files with 7 additions and 8 deletions
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13
fs/xfs/libxfs/xfs_iext_tree.c
View File

@ -614,16 +614,15 @@ xfs_iext_realloc_root(
}
/*
* Increment the sequence counter if we are on a COW fork. This allows
* the writeback code to skip looking for a COW extent if the COW fork
* hasn't changed. We use WRITE_ONCE here to ensure the update to the
* sequence counter is seen before the modifications to the extent
* tree itself take effect.
* Increment the sequence counter on extent tree changes. If we are on a COW
* fork, this allows the writeback code to skip looking for a COW extent if the
* COW fork hasn't changed. We use WRITE_ONCE here to ensure the update to the
* sequence counter is seen before the modifications to the extent tree itself
* take effect.
*/
static inline void xfs_iext_inc_seq(struct xfs_ifork *ifp, int state)
{
if (state & BMAP_COWFORK)
WRITE_ONCE(ifp->if_seq, READ_ONCE(ifp->if_seq) + 1);
WRITE_ONCE(ifp->if_seq, READ_ONCE(ifp->if_seq) + 1);
}
void

2
fs/xfs/libxfs/xfs_inode_fork.h
View File

@ -14,7 +14,7 @@ struct xfs_dinode;
*/
struct xfs_ifork {
int if_bytes; /* bytes in if_u1 */
unsigned int if_seq; /* cow fork mod counter */
unsigned int if_seq; /* fork mod counter */
struct xfs_btree_block *if_broot; /* file's incore btree root */
short if_broot_bytes; /* bytes allocated for root */
unsigned char if_flags; /* per-fork flags */