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xfs: don't be so eager to clear the cowblocks tag on truncate 

Currently, xfs_itruncate_extents clears the cowblocks tag if i_cnextents
is zero.  This is wrong, since i_cnextents only tracks real extents in
the CoW fork, which means that we could have some delayed CoW
reservations still in there that will now never get cleaned.

Fix a further bug where we /don't/ clear the reflink iflag if there are
any attribute blocks -- really, it's only safe to clear the reflink flag
if there are no data fork extents and no cow fork extents.

Found by adding clonerange to fsstress in xfs/017.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong 2017-12-14 15:42:59 -08:00
parent 91aae6be41
commit 363e59baa4
1 changed files with 19 additions and 9 deletions
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28
fs/xfs/xfs_inode.c
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@ -1487,6 +1487,24 @@ xfs_link(
return error;
}
/* Clear the reflink flag and the cowblocks tag if possible. */
static void
xfs_itruncate_clear_reflink_flags(
struct xfs_inode *ip)
{
struct xfs_ifork *dfork;
struct xfs_ifork *cfork;
if (!xfs_is_reflink_inode(ip))
return;
dfork = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
cfork = XFS_IFORK_PTR(ip, XFS_COW_FORK);
if (dfork->if_bytes == 0 && cfork->if_bytes == 0)
ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
if (cfork->if_bytes == 0)
xfs_inode_clear_cowblocks_tag(ip);
}
/*
* Free up the underlying blocks past new_size. The new size must be smaller
* than the current size. This routine can be used both for the attribute and
@ -1583,15 +1601,7 @@ xfs_itruncate_extents(
if (error)
goto out;
/*
* Clear the reflink flag if there are no data fork blocks and
* there are no extents staged in the cow fork.
*/
if (xfs_is_reflink_inode(ip) && ip->i_cnextents == 0) {
if (ip->i_d.di_nblocks == 0)
ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
xfs_inode_clear_cowblocks_tag(ip);
}
xfs_itruncate_clear_reflink_flags(ip);
/*
* Always re-log the inode so that our permanent transaction can keep