[XFS] Make hole punching at EOF atomic.
If hole punching at EOF is done as two steps (i.e. truncate then extend)
the file is in a transient state between the two steps where an
application can see the incorrect file size. Punching a hole to EOF needs
to be treated in teh same way as all other hole punching cases so that the
file size is never seen to change.
SGI-PV: 962012
SGI-Modid: xfs-linux-melb:xfs-kern:28641a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Vlad Apostolov <vapo@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 70bc82f..6420ca8 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -1201,13 +1201,15 @@
}
/*
- * This is called by xfs_inactive to free any blocks beyond eof,
- * when the link count isn't zero.
+ * This is called by xfs_inactive to free any blocks beyond eof
+ * when the link count isn't zero and by xfs_dm_punch_hole() when
+ * punching a hole to EOF.
*/
-STATIC int
-xfs_inactive_free_eofblocks(
+int
+xfs_free_eofblocks(
xfs_mount_t *mp,
- xfs_inode_t *ip)
+ xfs_inode_t *ip,
+ int flags)
{
xfs_trans_t *tp;
int error;
@@ -1216,6 +1218,7 @@
xfs_filblks_t map_len;
int nimaps;
xfs_bmbt_irec_t imap;
+ int use_iolock = (flags & XFS_FREE_EOF_LOCK);
/*
* Figure out if there are any blocks beyond the end
@@ -1256,11 +1259,13 @@
* cache and we can't
* do that within a transaction.
*/
- xfs_ilock(ip, XFS_IOLOCK_EXCL);
+ if (use_iolock)
+ xfs_ilock(ip, XFS_IOLOCK_EXCL);
error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE,
ip->i_size);
if (error) {
- xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+ if (use_iolock)
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
return error;
}
@@ -1297,7 +1302,8 @@
error = xfs_trans_commit(tp,
XFS_TRANS_RELEASE_LOG_RES);
}
- xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
+ xfs_iunlock(ip, (use_iolock ? (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)
+ : XFS_ILOCK_EXCL));
}
return error;
}
@@ -1573,7 +1579,8 @@
(ip->i_df.if_flags & XFS_IFEXTENTS)) &&
(!(ip->i_d.di_flags &
(XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))) {
- if ((error = xfs_inactive_free_eofblocks(mp, ip)))
+ error = xfs_free_eofblocks(mp, ip, XFS_FREE_EOF_LOCK);
+ if (error)
return error;
/* Update linux inode block count after free above */
vn_to_inode(vp)->i_blocks = XFS_FSB_TO_BB(mp,
@@ -1654,7 +1661,8 @@
(!(ip->i_d.di_flags &
(XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)) ||
(ip->i_delayed_blks != 0)))) {
- if ((error = xfs_inactive_free_eofblocks(mp, ip)))
+ error = xfs_free_eofblocks(mp, ip, XFS_FREE_EOF_LOCK);
+ if (error)
return VN_INACTIVE_CACHE;
/* Update linux inode block count after free above */
vn_to_inode(vp)->i_blocks = XFS_FSB_TO_BB(mp,
