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authorTakashi Sato <t-sato@yk.jp.nec.com>2009-01-09 19:40:58 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-09 19:54:42 -0500
commitc4be0c1dc4cdc37b175579be1460f15ac6495e9a (patch)
tree716ea88318211ed27cadcebda0fd85c1f8246edb /fs/xfs/xfs_fsops.h
parent69347a236b22c3962ea812511495e502dedfd50c (diff)
filesystem freeze: add error handling of write_super_lockfs/unlockfs
Currently, ext3 in mainline Linux doesn't have the freeze feature which suspends write requests. So, we cannot take a backup which keeps the filesystem's consistency with the storage device's features (snapshot and replication) while it is mounted. In many case, a commercial filesystem (e.g. VxFS) has the freeze feature and it would be used to get the consistent backup. If Linux's standard filesystem ext3 has the freeze feature, we can do it without a commercial filesystem. So I have implemented the ioctls of the freeze feature. I think we can take the consistent backup with the following steps. 1. Freeze the filesystem with the freeze ioctl. 2. Separate the replication volume or create the snapshot with the storage device's feature. 3. Unfreeze the filesystem with the unfreeze ioctl. 4. Take the backup from the separated replication volume or the snapshot. This patch: VFS: Changed the type of write_super_lockfs and unlockfs from "void" to "int" so that they can return an error. Rename write_super_lockfs and unlockfs of the super block operation freeze_fs and unfreeze_fs to avoid a confusion. ext3, ext4, xfs, gfs2, jfs: Changed the type of write_super_lockfs and unlockfs from "void" to "int" so that write_super_lockfs returns an error if needed, and unlockfs always returns 0. reiserfs: Changed the type of write_super_lockfs and unlockfs from "void" to "int" so that they always return 0 (success) to keep a current behavior. Signed-off-by: Takashi Sato <t-sato@yk.jp.nec.com> Signed-off-by: Masayuki Hamaguchi <m-hamaguchi@ys.jp.nec.com> Cc: <xfs-masters@oss.sgi.com> Cc: <linux-ext4@vger.kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/xfs/xfs_fsops.h')
-rw-r--r--fs/xfs/xfs_fsops.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
index 300d0c9d61ad..88435e0a77c9 100644
--- a/fs/xfs/xfs_fsops.h
+++ b/fs/xfs/xfs_fsops.h
@@ -25,6 +25,6 @@ extern int xfs_fs_counts(xfs_mount_t *mp, xfs_fsop_counts_t *cnt);
25extern int xfs_reserve_blocks(xfs_mount_t *mp, __uint64_t *inval, 25extern int xfs_reserve_blocks(xfs_mount_t *mp, __uint64_t *inval,
26 xfs_fsop_resblks_t *outval); 26 xfs_fsop_resblks_t *outval);
27extern int xfs_fs_goingdown(xfs_mount_t *mp, __uint32_t inflags); 27extern int xfs_fs_goingdown(xfs_mount_t *mp, __uint32_t inflags);
28extern void xfs_fs_log_dummy(xfs_mount_t *mp); 28extern int xfs_fs_log_dummy(xfs_mount_t *mp);
29 29
30#endif /* __XFS_FSOPS_H__ */ 30#endif /* __XFS_FSOPS_H__ */