linux/fs/ext3
Takashi Sato c4be0c1dc4 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>
2009-01-09 16:54:42 -08:00
..
acl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
acl.h [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
balloc.c CRED: Wrap task credential accesses in the Ext3 filesystem 2008-11-14 10:38:51 +11:00
bitmap.c fs: mark nibblemap const 2007-10-17 08:42:47 -07:00
dir.c ext3: Fix duplicate entries returned from getdents() system call 2008-10-25 22:37:44 -04:00
ext3_jbd.c ext3: replace remaining __FUNCTION__ occurrences 2008-04-28 08:58:45 -07:00
file.c generic block based fiemap implementation 2008-10-03 17:32:43 -04:00
fsync.c ext3: fdatasync should skip metadata writeout when overwriting 2008-04-28 08:58:43 -07:00
hash.c ext3: Add support for non-native signed/unsigned htree hash algorithms 2008-10-28 13:21:55 -04:00
ialloc.c ext3: tighten restrictions on inode flags 2009-01-08 08:31:01 -08:00
inode.c fs: symlink write_begin allocation context fix 2009-01-04 13:33:20 -08:00
ioctl.c ext3: tighten restrictions on inode flags 2009-01-08 08:31:01 -08:00
Kconfig fs/Kconfig: move ext2, ext3, ext4, JBD, JBD2 out 2008-10-20 11:43:59 -07:00
Makefile [PATCH] ext3: uninline large functions 2006-12-07 08:39:35 -08:00
namei.c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2009-01-08 17:14:59 -08:00
namei.h
resize.c ext3: don't try to resize if there are no reserved gdt blocks left 2008-10-20 08:52:37 -07:00
super.c filesystem freeze: add error handling of write_super_lockfs/unlockfs 2009-01-09 16:54:42 -08:00
symlink.c [PATCH] mark struct inode_operations const 1 2007-02-12 09:48:46 -08:00
xattr_security.c ext3: remove double definitions of xattr macros 2008-07-25 10:53:32 -07:00
xattr_trusted.c ext3: remove double definitions of xattr macros 2008-07-25 10:53:32 -07:00
xattr_user.c ext3: remove double definitions of xattr macros 2008-07-25 10:53:32 -07:00
xattr.c ext3/4: fix uninitialized bs in ext3/4_xattr_set_handle() 2008-05-14 19:11:14 -07:00
xattr.h make ext3_xattr_list() static 2008-04-28 08:58:44 -07:00