linux_dsm_epyc7002/Documentation/filesystems
Eric Sandeen cf7eff4666 ext3: allow specifying external journal by pathname mount option
It's always been a hassle that if an external journal's
device number changes, the filesystem won't mount.
And since boot-time enumeration can change, device number
changes aren't unusual.

The current mechanism to update the journal location is by
passing in a mount option w/ a new devnum, but that's a hassle;
it's a manual approach, fixing things after the fact.

Adding a mount option, "-o journal_path=/dev/$DEVICE" would
help, since then we can do i.e.

# mount -o journal_path=/dev/disk/by-label/$JOURNAL_LABEL ...

and it'll mount even if the devnum has changed, as shown here:

# losetup /dev/loop0 journalfile
# mke2fs -L mylabel-journal -O journal_dev /dev/loop0
# mkfs.ext3 -L mylabel -J device=/dev/loop0 /dev/sdb1

Change the journal device number:

# losetup -d /dev/loop0
# losetup /dev/loop1 journalfile

And today it will fail:

# mount /dev/sdb1 /mnt/test
mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

# dmesg | tail -n 1
[17343.240702] EXT3-fs (sdb1): error: couldn't read superblock of external journal

But with this new mount option, we can specify the new path:

# mount -o journal_path=/dev/loop1 /dev/sdb1 /mnt/test
#

(which does update the encoded device number, incidentally):

# umount /dev/sdb1
# dumpe2fs -h /dev/sdb1 | grep "Journal device"
dumpe2fs 1.41.12 (17-May-2010)
Journal device:	          0x0701

But best of all we can just always mount by journal-path, and
it'll always work:

# mount -o journal_path=/dev/disk/by-label/mylabel-journal /dev/sdb1 /mnt/test
#

So the journal_path option can be specified in fstab, and as long as
the disk is available somewhere, and findable by label (or by UUID),
we can mount.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2013-07-31 22:11:15 +02:00
..
caching FS-Cache: Provide proper invalidation 2012-12-20 22:04:07 +00:00
configfs configfs: convert to umode_t 2012-01-03 22:54:57 -05:00
nfs SUNRPC: Use gssproxy upcall for server RPCGSS authentication. 2013-04-26 11:41:28 -04:00
pohmelfs Documentation: Fix multiple typo in Documentation 2012-03-07 16:08:24 +01:00
9p.txt 9p: fix 9p.txt to advertise msize instead of maxdata 2011-10-24 11:13:12 -05:00
00-INDEX Introduce a new file system, Flash-Friendly File System (F2FS), to Linux 3.8. 2012-12-20 13:54:52 -08:00
adfs.txt adfs: add hexadecimal filetype suffix option 2011-03-22 17:44:17 -07:00
affs.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
afs.txt AFS: Documentation updates 2009-08-19 10:40:13 -07:00
autofs4-mount-control.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
automount-support.txt
befs.txt Documentation: befs.txt: no maintainer, orphaned 2011-08-13 18:34:03 -07:00
bfs.txt
btrfs.txt btrfs: document mount options in Documentation/fs/btrfs.txt 2013-05-06 15:54:26 -04:00
ceph.txt ceph: enable/disable dentry complete flags via mount option 2012-01-12 11:00:40 -08:00
cifs.txt
coda.txt
cramfs.txt
debugfs.txt debugfs: more tightly restrict default mount mode 2012-08-27 13:42:02 -07:00
devpts.txt Document usage of multiple-instances of devpts 2009-01-02 10:19:36 -08:00
directory-locking
dlmfs.txt Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
dnotify_test.c Documentation/fs/: split txt and source files 2010-03-12 15:52:35 -08:00
dnotify.txt Documentation/fs/: split txt and source files 2010-03-12 15:52:35 -08:00
ecryptfs.txt
efivarfs.txt efivarfs: Add documentation for the EFI variable filesystem 2012-10-30 10:39:18 +00:00
exofs.txt exofs: Add option to mount by osdname 2011-03-15 15:02:51 +02:00
ext2.txt Doc fix: ext2 can only have 32,000 subdirs, not 32,768 2009-06-18 13:03:44 -07:00
ext3.txt ext3: allow specifying external journal by pathname mount option 2013-07-31 22:11:15 +02:00
ext4.txt ext4: introduce reserved space 2013-04-09 22:11:22 -04:00
f2fs.txt f2fs: add remount_fs callback support 2013-06-17 21:17:55 +09:00
fiemap.txt Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
files.txt Wrap accesses to the fd_sets in struct fdtable 2012-02-19 10:30:52 -08:00
fuse.txt Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
gfs2-glocks.txt GFS2: Update glock doc to add new stats info 2012-05-10 12:41:40 +01:00
gfs2-uevents.txt Documentation: Fix multiple typo in Documentation 2012-03-07 16:08:24 +01:00
gfs2.txt GFS2: Update main gfs2 doc 2012-05-10 11:45:31 +01:00
hfs.txt Documentation: HFS is orphaned 2011-11-04 12:01:48 -07:00
hfsplus.txt
hpfs.txt Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
inotify.txt Documentation: fix inotify source file paths 2011-11-04 12:01:47 -07:00
isofs.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
jfs.txt doc: fix misspellings with 'codespell' tool 2013-05-28 12:02:12 +02:00
Locking Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-07-03 09:10:19 -07:00
locks.txt doc: fix broken references 2011-09-27 18:08:04 +02:00
logfs.txt fix "seperate" typos in comments 2010-05-10 11:56:30 +02:00
Makefile Documentation/fs/: split txt and source files 2010-03-12 15:52:35 -08:00
mandatory-locking.txt
ncpfs.txt ncpfs: remove dead URL from documentation 2009-09-23 07:39:42 -07:00
nilfs2.txt nilfs2: remove resize from unsupported features list 2011-07-13 16:08:59 +09:00
ntfs.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
ocfs2.txt ocfs2: clean up mount option about atime in ocfs2.txt 2011-05-23 23:37:12 -07:00
omfs.txt
path-lookup.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
porting [readdir] ->readdir() is gone 2013-06-29 12:57:04 +04:00
proc.txt mm: soft-dirty bits for user memory changes tracking 2013-07-03 16:07:26 -07:00
qnx6.txt doc: fix misspellings with 'codespell' tool 2013-05-28 12:02:12 +02:00
quota.txt
ramfs-rootfs-initramfs.txt Documentation: Fix Broken URL "freshmeat" 2012-02-21 11:43:45 +01:00
relay.txt
romfs.txt Documentation/filesystems/romfs.txt: fixing link to genromfs 2011-02-17 22:04:46 +01:00
seq_file.txt seq_file: use proc_create() in documentation 2009-12-16 07:20:07 -08:00
sharedsubtree.txt Documentation: Fix trivial typo in filesystems/sharedsubtree.txt 2010-10-25 21:18:21 -04:00
spufs.txt
squashfs.txt Squashfs: Update documentation to include xattrs 2011-12-30 01:20:24 +00:00
sysfs-pci.txt PCI: Allow read/write access to sysfs I/O port resources 2010-07-30 09:32:08 -07:00
sysfs-tagging.txt sysfs-namespaces: add a high-level Documentation file 2010-05-21 09:37:31 -07:00
sysfs.txt sysfs: propagate umode_t 2012-01-03 22:55:03 -05:00
sysv-fs.txt
tmpfs.txt mempolicy: document cpuset interaction with tmpfs mpol mount option 2010-05-25 08:06:57 -07:00
ubifs.txt UBIFS: switch self-check knobs to debugfs 2011-07-04 10:54:28 +03:00
udf.txt udf: implement mode and dmode mounting options 2009-04-02 12:29:50 +02:00
ufs.txt
vfat.txt doc: fix misspellings with 'codespell' tool 2013-05-28 12:02:12 +02:00
vfs.txt documentation: document the is_dirty_writeback aops callback 2013-07-03 16:07:40 -07:00
xfs-delayed-logging-design.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
xfs-self-describing-metadata.txt xfs: add metadata CRC documentation 2013-04-27 13:27:43 -05:00
xfs.txt xfs: update mount options documentation 2013-07-09 16:26:18 -05:00
xip.txt DOC: update xip method info 2008-11-12 17:17:17 -08:00