diff options
| author | Andrew Morton <akpm@zip.com.au> | 2002-05-27 05:13:29 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@home.transmeta.com> | 2002-05-27 05:13:29 -0700 |
| commit | bb772c58ab8542b34162f356faac2ed18fb7afe4 (patch) | |
| tree | cba428387bc8268d704ee4fea4fff9f8418e2c2c /include/linux/ext3_fs.h | |
| parent | 7d608fac351b06ae0192bba9e116a965c2f35c5d (diff) | |
[PATCH] dirsync
An implementation of directory-synchronous mounts.
I sent this out some months ago and it didn't generate a lot of
interest. Later we had one of the usual cheery exchanges with Wietse
Venema (postfix development) and he agreed that directory synchronous
mounts were something that he could use, and that there was benefit in
implementing them in Linux. If you choose to apply this I'll push the
2.4 patch.
Patch against e2fsprogs-1.26:
http://www.zip.com.au/~akpm/linux/dirsync/e2fsprogs-1.26.patch
Patch against util-linux-2.11n:
http://www.zip.com.au/~akpm/linux/dirsync/util-linux-2.11n.patch
The kernel patch includes implementations for ext2 and ext3. It's
pretty simple.
- When dirsync is in operation against a directory, the following operations
are synchronous within that directory: create, link, unlink, symlink,
mkdir, rmdir, mknod, rename (synchronous if either the source or dest
directory is dirsync).
- dirsync is a subset of sync. So `mount -o sync' or `chattr +S'
give you everything which `mount -o dirsync' or `chattr +D' gives,
plus synchronous file writes.
- ext2's inode.i_attr_flags is unused, and is removed.
- mount /dev/foo /mnt/bar -o dirsync works as expected.
- An ext2 or ext3 directory tree can be set dirsync with `chattr +D -R'.
- dirsync is maintained as new directories are created under
a `chattr +D' directory. Like `chattr +S'.
- Other filesystems can trivially be taught about dirsync. It's just
a matter of replacing `IS_SYNC(inode)' with `IS_DIRSYNC(inode)' in
the directory update functions. IS_SYNC will still be honoured when
IS_DIRSYNC is used.
- Non-directory files do not have their dirsync flag propagated. So
an S_ISREG file which is created inside a dirsync directory will not
have its dirsync bit set. chattr needs to do this as well.
- There was a bit of version skew between e2fsprogs' idea of the
inode flags and the kernel's. That is sorted out here.
- `lsattr' shows the dirsync flag as "D". The letter "D" was
previously being used for Compressed_Dirty_File. I changed
Compressed_Dirty_File to use "Z". Is that OK?
The mount(2) manpage needs to be taught about MS_DIRSYNC.
Diffstat (limited to 'include/linux/ext3_fs.h')
| -rw-r--r-- | include/linux/ext3_fs.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/ext3_fs.h b/include/linux/ext3_fs.h index 14a44ec2534d..f8630de86518 100644 --- a/include/linux/ext3_fs.h +++ b/include/linux/ext3_fs.h @@ -203,10 +203,12 @@ struct ext3_group_desc #define EXT3_INDEX_FL 0x00001000 /* hash-indexed directory */ #define EXT3_IMAGIC_FL 0x00002000 /* AFS directory */ #define EXT3_JOURNAL_DATA_FL 0x00004000 /* file data should be journaled */ +#define EXT3_NOTAIL_FL 0x00008000 /* file tail should not be merged */ +#define EXT3_DIRSYNC_FL 0x00010000 /* dirsync behaviour (directories only) */ #define EXT3_RESERVED_FL 0x80000000 /* reserved for ext3 lib */ -#define EXT3_FL_USER_VISIBLE 0x00005FFF /* User visible flags */ -#define EXT3_FL_USER_MODIFIABLE 0x000000FF /* User modifiable flags */ +#define EXT3_FL_USER_VISIBLE 0x00015FFF /* User visible flags */ +#define EXT3_FL_USER_MODIFIABLE 0x000100FF /* User modifiable flags */ /* * Inode dynamic state flags |