Hi Nick,
On Mon, Mar 30, 2009 at 01:33:54PM +0200, Nick Piggin wrote:
>
> fs: invalidate sb->s_bdev on remount,ro
>
> Fixes a problem reported by "Jorge Boncompte [DTI2]" <jorge@xxxxxxxx>
> who is trying to snapshot a minix filesystem image.
>
> Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
>
> ---
> fs/super.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> Index: linux-2.6/fs/super.c
> ===================================================================
> --- linux-2.6.orig/fs/super.c
> +++ linux-2.6/fs/super.c
> @@ -647,6 +647,14 @@ int do_remount_sb(struct super_block *sb
> acct_auto_close(sb);
> shrink_dcache_sb(sb);
Not a question to this patch: can we avoid shrink_dcache_sb() on
ro=>rw remounts? They will happen at system boot time, and eliminating
the shrink_dcache_sb() could help reduce the boot time.
> fsync_super(sb);
> + /* Some filesystems modify their metadata via some other path
> + than the bdev buffer cache (eg. use a private mapping, or
> + directories in pagecache, etc). Also file data modifications
> + go via their own mappings. So If we try to mount readonly
> + then copy the filesystem from bdev, we could get stale data,
> + so invalidate it to give a best effort at coherency. */
> + if (flags & MS_RDONLY && sb->s_bdev)
> + invalidate_bdev(sb->s_bdev);
Or move the above lines to...
> /* If we are remounting RDONLY and current sb is read/write,
> make sure there are no rw files opened */
if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
if (force)
mark_files_ro(sb);
else if (!fs_may_remount_ro(sb))
return -EBUSY;
retval = vfs_dq_off(sb, 1);
if (retval < 0 && retval != -ENOSYS)
return -EBUSY;
}
...here?
Thanks,
Fengguang
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