Messages in this thread Patch in this message | | | From | Artem Bityutskiy <> | Subject | [RFC] [PATCH] vfs: remount all file-systems R/O on emergency remount. | Date | Fri, 24 Aug 2012 10:26:06 +0300 |
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From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Currently the emergency remount (triggered by Sysrq-u) re-mounting only those file-systems R/O, which have an associated block device (sb->s_bdev). This does not work for file-systems like UBIFS and JFFS2 which work on top of MTD devices (character devices) and always have sb->s_bdev = NULL.
This also does not work for tmpfs.
Most probably the intention was to avoid re-mounting R/O file-systems like procfs, sysfs, cgroup, and debugfs. However, I do not really see why not to remount them R/O as well in case of emergency.
This patch removes the 'sb->s_bdev != NULL' check from 'do_emergency_remount()', so _all_ file-systems will be re-mounted R/O.
Tested in Fedora - all file-systems (ext4, ubifs, procfs, sysfs, cgroup, and debugfs) become R/O on Sysrq-u with this patch.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> --- fs/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/super.c b/fs/super.c index 0902cfa..95cf173 100644 --- a/fs/super.c +++ b/fs/super.c @@ -812,7 +812,7 @@ static void do_emergency_remount(struct work_struct *work) sb->s_count++; spin_unlock(&sb_lock); down_write(&sb->s_umount); - if (sb->s_root && sb->s_bdev && (sb->s_flags & MS_BORN) && + if (sb->s_root && (sb->s_flags & MS_BORN) && !(sb->s_flags & MS_RDONLY)) { /* * What lock protects sb->s_flags?? -- 1.7.10.4
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