UBIFS: introduce new flags for RO mounts
Commit 2fde99cb55fb9d9b88180512a5e8a5d939d27fec "UBIFS: mark VFS SB RO too"
introduced regression. This commit made UBIFS set the 'MS_RDONLY' flag in the
VFS superblock when it switches to R/O mode due to an error. This was done
to make VFS show the R/O UBIFS flag in /proc/mounts.
However, several places in UBIFS relied on the 'MS_RDONLY' flag and assume this
flag can only change when we re-mount. For example, 'ubifs_put_super()'.
This patch introduces new UBIFS flag - 'c->ro_mount' which changes only when
we re-mount, and preserves the way UBIFS was originally mounted (R/W or R/O).
This allows us to de-initialize UBIFS cleanly in 'ubifs_put_super()'.
This patch also changes all 'ubifs_assert(!c->ro_media)' assertions to
'ubifs_assert(!c->ro_media && !c->ro_mount)', because we never should write
anything if the FS was mounter R/O.
All the places where we test for 'MS_RDONLY' flag in the VFS SB were changed
and now we test the 'c->ro_mount' flag instead, because it preserves the
original UBIFS mount type, unlike the 'MS_RDONLY' flag.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 1cfeec5..4e5bf3f 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1137,11 +1137,11 @@
*/
static int mount_ubifs(struct ubifs_info *c)
{
- struct super_block *sb = c->vfs_sb;
- int err, mounted_read_only = (sb->s_flags & MS_RDONLY);
+ int err;
long long x;
size_t sz;
+ c->ro_mount = !!(c->vfs_sb->s_flags & MS_RDONLY);
err = init_constants_early(c);
if (err)
return err;
@@ -1154,7 +1154,7 @@
if (err)
goto out_free;
- if (c->empty && (mounted_read_only || c->ro_media)) {
+ if (c->empty && (c->ro_mount || c->ro_media)) {
/*
* This UBI volume is empty, and read-only, or the file system
* is mounted read-only - we cannot format it.
@@ -1165,7 +1165,7 @@
goto out_free;
}
- if (c->ro_media && !mounted_read_only) {
+ if (c->ro_media && !c->ro_mount) {
ubifs_err("cannot mount read-write - read-only media");
err = -EROFS;
goto out_free;
@@ -1185,7 +1185,7 @@
if (!c->sbuf)
goto out_free;
- if (!mounted_read_only) {
+ if (!c->ro_mount) {
c->ileb_buf = vmalloc(c->leb_size);
if (!c->ileb_buf)
goto out_free;
@@ -1228,7 +1228,7 @@
}
sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num, c->vi.vol_id);
- if (!mounted_read_only) {
+ if (!c->ro_mount) {
err = alloc_wbufs(c);
if (err)
goto out_cbuf;
@@ -1254,12 +1254,12 @@
if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
ubifs_msg("recovery needed");
c->need_recovery = 1;
- if (!mounted_read_only) {
+ if (!c->ro_mount) {
err = ubifs_recover_inl_heads(c, c->sbuf);
if (err)
goto out_master;
}
- } else if (!mounted_read_only) {
+ } else if (!c->ro_mount) {
/*
* Set the "dirty" flag so that if we reboot uncleanly we
* will notice this immediately on the next mount.
@@ -1270,7 +1270,7 @@
goto out_master;
}
- err = ubifs_lpt_init(c, 1, !mounted_read_only);
+ err = ubifs_lpt_init(c, 1, !c->ro_mount);
if (err)
goto out_lpt;
@@ -1285,11 +1285,11 @@
/* Calculate 'min_idx_lebs' after journal replay */
c->min_idx_lebs = ubifs_calc_min_idx_lebs(c);
- err = ubifs_mount_orphans(c, c->need_recovery, mounted_read_only);
+ err = ubifs_mount_orphans(c, c->need_recovery, c->ro_mount);
if (err)
goto out_orphans;
- if (!mounted_read_only) {
+ if (!c->ro_mount) {
int lnum;
err = check_free_space(c);
@@ -1351,7 +1351,7 @@
spin_unlock(&ubifs_infos_lock);
if (c->need_recovery) {
- if (mounted_read_only)
+ if (c->ro_mount)
ubifs_msg("recovery deferred");
else {
c->need_recovery = 0;
@@ -1378,7 +1378,7 @@
ubifs_msg("mounted UBI device %d, volume %d, name \"%s\"",
c->vi.ubi_num, c->vi.vol_id, c->vi.name);
- if (mounted_read_only)
+ if (c->ro_mount)
ubifs_msg("mounted read-only");
x = (long long)c->main_lebs * c->leb_size;
ubifs_msg("file system size: %lld bytes (%lld KiB, %lld MiB, %d "
@@ -1640,7 +1640,7 @@
}
dbg_gen("re-mounted read-write");
- c->vfs_sb->s_flags &= ~MS_RDONLY;
+ c->ro_mount = 0;
c->remounting_rw = 0;
c->always_chk_crc = 0;
err = dbg_check_space_info(c);
@@ -1676,7 +1676,7 @@
int i, err;
ubifs_assert(!c->need_recovery);
- ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY));
+ ubifs_assert(!c->ro_mount);
mutex_lock(&c->umount_mutex);
if (c->bgt) {
@@ -1704,6 +1704,7 @@
vfree(c->ileb_buf);
c->ileb_buf = NULL;
ubifs_lpt_free(c, 1);
+ c->ro_mount = 1;
err = dbg_check_space_info(c);
if (err)
ubifs_ro_mode(c, err);
@@ -1735,7 +1736,7 @@
* the mutex is locked.
*/
mutex_lock(&c->umount_mutex);
- if (!(c->vfs_sb->s_flags & MS_RDONLY)) {
+ if (!c->ro_mount) {
/*
* First of all kill the background thread to make sure it does
* not interfere with un-mounting and freeing resources.
@@ -1745,23 +1746,23 @@
c->bgt = NULL;
}
- /* Synchronize write-buffers */
- if (c->jheads)
- for (i = 0; i < c->jhead_cnt; i++)
- ubifs_wbuf_sync(&c->jheads[i].wbuf);
-
/*
* On fatal errors c->ro_error is set to 1, in which case we do
* not write the master node.
*/
if (!c->ro_error) {
+ int err;
+
+ /* Synchronize write-buffers */
+ if (c->jheads)
+ for (i = 0; i < c->jhead_cnt; i++)
+ ubifs_wbuf_sync(&c->jheads[i].wbuf);
+
/*
* We are being cleanly unmounted which means the
* orphans were killed - indicate this in the master
* node. Also save the reserved GC LEB number.
*/
- int err;
-
c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
@@ -1797,7 +1798,7 @@
return err;
}
- if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
+ if (c->ro_mount && !(*flags & MS_RDONLY)) {
if (c->ro_error) {
ubifs_msg("cannot re-mount R/W due to prior errors");
return -EROFS;
@@ -1809,7 +1810,7 @@
err = ubifs_remount_rw(c);
if (err)
return err;
- } else if (!(sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY)) {
+ } else if (!c->ro_mount && (*flags & MS_RDONLY)) {
if (c->ro_error) {
ubifs_msg("cannot re-mount R/O due to prior errors");
return -EROFS;
@@ -2068,9 +2069,11 @@
}
if (sb->s_root) {
+ struct ubifs_info *c1 = sb->s_fs_info;
+
/* A new mount point for already mounted UBIFS */
dbg_gen("this ubi volume is already mounted");
- if ((flags ^ sb->s_flags) & MS_RDONLY) {
+ if (!!(flags & MS_RDONLY) != c1->ro_mount) {
err = -EBUSY;
goto out_deact;
}