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-rw-r--r--fs/super.c51
1 files changed, 36 insertions, 15 deletions
diff --git a/fs/super.c b/fs/super.c
index 938119ab8dcb..9674ab2c8718 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -305,8 +305,13 @@ retry:
if (s) {
up_write(&s->s_umount);
destroy_super(s);
+ s = NULL;
}
down_write(&old->s_umount);
+ if (unlikely(!(old->s_flags & MS_BORN))) {
+ deactivate_locked_super(old);
+ goto retry;
+ }
return old;
}
}
@@ -358,10 +363,10 @@ EXPORT_SYMBOL(drop_super);
*/
void sync_supers(void)
{
- struct super_block *sb, *n;
+ struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
- list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+ list_for_each_entry(sb, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
if (sb->s_op->write_super && sb->s_dirt) {
@@ -374,11 +379,13 @@ void sync_supers(void)
up_read(&sb->s_umount);
spin_lock(&sb_lock);
- /* lock was dropped, must reset next */
- list_safe_reset_next(sb, n, s_list);
- __put_super(sb);
+ if (p)
+ __put_super(p);
+ p = sb;
}
}
+ if (p)
+ __put_super(p);
spin_unlock(&sb_lock);
}
@@ -392,10 +399,10 @@ void sync_supers(void)
*/
void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
{
- struct super_block *sb, *n;
+ struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
- list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+ list_for_each_entry(sb, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
sb->s_count++;
@@ -407,10 +414,12 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
up_read(&sb->s_umount);
spin_lock(&sb_lock);
- /* lock was dropped, must reset next */
- list_safe_reset_next(sb, n, s_list);
- __put_super(sb);
+ if (p)
+ __put_super(p);
+ p = sb;
}
+ if (p)
+ __put_super(p);
spin_unlock(&sb_lock);
}
@@ -572,10 +581,10 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
static void do_emergency_remount(struct work_struct *work)
{
- struct super_block *sb, *n;
+ struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
- list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+ list_for_each_entry(sb, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
sb->s_count++;
@@ -589,10 +598,12 @@ static void do_emergency_remount(struct work_struct *work)
}
up_write(&sb->s_umount);
spin_lock(&sb_lock);
- /* lock was dropped, must reset next */
- list_safe_reset_next(sb, n, s_list);
- __put_super(sb);
+ if (p)
+ __put_super(p);
+ p = sb;
}
+ if (p)
+ __put_super(p);
spin_unlock(&sb_lock);
kfree(work);
printk("Emergency Remount complete\n");
@@ -773,7 +784,16 @@ int get_sb_bdev(struct file_system_type *fs_type,
goto error_bdev;
}
+ /*
+ * s_umount nests inside bd_mutex during
+ * __invalidate_device(). close_bdev_exclusive()
+ * acquires bd_mutex and can't be called under
+ * s_umount. Drop s_umount temporarily. This is safe
+ * as we're holding an active reference.
+ */
+ up_write(&s->s_umount);
close_bdev_exclusive(bdev, mode);
+ down_write(&s->s_umount);
} else {
char b[BDEVNAME_SIZE];
@@ -909,6 +929,7 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
goto out_free_secdata;
BUG_ON(!mnt->mnt_sb);
WARN_ON(!mnt->mnt_sb->s_bdi);
+ mnt->mnt_sb->s_flags |= MS_BORN;
error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
if (error)