fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away

We don't have proper reference counting for this yet, so we run into
cases where the device is pulled and we OOPS on flushing the fs data.
This happens even though the dirty inodes have already been
migrated to the default_backing_dev_info.

Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Tested-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Jens Axboe 2011-03-17 11:13:12 +01:00
parent a91a2785b2
commit 95f28604a6
3 changed files with 5 additions and 3 deletions

View file

@ -71,6 +71,7 @@ static struct super_block *alloc_super(struct file_system_type *type)
#else
INIT_LIST_HEAD(&s->s_files);
#endif
s->s_bdi = &default_backing_dev_info;
INIT_LIST_HEAD(&s->s_instances);
INIT_HLIST_BL_HEAD(&s->s_anon);
INIT_LIST_HEAD(&s->s_inodes);
@ -1003,6 +1004,7 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
}
BUG_ON(!mnt->mnt_sb);
WARN_ON(!mnt->mnt_sb->s_bdi);
WARN_ON(mnt->mnt_sb->s_bdi == &default_backing_dev_info);
mnt->mnt_sb->s_flags |= MS_BORN;
error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);

View file

@ -33,7 +33,7 @@ static int __sync_filesystem(struct super_block *sb, int wait)
* This should be safe, as we require bdi backing to actually
* write out data in the first place
*/
if (!sb->s_bdi || sb->s_bdi == &noop_backing_dev_info)
if (sb->s_bdi == &noop_backing_dev_info)
return 0;
if (sb->s_qcop && sb->s_qcop->quota_sync)
@ -79,7 +79,7 @@ EXPORT_SYMBOL_GPL(sync_filesystem);
static void sync_one_sb(struct super_block *sb, void *arg)
{
if (!(sb->s_flags & MS_RDONLY) && sb->s_bdi)
if (!(sb->s_flags & MS_RDONLY))
__sync_filesystem(sb, *(int *)arg);
}
/*

View file

@ -598,7 +598,7 @@ static void bdi_prune_sb(struct backing_dev_info *bdi)
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (sb->s_bdi == bdi)
sb->s_bdi = NULL;
sb->s_bdi = &default_backing_dev_info;
}
spin_unlock(&sb_lock);
}