Commit 95f28604 authored by Jens Axboe's avatar Jens Axboe
Browse files

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: default avatarTorsten Hilbrich <torsten.hilbrich@secunet.com>
Tested-by: default avatarTorsten Hilbrich <torsten.hilbrich@secunet.com>
Cc: stable@kernel.org
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent a91a2785

fs/super.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

fs/sync.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

}

/*

mm/backing-dev.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

}

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