[resend PATCH 2/3] xfs: handle shutdown notifications

[Dan Williams <dan.j.williams@xxxxxxxxx>]

Force a filesystem shutdown when the backing device is known to be dead.
I.e. blk_queue_enter() permanently returns -ENODEV.

Cc: xfs@xxxxxxxxxxx
Suggested-by: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 fs/block_dev.c     |    3 ++-
 fs/xfs/xfs_super.c |    9 +++++++++
 include/linux/fs.h |    2 ++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 739e43a37e64..7d6c66148948 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1806,7 +1806,7 @@ int __invalidate_device(struct block_device *bdev, bool 
kill_dirty)
 }
 EXPORT_SYMBOL(__invalidate_device);
 
-static void generic_bdi_gone(struct super_block *sb)
+void generic_bdi_gone(struct super_block *sb)
 {
        struct inode *inode, *_inode = NULL;
 
@@ -1832,6 +1832,7 @@ static void generic_bdi_gone(struct super_block *sb)
        spin_unlock(&sb->s_inode_list_lock);
        iput(_inode);
 }
+EXPORT_SYMBOL(generic_bdi_gone);
 
 void shutdown_partition(struct gendisk *disk, int partno)
 {
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 36bd8825bfb0..63c36508e9db 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1618,6 +1618,14 @@ xfs_fs_free_cached_objects(
        return xfs_reclaim_inodes_nr(XFS_M(sb), sc->nr_to_scan);
 }
 
+static void
+xfs_fs_bdi_gone(
+       struct super_block *sb)
+{
+       xfs_force_shutdown(XFS_M(sb), SHUTDOWN_DEVICE_REQ);
+       generic_bdi_gone(sb);
+}
+
 static const struct super_operations xfs_super_operations = {
        .alloc_inode            = xfs_fs_alloc_inode,
        .destroy_inode          = xfs_fs_destroy_inode,
@@ -1632,6 +1640,7 @@ static const struct super_operations xfs_super_operations 
= {
        .show_options           = xfs_fs_show_options,
        .nr_cached_objects      = xfs_fs_nr_cached_objects,
        .free_cached_objects    = xfs_fs_free_cached_objects,
+       .bdi_gone               = xfs_fs_bdi_gone,
 };
 
 static struct file_system_type xfs_fs_type = {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0e201ed38045..b1e8e049e4b8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2265,6 +2265,7 @@ extern struct super_block *freeze_bdev(struct 
block_device *);
 extern void emergency_thaw_all(void);
 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
 extern int fsync_bdev(struct block_device *);
+extern void generic_bdi_gone(struct super_block *sb);
 
 extern struct super_block *blockdev_superblock;
 
@@ -2277,6 +2278,7 @@ static inline void bd_forget(struct inode *inode) {}
 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
 static inline void kill_bdev(struct block_device *bdev) {}
 static inline void invalidate_bdev(struct block_device *bdev) {}
+static inline void generic_bdi_gone(struct super_block *sb) {}
 
 static inline struct super_block *freeze_bdev(struct block_device *sb)
 {