[PATCH 06/13] xfs: close the external block devices in xfs_mount_free

Christoph Hellwig
2023-08-09T22:05:55Z

blkdev_put must not be called under sb->s_umount to avoid a lock order
reversal with disk->open_mutex. Move closing the buftargs into ->kill_sb
to archive that. Note that the flushing of the disk caches and
block device mapping invalidated needs to stay in ->put_super as the main
block device is closed in kill_block_super already.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_buf.c | 2 --
fs/xfs/xfs_super.c | 36 ++++++++++++++++++++++++++----------
2 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index e33eb17648dfed..3b903f6bce98d8 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1945,8 +1945,6 @@ xfs_free_buftarg(
percpu_counter_destroy(&btp->bt_io_count);
list_lru_destroy(&btp->bt_lru);

- blkdev_issue_flush(btp->bt_bdev);
- invalidate_bdev(btp->bt_bdev);
fs_put_dax(btp->bt_daxdev, btp->bt_mount);
/* the main block device is closed by kill_block_super */
if (bdev != btp->bt_mount->m_super->s_bdev)
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 368c05a2dea5b9..4ae3b01ed038c7 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -396,14 +396,19 @@ xfs_blkdev_get(
}

STATIC void
-xfs_close_devices(
+xfs_shutdown_devices(
struct xfs_mount *mp)
{
- if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
- xfs_free_buftarg(mp->m_logdev_targp);
- if (mp->m_rtdev_targp)
- xfs_free_buftarg(mp->m_rtdev_targp);
- xfs_free_buftarg(mp->m_ddev_targp);
+ if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp) {
+ blkdev_issue_flush(mp->m_logdev_targp->bt_bdev);
+ invalidate_bdev(mp->m_logdev_targp->bt_bdev);
+ }
+ if (mp->m_rtdev_targp) {
+ blkdev_issue_flush(mp->m_rtdev_targp->bt_bdev);
+ invalidate_bdev(mp->m_rtdev_targp->bt_bdev);
+ }
+ blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
+ invalidate_bdev(mp->m_ddev_targp->bt_bdev);
}

/*
@@ -741,6 +746,17 @@ static void
xfs_mount_free(
struct xfs_mount *mp)
{
+ /*
+ * Free the buftargs here because blkdev_put needs to be called outside
+ * of sb->s_umount, which is held around the call to ->put_super.
+ */
+ if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
+ xfs_free_buftarg(mp->m_logdev_targp);
+ if (mp->m_rtdev_targp)
+ xfs_free_buftarg(mp->m_rtdev_targp);
+ if (mp->m_ddev_targp)
+ xfs_free_buftarg(mp->m_ddev_targp);
+
kfree(mp->m_rtname);
kfree(mp->m_logname);
kmem_free(mp);
@@ -1126,7 +1142,7 @@ xfs_fs_put_super(
xfs_inodegc_free_percpu(mp);
xfs_destroy_percpu_counters(mp);
xfs_destroy_mount_workqueues(mp);
- xfs_close_devices(mp);
+ xfs_shutdown_devices(mp);
}

static long
@@ -1499,7 +1515,7 @@ xfs_fs_fill_super(

error = xfs_init_mount_workqueues(mp);
if (error)
- goto out_close_devices;
+ goto out_shutdown_devices;

error = xfs_init_percpu_counters(mp);
if (error)
@@ -1713,8 +1729,8 @@ xfs_fs_fill_super(
xfs_destroy_percpu_counters(mp);
out_destroy_workqueues:
xfs_destroy_mount_workqueues(mp);
- out_close_devices:
- xfs_close_devices(mp);
+ out_shutdown_devices:
+ xfs_shutdown_devices(mp);
return error;

out_unmount:
--
2.39.2