[PATCH 11/12] xfs: drop s_umount over opening the log and RT devices
From: Christoph Hellwig <hch@lst.de>
Date: 2023-08-02 15:43:34
Also in:
linux-block, linux-btrfs, linux-f2fs-devel, linux-fsdevel, linux-xfs
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
Just like get_tree_bdev needs to drop s_umount when opening the main device, we need to do the same for the xfs log and RT devices to avoid a potential lock order reversal with s_unmount for the mark_dead path. It might be preferable to just drop s_umount over ->fill_super entirely, but that will require a fairly massive audit first, so we'll do the easy version here first. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/xfs_super.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 8185102431301d..d5042419ed9997 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c@@ -448,17 +448,21 @@ STATIC int xfs_open_devices( struct xfs_mount *mp) { - struct block_device *ddev = mp->m_super->s_bdev; + struct super_block *sb = mp->m_super; + struct block_device *ddev = sb->s_bdev; struct block_device *logdev = NULL, *rtdev = NULL; int error; + /* see get_tree_bdev why this is needed and safe */ + up_write(&sb->s_umount); + /* * Open real time and log devices - order is important. */ if (mp->m_logname) { error = xfs_blkdev_get(mp, mp->m_logname, &logdev); if (error) - return error; + goto out_unlock; } if (mp->m_rtname) {
@@ -496,7 +500,10 @@ xfs_open_devices( mp->m_logdev_targp = mp->m_ddev_targp; } - return 0; + error = 0; +out_unlock: + down_write(&sb->s_umount); + return error; out_free_rtdev_targ: if (mp->m_rtdev_targp)
@@ -508,7 +515,7 @@ xfs_open_devices( out_close_logdev: if (logdev && logdev != ddev) xfs_blkdev_put(mp, logdev); - return error; + goto out_unlock; } /*
--
2.39.2