[PATCH 08/13] ext4: close the external journal device in ->kill_sb

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 external journal device
into ->kill_sb to archive that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/ext4/super.c | 50 ++++++++++++++++++++++++-------------------------
1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e6384782b4d036..60d2815a0b7ea5 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -93,6 +93,7 @@ static int ext4_get_tree(struct fs_context *fc);
static int ext4_reconfigure(struct fs_context *fc);
static void ext4_fc_free(struct fs_context *fc);
static int ext4_init_fs_context(struct fs_context *fc);
+static void ext4_kill_sb(struct super_block *sb);
static const struct fs_parameter_spec ext4_param_specs[];

/*
@@ -135,7 +136,7 @@ static struct file_system_type ext2_fs_type = {
.name = "ext2",
.init_fs_context = ext4_init_fs_context,
.parameters = ext4_param_specs,
- .kill_sb = kill_block_super,
+ .kill_sb = ext4_kill_sb,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("ext2");
@@ -151,7 +152,7 @@ static struct file_system_type ext3_fs_type = {
.name = "ext3",
.init_fs_context = ext4_init_fs_context,
.parameters = ext4_param_specs,
- .kill_sb = kill_block_super,
+ .kill_sb = ext4_kill_sb,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("ext3");
@@ -1116,25 +1117,6 @@ static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
return NULL;
}

-/*
- * Release the journal device
- */
-static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
-{
- struct block_device *bdev;
- bdev = sbi->s_journal_bdev;
- if (bdev) {
- /*
- * Invalidate the journal device's buffers. We don't want them
- * floating about in memory - the physical journal device may
- * hotswapped, and it breaks the `ro-after' testing code.
- */
- invalidate_bdev(bdev);
- blkdev_put(bdev, sbi->s_sb);
- sbi->s_journal_bdev = NULL;
- }
-}
-
static inline struct inode *orphan_list_entry(struct list_head *l)
{
return &list_entry(l, struct ext4_inode_info, i_orphan)->vfs_inode;
@@ -1330,8 +1312,13 @@ static void ext4_put_super(struct super_block *sb)
sync_blockdev(sb->s_bdev);
invalidate_bdev(sb->s_bdev);
if (sbi->s_journal_bdev) {
+ /*
+ * Invalidate the journal device's buffers. We don't want them
+ * floating about in memory - the physical journal device may
+ * hotswapped, and it breaks the `ro-after' testing code.
+ */
sync_blockdev(sbi->s_journal_bdev);
- ext4_blkdev_remove(sbi);
+ invalidate_bdev(sbi->s_journal_bdev);
}

ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
@@ -5654,9 +5641,11 @@ failed_mount9: __maybe_unused
kfree(get_qf_name(sb, sbi, i));
#endif
fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
- /* ext4_blkdev_remove() calls kill_bdev(), release bh before it. */
brelse(sbi->s_sbh);
- ext4_blkdev_remove(sbi);
+ if (sbi->s_journal_bdev) {
+ invalidate_bdev(sbi->s_journal_bdev);
+ blkdev_put(sbi->s_journal_bdev, sb);
+ }
out_fail:
invalidate_bdev(sb->s_bdev);
sb->s_fs_info = NULL;
@@ -7266,12 +7255,23 @@ static inline int ext3_feature_set_ok(struct super_block *sb)
return 1;
}

+static void ext4_kill_sb(struct super_block *sb)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct block_device *journal_bdev = sbi ? sbi->s_journal_bdev : NULL;
+
+ kill_block_super(sb);
+
+ if (journal_bdev)
+ blkdev_put(journal_bdev, sb);
+}
+
static struct file_system_type ext4_fs_type = {
.owner = THIS_MODULE,
.name = "ext4",
.init_fs_context = ext4_init_fs_context,
.parameters = ext4_param_specs,
- .kill_sb = kill_block_super,
+ .kill_sb = ext4_kill_sb,
.fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
};
MODULE_ALIAS_FS("ext4");
--
2.39.2