[PATCH v4 1/6] fs: enhance and rename shutdown() callback to remove_bdev()

Qu Wenruo
2025-07-04T00:42:58Z

Currently all the filesystems implementing the
super_opearations::shutdown() callback can not afford losing a device.

Thus fs_bdev_mark_dead() will just call the shutdown() callback for the
involved filesystem.

But it will no longer be the case, with multi-device filesystems like
btrfs and bcachefs the filesystem can handle certain device loss without
shutting down the whole filesystem.

To allow those multi-device filesystems to be integrated to use
fs_holder_ops:

- Replace super_opearation::shutdown() with
super_opearations::remove_bdev()
To better describe when the callback is called.

- Add a new @bdev parameter to remove_bdev() callback
To allow the fs to determine which device is missing, and do the
proper handling when needed.

For the existing shutdown callback users, the change is minimal.
They only need to follow the rename and the new parameter list.
The new @bdev parameter can be ignored if the filesystem can not afford
losing any device, and continue using the old shutdown behavior.

Btrfs is going to implement the callback soon, which will either
shutdown the fs or continue read-write operations.

Cc: linux-fsdevel@vger.kernel.org
Cc: linux-ext4@vger.kernel.org
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: ntfs3@lists.linux.dev
Cc: linux-xfs@vger.kernel.org
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/exfat/super.c | 4 ++--
fs/ext4/super.c | 4 ++--
fs/f2fs/super.c | 4 ++--
fs/ntfs3/super.c | 6 +++---
fs/super.c | 4 ++--
fs/xfs/xfs_super.c | 7 ++++---
include/linux/fs.h | 7 ++++++-
7 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 7ed858937d45..a0e11166b194 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -172,7 +172,7 @@ int exfat_force_shutdown(struct super_block *sb, u32 flags)
return 0;
}

-static void exfat_shutdown(struct super_block *sb)
+static void exfat_remove_bdev(struct super_block *sb, struct block_device *bdev)
{
exfat_force_shutdown(sb, EXFAT_GOING_DOWN_NOSYNC);
}
@@ -202,7 +202,7 @@ static const struct super_operations exfat_sops = {
.put_super = exfat_put_super,
.statfs = exfat_statfs,
.show_options = exfat_show_options,
- .shutdown = exfat_shutdown,
+ .remove_bdev = exfat_remove_bdev,
};

enum {
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c7d39da7e733..d75b416401ae 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1456,7 +1456,7 @@ static void ext4_destroy_inode(struct inode *inode)
EXT4_I(inode)->i_reserved_data_blocks);
}

-static void ext4_shutdown(struct super_block *sb)
+static void ext4_remove_bdev(struct super_block *sb, struct block_device *bdev)
{
ext4_force_shutdown(sb, EXT4_GOING_FLAGS_NOLOGFLUSH);
}
@@ -1620,7 +1620,7 @@ static const struct super_operations ext4_sops = {
.unfreeze_fs = ext4_unfreeze,
.statfs = ext4_statfs,
.show_options = ext4_show_options,
- .shutdown = ext4_shutdown,
+ .remove_bdev = ext4_remove_bdev,
#ifdef CONFIG_QUOTA
.quota_read = ext4_quota_read,
.quota_write = ext4_quota_write,
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index bbf1dad6843f..8667af9f76e4 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2640,7 +2640,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
return err;
}

-static void f2fs_shutdown(struct super_block *sb)
+static void f2fs_remove_bdev(struct super_block *sb, struct block_device *bdev)
{
f2fs_do_shutdown(F2FS_SB(sb), F2FS_GOING_DOWN_NOSYNC, false, false);
}
@@ -3264,7 +3264,7 @@ static const struct super_operations f2fs_sops = {
.unfreeze_fs = f2fs_unfreeze,
.statfs = f2fs_statfs,
.remount_fs = f2fs_remount,
- .shutdown = f2fs_shutdown,
+ .remove_bdev = f2fs_remove_bdev,
};

#ifdef CONFIG_FS_ENCRYPTION
diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index 920a1ab47b63..3e69dc805e3a 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -762,9 +762,9 @@ static int ntfs_show_options(struct seq_file *m, struct dentry *root)
}

/*
- * ntfs_shutdown - super_operations::shutdown
+ * ntfs_remove_bdev - super_operations::remove_bdev
*/
-static void ntfs_shutdown(struct super_block *sb)
+static void ntfs_remove_bdev(struct super_block *sb, struct block_device *bdev)
{
set_bit(NTFS_FLAGS_SHUTDOWN_BIT, &ntfs_sb(sb)->flags);
}
@@ -821,7 +821,7 @@ static const struct super_operations ntfs_sops = {
.put_super = ntfs_put_super,
.statfs = ntfs_statfs,
.show_options = ntfs_show_options,
- .shutdown = ntfs_shutdown,
+ .remove_bdev = ntfs_remove_bdev,
.sync_fs = ntfs_sync_fs,
.write_inode = ntfs3_write_inode,
};
diff --git a/fs/super.c b/fs/super.c
index 80418ca8e215..c972efb38f6a 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1463,8 +1463,8 @@ static void fs_bdev_mark_dead(struct block_device *bdev, bool surprise)
sync_filesystem(sb);
shrink_dcache_sb(sb);
evict_inodes(sb);
- if (sb->s_op->shutdown)
- sb->s_op->shutdown(sb);
+ if (sb->s_op->remove_bdev)
+ sb->s_op->remove_bdev(sb, bdev);

super_unlock_shared(sb);
}
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 0bc4b5489078..8e307b036133 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1276,8 +1276,9 @@ xfs_fs_free_cached_objects(
}

static void
-xfs_fs_shutdown(
- struct super_block *sb)
+xfs_fs_remove_bdev(
+ struct super_block *sb,
+ struct block_device *bdev)
{
xfs_force_shutdown(XFS_M(sb), SHUTDOWN_DEVICE_REMOVED);
}
@@ -1308,7 +1309,7 @@ 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,
- .shutdown = xfs_fs_shutdown,
+ .remove_bdev = xfs_fs_remove_bdev,
.show_stats = xfs_fs_show_stats,
};

diff --git a/include/linux/fs.h b/include/linux/fs.h
index b085f161ed22..b08af63d2d4f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2367,7 +2367,12 @@ struct super_operations {
struct shrink_control *);
long (*free_cached_objects)(struct super_block *,
struct shrink_control *);
- void (*shutdown)(struct super_block *sb);
+ /*
+ * Called when block device @bdev belonging to @sb is removed.
+ *
+ * If the fs can't afford the device loss, it should be shutdown.
+ */
+ void (*remove_bdev)(struct super_block *sb, struct block_device *bdev);
};

/*
--
2.50.0