diff options
| author | Christian Brauner <brauner@kernel.org> | 2024-03-14 15:24:13 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-03-18 10:32:44 +0100 |
| commit | 59a55a63c24624c7ad268f12c8f82d142ef6a6d4 (patch) | |
| tree | 95f2bb37ccdb6db29f06645c68946f3f2c7d4c8c | |
| parent | b74c02a37987d3ea755f96119c527f5e91950592 (diff) | |
fs,block: get holder during claim
Now that we open block devices as files we need to deal with the
realities that closing is a deferred operation. An operation on the
block device such as e.g., freeze, thaw, or removal that runs
concurrently with umount, tries to acquire a stable reference on the
holder. The holder might already be gone though. Make that reliable by
grabbing a passive reference to the holder during bdev_open() and
releasing it during bdev_release().
Fixes: f3a608827d1f ("bdev: open block device as files") # mainline only
Reported-by: Christoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/r/ZfEQQ9jZZVes0WCZ@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Reported-by: https://lore.kernel.org/r/CAHj4cs8tbDwKRwfS1=DmooP73ysM__xAb2PQc6XsAmWR+VuYmg@mail.gmail.com
Link: https://lore.kernel.org/r/20240315-freibad-annehmbar-ca68c375af91@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | block/bdev.c | 7 | ||||
| -rw-r--r-- | fs/super.c | 18 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 10 |
3 files changed, 35 insertions, 0 deletions
diff --git a/block/bdev.c b/block/bdev.c index e7adaaf1c219..7a5f611c3d2e 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -583,6 +583,9 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder, mutex_unlock(&bdev->bd_holder_lock); bd_clear_claiming(whole, holder); mutex_unlock(&bdev_lock); + + if (hops && hops->get_holder) + hops->get_holder(holder); } /** @@ -605,6 +608,7 @@ EXPORT_SYMBOL(bd_abort_claiming); static void bd_end_claim(struct block_device *bdev, void *holder) { struct block_device *whole = bdev_whole(bdev); + const struct blk_holder_ops *hops = bdev->bd_holder_ops; bool unblock = false; /* @@ -627,6 +631,9 @@ static void bd_end_claim(struct block_device *bdev, void *holder) whole->bd_holder = NULL; mutex_unlock(&bdev_lock); + if (hops && hops->put_holder) + hops->put_holder(holder); + /* * If this was the last claim, remove holder link and unblock evpoll if * it was a write holder. diff --git a/fs/super.c b/fs/super.c index ee05ab6b37e7..71d9779c42b1 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1515,11 +1515,29 @@ static int fs_bdev_thaw(struct block_device *bdev) return error; } +static void fs_bdev_super_get(void *data) +{ + struct super_block *sb = data; + + spin_lock(&sb_lock); + sb->s_count++; + spin_unlock(&sb_lock); +} + +static void fs_bdev_super_put(void *data) +{ + struct super_block *sb = data; + + put_super(sb); +} + const struct blk_holder_ops fs_holder_ops = { .mark_dead = fs_bdev_mark_dead, .sync = fs_bdev_sync, .freeze = fs_bdev_freeze, .thaw = fs_bdev_thaw, + .get_holder = fs_bdev_super_get, + .put_holder = fs_bdev_super_put, }; EXPORT_SYMBOL_GPL(fs_holder_ops); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index f9b87c39cab0..c3e8f7cf96be 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1505,6 +1505,16 @@ struct blk_holder_ops { * Thaw the file system mounted on the block device. */ int (*thaw)(struct block_device *bdev); + + /* + * If needed, get a reference to the holder. + */ + void (*get_holder)(void *holder); + + /* + * Release the holder. + */ + void (*put_holder)(void *holder); }; /* |