Merge tag 'vfs-6.9-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:
 "This contains a few small fixes. This comes with some delay because I
  wanted to wait on people running their reproducers and the Easter
  Holidays meant that those replies came in a little later than usual:

   - Fix handling of preventing writes to mounted block devices.

     Since last kernel we allow to prevent writing to mounted block
     devices provided CONFIG_BLK_DEV_WRITE_MOUNTED isn't set and the
     block device is opened with restricted writes. When we switched to
     opening block devices as files we altered the mechanism by which we
     recognize when a block device has been opened with write
     restrictions.

     The detection logic assumed that only read-write mounted
     filesystems would apply write restrictions to their block devices
     from other openers. That of course is not true since it also makes
     sense to apply write restrictions for filesystems that are
     read-only.

     Fix the detection logic using an FMODE_* bit. We still have a few
     left since we freed up a couple a while ago. I also picked up a
     patch to free up four additional FMODE_* bits scheduled for the
     next merge window.

   - Fix counting the number of writers to a block device. This just
     changes the logic to be consistent.

   - Fix a bug in aio causing a NULL pointer derefernce after we
     implemented batched processing in aio.

   - Finally, add the changes we discussed that allows to yield block
     devices early even though file closing itself is deferred.

     This also allows us to remove two holder operations to get and
     release the holder to align lifetime of file and holder of the
     block device"

* tag 'vfs-6.9-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  aio: Fix null ptr deref in aio_complete() wakeup
  fs,block: yield devices early
  block: count BLK_OPEN_RESTRICT_WRITES openers
  block: handle BLK_OPEN_RESTRICT_WRITES correctly

2 files changed, 3 insertions, 10 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c3e8f7cf96be..172c91879999 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1505,16 +1505,6 @@ 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);
 };
 
 /*
@@ -1585,6 +1575,7 @@ static inline int early_lookup_bdev(const char *pathname, dev_t *dev)
 
 int bdev_freeze(struct block_device *bdev);
 int bdev_thaw(struct block_device *bdev);
+void bdev_fput(struct file *bdev_file);
 
 struct io_comp_batch {
 	struct request *req_list;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 00fc429b0af0..8dfd53b52744 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -121,6 +121,8 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 #define FMODE_PWRITE		((__force fmode_t)0x10)
 /* File is opened for execution with sys_execve / sys_uselib */
 #define FMODE_EXEC		((__force fmode_t)0x20)
+/* File writes are restricted (block device specific) */
+#define FMODE_WRITE_RESTRICTED  ((__force fmode_t)0x40)
 /* 32bit hashes as llseek() offset (for directories) */
 #define FMODE_32BITHASH         ((__force fmode_t)0x200)
 /* 64bit hashes as llseek() offset (for directories) */