15 files changed, 89 insertions, 66 deletions

diff --git a/block/bdev.c b/block/bdev.c
index 7a5f611c3d2e3..b8e32d933a636 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -583,9 +583,6 @@ 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);
 }
 
 /**
@@ -608,7 +605,6 @@ 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;
 
 	/*
@@ -631,9 +627,6 @@ 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.
@@ -776,17 +769,17 @@ void blkdev_put_no_open(struct block_device *bdev)
 
 static bool bdev_writes_blocked(struct block_device *bdev)
 {
-	return bdev->bd_writers == -1;
+	return bdev->bd_writers < 0;
 }
 
 static void bdev_block_writes(struct block_device *bdev)
 {
-	bdev->bd_writers = -1;
+	bdev->bd_writers--;
 }
 
 static void bdev_unblock_writes(struct block_device *bdev)
 {
-	bdev->bd_writers = 0;
+	bdev->bd_writers++;
 }
 
 static bool bdev_may_open(struct block_device *bdev, blk_mode_t mode)
@@ -813,6 +806,11 @@ static void bdev_claim_write_access(struct block_device *bdev, blk_mode_t mode)
 		bdev->bd_writers++;
 }
 
+static inline bool bdev_unclaimed(const struct file *bdev_file)
+{
+	return bdev_file->private_data == BDEV_I(bdev_file->f_mapping->host);
+}
+
 static void bdev_yield_write_access(struct file *bdev_file)
 {
 	struct block_device *bdev;
@@ -820,14 +818,15 @@ static void bdev_yield_write_access(struct file *bdev_file)
 	if (bdev_allow_write_mounted)
 		return;
 
+	if (bdev_unclaimed(bdev_file))
+		return;
+
 	bdev = file_bdev(bdev_file);
-	/* Yield exclusive or shared write access. */
-	if (bdev_file->f_mode & FMODE_WRITE) {
-		if (bdev_writes_blocked(bdev))
-			bdev_unblock_writes(bdev);
-		else
-			bdev->bd_writers--;
-	}
+
+	if (bdev_file->f_mode & FMODE_WRITE_RESTRICTED)
+		bdev_unblock_writes(bdev);
+	else if (bdev_file->f_mode & FMODE_WRITE)
+		bdev->bd_writers--;
 }
 
 /**
@@ -907,6 +906,8 @@ int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
 	bdev_file->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT;
 	if (bdev_nowait(bdev))
 		bdev_file->f_mode |= FMODE_NOWAIT;
+	if (mode & BLK_OPEN_RESTRICT_WRITES)
+		bdev_file->f_mode |= FMODE_WRITE_RESTRICTED;
 	bdev_file->f_mapping = bdev->bd_inode->i_mapping;
 	bdev_file->f_wb_err = filemap_sample_wb_err(bdev_file->f_mapping);
 	bdev_file->private_data = holder;
@@ -1012,6 +1013,20 @@ struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode,
 }
 EXPORT_SYMBOL(bdev_file_open_by_path);
 
+static inline void bd_yield_claim(struct file *bdev_file)
+{
+	struct block_device *bdev = file_bdev(bdev_file);
+	void *holder = bdev_file->private_data;
+
+	lockdep_assert_held(&bdev->bd_disk->open_mutex);
+
+	if (WARN_ON_ONCE(IS_ERR_OR_NULL(holder)))
+		return;
+
+	if (!bdev_unclaimed(bdev_file))
+		bd_end_claim(bdev, holder);
+}
+
 void bdev_release(struct file *bdev_file)
 {
 	struct block_device *bdev = file_bdev(bdev_file);
@@ -1036,7 +1051,7 @@ void bdev_release(struct file *bdev_file)
 	bdev_yield_write_access(bdev_file);
 
 	if (holder)
-		bd_end_claim(bdev, holder);
+		bd_yield_claim(bdev_file);
 
 	/*
 	 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
@@ -1057,6 +1072,39 @@ put_no_open:
 }
 
 /**
+ * bdev_fput - yield claim to the block device and put the file
+ * @bdev_file: open block device
+ *
+ * Yield claim on the block device and put the file. Ensure that the
+ * block device can be reclaimed before the file is closed which is a
+ * deferred operation.
+ */
+void bdev_fput(struct file *bdev_file)
+{
+	if (WARN_ON_ONCE(bdev_file->f_op != &def_blk_fops))
+		return;
+
+	if (bdev_file->private_data) {
+		struct block_device *bdev = file_bdev(bdev_file);
+		struct gendisk *disk = bdev->bd_disk;
+
+		mutex_lock(&disk->open_mutex);
+		bdev_yield_write_access(bdev_file);
+		bd_yield_claim(bdev_file);
+		/*
+		 * Tell release we already gave up our hold on the
+		 * device and if write restrictions are available that
+		 * we already gave up write access to the device.
+		 */
+		bdev_file->private_data = BDEV_I(bdev_file->f_mapping->host);
+		mutex_unlock(&disk->open_mutex);
+	}
+
+	fput(bdev_file);
+}
+EXPORT_SYMBOL(bdev_fput);
+
+/**
  * lookup_bdev() - Look up a struct block_device by name.
  * @pathname: Name of the block device in the filesystem.
  * @dev: Pointer to the block device's dev_t, if found.
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index 97a00ec9a4d48..caacdc0a38194 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -209,7 +209,7 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
 
 	if (dev->bdev_file) {
 		invalidate_mapping_pages(dev->bdev_file->f_mapping, 0, -1);
-		fput(dev->bdev_file);
+		bdev_fput(dev->bdev_file);
 	}
 
 	kfree(dev);
diff --git a/fs/aio.c b/fs/aio.c
index 9cdaa2faa5363..0f4f531c97800 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1202,8 +1202,8 @@ static void aio_complete(struct aio_kiocb *iocb)
 		spin_lock_irqsave(&ctx->wait.lock, flags);
 		list_for_each_entry_safe(curr, next, &ctx->wait.head, w.entry)
 			if (avail >= curr->min_nr) {
-				list_del_init_careful(&curr->w.entry);
 				wake_up_process(curr->w.private);
+				list_del_init_careful(&curr->w.entry);
 			}
 		spin_unlock_irqrestore(&ctx->wait.lock, flags);
 	}
diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
index e0aa3655b63b4..5eee055ee2721 100644
--- a/fs/bcachefs/super-io.c
+++ b/fs/bcachefs/super-io.c
@@ -143,7 +143,7 @@ void bch2_free_super(struct bch_sb_handle *sb)
 {
 	kfree(sb->bio);
 	if (!IS_ERR_OR_NULL(sb->s_bdev_file))
-		fput(sb->s_bdev_file);
+		bdev_fput(sb->s_bdev_file);
 	kfree(sb->holder);
 	kfree(sb->sb_name);
 
diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index 39e75131fd5aa..9901057a15ba7 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -495,7 +495,7 @@ static void cramfs_kill_sb(struct super_block *sb)
 		sb->s_mtd = NULL;
 	} else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV) && sb->s_bdev) {
 		sync_blockdev(sb->s_bdev);
-		fput(sb->s_bdev_file);
+		bdev_fput(sb->s_bdev_file);
 	}
 	kfree(sbi);
 }
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index cfb8449c731f9..044135796f2b6 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5668,7 +5668,7 @@ failed_mount:
 	brelse(sbi->s_sbh);
 	if (sbi->s_journal_bdev_file) {
 		invalidate_bdev(file_bdev(sbi->s_journal_bdev_file));
-		fput(sbi->s_journal_bdev_file);
+		bdev_fput(sbi->s_journal_bdev_file);
 	}
 out_fail:
 	invalidate_bdev(sb->s_bdev);
@@ -5913,7 +5913,7 @@ static struct file *ext4_get_journal_blkdev(struct super_block *sb,
 out_bh:
 	brelse(bh);
 out_bdev:
-	fput(bdev_file);
+	bdev_fput(bdev_file);
 	return ERR_PTR(errno);
 }
 
@@ -5952,7 +5952,7 @@ static journal_t *ext4_open_dev_journal(struct super_block *sb,
 out_journal:
 	jbd2_journal_destroy(journal);
 out_bdev:
-	fput(bdev_file);
+	bdev_fput(bdev_file);
 	return ERR_PTR(errno);
 }
 
@@ -7327,7 +7327,7 @@ static void ext4_kill_sb(struct super_block *sb)
 	kill_block_super(sb);
 
 	if (bdev_file)
-		fput(bdev_file);
+		bdev_fput(bdev_file);
 }
 
 static struct file_system_type ext4_fs_type = {
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index a6867f26f1418..a4bc26dfdb1af 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1558,7 +1558,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
 
 	for (i = 0; i < sbi->s_ndevs; i++) {
 		if (i > 0)
-			fput(FDEV(i).bdev_file);
+			bdev_fput(FDEV(i).bdev_file);
 #ifdef CONFIG_BLK_DEV_ZONED
 		kvfree(FDEV(i).blkz_seq);
 #endif
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 73389c68e2517..9609349e92e5e 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1141,7 +1141,7 @@ journal_found:
 	lbmLogShutdown(log);
 
       close:		/* close external log device */
-	fput(bdev_file);
+	bdev_fput(bdev_file);
 
       free:		/* free log descriptor */
 	mutex_unlock(&jfs_log_mutex);
@@ -1485,7 +1485,7 @@ int lmLogClose(struct super_block *sb)
 	bdev_file = log->bdev_file;
 	rc = lmLogShutdown(log);
 
-	fput(bdev_file);
+	bdev_fput(bdev_file);
 
 	kfree(log);
 
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 6474529c42530..e539ccd39e1ee 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2589,7 +2589,7 @@ static void journal_list_init(struct super_block *sb)
 static void release_journal_dev(struct reiserfs_journal *journal)
 {
 	if (journal->j_bdev_file) {
-		fput(journal->j_bdev_file);
+		bdev_fput(journal->j_bdev_file);
 		journal->j_bdev_file = NULL;
 	}
 }
diff --git a/fs/romfs/super.c b/fs/romfs/super.c
index 2be227532f399..2cbb924620747 100644
--- a/fs/romfs/super.c
+++ b/fs/romfs/super.c
@@ -594,7 +594,7 @@ static void romfs_kill_sb(struct super_block *sb)
 #ifdef CONFIG_ROMFS_ON_BLOCK
 	if (sb->s_bdev) {
 		sync_blockdev(sb->s_bdev);
-		fput(sb->s_bdev_file);
+		bdev_fput(sb->s_bdev_file);
 	}
 #endif
 }
diff --git a/fs/super.c b/fs/super.c
index 71d9779c42b10..69ce6c6009684 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1515,29 +1515,11 @@ 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);
 
@@ -1562,7 +1544,7 @@ int setup_bdev_super(struct super_block *sb, int sb_flags,
 	 * writable from userspace even for a read-only block device.
 	 */
 	if ((mode & BLK_OPEN_WRITE) && bdev_read_only(bdev)) {
-		fput(bdev_file);
+		bdev_fput(bdev_file);
 		return -EACCES;
 	}
 
@@ -1573,7 +1555,7 @@ int setup_bdev_super(struct super_block *sb, int sb_flags,
 	if (atomic_read(&bdev->bd_fsfreeze_count) > 0) {
 		if (fc)
 			warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev);
-		fput(bdev_file);
+		bdev_fput(bdev_file);
 		return -EBUSY;
 	}
 	spin_lock(&sb_lock);
@@ -1693,7 +1675,7 @@ void kill_block_super(struct super_block *sb)
 	generic_shutdown_super(sb);
 	if (bdev) {
 		sync_blockdev(bdev);
-		fput(sb->s_bdev_file);
+		bdev_fput(sb->s_bdev_file);
 	}
 }
 
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 1a18c381127e2..f0fa02264edaa 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -2030,7 +2030,7 @@ xfs_free_buftarg(
 	fs_put_dax(btp->bt_daxdev, btp->bt_mount);
 	/* the main block device is closed by kill_block_super */
 	if (btp->bt_bdev != btp->bt_mount->m_super->s_bdev)
-		fput(btp->bt_bdev_file);
+		bdev_fput(btp->bt_bdev_file);
 	kfree(btp);
 }
 
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index c21f10ab0f5db..bce020374c5eb 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -485,7 +485,7 @@ xfs_open_devices(
 		mp->m_logdev_targp = mp->m_ddev_targp;
 		/* Handle won't be used, drop it */
 		if (logdev_file)
-			fput(logdev_file);
+			bdev_fput(logdev_file);
 	}
 
 	return 0;
@@ -497,10 +497,10 @@ xfs_open_devices(
 	xfs_free_buftarg(mp->m_ddev_targp);
  out_close_rtdev:
 	 if (rtdev_file)
-		fput(rtdev_file);
+		bdev_fput(rtdev_file);
  out_close_logdev:
 	if (logdev_file)
-		fput(logdev_file);
+		bdev_fput(logdev_file);
 	return error;
 }
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c3e8f7cf96be9..172c918799995 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 00fc429b0af0f..8dfd53b52744a 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) */