1 files changed, 91 insertions, 93 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 8ae833e00443..9e84b1928b94 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -103,6 +103,35 @@ void invalidate_bdev(struct block_device *bdev)
 }
 EXPORT_SYMBOL(invalidate_bdev);
 
+/*
+ * Drop all buffers & page cache for given bdev range. This function bails
+ * with error if bdev has other exclusive owner (such as filesystem).
+ */
+int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
+			loff_t lstart, loff_t lend)
+{
+	struct block_device *claimed_bdev = NULL;
+	int err;
+
+	/*
+	 * If we don't hold exclusive handle for the device, upgrade to it
+	 * while we discard the buffer cache to avoid discarding buffers
+	 * under live filesystem.
+	 */
+	if (!(mode & FMODE_EXCL)) {
+		claimed_bdev = bdev->bd_contains;
+		err = bd_prepare_to_claim(bdev, claimed_bdev,
+					  truncate_bdev_range);
+		if (err)
+			return err;
+	}
+	truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
+	if (claimed_bdev)
+		bd_abort_claiming(bdev, claimed_bdev, truncate_bdev_range);
+	return 0;
+}
+EXPORT_SYMBOL(truncate_bdev_range);
+
 static void set_init_blocksize(struct block_device *bdev)
 {
 	bdev->bd_inode->i_blkbits = blksize_bits(bdev_logical_block_size(bdev));
@@ -862,7 +891,7 @@ static int bdev_set(struct inode *inode, void *data)
 	return 0;
 }
 
-struct block_device *bdget(dev_t dev)
+static struct block_device *bdget(dev_t dev)
 {
 	struct block_device *bdev;
 	struct inode *inode;
@@ -876,11 +905,11 @@ struct block_device *bdget(dev_t dev)
 	bdev = &BDEV_I(inode)->bdev;
 
 	if (inode->i_state & I_NEW) {
+		spin_lock_init(&bdev->bd_size_lock);
 		bdev->bd_contains = NULL;
 		bdev->bd_super = NULL;
 		bdev->bd_inode = inode;
 		bdev->bd_part_count = 0;
-		bdev->bd_invalidated = 0;
 		inode->i_mode = S_IFBLK;
 		inode->i_rdev = dev;
 		inode->i_bdev = bdev;
@@ -891,8 +920,6 @@ struct block_device *bdget(dev_t dev)
 	return bdev;
 }
 
-EXPORT_SYMBOL(bdget);
-
 /**
  * bdgrab -- Grab a reference to an already referenced block device
  * @bdev:	Block device to grab a reference to.
@@ -904,6 +931,11 @@ struct block_device *bdgrab(struct block_device *bdev)
 }
 EXPORT_SYMBOL(bdgrab);
 
+struct block_device *bdget_part(struct hd_struct *part)
+{
+	return bdget(part_devt(part));
+}
+
 long nr_blockdev_pages(void)
 {
 	struct inode *inode;
@@ -1290,6 +1322,7 @@ static void check_disk_size_change(struct gendisk *disk,
 {
 	loff_t disk_size, bdev_size;
 
+	spin_lock(&bdev->bd_size_lock);
 	disk_size = (loff_t)get_capacity(disk) << 9;
 	bdev_size = i_size_read(bdev->bd_inode);
 	if (disk_size != bdev_size) {
@@ -1299,85 +1332,51 @@ static void check_disk_size_change(struct gendisk *disk,
 			       disk->disk_name, bdev_size, disk_size);
 		}
 		i_size_write(bdev->bd_inode, disk_size);
-		if (bdev_size > disk_size && __invalidate_device(bdev, false))
+	}
+	spin_unlock(&bdev->bd_size_lock);
+
+	if (bdev_size > disk_size) {
+		if (__invalidate_device(bdev, false))
 			pr_warn("VFS: busy inodes on resized disk %s\n",
 				disk->disk_name);
 	}
-	bdev->bd_invalidated = 0;
 }
 
 /**
- * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
- * @disk: struct gendisk to be revalidated
+ * revalidate_disk_size - checks for disk size change and adjusts bdev size.
+ * @disk: struct gendisk to check
+ * @verbose: if %true log a message about a size change if there is any
  *
- * This routine is a wrapper for lower-level driver's revalidate_disk
- * call-backs.  It is used to do common pre and post operations needed
- * for all revalidate_disk operations.
+ * This routine checks to see if the bdev size does not match the disk size
+ * and adjusts it if it differs. When shrinking the bdev size, its all caches
+ * are freed.
  */
-int revalidate_disk(struct gendisk *disk)
+void revalidate_disk_size(struct gendisk *disk, bool verbose)
 {
-	int ret = 0;
-
-	if (disk->fops->revalidate_disk)
-		ret = disk->fops->revalidate_disk(disk);
+	struct block_device *bdev;
 
 	/*
 	 * Hidden disks don't have associated bdev so there's no point in
-	 * revalidating it.
+	 * revalidating them.
 	 */
-	if (!(disk->flags & GENHD_FL_HIDDEN)) {
-		struct block_device *bdev = bdget_disk(disk, 0);
-
-		if (!bdev)
-			return ret;
+	if (disk->flags & GENHD_FL_HIDDEN)
+		return;
 
-		mutex_lock(&bdev->bd_mutex);
-		check_disk_size_change(disk, bdev, ret == 0);
-		mutex_unlock(&bdev->bd_mutex);
+	bdev = bdget_disk(disk, 0);
+	if (bdev) {
+		check_disk_size_change(disk, bdev, verbose);
 		bdput(bdev);
 	}
-	return ret;
 }
-EXPORT_SYMBOL(revalidate_disk);
+EXPORT_SYMBOL(revalidate_disk_size);
 
-/*
- * This routine checks whether a removable media has been changed,
- * and invalidates all buffer-cache-entries in that case. This
- * is a relatively slow routine, so we have to try to minimize using
- * it. Thus it is called only upon a 'mount' or 'open'. This
- * is the best way of combining speed and utility, I think.
- * People changing diskettes in the middle of an operation deserve
- * to lose :-)
- */
-int check_disk_change(struct block_device *bdev)
+void bd_set_nr_sectors(struct block_device *bdev, sector_t sectors)
 {
-	struct gendisk *disk = bdev->bd_disk;
-	const struct block_device_operations *bdops = disk->fops;
-	unsigned int events;
-
-	events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE |
-				   DISK_EVENT_EJECT_REQUEST);
-	if (!(events & DISK_EVENT_MEDIA_CHANGE))
-		return 0;
-
-	if (__invalidate_device(bdev, true))
-		pr_warn("VFS: busy inodes on changed media %s\n",
-			disk->disk_name);
-	bdev->bd_invalidated = 1;
-	if (bdops->revalidate_disk)
-		bdops->revalidate_disk(bdev->bd_disk);
-	return 1;
-}
-
-EXPORT_SYMBOL(check_disk_change);
-
-void bd_set_size(struct block_device *bdev, loff_t size)
-{
-	inode_lock(bdev->bd_inode);
-	i_size_write(bdev->bd_inode, size);
-	inode_unlock(bdev->bd_inode);
+	spin_lock(&bdev->bd_size_lock);
+	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
+	spin_unlock(&bdev->bd_size_lock);
 }
-EXPORT_SYMBOL(bd_set_size);
+EXPORT_SYMBOL(bd_set_nr_sectors);
 
 static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
 
@@ -1388,6 +1387,8 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 
 	lockdep_assert_held(&bdev->bd_mutex);
 
+	clear_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
+
 rescan:
 	ret = blk_drop_partitions(bdev);
 	if (ret)
@@ -1446,22 +1447,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 	struct gendisk *disk;
 	int ret;
 	int partno;
-	int perm = 0;
 	bool first_open = false, unblock_events = true, need_restart;
 
-	if (mode & FMODE_READ)
-		perm |= MAY_READ;
-	if (mode & FMODE_WRITE)
-		perm |= MAY_WRITE;
-	/*
-	 * hooks: /n/, see "layering violations".
-	 */
-	if (!for_part) {
-		ret = devcgroup_inode_permission(bdev->bd_inode, perm);
-		if (ret != 0)
-			return ret;
-	}
-
  restart:
 	need_restart = false;
 	ret = -ENXIO;
@@ -1514,7 +1501,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			}
 
 			if (!ret) {
-				bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
+				bd_set_nr_sectors(bdev, get_capacity(disk));
 				set_init_blocksize(bdev);
 			}
 
@@ -1524,7 +1511,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			 * The latter is necessary to prevent ghost
 			 * partitions on a removed medium.
 			 */
-			if (bdev->bd_invalidated &&
+			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
 			    (!ret || ret == -ENOMEDIUM))
 				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 
@@ -1542,7 +1529,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 				ret = -ENXIO;
 				goto out_clear;
 			}
-			bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
+			bd_set_nr_sectors(bdev, bdev->bd_part->nr_sects);
 			set_init_blocksize(bdev);
 		}
 
@@ -1554,7 +1541,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 			if (bdev->bd_disk->fops->open)
 				ret = bdev->bd_disk->fops->open(bdev, mode);
 			/* the same as first opener case, read comment there */
-			if (bdev->bd_invalidated &&
+			if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
 			    (!ret || ret == -ENOMEDIUM))
 				bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 			if (ret)
@@ -1632,16 +1619,27 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
  * RETURNS:
  * 0 on success, -errno on failure.
  */
-int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
+static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 {
-	int res;
+	int ret, perm = 0;
 
-	res =__blkdev_get(bdev, mode, holder, 0);
-	if (res)
-		bdput(bdev);
-	return res;
+	if (mode & FMODE_READ)
+		perm |= MAY_READ;
+	if (mode & FMODE_WRITE)
+		perm |= MAY_WRITE;
+	ret = devcgroup_inode_permission(bdev->bd_inode, perm);
+	if (ret)
+		goto bdput;
+
+	ret =__blkdev_get(bdev, mode, holder, 0);
+	if (ret)
+		goto bdput;
+	return 0;
+
+bdput:
+	bdput(bdev);
+	return ret;
 }
-EXPORT_SYMBOL(blkdev_get);
 
 /**
  * blkdev_get_by_path - open a block device by name
@@ -1889,7 +1887,7 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (bdev_read_only(I_BDEV(bd_inode)))
 		return -EPERM;
 
-	if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode))
+	if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
 		return -ETXTBSY;
 
 	if (!iov_iter_count(from))
@@ -1969,7 +1967,6 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
 			     loff_t len)
 {
 	struct block_device *bdev = I_BDEV(bdev_file_inode(file));
-	struct address_space *mapping;
 	loff_t end = start + len - 1;
 	loff_t isize;
 	int error;
@@ -1997,8 +1994,9 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
 		return -EINVAL;
 
 	/* Invalidate the page cache, including dirty pages. */
-	mapping = bdev->bd_inode->i_mapping;
-	truncate_inode_pages_range(mapping, start, end);
+	error = truncate_bdev_range(bdev, file->f_mode, start, end);
+	if (error)
+		return error;
 
 	switch (mode) {
 	case FALLOC_FL_ZERO_RANGE:
@@ -2025,7 +2023,7 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
 	 * the caller will be given -EBUSY.  The third argument is
 	 * inclusive, so the rounding here is safe.
 	 */
-	return invalidate_inode_pages2_range(mapping,
+	return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
 					     start >> PAGE_SHIFT,
 					     end >> PAGE_SHIFT);
 }