xfs: Convert to bdev_open_by_path()

Convert xfs to use bdev_open_by_path() and pass the handle around.

CC: "Darrick J. Wong" <djwong@kernel.org>
CC: linux-xfs@vger.kernel.org
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-28-jack@suse.cz
Acked-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/xfs/xfs_buf.c

@@ -1945,17 +1945,15 @@ void
 xfs_free_buftarg(
 	struct xfs_buftarg	*btp)
 {
-	struct block_device	*bdev = btp->bt_bdev;
-
 	unregister_shrinker(&btp->bt_shrinker);
 	ASSERT(percpu_counter_sum(&btp->bt_io_count) == 0);
 	percpu_counter_destroy(&btp->bt_io_count);
 	list_lru_destroy(&btp->bt_lru);
 
 	fs_put_dax(btp->bt_daxdev, btp->bt_mount);
 	/* the main block device is closed by kill_block_super */
-	if (bdev != btp->bt_mount->m_super->s_bdev)
-		blkdev_put(bdev, btp->bt_mount->m_super);
+	if (btp->bt_bdev != btp->bt_mount->m_super->s_bdev)
+		bdev_release(btp->bt_bdev_handle);
 
 	kmem_free(btp);
 }
@@ -1990,16 +1988,15 @@ xfs_setsize_buftarg(
  */
 STATIC int
 xfs_setsize_buftarg_early(
-	xfs_buftarg_t		*btp,
-	struct block_device	*bdev)
+	xfs_buftarg_t		*btp)
 {
-	return xfs_setsize_buftarg(btp, bdev_logical_block_size(bdev));
+	return xfs_setsize_buftarg(btp, bdev_logical_block_size(btp->bt_bdev));
 }
 
 struct xfs_buftarg *
 xfs_alloc_buftarg(
 	struct xfs_mount	*mp,
-	struct block_device	*bdev)
+	struct bdev_handle	*bdev_handle)
 {
 	xfs_buftarg_t		*btp;
 	const struct dax_holder_operations *ops = NULL;
@@ -2010,9 +2007,10 @@ xfs_alloc_buftarg(
 	btp = kmem_zalloc(sizeof(*btp), KM_NOFS);
 
 	btp->bt_mount = mp;
-	btp->bt_dev =  bdev->bd_dev;
-	btp->bt_bdev = bdev;
-	btp->bt_daxdev = fs_dax_get_by_bdev(bdev, &btp->bt_dax_part_off,
+	btp->bt_bdev_handle = bdev_handle;
+	btp->bt_dev = bdev_handle->bdev->bd_dev;
+	btp->bt_bdev = bdev_handle->bdev;
+	btp->bt_daxdev = fs_dax_get_by_bdev(btp->bt_bdev, &btp->bt_dax_part_off,
 					    mp, ops);
 
 	/*
@@ -2022,7 +2020,7 @@ xfs_alloc_buftarg(
 	ratelimit_state_init(&btp->bt_ioerror_rl, 30 * HZ,
 			     DEFAULT_RATELIMIT_BURST);
 
-	if (xfs_setsize_buftarg_early(btp, bdev))
+	if (xfs_setsize_buftarg_early(btp))
 		goto error_free;
 
 	if (list_lru_init(&btp->bt_lru))

fs/xfs/xfs_buf.h

@@ -98,6 +98,7 @@ typedef unsigned int xfs_buf_flags_t;
  */
 typedef struct xfs_buftarg {
 	dev_t			bt_dev;
+	struct bdev_handle	*bt_bdev_handle;
 	struct block_device	*bt_bdev;
 	struct dax_device	*bt_daxdev;
 	u64			bt_dax_part_off;
@@ -364,7 +365,7 @@ xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
  *	Handling of buftargs.
  */
 struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *mp,
-		struct block_device *bdev);
+		struct bdev_handle *bdev_handle);
 extern void xfs_free_buftarg(struct xfs_buftarg *);
 extern void xfs_buftarg_wait(struct xfs_buftarg *);
 extern void xfs_buftarg_drain(struct xfs_buftarg *);

fs/xfs/xfs_super.c

@@ -361,14 +361,15 @@ STATIC int
 xfs_blkdev_get(
 	xfs_mount_t		*mp,
 	const char		*name,
-	struct block_device	**bdevp)
+	struct bdev_handle	**handlep)
 {
 	int			error = 0;
 
-	*bdevp = blkdev_get_by_path(name, BLK_OPEN_READ | BLK_OPEN_WRITE,
-				    mp->m_super, &fs_holder_ops);
-	if (IS_ERR(*bdevp)) {
-		error = PTR_ERR(*bdevp);
+	*handlep = bdev_open_by_path(name, BLK_OPEN_READ | BLK_OPEN_WRITE,
+				     mp->m_super, &fs_holder_ops);
+	if (IS_ERR(*handlep)) {
+		error = PTR_ERR(*handlep);
+		*handlep = NULL;
 		xfs_warn(mp, "Invalid device [%s], error=%d", name, error);
 	}
 
@@ -433,7 +434,7 @@ xfs_open_devices(
 {
 	struct super_block	*sb = mp->m_super;
 	struct block_device	*ddev = sb->s_bdev;
-	struct block_device	*logdev = NULL, *rtdev = NULL;
+	struct bdev_handle	*logdev_handle = NULL, *rtdev_handle = NULL;
 	int			error;
 
 	/*
@@ -446,17 +447,19 @@ xfs_open_devices(
 	 * Open real time and log devices - order is important.
 	 */
 	if (mp->m_logname) {
-		error = xfs_blkdev_get(mp, mp->m_logname, &logdev);
+		error = xfs_blkdev_get(mp, mp->m_logname, &logdev_handle);
 		if (error)
 			goto out_relock;
 	}
 
 	if (mp->m_rtname) {
-		error = xfs_blkdev_get(mp, mp->m_rtname, &rtdev);
+		error = xfs_blkdev_get(mp, mp->m_rtname, &rtdev_handle);
 		if (error)
 			goto out_close_logdev;
 
-		if (rtdev == ddev || rtdev == logdev) {
+		if (rtdev_handle->bdev == ddev ||
+		    (logdev_handle &&
+		     rtdev_handle->bdev == logdev_handle->bdev)) {
 			xfs_warn(mp,
 	"Cannot mount filesystem with identical rtdev and ddev/logdev.");
 			error = -EINVAL;
@@ -468,22 +471,25 @@ xfs_open_devices(
 	 * Setup xfs_mount buffer target pointers
 	 */
 	error = -ENOMEM;
-	mp->m_ddev_targp = xfs_alloc_buftarg(mp, ddev);
+	mp->m_ddev_targp = xfs_alloc_buftarg(mp, sb->s_bdev_handle);
 	if (!mp->m_ddev_targp)
 		goto out_close_rtdev;
 
-	if (rtdev) {
-		mp->m_rtdev_targp = xfs_alloc_buftarg(mp, rtdev);
+	if (rtdev_handle) {
+		mp->m_rtdev_targp = xfs_alloc_buftarg(mp, rtdev_handle);
 		if (!mp->m_rtdev_targp)
 			goto out_free_ddev_targ;
 	}
 
-	if (logdev && logdev != ddev) {
-		mp->m_logdev_targp = xfs_alloc_buftarg(mp, logdev);
+	if (logdev_handle && logdev_handle->bdev != ddev) {
+		mp->m_logdev_targp = xfs_alloc_buftarg(mp, logdev_handle);
 		if (!mp->m_logdev_targp)
 			goto out_free_rtdev_targ;
 	} else {
 		mp->m_logdev_targp = mp->m_ddev_targp;
+		/* Handle won't be used, drop it */
+		if (logdev_handle)
+			bdev_release(logdev_handle);
 	}
 
 	error = 0;
@@ -497,11 +503,11 @@ xfs_open_devices(
  out_free_ddev_targ:
 	xfs_free_buftarg(mp->m_ddev_targp);
  out_close_rtdev:
-	 if (rtdev)
-		 blkdev_put(rtdev, sb);
+	 if (rtdev_handle)
+		bdev_release(rtdev_handle);
  out_close_logdev:
-	if (logdev && logdev != ddev)
-		blkdev_put(logdev, sb);
+	if (logdev_handle)
+		bdev_release(logdev_handle);
 	goto out_relock;
 }