[PATCH v2 5/7] btrfs: unlock inode and extent in caller when uring read extent fails

btrfs_uring_read_extent() runs only after btrfs_encoded_read() has
taken the inode shared lock and the extent lock.  On failure it used to
unlock in out_fail, and a pages-array allocation failure returned
-ENOMEM without unlocking at all.

Unlock in the caller instead, matching the copy_to_user() error path.
out_fail only frees the local priv/pages allocations, and the pages
array failure joins that path.

Fixes: 34310c442e17 ("btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)")
Suggested-by: Qu Wenruo <[email protected]>
Signed-off-by: Yang Xiuwei <[email protected]>
---
 fs/btrfs/ioctl.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 939c4a9d47b6..b576887469bb 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4552,7 +4552,7 @@ static void btrfs_uring_read_finished(struct io_tw_req tw_req, io_tw_token_t tw)
 	size_t page_offset;
 	ssize_t ret;
 
-	/* The inode lock has already been acquired in btrfs_uring_read_extent.  */
+	/* The inode lock has already been acquired in btrfs_encoded_read(). */
 	btrfs_lockdep_inode_acquire(inode, i_rwsem);
 
 	if (priv->err) {
@@ -4618,7 +4618,6 @@ static int btrfs_uring_read_extent(struct kiocb *iocb, struct iov_iter *iter,
 				   struct iovec *iov, struct io_uring_cmd *cmd)
 {
 	struct btrfs_inode *inode = BTRFS_I(file_inode(iocb->ki_filp));
-	struct extent_io_tree *io_tree = &inode->io_tree;
 	struct page **pages = NULL;
 	struct btrfs_uring_priv *priv = NULL;
 	unsigned long nr_pages;
@@ -4626,8 +4625,10 @@ static int btrfs_uring_read_extent(struct kiocb *iocb, struct iov_iter *iter,
 
 	nr_pages = DIV_ROUND_UP(disk_io_size, PAGE_SIZE);
 	pages = kzalloc_objs(struct page *, nr_pages, GFP_NOFS);
-	if (!pages)
-		return -ENOMEM;
+	if (!pages) {
+		ret = -ENOMEM;
+		goto out_fail;
+	}
 	ret = btrfs_alloc_page_array(nr_pages, pages, GFP_NOFS);
 	if (ret) {
 		ret = -ENOMEM;
@@ -4674,12 +4675,12 @@ static int btrfs_uring_read_extent(struct kiocb *iocb, struct iov_iter *iter,
 	return -EIOCBQUEUED;
 
 out_fail:
-	btrfs_unlock_extent(io_tree, start, lockend, &cached_state);
-	btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
 	kfree(priv);
-	for (int i = 0; i < nr_pages; i++) {
-		if (pages[i])
-			__free_page(pages[i]);
+	if (pages) {
+		for (int i = 0; i < nr_pages; i++) {
+			if (pages[i])
+				__free_page(pages[i]);
+		}
 	}
 	kfree(pages);
 	return ret;
@@ -4819,6 +4820,8 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue
 					      data->iov, cmd);
 		if (ret == -EIOCBQUEUED)
 			goto out_acct;
+		btrfs_unlock_extent(io_tree, start, lockend, &cached_state);
+		btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
 	}
 
 out_free:
-- 
2.25.1