linux-kernel - [PATCH 6.1.y] udf: Fold udf_getblk() into udf

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Message-ID: <3996808f-711a-3861-8388-c729045bd28a@omp.ru>
Date: Wed, 18 Sep 2024 22:46:38 +0300
From: Sergey Shtylyov <s.shtylyov@....ru>
To: Jan Kara <jack@...e.cz>, <linux-kernel@...r.kernel.org>,
	<stable@...r.kernel.org>
CC: <lvc-project@...uxtesting.org>
Subject: [PATCH 6.1.y] udf: Fold udf_getblk() into udf_bread()

From: Jan Kara <jack@...e.cz>

udf_getblk() has a single call site. Fold it there.

[Sergey: moved back to using udf_get_block() and buffer_{mapped|new}().]

Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Sergey Shtylyov <s.shtylyov@....ru>

---
This patch prevents NULL pointer dereference in case sb_getblk() fails...

 fs/udf/inode.c |   45 +++++++++++++++++++--------------------------
 1 file changed, 19 insertions(+), 26 deletions(-)

Index: linux-stable/fs/udf/inode.c
===================================================================
--- linux-stable.orig/fs/udf/inode.c
+++ linux-stable/fs/udf/inode.c
@@ -459,30 +459,6 @@ abort:
 	return err;
 }
 
-static struct buffer_head *udf_getblk(struct inode *inode, udf_pblk_t block,
-				      int create, int *err)
-{
-	struct buffer_head *bh;
-	struct buffer_head dummy;
-
-	dummy.b_state = 0;
-	dummy.b_blocknr = -1000;
-	*err = udf_get_block(inode, block, &dummy, create);
-	if (!*err && buffer_mapped(&dummy)) {
-		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
-		if (buffer_new(&dummy)) {
-			lock_buffer(bh);
-			memset(bh->b_data, 0x00, inode->i_sb->s_blocksize);
-			set_buffer_uptodate(bh);
-			unlock_buffer(bh);
-			mark_buffer_dirty_inode(bh, inode);
-		}
-		return bh;
-	}
-
-	return NULL;
-}
-
 /* Extend the file with new blocks totaling 'new_block_bytes',
  * return the number of extents added
  */
@@ -1198,10 +1174,27 @@ struct buffer_head *udf_bread(struct ino
 			      int create, int *err)
 {
 	struct buffer_head *bh = NULL;
+	struct buffer_head dummy;
+
+	dummy.b_state = 0;
+	dummy.b_blocknr = -1000;
+	*err = udf_get_block(inode, block, &dummy, create);
+	if (*err || !buffer_mapped(&dummy))
+		return NULL;
 
-	bh = udf_getblk(inode, block, create, err);
-	if (!bh)
+	bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
+	if (!bh) {
+		*err = -ENOMEM;
 		return NULL;
+	}
+	if (buffer_new(&dummy)) {
+		lock_buffer(bh);
+		memset(bh->b_data, 0x00, inode->i_sb->s_blocksize);
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+		mark_buffer_dirty_inode(bh, inode);
+		return bh;
+	}
 
 	if (bh_read(bh, 0) >= 0)
 		return bh;