jfs: fix metapage reference count leak in dbAllocCtl

In dbAllocCtl(), read_metapage() increases the reference count of the
metapage. However, when dp->tree.budmin < 0, the function returns -EIO
without calling release_metapage() to decrease the reference count,
leading to a memory leak.

Add release_metapage(mp) before the error return to properly manage
the metapage reference count and prevent the leak.

Fixes: a5f5e46 ("jfs: fix shift-out-of-bounds in dbSplit")

Signed-off-by: Zheng Yu <[email protected]>
Signed-off-by: Dave Kleikamp <[email protected]>

Author: cla7aye15I4nd

fs/jfs/jfs_dmap.c

@@ -1815,8 +1815,10 @@ dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
 			return -EIO;
 		dp = (struct dmap *) mp->data;
 
-		if (dp->tree.budmin < 0)
+		if (dp->tree.budmin < 0) {
+			release_metapage(mp);
 			return -EIO;
+		}
 
 		/* try to allocate the blocks.
 		 */