btrfs: fix invalid-free in btrfs_extent_same

If this condition ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
		   (BTRFS_I(dst)->flags & BTRFS_INODE_NODATASUM))
is hit, we will go to free the uninitialized cmp.src_pages and
cmp.dst_pages.

Fixes: 67b07bd4bec5 ("Btrfs: reuse cmp workspace in EXTENT_SAME ioctl")
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 5556e9ea2a4b540659c2193e00f53615c9a3c652..a4d2856a4df1facc9150676e3cd06f38432f9bb1 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3577,7 +3577,7 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
                ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
                                              dst, dst_loff, &cmp);
                if (ret)
-                       goto out_unlock;
+                       goto out_free;
 
                loff += BTRFS_MAX_DEDUPE_LEN;
                dst_loff += BTRFS_MAX_DEDUPE_LEN;
@@ -3587,16 +3587,16 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
                ret = btrfs_extent_same_range(src, loff, tail_len, dst,
                                              dst_loff, &cmp);
 
+out_free:
+       kvfree(cmp.src_pages);
+       kvfree(cmp.dst_pages);
+
 out_unlock:
        if (same_inode)
                inode_unlock(src);
        else
                btrfs_double_inode_unlock(src, dst);
 
-out_free:
-       kvfree(cmp.src_pages);
-       kvfree(cmp.dst_pages);
-
        return ret;
 }