vfs: fix isize/pos/len checks for reflink & dedupe

Strengthen the checking of pos/len vs. i_size, clarify the return values
for the clone prep function, and remove pointless code.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index d171d2c53f7f8928762acb9731d202063328967b..f8933cb53d682aaf4c7e22efb75a43d4c1c688ac 100644 (file)
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -4834,7 +4834,7 @@ int ocfs2_reflink_remap_range(struct file *file_in,
 
        ret = vfs_clone_file_prep_inodes(inode_in, pos_in, inode_out, pos_out,
                        &len, is_dedupe);
-       if (ret || len == 0)
+       if (ret <= 0)
                goto out_unlock;
 
        /* Lock out changes to the allocation maps and remap. */

diff --git a/fs/read_write.c b/fs/read_write.c
index da6de12b5c46d4a56e15e892f527153682ff6e30..7537b6b6b5a2dc80caa8774f8534ccc5e6b4fee2 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1669,6 +1669,9 @@ static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write)
  * Check that the two inodes are eligible for cloning, the ranges make
  * sense, and then flush all dirty data.  Caller must ensure that the
  * inodes have been locked against any other modifications.
+ *
+ * Returns: 0 for "nothing to clone", 1 for "something to clone", or
+ * the usual negative error code.
  */
 int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
                               struct inode *inode_out, loff_t pos_out,
@@ -1695,17 +1698,15 @@ int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
 
        /* Are we going all the way to the end? */
        isize = i_size_read(inode_in);
-       if (isize == 0) {
-               *len = 0;
+       if (isize == 0)
                return 0;
-       }
 
        /* Zero length dedupe exits immediately; reflink goes to EOF. */
        if (*len == 0) {
-               if (is_dedupe) {
-                       *len = 0;
+               if (is_dedupe || pos_in == isize)
                        return 0;
-               }
+               if (pos_in > isize)
+                       return -EINVAL;
                *len = isize - pos_in;
        }
 
@@ -1769,7 +1770,7 @@ int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
                        return -EBADE;
        }
 
-       return 0;
+       return 1;
 }
 EXPORT_SYMBOL(vfs_clone_file_prep_inodes);
 
@@ -1955,6 +1956,9 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
                goto out;
        ret = 0;
 
+       if (off + len > i_size_read(src))
+               return -EINVAL;
+
        /* pre-format output fields to sane values */
        for (i = 0; i < count; i++) {
                same->info[i].bytes_deduped = 0ULL;

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index aca2d4bd4303b07b41a86d0bbe1e43bb4fe88308..07593a362cd03d0fdae120122d6d1c5aba8d809b 100644 (file)
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1161,7 +1161,7 @@ xfs_reflink_remap_range(
 
        ret = vfs_clone_file_prep_inodes(inode_in, pos_in, inode_out, pos_out,
                        &len, is_dedupe);
-       if (ret || len == 0)
+       if (ret <= 0)
                goto out_unlock;
 
        trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);