ext4: fix the length returned by fiemap for an unallocated extent

If the file's blocks have not yet been allocated because of delayed
allocation, the length of the extent returned by fiemap is incorrect.
This commit fixes this bug.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 5f7295287de1d443218118ac8f010f56e6612432..4fec6b7463823244cb186ce0c4082b7b1dfc2eaa 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3244,8 +3244,15 @@ static int ext4_ext_fiemap_cb(struct inode *inode, struct ext4_ext_path *path,
         * XXX this might miss a single-block extent at EXT_MAX_BLOCK
         */
        if (ext4_ext_next_allocated_block(path) == EXT_MAX_BLOCK ||
-           newex->ec_block + newex->ec_len - 1 == EXT_MAX_BLOCK)
+           newex->ec_block + newex->ec_len - 1 == EXT_MAX_BLOCK) {
+               loff_t size = i_size_read(inode);
+               loff_t bs = EXT4_BLOCK_SIZE(inode->i_sb);
+
                flags |= FIEMAP_EXTENT_LAST;
+               if ((flags & FIEMAP_EXTENT_DELALLOC) &&
+                   logical+length > size)
+                       length = (size - logical + bs - 1) & ~(bs-1);
+       }
 
        error = fiemap_fill_next_extent(fieinfo, logical, physical,
                                        length, flags);