ext4: ext4_inline_data_fiemap should respect callers argument

Currently ext4_inline_data_fiemap ignores requested arguments (start
and len) which may lead endless loop if start != 0.  Also fix incorrect
extent length determination.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 13 insertions, 6 deletions

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index efdcede40c22..b32d77bfb3a1 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1808,11 +1808,12 @@ int ext4_destroy_inline_data(handle_t *handle, struct inode *inode)
 
 int ext4_inline_data_fiemap(struct inode *inode,
                             struct fiemap_extent_info *fieinfo,
-                            int *has_inline)
+                            int *has_inline, __u64 start, __u64 len)
 {
         __u64 physical = 0;
-        __u64 length;
-        __u32 flags = FIEMAP_EXTENT_DATA_INLINE | FIEMAP_EXTENT_LAST;
+        __u64 inline_len;
+        __u32 flags = FIEMAP_EXTENT_DATA_INLINE | FIEMAP_EXTENT_NOT_ALIGNED |
+                FIEMAP_EXTENT_LAST;
         int error = 0;
         struct ext4_iloc iloc;
 
@@ -1821,6 +1822,13 @@ int ext4_inline_data_fiemap(struct inode *inode,
                 *has_inline = 0;
                 goto out;
         }
+        inline_len = min_t(size_t, ext4_get_inline_size(inode),
+                           i_size_read(inode));
+        if (start >= inline_len)
+                goto out;
+        if (start + len < inline_len)
+                inline_len = start + len;
+        inline_len -= start;
 
         error = ext4_get_inode_loc(inode, &iloc);
         if (error)
@@ -1829,11 +1837,10 @@ int ext4_inline_data_fiemap(struct inode *inode,
         physical = (__u64)iloc.bh->b_blocknr << inode->i_sb->s_blocksize_bits;
         physical += (char *)ext4_raw_inode(&iloc) - iloc.bh->b_data;
         physical += offsetof(struct ext4_inode, i_block);
-        length = i_size_read(inode);
 
         if (physical)
-                error = fiemap_fill_next_extent(fieinfo, 0, physical,
-                                                length, flags);
+                error = fiemap_fill_next_extent(fieinfo, start, physical,
+                                                inline_len, flags);
         brelse(iloc.bh);
 out:
         up_read(&EXT4_I(inode)->xattr_sem);