[PATCH 25/49] ext4: fix the length returned by fiemap for an unallocated extent

Theodore Ts'o
2009-06-08T19:32:21Z

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>
---
fs/ext4/extents.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 5f72952..4fec6b7 100644
--- 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);
--
1.6.3.2.1.gb9f7d.dirty