From: Ritesh Harjani <[email protected]>

commit d1e18b8824dd50cff255e6cecf515ea598eaf9f0 upstream.

left shifting m_lblk by blkbits was causing value overflow and hence
it was not able to convert unwritten to written extent.
So, make sure we typecast it to loff_t before do left shift operation.
Also in func ext4_convert_unwritten_io_end_vec(), make sure to initialize
ret variable to avoid accidentally returning an uninitialized ret.

This patch fixes the issue reported in ext4 for bs < ps with
dioread_nolock mount option.

Fixes: c8cc88163f40df39e50c ("ext4: Add support for blocksize < pagesize in 
dioread_nolock")
Cc: [email protected]
Reported-by: Aneesh Kumar K.V <[email protected]>
Signed-off-by: Ritesh Harjani <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: 
https://lore.kernel.org/r/af902b5db99e8b73980c795d84ad7bb417487e76.1602168865.git.rite...@linux.ibm.com
Signed-off-by: Theodore Ts'o <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 fs/ext4/extents.c |    2 +-
 fs/ext4/inode.c   |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4770,7 +4770,7 @@ int ext4_convert_unwritten_extents(handl
 
 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
 {
-       int ret, err = 0;
+       int ret = 0, err = 0;
        struct ext4_io_end_vec *io_end_vec;
 
        /*
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2257,7 +2257,7 @@ static int mpage_process_page(struct mpa
                                        err = PTR_ERR(io_end_vec);
                                        goto out;
                                }
-                               io_end_vec->offset = mpd->map.m_lblk << blkbits;
+                               io_end_vec->offset = (loff_t)mpd->map.m_lblk << 
blkbits;
                        }
                        *map_bh = true;
                        goto out;


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