2009-11-18 07:30:26

by Akira Fujita

[permalink] [raw]
Subject: [PATCH 2/3]ext4: Initialize moved_len before calling ext4_move_extents()

# This is a RESENT patch
http://marc.info/?l=linux-ext4&m=125498954712519&w=4

ext4: initialize moved_len before calling ext4_move_extents()

From: Kazuya Mio <[email protected]>

moved_len of struct move_extent is used to notify
exchanged blocks count to the user space.
So at the beginning of the EXT4_IOC_MOVE_EXT,
moved_len should be always zero.
Without this patch, if wrong moved_len is passed from the user space,
EXT4_IOC_MOVE_EXT will return wrong blocks count.

Signed-off-by: Kazuya Mio <[email protected]>
Signed-off-by: Akira Fujita <[email protected]>
---
ioctl.c | 1 +
move_extent.c | 12 ++----------
2 files changed, 3 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index d1fe495..dbf9a8b 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -251,6 +251,7 @@ setversion_out:
}
}

+ me.moved_len = 0;
err = ext4_move_extents(filp, donor_filp, me.orig_start,
me.donor_start, me.len, &me.moved_len);
fput(donor_filp);
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 25b6b14..e2e99fd 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -962,7 +962,6 @@ out2:
* @orig_start: logical start offset in block for orig
* @donor_start: logical start offset in block for donor
* @len: the number of blocks to be moved
- * @moved_len: moved block length
*
* Check the arguments of ext4_move_extents() whether the files can be
* exchanged with each other.
@@ -971,7 +970,7 @@ out2:
static int
mext_check_arguments(struct inode *orig_inode,
struct inode *donor_inode, __u64 orig_start,
- __u64 donor_start, __u64 *len, __u64 moved_len)
+ __u64 donor_start, __u64 *len)
{
ext4_lblk_t orig_blocks, donor_blocks;
unsigned int blkbits = orig_inode->i_blkbits;
@@ -1025,13 +1024,6 @@ mext_check_arguments(struct inode *orig_inode,
return -EINVAL;
}

- if (moved_len) {
- ext4_debug("ext4 move extent: moved_len should be 0 "
- "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
- donor_inode->i_ino);
- return -EINVAL;
- }


2009-11-24 15:31:19

by Theodore Ts'o

[permalink] [raw]
Subject: Re: [PATCH 2/3]ext4: Initialize moved_len before calling ext4_move_extents()

On Wed, Nov 18, 2009 at 04:26:10PM +0900, Akira Fujita wrote:
> ext4: initialize moved_len before calling ext4_move_extents()
>
> From: Kazuya Mio <[email protected]>
>
> moved_len of struct move_extent is used to notify
> exchanged blocks count to the user space.
> So at the beginning of the EXT4_IOC_MOVE_EXT,
> moved_len should be always zero.
> Without this patch, if wrong moved_len is passed from the user space,
> EXT4_IOC_MOVE_EXT will return wrong blocks count.

Applied with the following rewording of the patch description:

ext4: initialize moved_len before calling ext4_move_extents()

From: Kazuya Mio <[email protected]>

The move_extent.moved_len is used to pass back the number of exchanged
blocks count to user space. Currently the caller must clear this
field; but we spend more code space checking for this requirement than
simply zeroing the field ourselves, so let's just make life easier for
everyone all around.

Signed-off-by: Kazuya Mio <[email protected]>
Signed-off-by: Akira Fujita <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>

- Ted