Btrfs devel - Sep 2011 - [PATCH] btrfs: fix directory offsets for '.' and '..' entries

Currently getdents syscall returns wrong offset for ''.''
directory entry,
which confuses some programs like wine. This can be observed with an
example program getdents(2) manpage:

$ ./a.out /testfs/
--------------- nread=96 ---------------
i-node#  file type  d_reclen  d_off   d_name
     256  directory    24          2  .
     256  directory    24          2  ..
     257  regular      24          3  a
     258  regular      24 2147483647  b

Fix this by passing correct offsets to filldir().

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
---
 fs/btrfs/inode.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 0ccc743..5e7460b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4125,7 +4125,7 @@ static int btrfs_real_readdir(struct file *filp, void
*dirent,
 
 	/* special case for "." */
 	if (filp->f_pos == 0) {
-		over = filldir(dirent, ".", 1, 1, btrfs_ino(inode), DT_DIR);
+		over = filldir(dirent, ".", 1, 0, btrfs_ino(inode), DT_DIR);
 		if (over)
 			return 0;
 		filp->f_pos = 1;
@@ -4133,8 +4133,7 @@ static int btrfs_real_readdir(struct file *filp, void
*dirent,
 	/* special case for .., just use the back ref */
 	if (filp->f_pos == 1) {
 		u64 pino = parent_ino(filp->f_path.dentry);
-		over = filldir(dirent, "..", 2,
-			       2, pino, DT_DIR);
+		over = filldir(dirent, "..", 2, 1, pino, DT_DIR);
 		if (over)
 			return 0;
 		filp->f_pos = 2;
-- 
1.7.0.4

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

On Sun, Sep 11, 2011 at 11:33:36PM +0300, Grazvydas Ignotas
wrote:
> Currently getdents syscall returns wrong offset for ''.''
directory entry,
> which confuses some programs like wine. This can be observed with an
> example program getdents(2) manpage:
Can you submit a patch to add your testcase to xfstests?

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

The same patch has been posted about one month ago.

  http://marc.info/?l=linux-btrfs&m=131363399500506&w=2

Thanks,
Tsutomu


(2011/09/12 5:33), Grazvydas Ignotas wrote:
> Currently getdents syscall returns wrong offset for ''.''
directory entry,
> which confuses some programs like wine. This can be observed with an
> example program getdents(2) manpage:
> 
> $ ./a.out /testfs/
> --------------- nread=96 ---------------
> i-node#  file type  d_reclen  d_off   d_name
>      256  directory    24          2  .
>      256  directory    24          2  ..
>      257  regular      24          3  a
>      258  regular      24 2147483647  b
> 
> Fix this by passing correct offsets to filldir().
> 
> Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
> ---
>  fs/btrfs/inode.c |    5 ++---
>  1 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 0ccc743..5e7460b 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -4125,7 +4125,7 @@ static int btrfs_real_readdir(struct file *filp, void
*dirent,
>  
>  	/* special case for "." */
>  	if (filp->f_pos == 0) {
> -		over = filldir(dirent, ".", 1, 1, btrfs_ino(inode), DT_DIR);
> +		over = filldir(dirent, ".", 1, 0, btrfs_ino(inode), DT_DIR);
>  		if (over)
>  			return 0;
>  		filp->f_pos = 1;
> @@ -4133,8 +4133,7 @@ static int btrfs_real_readdir(struct file *filp, void
*dirent,
>  	/* special case for .., just use the back ref */
>  	if (filp->f_pos == 1) {
>  		u64 pino = parent_ino(filp->f_path.dentry);
> -		over = filldir(dirent, "..", 2,
> -			       2, pino, DT_DIR);
> +		over = filldir(dirent, "..", 2, 1, pino, DT_DIR);
>  		if (over)
>  			return 0;
>  		filp->f_pos = 2;
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

On Mon, Sep 12, 2011 at 12:06 AM, Christoph Hellwig <hch@infradead.org>
wrote:
> On Sun, Sep 11, 2011 at 11:33:36PM +0300, Grazvydas Ignotas wrote:
>> Currently getdents syscall returns wrong offset for
''.'' directory entry,
>> which confuses some programs like wine. This can be observed with an
>> example program getdents(2) manpage:
>
> Can you submit a patch to add your testcase to xfstests?
Sent, hopefully did it right.


-- 
Gražvydas
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Excerpts from Tsutomu Itoh''s message of 2011-09-11 19:49:22
-0400:
> The same patch has been posted about one month ago.
> 
>   http://marc.info/?l=linux-btrfs&m=131363399500506&w=2
Thanks, I''ve queued up the fujitsu version (just because they sent it
first).

-chris
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html