[PATCH] btrfs: fix directory offsets for '.' and '..' entries

[PATCH] btrfs: fix directory offsets for '.' and '..' entries

[Grazvydas Ignotas]

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

Re: [PATCH] btrfs: fix directory offsets for '.' and '..' entries

[Christoph Hellwig]

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?

Re: [PATCH] btrfs: fix directory offsets for '.' and '..' entries

[Tsutomu Itoh]

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;

Re: [PATCH] btrfs: fix directory offsets for '.' and '..' entries

[Grazvydas Ignotas]

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 en=
try,
>> 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.


--=20
Gra=C5=BEvydas
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Re: [PATCH] btrfs: fix directory offsets for '.' and '..' entries

[Chris Mason]

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