[PATCH]] Btrfs: fix destroy snapshot to get the right parent dentry

[PATCH]] Btrfs: fix destroy snapshot to get the right parent dentry

[Rui Miguel Silva]

In snapshot destroy the dentry used for parent was the snapshot dentry
itself. Remove d_invalidate since always return EBUSY, making possible
to remove a snapshot using the btrfsctl -D option.

Signed-off-by: Rui Miguel Silva <rmfrfs@gmail.com>
---
 fs/btrfs/ioctl.c |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index cdbb054..fe6ac9a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -741,7 +741,7 @@ out:
 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
 					     void __user *arg)
 {
-	struct dentry *parent = fdentry(file);
+	struct dentry *parent = file->f_path.dentry->d_parent;
 	struct dentry *dentry;
 	struct inode *dir = parent->d_inode;
 	struct inode *inode;
@@ -793,9 +793,6 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
 	dest = BTRFS_I(inode)->root;
 
 	mutex_lock(&inode->i_mutex);
-	err = d_invalidate(dentry);
-	if (err)
-		goto out_unlock;
 
 	down_write(&root->fs_info->subvol_sem);
 
@@ -827,7 +824,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file,
 	inode->i_flags |= S_DEAD;
 out_up_write:
 	up_write(&root->fs_info->subvol_sem);
-out_unlock:
+
 	mutex_unlock(&inode->i_mutex);
 	if (!err) {
 		shrink_dcache_sb(root->fs_info->sb);
-- 
1.6.5.1

Re: [PATCH]] Btrfs: fix destroy snapshot to get the right parent dentry

[Yan, Zheng]

On Wed, Nov 4, 2009 at 12:10 AM, Rui Miguel Silva <rmfrfs@gmail.com> wr=
ote:
> In snapshot destroy the dentry used for parent was the snapshot dentr=
y
> itself. Remove d_invalidate since always return EBUSY, making possibl=
e
> to remove a snapshot using the btrfsctl -D option.
>

This is not correct. The snapshot destroy ioctl receives two parameters=
=2E
The first one provides directory that the snapshot is in, the second on=
e
provides the name of snapshot..

The usage of 'btrfsctl -D' is:
btrfsctl -D [name of snapshot] [directory that holds the snapshot]

Yan, Zheng


> Signed-off-by: Rui Miguel Silva <rmfrfs@gmail.com>
> ---
> =A0fs/btrfs/ioctl.c | =A0 =A07 ++-----
> =A01 files changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index cdbb054..fe6ac9a 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -741,7 +741,7 @@ out:
> =A0static noinline int btrfs_ioctl_snap_destroy(struct file *file,
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
 =A0 =A0 =A0 =A0 void __user *arg)
> =A0{
> - =A0 =A0 =A0 struct dentry *parent =3D fdentry(file);
> + =A0 =A0 =A0 struct dentry *parent =3D file->f_path.dentry->d_parent=
;
> =A0 =A0 =A0 =A0struct dentry *dentry;
> =A0 =A0 =A0 =A0struct inode *dir =3D parent->d_inode;
> =A0 =A0 =A0 =A0struct inode *inode;
> @@ -793,9 +793,6 @@ static noinline int btrfs_ioctl_snap_destroy(stru=
ct file *file,
> =A0 =A0 =A0 =A0dest =3D BTRFS_I(inode)->root;
>
> =A0 =A0 =A0 =A0mutex_lock(&inode->i_mutex);
> - =A0 =A0 =A0 err =3D d_invalidate(dentry);
> - =A0 =A0 =A0 if (err)
> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 goto out_unlock;
>
> =A0 =A0 =A0 =A0down_write(&root->fs_info->subvol_sem);
>
> @@ -827,7 +824,7 @@ static noinline int btrfs_ioctl_snap_destroy(stru=
ct file *file,
> =A0 =A0 =A0 =A0inode->i_flags |=3D S_DEAD;
> =A0out_up_write:
> =A0 =A0 =A0 =A0up_write(&root->fs_info->subvol_sem);
> -out_unlock:
> +
> =A0 =A0 =A0 =A0mutex_unlock(&inode->i_mutex);
> =A0 =A0 =A0 =A0if (!err) {
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0shrink_dcache_sb(root->fs_info->sb);
--
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

Re: [PATCH]] Btrfs: fix destroy snapshot to get the right parent dentry

[Rui Miguel Silva]

On Tue, 03 Nov 2009 23:20:02 -0000, Yan, Zheng  <yanzheng@21cn.com> wrote:

> On Wed, Nov 4, 2009 at 12:10 AM, Rui Miguel Silva <rmfrfs@gmail.com>  
> wrote:
>> In snapshot destroy the dentry used for parent was the snapshot dentry
>> itself. Remove d_invalidate since always return EBUSY, making possible
>> to remove a snapshot using the btrfsctl -D option.
>>
>
> This is not correct. The snapshot destroy ioctl receives two parameters.
> The first one provides directory that the snapshot is in, the second one
> provides the name of snapshot..
>
> The usage of 'btrfsctl -D' is:
> btrfsctl -D [name of snapshot] [directory that holds the snapshot]
>
> Yan, Zheng
>
Hi,
thanks for the explanation. I just saw the usage output: " [-D dir .]"  
"-D: delete snapshot" and I didn't understand it like the usage that you  
explained above.
I understood it like this: btrfsctl -D relative/path/to/snapshot comparing  
to the -s option "-s snap_name dir: creates a new snapshot of dir" which  
is more clear.

That makes the patch completely wrong. Once again many thanks.

Cheers,
-- Rui
>
>> Signed-off-by: Rui Miguel Silva <rmfrfs@gmail.com>
>> ---
>>  fs/btrfs/ioctl.c |    7 ++-----
>>  1 files changed, 2 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index cdbb054..fe6ac9a 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -741,7 +741,7 @@ out:
>>  static noinline int btrfs_ioctl_snap_destroy(struct file *file,
>>                                             void __user *arg)
>>  {
>> -       struct dentry *parent = fdentry(file);
>> +       struct dentry *parent = file->f_path.dentry->d_parent;
>>        struct dentry *dentry;
>>        struct inode *dir = parent->d_inode;
>>        struct inode *inode;
>> @@ -793,9 +793,6 @@ static noinline int btrfs_ioctl_snap_destroy(struct  
>> file *file,
>>        dest = BTRFS_I(inode)->root;
>>
>>        mutex_lock(&inode->i_mutex);
>> -       err = d_invalidate(dentry);
>> -       if (err)
>> -               goto out_unlock;
>>
>>        down_write(&root->fs_info->subvol_sem);
>>
>> @@ -827,7 +824,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct  
>> file *file,
>>        inode->i_flags |= S_DEAD;
>>  out_up_write:
>>        up_write(&root->fs_info->subvol_sem);
>> -out_unlock:
>> +
>>        mutex_unlock(&inode->i_mutex);
>>        if (!err) {
>>                shrink_dcache_sb(root->fs_info->sb);


--