[4/4] statx: AFS: Return enhanced file attributes
diff mbox

Message ID 147938972442.13574.1819690786475800772.stgit@warthog.procyon.org.uk
State New
Headers show

Commit Message

David Howells Nov. 17, 2016, 1:35 p.m. UTC
Return enhanced file attributes from the AFS filesystem.  This includes the
following:

 (1) The data version number as st_version, setting STATX_VERSION.

 (2) STATX_ATTR_AUTOMOUNT will be set on automount directories by virtue of
     S_AUTOMOUNT being set on the inode.  These are referrals to other
     volumes or other cells.

 (3) STATX_ATTR_UNLISTED_DENTS on a directory that does cell lookup for
     non-existent names and mounts them (typically mounted on /afs with -o
     autocell).  The resulting directories are marked STATX_ATTR_FABRICATED
     as they do not actually exist in the mounted AFS directory.

 (4) Files, directories and symlinks accessed over AFS are marked
     STATX_ATTR_REMOTE.

STATX_ATIME, STATX_CTIME and STATX_BLOCKS are cleared as AFS does not
support them.

Example output:

	[root@andromeda ~]# ./samples/statx/test-statx /afs
	statx(/afs) = 0
	results=7ef
	  Size: 2048            Blocks: 0          IO Block: 4096    directory
	Device: 00:25           Inode: 1           Links: 2
	Access: (0777/drwxrwxrwx)  Uid:     0   Gid:     0
	Access: 2006-05-07 00:21:15.000000000+0100
	Modify: 2006-05-07 00:21:15.000000000+0100
	Change: 2006-05-07 00:21:15.000000000+0100
	IO-blocksize: blksize=4096

Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/afs/inode.c |   21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)


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Comments

Andreas Dilger Nov. 18, 2016, 3:34 a.m. UTC | #1
On Nov 17, 2016, at 6:35 AM, David Howells <dhowells@redhat.com> wrote:
> 
> Return enhanced file attributes from the AFS filesystem.  This includes the
> following:
> 
> (1) The data version number as st_version, setting STATX_VERSION.
> 
> (2) STATX_ATTR_AUTOMOUNT will be set on automount directories by virtue of
>     S_AUTOMOUNT being set on the inode.  These are referrals to other
>     volumes or other cells.
> 
> (3) STATX_ATTR_UNLISTED_DENTS on a directory that does cell lookup for
>     non-existent names and mounts them (typically mounted on /afs with -o
>     autocell).  The resulting directories are marked STATX_ATTR_FABRICATED
>     as they do not actually exist in the mounted AFS directory.
> 
> (4) Files, directories and symlinks accessed over AFS are marked
>     STATX_ATTR_REMOTE.
> 
> STATX_ATIME, STATX_CTIME and STATX_BLOCKS are cleared as AFS does not
> support them.

Rather than clearing specific flags, wouldn't it be better to explicitly
set the flags that are actually being returned?  Otherwise, this would
have the problem that Dave pointed out on the 0/4 patch, that there may
be flags still set from userspace that do not mean anything to AFS.

Cheers, Andreas

> 
> Example output:
> 
> 	[root@andromeda ~]# ./samples/statx/test-statx /afs
> 	statx(/afs) = 0
> 	results=7ef
> 	  Size: 2048            Blocks: 0          IO Block: 4096    directory
> 	Device: 00:25           Inode: 1           Links: 2
> 	Access: (0777/drwxrwxrwx)  Uid:     0   Gid:     0
> 	Access: 2006-05-07 00:21:15.000000000+0100
> 	Modify: 2006-05-07 00:21:15.000000000+0100
> 	Change: 2006-05-07 00:21:15.000000000+0100
> 	IO-blocksize: blksize=4096
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
> 
> fs/afs/inode.c |   21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/afs/inode.c b/fs/afs/inode.c
> index 86cc7264c21c..b08c405a7e1b 100644
> --- a/fs/afs/inode.c
> +++ b/fs/afs/inode.c
> @@ -72,9 +72,9 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
> 	inode->i_uid		= vnode->status.owner;
> 	inode->i_gid		= GLOBAL_ROOT_GID;
> 	inode->i_size		= vnode->status.size;
> -	inode->i_ctime.tv_sec	= vnode->status.mtime_server;
> -	inode->i_ctime.tv_nsec	= 0;
> -	inode->i_atime		= inode->i_mtime = inode->i_ctime;
> +	inode->i_mtime.tv_sec	= vnode->status.mtime_server;
> +	inode->i_mtime.tv_nsec	= 0;
> +	inode->i_atime		= inode->i_ctime = inode->i_mtime;
> 	inode->i_blocks		= 0;
> 	inode->i_generation	= vnode->fid.unique;
> 	inode->i_version	= vnode->status.data_version;
> @@ -375,8 +375,7 @@ int afs_validate(struct afs_vnode *vnode, struct key *key)
> /*
>  * read the attributes of an inode
>  */
> -int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
> -		      struct kstat *stat)
> +int afs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
> {
> 	struct inode *inode;
> 
> @@ -385,6 +384,18 @@ int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
> 	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
> 
> 	generic_fillattr(inode, stat);
> +
> +	stat->result_mask &= ~(STATX_ATIME | STATX_CTIME | STATX_BLOCKS);
> +	stat->result_mask |= STATX_VERSION;
> +	stat->version = inode->i_version;
> +
> +	if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags))
> +		stat->attributes |= STATX_ATTR_UNLISTED_DENTS;
> +
> +	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
> +		stat->attributes |= STATX_ATTR_FABRICATED;
> +	else
> +		stat->attributes |= STATX_ATTR_REMOTE;
> 	return 0;
> }
> 
> 
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Cheers, Andreas
David Howells Nov. 18, 2016, 8:47 a.m. UTC | #2
Andreas Dilger <adilger@dilger.ca> wrote:

> > STATX_ATIME, STATX_CTIME and STATX_BLOCKS are cleared as AFS does not
> > support them.
> 
> Rather than clearing specific flags, wouldn't it be better to explicitly
> set the flags that are actually being returned?  Otherwise, this would
> have the problem that Dave pointed out on the 0/4 patch, that there may
> be flags still set from userspace that do not mean anything to AFS.

I'm not sure it make a difference.  generic_fillattr() has to initialise
result_mask to STATX_BASIC_STATS for the support of any unmodified filesystem.
We can then either clear the bits we don't want or just overwrite the mask
entirely with the bits we do want.

Bits in request_mask that are beyond STATX_BASIC_STATS are not automatically
propagated to result_mask.

Possibly vfs_xgetattr_nosec() should preset the result_mask rather than doing
this in generic_fillattr().

David
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Patch
diff mbox

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 86cc7264c21c..b08c405a7e1b 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -72,9 +72,9 @@  static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
 	inode->i_uid		= vnode->status.owner;
 	inode->i_gid		= GLOBAL_ROOT_GID;
 	inode->i_size		= vnode->status.size;
-	inode->i_ctime.tv_sec	= vnode->status.mtime_server;
-	inode->i_ctime.tv_nsec	= 0;
-	inode->i_atime		= inode->i_mtime = inode->i_ctime;
+	inode->i_mtime.tv_sec	= vnode->status.mtime_server;
+	inode->i_mtime.tv_nsec	= 0;
+	inode->i_atime		= inode->i_ctime = inode->i_mtime;
 	inode->i_blocks		= 0;
 	inode->i_generation	= vnode->fid.unique;
 	inode->i_version	= vnode->status.data_version;
@@ -375,8 +375,7 @@  int afs_validate(struct afs_vnode *vnode, struct key *key)
 /*
  * read the attributes of an inode
  */
-int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
-		      struct kstat *stat)
+int afs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
 {
 	struct inode *inode;
 
@@ -385,6 +384,18 @@  int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
 
 	generic_fillattr(inode, stat);
+
+	stat->result_mask &= ~(STATX_ATIME | STATX_CTIME | STATX_BLOCKS);
+	stat->result_mask |= STATX_VERSION;
+	stat->version = inode->i_version;
+
+	if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags))
+		stat->attributes |= STATX_ATTR_UNLISTED_DENTS;
+
+	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
+		stat->attributes |= STATX_ATTR_FABRICATED;
+	else
+		stat->attributes |= STATX_ATTR_REMOTE;
 	return 0;
 }