Re: [PATCH 2/3] cifs: use CreationTime like an i_generation field

[Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org>]

On 06/28/2010 04:40 PM, Jeff Layton wrote:
> Reduce false inode collisions by using the CreationTime like an
> i_generation field. This way, even if the server ends up reusing
> a uniqueid after a delete/create cycle, we can avoid matching
> the inode incorrectly.
> 
> Signed-off-by: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  fs/cifs/cifsfs.c   |    2 ++
>  fs/cifs/cifsglob.h |    2 ++
>  fs/cifs/inode.c    |    6 ++++++
>  fs/cifs/readdir.c  |    1 +
>  4 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index 484e52b..e409216 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -314,6 +314,8 @@ cifs_alloc_inode(struct super_block *sb)
>  	cifs_inode->invalid_mapping = false;
>  	cifs_inode->vfs_inode.i_blkbits = 14;  /* 2**14 = CIFS_MAX_MSGSIZE */
>  	cifs_inode->server_eof = 0;
> +	cifs_inode->uniqueid = 0;
> +	cifs_inode->createtime = 0;
>  
>  	/* Can not set i_flags here - they get immediately overwritten
>  	   to zero by the VFS */
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index e15d7a5..a0fd2c2 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -382,6 +382,7 @@ struct cifsInodeInfo {
>  	bool invalid_mapping:1;		/* pagecache is invalid */
>  	u64  server_eof;		/* current file size on server */
>  	u64  uniqueid;			/* server inode number */
> +	u64  createtime;		/* creation time on server */
>  	struct inode vfs_inode;
>  };
>  
> @@ -499,6 +500,7 @@ struct cifs_fattr {
>  	u64		cf_uniqueid;
>  	u64		cf_eof;
>  	u64		cf_bytes;
> +	u64		cf_createtime;
>  	uid_t		cf_uid;
>  	gid_t		cf_gid;
>  	umode_t		cf_mode;
> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> index f64b95f..35e2466 100644
> --- a/fs/cifs/inode.c
> +++ b/fs/cifs/inode.c
> @@ -487,6 +487,7 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
>  
>  	fattr->cf_eof = le64_to_cpu(info->EndOfFile);
>  	fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
> +	fattr->cf_createtime = le64_to_cpu(info->CreationTime);
>  
>  	if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
>  		fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
> @@ -727,6 +728,10 @@ cifs_find_inode(struct inode *inode, void *opaque)
>  	if (CIFS_I(inode)->uniqueid != fattr->cf_uniqueid)
>  		return 0;
>  
> +	/* use createtime like an i_generation field */
> +	if (CIFS_I(inode)->createtime != fattr->cf_createtime)
> +		return 0;
> +
>  	/* don't match inode of different type */
>  	if ((inode->i_mode & S_IFMT) != (fattr->cf_mode & S_IFMT))
>  		return 0;
> @@ -750,6 +755,7 @@ cifs_init_inode(struct inode *inode, void *opaque)
>  	struct cifs_fattr *fattr = (struct cifs_fattr *) opaque;
>  
>  	CIFS_I(inode)->uniqueid = fattr->cf_uniqueid;
> +	CIFS_I(inode)->createtime = fattr->cf_createtime;
>  	return 0;
>  }
>  
> diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
> index daf1753..8bd18be 100644
> --- a/fs/cifs/readdir.c
> +++ b/fs/cifs/readdir.c
> @@ -160,6 +160,7 @@ cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
>  	fattr->cf_cifsattrs = le32_to_cpu(info->ExtFileAttributes);
>  	fattr->cf_eof = le64_to_cpu(info->EndOfFile);
>  	fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
> +	fattr->cf_createtime = le64_to_cpu(info->CreationTime);

cifs_std_info_to_fattr() needs this too?

>  	fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
>  	fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
>  	fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);


-- 
Suresh Jayaraman