cifs: use CreationTime like an i_generation field
Jeff Layton [Fri, 7 Jan 2011 16:30:27 +0000 (11:30 -0500)]
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@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsfs.c
fs/cifs/cifsglob.h
fs/cifs/inode.c
fs/cifs/readdir.c

index 5abfeda..5e7075d 100644 (file)
@@ -329,6 +329,8 @@ 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 */
index e6590e6..606ca8b 100644 (file)
@@ -453,6 +453,7 @@ 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 */
 #ifdef CONFIG_CIFS_FSCACHE
        struct fscache_cookie *fscache;
 #endif
@@ -573,6 +574,7 @@ 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;
index a853a89..0c7e369 100644 (file)
@@ -518,6 +518,7 @@ 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;
@@ -779,6 +780,10 @@ 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;
@@ -796,6 +801,7 @@ 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;
 }
 
index ec5b68e..76b1b37 100644 (file)
@@ -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);
        fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
        fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
        fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);