cifs: use CreationTime like an i_generation field

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>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index a853a89857a5..0c7e36910e31 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -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;
 }