[CIFS] Enable DFS support for Unix query path info

Final piece for handling DFS in unix_query_path_info, constructing a
fake inode for the junction directory which the submount will cover.

Acked-by: Igor Mammedov <niallain@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 74 insertions, 43 deletions

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 9d9b56a9c08e..422d4e219fa4 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -161,77 +161,108 @@ static void cifs_unix_info_to_inode(struct inode *inode,
         spin_unlock(&inode->i_lock);
 }
 
+static void fill_fake_finddataunix(FILE_UNIX_BASIC_INFO *pfnd_dat,
+                               struct super_block *sb)
+{
+        struct inode *pinode = NULL;
+
+        memset(pfnd_dat, sizeof(FILE_UNIX_BASIC_INFO), 0);
+
+/*      __le64 pfnd_dat->EndOfFile = cpu_to_le64(0);
+        __le64 pfnd_dat->NumOfBytes = cpu_to_le64(0);
+        __u64 UniqueId = 0;  */
+        pfnd_dat->LastStatusChange =
+                cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
+        pfnd_dat->LastAccessTime =
+                cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
+        pfnd_dat->LastModificationTime =
+                cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
+        pfnd_dat->Type = cpu_to_le32(UNIX_DIR);
+        pfnd_dat->Permissions = cpu_to_le64(S_IXUGO | S_IRWXU);
+        pfnd_dat->Nlinks = cpu_to_le64(2);
+        if (sb->s_root)
+                pinode = sb->s_root->d_inode;
+        if (pinode == NULL)
+                return;
+
+        /* fill in default values for the remaining based on root
+           inode since we can not query the server for this inode info */
+        pfnd_dat->DevMajor = cpu_to_le64(MAJOR(pinode->i_rdev));
+        pfnd_dat->DevMinor = cpu_to_le64(MINOR(pinode->i_rdev));
+        pfnd_dat->Uid = cpu_to_le64(pinode->i_uid);
+        pfnd_dat->Gid = cpu_to_le64(pinode->i_gid);
+}
+
 int cifs_get_inode_info_unix(struct inode **pinode,
         const unsigned char *full_path, struct super_block *sb, int xid)
 {
         int rc = 0;
-        FILE_UNIX_BASIC_INFO findData;
+        FILE_UNIX_BASIC_INFO find_data;
         struct cifsTconInfo *pTcon;
         struct inode *inode;
         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
         bool is_dfs_referral = false;
+        struct cifsInodeInfo *cifsInfo;
+        __u64 num_of_bytes;
+        __u64 end_of_file;
 
         pTcon = cifs_sb->tcon;
         cFYI(1, ("Getting info on %s", full_path));
 
-try_again_CIFSSMBUnixQPathInfo:
         /* could have done a find first instead but this returns more info */
-        rc = CIFSSMBUnixQPathInfo(xid, pTcon, full_path, &findData,
+        rc = CIFSSMBUnixQPathInfo(xid, pTcon, full_path, &find_data,
                                   cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
                                         CIFS_MOUNT_MAP_SPECIAL_CHR);
-/*      dump_mem("\nUnixQPathInfo return data", &findData,
-                 sizeof(findData)); */
         if (rc) {
                 if (rc == -EREMOTE && !is_dfs_referral) {
                         is_dfs_referral = true;
-                        goto try_again_CIFSSMBUnixQPathInfo;
+                        cERROR(1, ("DFS ref")); /* BB removeme BB */
+                        /* for DFS, server does not give us real inode data */
+                        fill_fake_finddataunix(&find_data, sb);
+                        rc = 0;
                 }
-                goto cgiiu_exit;
-        } else {
-                struct cifsInodeInfo *cifsInfo;
-                __u64 num_of_bytes = le64_to_cpu(findData.NumOfBytes);
-                __u64 end_of_file = le64_to_cpu(findData.EndOfFile);
+        }
+        num_of_bytes = le64_to_cpu(find_data.NumOfBytes);
+        end_of_file = le64_to_cpu(find_data.EndOfFile);
 
-                /* get new inode */
+        /* get new inode */
+        if (*pinode == NULL) {
+                *pinode = new_inode(sb);
                 if (*pinode == NULL) {
-                        *pinode = new_inode(sb);
-                        if (*pinode == NULL) {
-                                rc = -ENOMEM;
-                                goto cgiiu_exit;
-                        }
-                        /* Is an i_ino of zero legal? */
-                        /* Are there sanity checks we can use to ensure that
-                           the server is really filling in that field? */
-                        if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
-                                (*pinode)->i_ino =
-                                        (unsigned long)findData.UniqueId;
-                        } /* note ino incremented to unique num in new_inode */
-                        if (sb->s_flags & MS_NOATIME)
-                                (*pinode)->i_flags |= S_NOATIME | S_NOCMTIME;
-
-                        insert_inode_hash(*pinode);
+                        rc = -ENOMEM;
+                goto cgiiu_exit;
                 }
+                /* Is an i_ino of zero legal? */
+                /* note ino incremented to unique num in new_inode */
+                /* Are there sanity checks we can use to ensure that
+                   the server is really filling in that field? */
+                if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)
+                        (*pinode)->i_ino = (unsigned long)find_data.UniqueId;
 
-                inode = *pinode;
-                cifsInfo = CIFS_I(inode);
+                if (sb->s_flags & MS_NOATIME)
+                        (*pinode)->i_flags |= S_NOATIME | S_NOCMTIME;
 
-                cFYI(1, ("Old time %ld", cifsInfo->time));
-                cifsInfo->time = jiffies;
-                cFYI(1, ("New time %ld", cifsInfo->time));
-                /* this is ok to set on every inode revalidate */
-                atomic_set(&cifsInfo->inUse, 1);
+                insert_inode_hash(*pinode);
+        }
 
-                cifs_unix_info_to_inode(inode, &findData, 0);
+        inode = *pinode;
+        cifsInfo = CIFS_I(inode);
 
+        cFYI(1, ("Old time %ld", cifsInfo->time));
+        cifsInfo->time = jiffies;
+        cFYI(1, ("New time %ld", cifsInfo->time));
+        /* this is ok to set on every inode revalidate */
+        atomic_set(&cifsInfo->inUse, 1);
 
-                if (num_of_bytes < end_of_file)
-                        cFYI(1, ("allocation size less than end of file"));
-                cFYI(1, ("Size %ld and blocks %llu",
-                        (unsigned long) inode->i_size,
-                        (unsigned long long)inode->i_blocks));
+        cifs_unix_info_to_inode(inode, &find_data, 0);
 
-                cifs_set_ops(inode, is_dfs_referral);
-        }
+        if (num_of_bytes < end_of_file)
+                cFYI(1, ("allocation size less than end of file"));
+        cFYI(1, ("Size %ld and blocks %llu",
+                (unsigned long) inode->i_size,
+                (unsigned long long)inode->i_blocks));
+
+        cifs_set_ops(inode, is_dfs_referral);
 cgiiu_exit:
         return rc;
 }