cifs: Include backup intent search flags during searches {try #2)

As observed and suggested by Tushar Gosavi...

---------
readdir calls these function to send TRANS2_FIND_FIRST and
TRANS2_FIND_NEXT command to the server. The current cifs module is
not specifying CIFS_SEARCH_BACKUP_SEARCH flag while sending these
command when backupuid/backupgid is specified. This can be resolved
by specifying CIFS_SEARCH_BACKUP_SEARCH flag.
---------

Cc: <stable@kernel.org>
Reported-and-Tested-by: Tushar Gosavi <tugosavi@in.ibm.com>
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

3 files changed, 22 insertions, 11 deletions

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index eeb789d8e85..0a3fa960b84 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -192,11 +192,13 @@ extern int CIFSTCon(unsigned int xid, struct cifs_ses *ses,
 
 extern int CIFSFindFirst(const int xid, struct cifs_tcon *tcon,
                 const char *searchName, const struct nls_table *nls_codepage,
-                __u16 *searchHandle, struct cifs_search_info *psrch_inf,
+                __u16 *searchHandle, __u16 search_flags,
+                struct cifs_search_info *psrch_inf,
                 int map, const char dirsep);
 
 extern int CIFSFindNext(const int xid, struct cifs_tcon *tcon,
-                __u16 searchHandle, struct cifs_search_info *psrch_inf);
+                __u16 searchHandle, __u16 search_flags,
+                struct cifs_search_info *psrch_inf);
 
 extern int CIFSFindClose(const int, struct cifs_tcon *tcon,
                         const __u16 search_handle);
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 45633da461a..3563c93d9f1 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -4238,7 +4238,7 @@ int
 CIFSFindFirst(const int xid, struct cifs_tcon *tcon,
               const char *searchName,
               const struct nls_table *nls_codepage,
-              __u16 *pnetfid,
+              __u16 *pnetfid, __u16 search_flags,
               struct cifs_search_info *psrch_inf, int remap, const char dirsep)
 {
 /* level 257 SMB_ */
@@ -4310,8 +4310,7 @@ findFirstRetry:
             cpu_to_le16(ATTR_READONLY | ATTR_HIDDEN | ATTR_SYSTEM |
                         ATTR_DIRECTORY);
         pSMB->SearchCount = cpu_to_le16(CIFSMaxBufSize/sizeof(FILE_UNIX_INFO));
-        pSMB->SearchFlags = cpu_to_le16(CIFS_SEARCH_CLOSE_AT_END |
-                CIFS_SEARCH_RETURN_RESUME);
+        pSMB->SearchFlags = cpu_to_le16(search_flags);
         pSMB->InformationLevel = cpu_to_le16(psrch_inf->info_level);
 
         /* BB what should we set StorageType to? Does it matter? BB */
@@ -4381,8 +4380,8 @@ findFirstRetry:
         return rc;
 }
 
-int CIFSFindNext(const int xid, struct cifs_tcon *tcon,
-                 __u16 searchHandle, struct cifs_search_info *psrch_inf)
+int CIFSFindNext(const int xid, struct cifs_tcon *tcon, __u16 searchHandle,
+                 __u16 search_flags, struct cifs_search_info *psrch_inf)
 {
         TRANSACTION2_FNEXT_REQ *pSMB = NULL;
         TRANSACTION2_FNEXT_RSP *pSMBr = NULL;
@@ -4425,8 +4424,7 @@ int CIFSFindNext(const int xid, struct cifs_tcon *tcon,
                 cpu_to_le16(CIFSMaxBufSize / sizeof(FILE_UNIX_INFO));
         pSMB->InformationLevel = cpu_to_le16(psrch_inf->info_level);
         pSMB->ResumeKey = psrch_inf->resume_key;
-        pSMB->SearchFlags =
-              cpu_to_le16(CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME);
+        pSMB->SearchFlags = cpu_to_le16(search_flags);
 
         name_len = psrch_inf->resume_name_len;
         params += name_len;
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index e2bbc683e01..0a8224d1c4c 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -219,6 +219,7 @@ int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 
 static int initiate_cifs_search(const int xid, struct file *file)
 {
+        __u16 search_flags;
         int rc = 0;
         char *full_path = NULL;
         struct cifsFileInfo *cifsFile;
@@ -270,8 +271,12 @@ ffirst_retry:
                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
         }
 
+        search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
+        if (backup_cred(cifs_sb))
+                search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
+
         rc = CIFSFindFirst(xid, pTcon, full_path, cifs_sb->local_nls,
-                &cifsFile->netfid, &cifsFile->srch_inf,
+                &cifsFile->netfid, search_flags, &cifsFile->srch_inf,
                 cifs_sb->mnt_cifs_flags &
                         CIFS_MOUNT_MAP_SPECIAL_CHR, CIFS_DIR_SEP(cifs_sb));
         if (rc == 0)
@@ -502,11 +507,13 @@ static int cifs_save_resume_key(const char *current_entry,
 static int find_cifs_entry(const int xid, struct cifs_tcon *pTcon,
         struct file *file, char **ppCurrentEntry, int *num_to_ret)
 {
+        __u16 search_flags;
         int rc = 0;
         int pos_in_buf = 0;
         loff_t first_entry_in_buffer;
         loff_t index_to_find = file->f_pos;
         struct cifsFileInfo *cifsFile = file->private_data;
+        struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
         /* check if index in the buffer */
 
         if ((cifsFile == NULL) || (ppCurrentEntry == NULL) ||
@@ -560,10 +567,14 @@ static int find_cifs_entry(const int xid, struct cifs_tcon *pTcon,
                                                 cifsFile);
         }
 
+        search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
+        if (backup_cred(cifs_sb))
+                search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
+
         while ((index_to_find >= cifsFile->srch_inf.index_of_last_entry) &&
               (rc == 0) && !cifsFile->srch_inf.endOfSearch) {
                 cFYI(1, "calling findnext2");
-                rc = CIFSFindNext(xid, pTcon, cifsFile->netfid,
+                rc = CIFSFindNext(xid, pTcon, cifsFile->netfid, search_flags,
                                   &cifsFile->srch_inf);
                 /* FindFirst/Next set last_entry to NULL on malformed reply */
                 if (cifsFile->srch_inf.last_entry)