add function to convert access flags to legacy open mode

SMBLegacyOpen always opens a file as r/w. This could be problematic
for files with ATTR_READONLY set. Have it interpret the access_mode
into a sane open mode.

Signed-off-by: Steve French <sfrench@us.ibm.com>

2 files changed, 16 insertions, 9 deletions

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 3c05c2de50e1..9c04ad404553 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1166,6 +1166,20 @@ static __u16 convert_disposition(int disposition)
         return ofun;
 }
 
+static int
+access_flags_to_smbopen_mode(const int access_flags)
+{
+        int masked_flags = access_flags & (GENERIC_READ | GENERIC_WRITE);
+
+        if (masked_flags == GENERIC_READ)
+                return SMBOPEN_READ;
+        else if (masked_flags == GENERIC_WRITE)
+                return SMBOPEN_WRITE;
+
+        /* just go for read/write */
+        return SMBOPEN_READWRITE;
+}
+
 int
 SMBLegacyOpen(const int xid, struct cifsTconInfo *tcon,
             const char *fileName, const int openDisposition,
@@ -1207,13 +1221,7 @@ OldOpenRetry:
                 pSMB->OpenFlags = cpu_to_le16(REQ_BATCHOPLOCK);
 
         pSMB->OpenFlags |= cpu_to_le16(REQ_MORE_INFO);
-        /* BB fixme add conversion for access_flags to bits 0 - 2 of mode */
-        /* 0 = read
-           1 = write
-           2 = rw
-           3 = execute
-         */
-        pSMB->Mode = cpu_to_le16(2);
+        pSMB->Mode = cpu_to_le16(access_flags_to_smbopen_mode(access_flags));
         pSMB->Mode |= cpu_to_le16(0x40); /* deny none */
         /* set file as system file if special file such
            as fifo and server expecting SFU style and
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index fcbdbb6ad7bf..2d53b436d511 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1502,8 +1502,7 @@ int cifs_setattr(struct dentry *direntry, struct iattr *attrs)
                                 int oplock = 0;
 
                                 rc = SMBLegacyOpen(xid, pTcon, full_path,
-                                        FILE_OPEN,
-                                        SYNCHRONIZE | FILE_WRITE_ATTRIBUTES,
+                                        FILE_OPEN, GENERIC_WRITE,
                                         CREATE_NOT_DIR, &netfid, &oplock,
                                         NULL, cifs_sb->local_nls,
                                         cifs_sb->mnt_cifs_flags &