cifs: fix flags handling in cifs_posix_open

The way flags are passed and converted for cifs_posix_open is rather
non-sensical. Some callers call cifs_posix_convert_flags on the flags
before they pass them to cifs_posix_open, whereas some don't. Two flag
conversion steps is just confusing though.

Change the function instead to clearly expect input in f_flags format,
and fix the callers to pass that in. Then, have cifs_posix_open call
cifs_convert_posix_flags to do the conversion. Move cifs_posix_open to
file.c as well so we can keep cifs_convert_posix_flags as a static
function.

Fix it also to not ignore O_CREAT, O_EXCL and O_TRUNC, and instead have
cifs_reopen_file mask those bits off before calling cifs_posix_open.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 88 insertions, 25 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c10f0851cd21..b1ca6a43ac1a 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -60,34 +60,32 @@ static inline int cifs_convert_flags(unsigned int flags)
                 FILE_READ_DATA);
 }
 
-static inline fmode_t cifs_posix_convert_flags(unsigned int flags)
+static u32 cifs_posix_convert_flags(unsigned int flags)
 {
-        fmode_t posix_flags = 0;
+        u32 posix_flags = 0;
 
         if ((flags & O_ACCMODE) == O_RDONLY)
-                posix_flags = FMODE_READ;
+                posix_flags = SMB_O_RDONLY;
         else if ((flags & O_ACCMODE) == O_WRONLY)
-                posix_flags = FMODE_WRITE;
-        else if ((flags & O_ACCMODE) == O_RDWR) {
-                /* GENERIC_ALL is too much permission to request
-                   can cause unnecessary access denied on create */
-                /* return GENERIC_ALL; */
-                posix_flags = FMODE_READ | FMODE_WRITE;
-        }
-        /* can not map O_CREAT or O_EXCL or O_TRUNC flags when
-           reopening a file.  They had their effect on the original open */
-        if (flags & O_APPEND)
-                posix_flags |= (fmode_t)O_APPEND;
+                posix_flags = SMB_O_WRONLY;
+        else if ((flags & O_ACCMODE) == O_RDWR)
+                posix_flags = SMB_O_RDWR;
+
+        if (flags & O_CREAT)
+                posix_flags |= SMB_O_CREAT;
+        if (flags & O_EXCL)
+                posix_flags |= SMB_O_EXCL;
+        if (flags & O_TRUNC)
+                posix_flags |= SMB_O_TRUNC;
+        /* be safe and imply O_SYNC for O_DSYNC */
         if (flags & O_DSYNC)
-                posix_flags |= (fmode_t)O_DSYNC;
-        if (flags & __O_SYNC)
-                posix_flags |= (fmode_t)__O_SYNC;
+                posix_flags |= SMB_O_SYNC;
         if (flags & O_DIRECTORY)
-                posix_flags |= (fmode_t)O_DIRECTORY;
+                posix_flags |= SMB_O_DIRECTORY;
         if (flags & O_NOFOLLOW)
-                posix_flags |= (fmode_t)O_NOFOLLOW;
+                posix_flags |= SMB_O_NOFOLLOW;
         if (flags & O_DIRECT)
-                posix_flags |= (fmode_t)O_DIRECT;
+                posix_flags |= SMB_O_DIRECT;
 
         return posix_flags;
 }
@@ -159,6 +157,68 @@ client_can_cache:
         return rc;
 }
 
+int cifs_posix_open(char *full_path, struct inode **pinode,
+                        struct super_block *sb, int mode, unsigned int f_flags,
+                        __u32 *poplock, __u16 *pnetfid, int xid)
+{
+        int rc;
+        FILE_UNIX_BASIC_INFO *presp_data;
+        __u32 posix_flags = 0;
+        struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+        struct cifs_fattr fattr;
+        struct tcon_link *tlink;
+        struct cifsTconInfo *tcon;
+
+        cFYI(1, "posix open %s", full_path);
+
+        presp_data = kzalloc(sizeof(FILE_UNIX_BASIC_INFO), GFP_KERNEL);
+        if (presp_data == NULL)
+                return -ENOMEM;
+
+        tlink = cifs_sb_tlink(cifs_sb);
+        if (IS_ERR(tlink)) {
+                rc = PTR_ERR(tlink);
+                goto posix_open_ret;
+        }
+
+        tcon = tlink_tcon(tlink);
+        mode &= ~current_umask();
+
+        posix_flags = cifs_posix_convert_flags(f_flags);
+        rc = CIFSPOSIXCreate(xid, tcon, posix_flags, mode, pnetfid, presp_data,
+                             poplock, full_path, cifs_sb->local_nls,
+                             cifs_sb->mnt_cifs_flags &
+                                        CIFS_MOUNT_MAP_SPECIAL_CHR);
+        cifs_put_tlink(tlink);
+
+        if (rc)
+                goto posix_open_ret;
+
+        if (presp_data->Type == cpu_to_le32(-1))
+                goto posix_open_ret; /* open ok, caller does qpathinfo */
+
+        if (!pinode)
+                goto posix_open_ret; /* caller does not need info */
+
+        cifs_unix_basic_to_fattr(&fattr, presp_data, cifs_sb);
+
+        /* get new inode and set it up */
+        if (*pinode == NULL) {
+                cifs_fill_uniqueid(sb, &fattr);
+                *pinode = cifs_iget(sb, &fattr);
+                if (!*pinode) {
+                        rc = -ENOMEM;
+                        goto posix_open_ret;
+                }
+        } else {
+                cifs_fattr_to_inode(*pinode, &fattr);
+        }
+
+posix_open_ret:
+        kfree(presp_data);
+        return rc;
+}
+
 int cifs_open(struct inode *inode, struct file *file)
 {
         int rc = -EACCES;
@@ -205,12 +265,10 @@ int cifs_open(struct inode *inode, struct file *file)
             (tcon->ses->capabilities & CAP_UNIX) &&
             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
                         le64_to_cpu(tcon->fsUnixInfo.Capability))) {
-                int oflags = (int) cifs_posix_convert_flags(file->f_flags);
-                oflags |= SMB_O_CREAT;
                 /* can not refresh inode info since size could be stale */
                 rc = cifs_posix_open(full_path, &inode, inode->i_sb,
                                 cifs_sb->mnt_file_mode /* ignored */,
-                                oflags, &oplock, &netfid, xid);
+                                file->f_flags, &oplock, &netfid, xid);
                 if (rc == 0) {
                         cFYI(1, "posix open succeeded");
 
@@ -426,8 +484,13 @@ reopen_error_exit:
         if (tcon->unix_ext && (tcon->ses->capabilities & CAP_UNIX) &&
             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
                         le64_to_cpu(tcon->fsUnixInfo.Capability))) {
-                int oflags = (int) cifs_posix_convert_flags(file->f_flags);
-                /* can not refresh inode info since size could be stale */
+
+                /*
+                 * O_CREAT, O_EXCL and O_TRUNC already had their effect on the
+                 * original open. Must mask them off for a reopen.
+                 */
+                unsigned int oflags = file->f_flags & ~(O_CREAT|O_EXCL|O_TRUNC);
+
                 rc = cifs_posix_open(full_path, NULL, inode->i_sb,
                                 cifs_sb->mnt_file_mode /* ignored */,
                                 oflags, &oplock, &netfid, xid);