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 c10f0851cd2..b1ca6a43ac1 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);