cifs: reorganize get_cifs_acl

Thus spake Christoph:

"But this whole set_cifs_acl function is a real mess anyway and needs
some splitting up."

With this change too, it's possible to call acl_to_uid_mode() with a
NULL inode pointer. That (or something close to it) will eventually be
necessary when cifs_get_inode_info is reorganized.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NShirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

fs/cifs/cifsacl.c

@@ -552,67 +552,66 @@ static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
 	return rc;
 }
 
-
-/* Retrieve an ACL from the server */
-static struct cifs_ntsd *get_cifs_acl(u32 *pacllen, struct inode *inode,
-				       const char *path, const __u16 *pfid)
+static struct cifs_ntsd *get_cifs_acl_by_fid(struct cifs_sb_info *cifs_sb,
+		__u16 fid, u32 *pacllen)
 {
-	struct cifsFileInfo *open_file = NULL;
-	bool unlock_file = false;
-	int xid;
-	int rc = -EIO;
-	__u16 fid;
-	struct super_block *sb;
-	struct cifs_sb_info *cifs_sb;
 	struct cifs_ntsd *pntsd = NULL;
+	int xid, rc;
 
-	cFYI(1, ("get mode from ACL for %s", path));
+	xid = GetXid();
+	rc = CIFSSMBGetCIFSACL(xid, cifs_sb->tcon, fid, &pntsd, pacllen);
+	FreeXid(xid);
 
-	if (inode == NULL)
-		return NULL;
 
-	xid = GetXid();
-	if (pfid == NULL)
-		open_file = find_readable_file(CIFS_I(inode));
-	else
-		fid = *pfid;
+	cFYI(1, ("GetCIFSACL rc = %d ACL len %d", rc, *pacllen));
+	return pntsd;
+}
 
-	sb = inode->i_sb;
-	if (sb == NULL) {
-		FreeXid(xid);
-		return NULL;
-	}
-	cifs_sb = CIFS_SB(sb);
+static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
+		const char *path, u32 *pacllen)
+{
+	struct cifs_ntsd *pntsd = NULL;
+	int oplock = 0;
+	int xid, rc;
+	__u16 fid;
 
-	if (open_file) {
-		unlock_file = true;
-		fid = open_file->netfid;
-	} else if (pfid == NULL) {
-		int oplock = 0;
-		/* open file */
-		rc = CIFSSMBOpen(xid, cifs_sb->tcon, path, FILE_OPEN,
-				READ_CONTROL, 0, &fid, &oplock, NULL,
-				cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
-					CIFS_MOUNT_MAP_SPECIAL_CHR);
-		if (rc != 0) {
-			cERROR(1, ("Unable to open file to get ACL"));
-			FreeXid(xid);
-			return NULL;
-		}
+	xid = GetXid();
+
+	rc = CIFSSMBOpen(xid, cifs_sb->tcon, path, FILE_OPEN, READ_CONTROL, 0,
+			 &fid, &oplock, NULL, cifs_sb->local_nls,
+			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+	if (rc) {
+		cERROR(1, ("Unable to open file to get ACL"));
+		goto out;
 	}
 
 	rc = CIFSSMBGetCIFSACL(xid, cifs_sb->tcon, fid, &pntsd, pacllen);
 	cFYI(1, ("GetCIFSACL rc = %d ACL len %d", rc, *pacllen));
-	if (unlock_file == true) /* find_readable_file increments ref count */
-		atomic_dec(&open_file->wrtPending);
-	else if (pfid == NULL) /* if opened above we have to close the handle */
-		CIFSSMBClose(xid, cifs_sb->tcon, fid);
-	/* else handle was passed in by caller */
 
+	CIFSSMBClose(xid, cifs_sb->tcon, fid);
+ out:
 	FreeXid(xid);
 	return pntsd;
 }
 
+/* Retrieve an ACL from the server */
+static struct cifs_ntsd *get_cifs_acl(struct cifs_sb_info *cifs_sb,
+				      struct inode *inode, const char *path,
+				      u32 *pacllen)
+{
+	struct cifs_ntsd *pntsd = NULL;
+	struct cifsFileInfo *open_file = NULL;
+
+	if (inode)
+		open_file = find_readable_file(CIFS_I(inode));
+	if (!open_file)
+		return get_cifs_acl_by_path(cifs_sb, path, pacllen);
+
+	pntsd = get_cifs_acl_by_fid(cifs_sb, open_file->netfid, pacllen);
+	atomic_dec(&open_file->wrtPending);
+	return pntsd;
+}
+
 /* Set an ACL on the server */
 static int set_cifs_acl(struct cifs_ntsd *pnntsd, __u32 acllen,
 				struct inode *inode, const char *path)
@@ -668,14 +667,19 @@ static int set_cifs_acl(struct cifs_ntsd *pnntsd, __u32 acllen,
 }
 
 /* Translate the CIFS ACL (simlar to NTFS ACL) for a file into mode bits */
-void acl_to_uid_mode(struct inode *inode, const char *path, const __u16 *pfid)
+void acl_to_uid_mode(struct cifs_sb_info *cifs_sb, struct inode *inode,
+		     const char *path, const __u16 *pfid)
 {
 	struct cifs_ntsd *pntsd = NULL;
 	u32 acllen = 0;
 	int rc = 0;
 
 	cFYI(DBG2, ("converting ACL to mode for %s", path));
-	pntsd = get_cifs_acl(&acllen, inode, path, pfid);
+
+	if (pfid)
+		pntsd = get_cifs_acl_by_fid(cifs_sb, *pfid, &acllen);
+	else
+		pntsd = get_cifs_acl(cifs_sb, inode, path, &acllen);
 
 	/* if we can retrieve the ACL, now parse Access Control Entries, ACEs */
 	if (pntsd)
@@ -698,7 +702,7 @@ int mode_to_acl(struct inode *inode, const char *path, __u64 nmode)
 	cFYI(DBG2, ("set ACL from mode for %s", path));
 
 	/* Get the security descriptor */
-	pntsd = get_cifs_acl(&secdesclen, inode, path, NULL);
+	pntsd = get_cifs_acl(CIFS_SB(inode->i_sb), inode, path, &secdesclen);
 
 	/* Add three ACEs for owner, group, everyone getting rid of
 	   other ACEs as chmod disables ACEs and set the security descriptor */

fs/cifs/cifsproto.h

@@ -108,8 +108,8 @@ extern int cifs_get_inode_info(struct inode **pinode,
 extern int cifs_get_inode_info_unix(struct inode **pinode,
 			const unsigned char *search_path,
 			struct super_block *sb, int xid);
-extern void acl_to_uid_mode(struct inode *inode, const char *path,
-			    const __u16 *pfid);
+extern void acl_to_uid_mode(struct cifs_sb_info *cifs_sb, struct inode *inode,
+			    const char *path, const __u16 *pfid);
 extern int mode_to_acl(struct inode *inode, const char *path, __u64);
 
 extern int cifs_mount(struct super_block *, struct cifs_sb_info *, char *,

fs/cifs/inode.c

@@ -626,7 +626,7 @@ int cifs_get_inode_info(struct inode **pinode,
 	/* fill in 0777 bits from ACL */
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) {
 		cFYI(1, ("Getting mode bits from ACL"));
-		acl_to_uid_mode(inode, full_path, pfid);
+		acl_to_uid_mode(cifs_sb, inode, full_path, pfid);
 	}
 #endif
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {