JFS: add uid, gid, and umask mount options

OS/2 doesn't initialize the uid, gid, or unix-style permission bits.  The
uid, gid, & umask mount options perform pretty much like those for the fat
file system, overriding what is stored on disk.  This is useful for users
sharing the file system with OS/2.

I implemented a little feature so that if you mask the execute bit, it
will be re-enabled on directories when the appropriate read bit is unmasked.
I didn't want to implement an fmask & dmask option.
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

fs/jfs/acl.c

@@ -183,6 +183,9 @@ cleanup:
 		posix_acl_release(acl);
 	} else
 		inode->i_mode &= ~current->fs->umask;
+	
+	JFS_IP(inode)->mode2 = (JFS_IP(inode)->mode2 & 0xffff0000) |
+			       inode->i_mode;
 
 	return rc;
 }

fs/jfs/jfs_imap.c

@@ -3074,14 +3074,40 @@ static void duplicateIXtree(struct super_block *sb, s64 blkno,
 static int copy_from_dinode(struct dinode * dip, struct inode *ip)
 {
 	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
 
 	jfs_ip->fileset = le32_to_cpu(dip->di_fileset);
 	jfs_ip->mode2 = le32_to_cpu(dip->di_mode);
 
 	ip->i_mode = le32_to_cpu(dip->di_mode) & 0xffff;
+	if (sbi->umask != -1) {
+		ip->i_mode = (ip->i_mode & ~0777) | (0777 & ~sbi->umask);
+		/* For directories, add x permission if r is allowed by umask */
+		if (S_ISDIR(ip->i_mode)) {
+			if (ip->i_mode & 0400)
+				ip->i_mode |= 0100;
+			if (ip->i_mode & 0040)
+				ip->i_mode |= 0010;
+			if (ip->i_mode & 0004)
+				ip->i_mode |= 0001;
+		}
+	}
 	ip->i_nlink = le32_to_cpu(dip->di_nlink);
-	ip->i_uid = le32_to_cpu(dip->di_uid);
-	ip->i_gid = le32_to_cpu(dip->di_gid);
+
+	jfs_ip->saved_uid = le32_to_cpu(dip->di_uid);
+	if (sbi->uid == -1)
+		ip->i_uid = jfs_ip->saved_uid;
+	else {
+		ip->i_uid = sbi->uid;
+	}
+
+	jfs_ip->saved_gid = le32_to_cpu(dip->di_gid);
+	if (sbi->gid == -1)
+		ip->i_gid = jfs_ip->saved_gid;
+	else {
+		ip->i_gid = sbi->gid;
+	}
+
 	ip->i_size = le64_to_cpu(dip->di_size);
 	ip->i_atime.tv_sec = le32_to_cpu(dip->di_atime.tv_sec);
 	ip->i_atime.tv_nsec = le32_to_cpu(dip->di_atime.tv_nsec);
@@ -3132,21 +3158,33 @@ static int copy_from_dinode(struct dinode * dip, struct inode *ip)
 static void copy_to_dinode(struct dinode * dip, struct inode *ip)
 {
 	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
+	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
 
 	dip->di_fileset = cpu_to_le32(jfs_ip->fileset);
-	dip->di_inostamp = cpu_to_le32(JFS_SBI(ip->i_sb)->inostamp);
+	dip->di_inostamp = cpu_to_le32(sbi->inostamp);
 	dip->di_number = cpu_to_le32(ip->i_ino);
 	dip->di_gen = cpu_to_le32(ip->i_generation);
 	dip->di_size = cpu_to_le64(ip->i_size);
 	dip->di_nblocks = cpu_to_le64(PBLK2LBLK(ip->i_sb, ip->i_blocks));
 	dip->di_nlink = cpu_to_le32(ip->i_nlink);
-	dip->di_uid = cpu_to_le32(ip->i_uid);
-	dip->di_gid = cpu_to_le32(ip->i_gid);
+	if (sbi->uid == -1)
+		dip->di_uid = cpu_to_le32(ip->i_uid);
+	else
+		dip->di_uid = cpu_to_le32(jfs_ip->saved_uid);
+	if (sbi->gid == -1)
+		dip->di_gid = cpu_to_le32(ip->i_gid);
+	else
+		dip->di_gid = cpu_to_le32(jfs_ip->saved_gid);
 	/*
 	 * mode2 is only needed for storing the higher order bits.
 	 * Trust i_mode for the lower order ones
 	 */
-	dip->di_mode = cpu_to_le32((jfs_ip->mode2 & 0xffff0000) | ip->i_mode);
+	if (sbi->umask == -1)
+		dip->di_mode = cpu_to_le32((jfs_ip->mode2 & 0xffff0000) |
+					   ip->i_mode);
+	else /* Leave the original permissions alone */
+		dip->di_mode = cpu_to_le32(jfs_ip->mode2);
+
 	dip->di_atime.tv_sec = cpu_to_le32(ip->i_atime.tv_sec);
 	dip->di_atime.tv_nsec = cpu_to_le32(ip->i_atime.tv_nsec);
 	dip->di_ctime.tv_sec = cpu_to_le32(ip->i_ctime.tv_sec);

fs/jfs/jfs_incore.h

@@ -38,6 +38,8 @@
 struct jfs_inode_info {
 	int	fileset;	/* fileset number (always 16)*/
 	uint	mode2;		/* jfs-specific mode		*/
+	uint	saved_uid;	/* saved for uid mount option */
+	uint	saved_gid;	/* saved for gid mount option */
 	pxd_t   ixpxd;		/* inode extent descriptor	*/
 	dxd_t	acl;		/* dxd describing acl	*/
 	dxd_t	ea;		/* dxd describing ea	*/
@@ -170,6 +172,9 @@ struct jfs_sb_info {
 	uint		state;		/* mount/recovery state	*/
 	unsigned long	flag;		/* mount time flags */
 	uint		p_state;	/* state prior to going no integrity */
+	uint		uid;		/* uid to override on-disk uid */
+	uint		gid;		/* gid to override on-disk gid */
+	uint		umask;		/* umask to override on-disk umask */
 };
 
 /* jfs_sb_info commit_state */

fs/jfs/jfs_inode.c

@@ -82,6 +82,13 @@ struct inode *ialloc(struct inode *parent, umode_t mode)
 	} else
 		inode->i_gid = current->fsgid;
 
+	/*
+	 * New inodes need to save sane values on disk when
+	 * uid & gid mount options are used
+	 */
+	jfs_inode->saved_uid = inode->i_uid;
+	jfs_inode->saved_gid = inode->i_gid;
+
 	/*
 	 * Allocate inode to quota.
 	 */

fs/jfs/super.c

@@ -194,7 +194,7 @@ static void jfs_put_super(struct super_block *sb)
 enum {
 	Opt_integrity, Opt_nointegrity, Opt_iocharset, Opt_resize,
 	Opt_resize_nosize, Opt_errors, Opt_ignore, Opt_err, Opt_quota,
-	Opt_usrquota, Opt_grpquota
+	Opt_usrquota, Opt_grpquota, Opt_uid, Opt_gid, Opt_umask
 };
 
 static match_table_t tokens = {
@@ -208,6 +208,9 @@ static match_table_t tokens = {
 	{Opt_ignore, "quota"},
 	{Opt_usrquota, "usrquota"},
 	{Opt_grpquota, "grpquota"},
+	{Opt_uid, "uid=%u"},
+	{Opt_gid, "gid=%u"},
+	{Opt_umask, "umask=%u"},
 	{Opt_err, NULL}
 };
 
@@ -312,7 +315,29 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
 			       "JFS: quota operations not supported\n");
 			break;
 #endif
-
+		case Opt_uid:
+		{
+			char *uid = args[0].from;
+			sbi->uid = simple_strtoul(uid, &uid, 0);
+			break;
+		}
+		case Opt_gid:
+		{
+			char *gid = args[0].from;
+			sbi->gid = simple_strtoul(gid, &gid, 0);
+			break;
+		}
+		case Opt_umask:
+		{
+			char *umask = args[0].from;
+			sbi->umask = simple_strtoul(umask, &umask, 8);
+			if (sbi->umask & ~0777) {
+				printk(KERN_ERR
+				       "JFS: Invalid value of umask\n");
+				goto cleanup;
+			}
+			break;
+		}
 		default:
 			printk("jfs: Unrecognized mount option \"%s\" "
 					" or missing value\n", p);
@@ -400,6 +425,7 @@ static int jfs_fill_super(struct super_block *sb, void *data, int silent)
 		return -ENOSPC;
 	sb->s_fs_info = sbi;
 	sbi->sb = sb;
+	sbi->uid = sbi->gid = sbi->umask = -1;
 
 	/* initialize the mount flag and determine the default error handler */
 	flag = JFS_ERR_REMOUNT_RO;
@@ -562,10 +588,14 @@ static int jfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 {
 	struct jfs_sb_info *sbi = JFS_SBI(vfs->mnt_sb);
 
+	if (sbi->uid != -1)
+		seq_printf(seq, ",uid=%d", sbi->uid);
+	if (sbi->gid != -1)
+		seq_printf(seq, ",gid=%d", sbi->gid);
+	if (sbi->umask != -1)
+		seq_printf(seq, ",umask=%03o", sbi->umask);
 	if (sbi->flag & JFS_NOINTEGRITY)
 		seq_puts(seq, ",nointegrity");
-	else
-		seq_puts(seq, ",integrity");
 
 #if defined(CONFIG_QUOTA)
 	if (sbi->flag & JFS_USRQUOTA)