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>

5 files changed, 93 insertions, 10 deletions

diff --git a/fs/jfs/acl.c b/fs/jfs/acl.c
index e0b6fdab200c..e2281300979c 100644
--- a/fs/jfs/acl.c
+++ b/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;
 }
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index b62a048b6881..ccbe60aff83d 100644
--- a/fs/jfs/jfs_imap.c
+++ b/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);
diff --git a/fs/jfs/jfs_incore.h b/fs/jfs/jfs_incore.h
index a97ead889a68..54d73716ca8c 100644
--- a/fs/jfs/jfs_incore.h
+++ b/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 */
diff --git a/fs/jfs/jfs_inode.c b/fs/jfs/jfs_inode.c
index ffd2a8a00787..495df402916d 100644
--- a/fs/jfs/jfs_inode.c
+++ b/fs/jfs/jfs_inode.c
@@ -83,6 +83,13 @@ struct inode *ialloc(struct inode *parent, umode_t mode)
                 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.
          */
         if (DQUOT_ALLOC_INODE(inode)) {
diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index ab6333347004..18f69e6aa719 100644
--- a/fs/jfs/super.c
+++ b/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)