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>

1 files changed, 44 insertions, 6 deletions

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);