isofs: let mode and dmode mount options override rock ridge mode setting

So far, permissions set via 'mode' and/or 'dmode' mount options were
effective only if the medium had no rock ridge extensions (or was mounted
without them).  Add 'overriderockmode' mount option to indicate that these
options should override permissions set in rock ridge extensions.  Maybe
this should be default but the current behavior is there since mount
options were created so I think we should not change how they behave.

Cc: <Hans-Joachim.Baader@cjt.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/filesystems/isofs.txt

@@ -23,8 +23,13 @@ Mount options unique to the isofs filesystem.
   map=off       Do not map non-Rock Ridge filenames to lower case
   map=normal    Map non-Rock Ridge filenames to lower case
   map=acorn     As map=normal but also apply Acorn extensions if present
-  mode=xxx      Sets the permissions on files to xxx
-  dmode=xxx     Sets the permissions on directories to xxx
+  mode=xxx      Sets the permissions on files to xxx unless Rock Ridge
+		extensions set the permissions otherwise
+  dmode=xxx     Sets the permissions on directories to xxx unless Rock Ridge
+		extensions set the permissions otherwise
+  overriderockperm Set permissions on files and directories according to
+		'mode' and 'dmode' even though Rock Ridge extensions are
+		present.
   nojoliet      Ignore Joliet extensions if they are present.
   norock        Ignore Rock Ridge extensions if they are present.
   hide		Completely strip hidden files from the file system.

fs/isofs/inode.c

@@ -148,6 +148,7 @@ struct iso9660_options{
 	char hide;
 	char showassoc;
 	char nocompress;
+	char overriderockperm;
 	unsigned char check;
 	unsigned int blocksize;
 	mode_t fmode;
@@ -312,7 +313,7 @@ enum {
 	Opt_block, Opt_check_r, Opt_check_s, Opt_cruft, Opt_gid, Opt_ignore,
 	Opt_iocharset, Opt_map_a, Opt_map_n, Opt_map_o, Opt_mode, Opt_nojoliet,
 	Opt_norock, Opt_sb, Opt_session, Opt_uid, Opt_unhide, Opt_utf8, Opt_err,
-	Opt_nocompress, Opt_hide, Opt_showassoc, Opt_dmode,
+	Opt_nocompress, Opt_hide, Opt_showassoc, Opt_dmode, Opt_overriderockperm,
 };
 
 static const match_table_t tokens = {
@@ -340,6 +341,7 @@ static const match_table_t tokens = {
 	{Opt_gid, "gid=%u"},
 	{Opt_mode, "mode=%u"},
 	{Opt_dmode, "dmode=%u"},
+	{Opt_overriderockperm, "overriderockperm"},
 	{Opt_block, "block=%u"},
 	{Opt_ignore, "conv=binary"},
 	{Opt_ignore, "conv=b"},
@@ -367,16 +369,12 @@ static int parse_options(char *options, struct iso9660_options *popt)
 	popt->check = 'u';		/* unset */
 	popt->nocompress = 0;
 	popt->blocksize = 1024;
-	popt->fmode = popt->dmode = S_IRUGO | S_IXUGO; /*
-					 * r-x for all.  The disc could
-					 * be shared with DOS machines so
-					 * virtually anything could be
-					 * a valid executable.
-					 */
+	popt->fmode = popt->dmode = ISOFS_INVALID_MODE;
 	popt->gid = 0;
 	popt->uid = 0;
 	popt->iocharset = NULL;
 	popt->utf8 = 0;
+	popt->overriderockperm = 0;
 	popt->session=-1;
 	popt->sbsector=-1;
 	if (!options)
@@ -466,6 +464,9 @@ static int parse_options(char *options, struct iso9660_options *popt)
 				return 0;
 			popt->dmode = option;
 			break;
+		case Opt_overriderockperm:
+			popt->overriderockperm = 1;
+			break;
 		case Opt_block:
 			if (match_int(&args[0], &option))
 				return 0;
@@ -811,13 +812,20 @@ static int isofs_fill_super(struct super_block *s, void *data, int silent)
 	sbi->s_gid = opt.gid;
 	sbi->s_utf8 = opt.utf8;
 	sbi->s_nocompress = opt.nocompress;
+	sbi->s_overriderockperm = opt.overriderockperm;
 	/*
 	 * It would be incredibly stupid to allow people to mark every file
 	 * on the disk as suid, so we merely allow them to set the default
 	 * permissions.
 	 */
+	if (opt.fmode != ISOFS_INVALID_MODE)
 		sbi->s_fmode = opt.fmode & 0777;
+	else
+		sbi->s_fmode = ISOFS_INVALID_MODE;
+	if (opt.dmode != ISOFS_INVALID_MODE)
 		sbi->s_dmode = opt.dmode & 0777;
+	else
+		sbi->s_dmode = ISOFS_INVALID_MODE;
 
 	/*
 	 * Read the root inode, which _may_ result in changing
@@ -1261,7 +1269,10 @@ static int isofs_read_inode(struct inode *inode)
 	ei->i_file_format = isofs_file_normal;
 
 	if (de->flags[-high_sierra] & 2) {
-		inode->i_mode = sbi->s_dmode | S_IFDIR;
+		if (sbi->s_dmode != ISOFS_INVALID_MODE)
+			inode->i_mode = S_IFDIR | sbi->s_dmode;
+		else
+			inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
 		inode->i_nlink = 1;	/*
 					 * Set to 1.  We know there are 2, but
 					 * the find utility tries to optimize
@@ -1270,8 +1281,16 @@ static int isofs_read_inode(struct inode *inode)
 					 * do it the hard way.
 					 */
 	} else {
-		/* Everybody gets to read the file. */
-		inode->i_mode = sbi->s_fmode | S_IFREG;
+		if (sbi->s_fmode != ISOFS_INVALID_MODE) {
+			inode->i_mode = S_IFREG | sbi->s_fmode;
+		} else {
+			/*
+			 * Set default permissions: r-x for all.  The disc
+			 * could be shared with DOS machines so virtually
+			 * anything could be a valid executable.
+			 */
+			inode->i_mode = S_IFREG | S_IRUGO | S_IXUGO;
+		}
 		inode->i_nlink = 1;
 	}
 	inode->i_uid = sbi->s_uid;
@@ -1349,6 +1368,13 @@ static int isofs_read_inode(struct inode *inode)
 		test_and_set_uid(&inode->i_uid, sbi->s_uid);
 		test_and_set_gid(&inode->i_gid, sbi->s_gid);
 	}
+	/* Now set final access rights if overriding rock ridge setting */
+	if (S_ISDIR(inode->i_mode) && sbi->s_overriderockperm &&
+	    sbi->s_dmode != ISOFS_INVALID_MODE)
+		inode->i_mode = S_IFDIR | sbi->s_dmode;
+	if (S_ISREG(inode->i_mode) && sbi->s_overriderockperm &&
+	    sbi->s_fmode != ISOFS_INVALID_MODE)
+		inode->i_mode = S_IFREG | sbi->s_fmode;
 
 	/* Install the inode operations vector */
 	if (S_ISREG(inode->i_mode)) {

fs/isofs/isofs.h

@@ -50,6 +50,7 @@ struct isofs_sb_info {
 	unsigned char s_nocompress;
 	unsigned char s_hide;
 	unsigned char s_showassoc;
+	unsigned char s_overriderockperm;
 
 	mode_t s_fmode;
 	mode_t s_dmode;
@@ -58,6 +59,8 @@ struct isofs_sb_info {
 	struct nls_table *s_nls_iocharset; /* Native language support table */
 };
 
+#define ISOFS_INVALID_MODE ((mode_t) -1)
+
 static inline struct isofs_sb_info *ISOFS_SB(struct super_block *sb)
 {
 	return sb->s_fs_info;