[PATCH] udf: fix uid/gid options and add uid/gid=ignore and forget options

[Phillip Susi <psusi@cfl.rr.com>]

This patch fixes a bug in udf where it would write uid/gid = 0 to the
disk for files owned by the id given with the uid=/gid= mount options.
It also adds 4 new mount options: uid/gid=forget and uid/gid=ignore.
Without any options the id in core and on disk always match.  Giving
uid/gid=nnn specifies a default ID to be used in core when the on disk ID
is -1.  uid/gid=ignore forces the in core ID to allways be used no matter
what the on disk ID is.  uid/gid=forget forces the on disk ID to always be
written out as -1.

The use of these options allows you to override ownerships on a disk or
disable ownwership information from being written, allowing the media
to be used portably between different computers and possibly different users
without permissions issues that would require root to correct.

Signed-off-by: Phillip Susi <psusi@cfl.rr.com>

---

fs/udf/inode.c  |   14 ++++++++++----
fs/udf/super.c  |   18 +++++++++++++++++-
fs/udf/udf_sb.h |    4 ++++
3 files changed, 31 insertions(+), 5 deletions(-)

2428c90c6e52a317808896b6cd639199388f7ddd
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 395e582..2f47bf6 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1045,10 +1045,12 @@ static void udf_fill_inode(struct inode 
	}

	inode->i_uid = le32_to_cpu(fe->uid);
-	if ( inode->i_uid == -1 ) inode->i_uid = UDF_SB(inode->i_sb)->s_uid;
+	if ( inode->i_uid == -1 || UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_UID_IGNORE) )
+	  inode->i_uid = UDF_SB(inode->i_sb)->s_uid;

	inode->i_gid = le32_to_cpu(fe->gid);
-	if ( inode->i_gid == -1 ) inode->i_gid = UDF_SB(inode->i_sb)->s_gid;
+	if ( inode->i_gid == -1 || UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_GID_IGNORE) )
+	  inode->i_gid = UDF_SB(inode->i_sb)->s_gid;

	inode->i_nlink = le16_to_cpu(fe->fileLinkCount);
	if (!inode->i_nlink)
@@ -1335,10 +1337,14 @@ udf_update_inode(struct inode *inode, in
		return err;
	}

-	if (inode->i_uid != UDF_SB(inode->i_sb)->s_uid)
+	if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_UID_FORGET))
+	  fe->uid = cpu_to_le32(-1);
+	else if (inode->i_uid != UDF_SB(inode->i_sb)->s_uid)
		fe->uid = cpu_to_le32(inode->i_uid);

-	if (inode->i_gid != UDF_SB(inode->i_sb)->s_gid)
+	if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_GID_FORGET))
+	  fe->gid = cpu_to_le32(-1);
+	else if (inode->i_gid != UDF_SB(inode->i_sb)->s_gid)
		fe->gid = cpu_to_le32(inode->i_gid);

	udfperms =	((inode->i_mode & S_IRWXO)     ) |
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 4a6f49a..368d8f8 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -269,7 +269,7 @@ enum {
	Opt_gid, Opt_uid, Opt_umask, Opt_session, Opt_lastblock,
	Opt_anchor, Opt_volume, Opt_partition, Opt_fileset,
	Opt_rootdir, Opt_utf8, Opt_iocharset,
-	Opt_err
+	Opt_err, Opt_uforget, Opt_uignore, Opt_gforget, Opt_gignore
};

static match_table_t tokens = {
@@ -282,6 +282,10 @@ static match_table_t tokens = {
	{Opt_adinicb, "adinicb"},
	{Opt_shortad, "shortad"},
	{Opt_longad, "longad"},
+	{Opt_uforget, "uid=forget"},
+	{Opt_uignore, "uid=ignore"},
+	{Opt_gforget, "gid=forget"},
+	{Opt_gignore, "gid=ignore"},
	{Opt_gid, "gid=%u"},
	{Opt_uid, "uid=%u"},
	{Opt_umask, "umask=%o"},
@@ -414,6 +418,18 @@ udf_parse_options(char *options, struct 
				uopt->flags |= (1 << UDF_FLAG_NLS_MAP);
				break;
#endif
+			case Opt_uignore:
+				uopt->flags |= (1 << UDF_FLAG_UID_IGNORE);
+				break;
+			case Opt_uforget:
+				uopt->flags |= (1 << UDF_FLAG_UID_FORGET);
+				break;
+			case Opt_gignore:
+			    uopt->flags |= (1 << UDF_FLAG_GID_IGNORE);
+				break;
+			case Opt_gforget:
+			    uopt->flags |= (1 << UDF_FLAG_GID_FORGET);
+				break;
			default:
				printk(KERN_ERR "udf: bad mount option \"%s\" "
						"or missing value\n", p);
diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 6636698..110f8d6 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -20,6 +20,10 @@
#define UDF_FLAG_VARCONV		8
#define UDF_FLAG_NLS_MAP		9
#define UDF_FLAG_UTF8			10
+#define UDF_FLAG_UID_FORGET     11    /* save -1 for uid to disk */
+#define UDF_FLAG_UID_IGNORE     12    /* use sb uid instead of on disk uid */
+#define UDF_FLAG_GID_FORGET     13
+#define UDF_FLAG_GID_IGNORE     14

#define UDF_PART_FLAG_UNALLOC_BITMAP	0x0001
#define UDF_PART_FLAG_UNALLOC_TABLE	0x0002
--
1.1.3

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