linux-kernel - [PATCH 3.16 130/305] hpfs: implement the show

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Message-ID: <lsq.1471110171.803237713@decadent.org.uk>
Date:	Sat, 13 Aug 2016 18:42:51 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "Mikulas Patocka" <mpatocka@...hat.com>,
	"Linus Torvalds" <torvalds@...ux-foundation.org>,
	"Mikulas Patocka" <mikulas@...bright.com>
Subject: [PATCH 3.16 130/305] hpfs: implement the show_options method

3.16.37-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Mikulas Patocka <mikulas@...bright.com>

commit 037369b872940cd923835a0a589763180c4a36bc upstream.

The HPFS filesystem used generic_show_options to produce string that is
displayed in /proc/mounts.  However, there is a problem that the options
may disappear after remount.  If we mount the filesystem with option1
and then remount it with option2, /proc/mounts should show both option1
and option2, however it only shows option2 because the whole option
string is replaced with replace_mount_options in hpfs_remount_fs.

To fix this bug, implement the hpfs_show_options function that prints
options that are currently selected.

Signed-off-by: Mikulas Patocka <mpatocka@...hat.com>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/hpfs/super.c | 43 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 32 insertions(+), 11 deletions(-)

--- a/fs/hpfs/super.c
+++ b/fs/hpfs/super.c
@@ -15,6 +15,7 @@
 #include <linux/sched.h>
 #include <linux/bitmap.h>
 #include <linux/slab.h>
+#include <linux/seq_file.h>
 
 /* Mark the filesystem dirty, so that chkdsk checks it when os/2 booted */
 
@@ -426,10 +427,6 @@ static int hpfs_remount_fs(struct super_
 	int lowercase, eas, chk, errs, chkdsk, timeshift;
 	int o;
 	struct hpfs_sb_info *sbi = hpfs_sb(s);
-	char *new_opts = kstrdup(data, GFP_KERNEL);
-
-	if (data && !new_opts)
-		return -ENOMEM;
 
 	sync_filesystem(s);
 
@@ -466,18 +463,44 @@ static int hpfs_remount_fs(struct super_
 
 	if (!(*flags & MS_RDONLY)) mark_dirty(s, 1);
 
-	if (new_opts)
-		replace_mount_options(s, new_opts);
-
 	hpfs_unlock(s);
 	return 0;
 
 out_err:
 	hpfs_unlock(s);
-	kfree(new_opts);
 	return -EINVAL;
 }
 
+static int hpfs_show_options(struct seq_file *seq, struct dentry *root)
+{
+	struct hpfs_sb_info *sbi = hpfs_sb(root->d_sb);
+
+	seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, sbi->sb_uid));
+	seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, sbi->sb_gid));
+	seq_printf(seq, ",umask=%03o", (~sbi->sb_mode & 0777));
+	if (sbi->sb_lowercase)
+		seq_printf(seq, ",case=lower");
+	if (!sbi->sb_chk)
+		seq_printf(seq, ",check=none");
+	if (sbi->sb_chk == 2)
+		seq_printf(seq, ",check=strict");
+	if (!sbi->sb_err)
+		seq_printf(seq, ",errors=continue");
+	if (sbi->sb_err == 2)
+		seq_printf(seq, ",errors=panic");
+	if (!sbi->sb_chkdsk)
+		seq_printf(seq, ",chkdsk=no");
+	if (sbi->sb_chkdsk == 2)
+		seq_printf(seq, ",chkdsk=always");
+	if (!sbi->sb_eas)
+		seq_printf(seq, ",eas=no");
+	if (sbi->sb_eas == 1)
+		seq_printf(seq, ",eas=ro");
+	if (sbi->sb_timeshift)
+		seq_printf(seq, ",timeshift=%d", sbi->sb_timeshift);
+	return 0;
+}
+
 /* Super operations */
 
 static const struct super_operations hpfs_sops =
@@ -488,7 +511,7 @@ static const struct super_operations hpf
 	.put_super	= hpfs_put_super,
 	.statfs		= hpfs_statfs,
 	.remount_fs	= hpfs_remount_fs,
-	.show_options	= generic_show_options,
+	.show_options	= hpfs_show_options,
 };
 
 static int hpfs_fill_super(struct super_block *s, void *options, int silent)
@@ -511,8 +534,6 @@ static int hpfs_fill_super(struct super_
 
 	int o;
 
-	save_mount_options(s, options);
-
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi) {
 		return -ENOMEM;