diff mbox

ext4: deprecate obsoleted mount options v2

Message ID 87bpffpxha.fsf_-_@openvz.org
State Changes Requested
Headers show

Commit Message

Dmitry Monakhov Feb. 23, 2010, 7:23 p.m. UTC 
Andreas Dilger <adilger@sun.com> writes:

> On 2010-02-19, at 07:39, Dmitry Monakhov wrote:
>> This patch deprecate some obsoleted functions.
>> It is not obvious what should we do in case of deprecated options on
>> mount.
>> Just printk and continue or fail the mount, i've implemented the
>> last one.
>> BTW: Do we need similar patch for e2fslib?
>
> I think deprecating an option is not the same as removing it entirely.
Ohh.. I've hoped to reuse freed bits for new crap.
> Even though I don't think these options are in wide usage,  I'd still
> prefer to add a printk() to the parsing code first, leave it  for a
> year, then remove them entirely after that.
So option deprecation result in code boosting instead of code shrinkage.
Indeed the second law of thermodynamics is absolutely true.
New version attached.
From 0d12e733a6dd87ed3bc4dea27126f6e814b5586b Mon Sep 17 00:00:00 2001
From: Dmitry Monakhov <dmonakhov@openvz.org>
Date: Tue, 23 Feb 2010 22:11:47 +0300
Subject: [PATCH] ext4: deprecate obsoleted mount options v2

Declare following list of mount options as deprecated:
 - bsddf, miniddf
 - grpid, bsdgroups, nogrpid, sysvgroups

Declare following list of default mount options as deprecated:
 - bsdgroups

Changes from v1
 - Mark options as deprecated instead of disabling it completely,
   they will be disabled after exportation period.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
 fs/ext4/ext4.h  |    2 +
 fs/ext4/super.c |   76 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 73 insertions(+), 5 deletions(-)

Comments

Theodore Ts'o Feb. 23, 2010, 8:13 p.m. UTC | #1 
On Tue, Feb 23, 2010 at 10:23:45PM +0300, Dmitry Monakhov wrote:
> >
> > I think deprecating an option is not the same as removing it entirely.
> Ohh.. I've hoped to reuse freed bits for new crap.

What "new crap" are you hoping to will need mount options?  One of the
things I want to do long term is to try to reduce/remove mount options
in general.

If we get general agreement that it's time to just turn on acl's and
xattr's by default, we can change the default, and in that case
removing the "noacl/noxattr" might be something that we might not need
to keep for as long, or maybe at all.  But for things like
bsddf/minixdf, we do need some kind of deprecation schedule.

The use of Opt_deprecated and Opt_disabled seems a little pointless;
nothing is using now, and nothing needs it.  All I'd probably do is
something like this:

static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
       "Contact linux-ext4@vger.kernel.org if you think we should keep it.\n"

And then in each option that we want to deprecate, just add:

    ext4_msg(sb, KERN_WARN, deprecated_msg, "bsddf", "2.6.39");

The extra opt_discard, and goto deprecated, etc., seems way more
complicated than what is necessary.

						- Ted
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diff mbox

Patch

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 67859fa..66ed482 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1185,6 +1185,8 @@  static inline void ext4_clear_inode_state(struct inode *inode, int bit)
 #define EXT4_DEFM_JMODE_DATA	0x0020
 #define EXT4_DEFM_JMODE_ORDERED	0x0040
 #define EXT4_DEFM_JMODE_WBACK	0x0060
+/* Deprecated default mount options mask */
+#define EXT4_DEFM_DEPRECATED	EXT4_DEFM_BSDGROUPS
 
 /*
  * Default journal batch times
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d5596ca..d07f506 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1114,7 +1114,7 @@  enum {
 	Opt_block_validity, Opt_noblock_validity,
 	Opt_inode_readahead_blks, Opt_journal_ioprio,
 	Opt_dioread_nolock, Opt_dioread_lock,
-	Opt_discard, Opt_nodiscard,
+	Opt_discard, Opt_nodiscard, Opt_deprecated, Opt_disabled,
 };
 
 static const match_table_t tokens = {
@@ -1188,6 +1188,18 @@  static const match_table_t tokens = {
 	{Opt_err, NULL},
 };
 
+static const match_table_t default_mountopt = {
+	{EXT4_DEFM_DEBUG, "debug"},
+	{EXT4_DEFM_BSDGROUPS, "bsdgroups"},
+	{EXT4_DEFM_XATTR_USER, "user_xattr"},
+	{EXT4_DEFM_ACL, "acl"},
+	{EXT4_DEFM_UID16, "uid16"},
+	{EXT4_DEFM_JMODE_WBACK, "journal_data_writeback"},
+	{EXT4_DEFM_JMODE_DATA, "journal_data"},
+	{EXT4_DEFM_JMODE_ORDERED, "journal_data_ordered"},
+	{0, NULL},
+};
+
 static ext4_fsblk_t get_sb_block(void **data)
 {
 	ext4_fsblk_t	sb_block;
@@ -1240,16 +1252,16 @@  static int parse_options(char *options, struct super_block *sb,
 		switch (token) {
 		case Opt_bsd_df:
 			clear_opt(sbi->s_mount_opt, MINIX_DF);
-			break;
+			goto deprecated;
 		case Opt_minix_df:
 			set_opt(sbi->s_mount_opt, MINIX_DF);
-			break;
+			goto deprecated;
 		case Opt_grpid:
 			set_opt(sbi->s_mount_opt, GRPID);
-			break;
+			goto deprecated;
 		case Opt_nogrpid:
 			clear_opt(sbi->s_mount_opt, GRPID);
-			break;
+			goto deprecated;
 		case Opt_resuid:
 			if (match_int(&args[0], &option))
 				return 0;
@@ -1622,6 +1634,21 @@  set_qf_format:
 		case Opt_dioread_lock:
 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
 			break;
+
+		case Opt_deprecated:
+deprecated:
+			ext4_msg(sb, KERN_ERR,
+				"Deprecated mount option \"%s\". Will be "
+				"removed soon. Please contact "
+				"linux-ext4@vger.kernel.org if you are still "
+				"using it.", p);
+			break;
+
+		case Opt_disabled:
+			ext4_msg(sb, KERN_ERR,
+				"Deprecated mount option \"%s\". And not "
+				"longer supported.", p);
+			return 0;
 		default:
 			ext4_msg(sb, KERN_ERR,
 			       "Unrecognized mount option \"%s\" "
@@ -2358,7 +2385,42 @@  static int ext4_feature_set_ok(struct super_block *sb, int readonly)
 	}
 	return 1;
 }
+static int handle_deprecated_defmopt(struct super_block *sb, unsigned int opt)
+{
+	int first = 1;
+	/*
+	 * When deprecated options are found they are not cleared from
+	 * super block by default. Just print error message and let
+	 * user clear it manually.
+	 */
+	printk(KERN_ERR "EXT4-fs (%s) Deprecated default mount options:",
+		sb->s_id);
+	/*
+	 * It is impossible to use simple bit traversing because,
+	 * some options use shared bits.
+	 */
+	opt &= EXT4_DEFM_DEPRECATED;
+	while (opt) {
+		const struct match_token *mt = default_mountopt;
+		while (mt->pattern != NULL) {
+			if ((opt & mt->token) == mt->token)
+				break;
+			mt++;
+		}
+		if (mt->pattern == NULL) {
+			printk("%s unknown", !first ? "," : "");
+			break;
+		} else {
+			printk("%s %s", !first ? "," : "", mt->pattern);
+			opt &= ~mt->token;
+		}
+		first = 0;
+	}
+	printk(". Please use tune2fs to disable it, or contact "
+		"linux-ext4@vger.kernel.org if you are still need it.");
 
+	return 0;
+}
 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 				__releases(kernel_lock)
 				__acquires(kernel_lock)
@@ -2443,6 +2505,10 @@  static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 
 	/* Set defaults before we parse the mount options */
 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
+	if (def_mount_opts & EXT4_DEFM_DEPRECATED) {
+		if (handle_deprecated_defmopt(sb, def_mount_opts))
+			goto failed_mount;
+	}
 	if (def_mount_opts & EXT4_DEFM_DEBUG)
 		set_opt(sbi->s_mount_opt, DEBUG);
 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS)