[PATCH v9 13/17] xfs: switch to use the new mount-api

[Ian Kent <raven@themaw.net>]

Define the struct fs_parameter_spec table that's used by the new
mount-api for options parsing.

Create the various fs context operations methods and define the
fs_context_operations struct.

Create the fs context initialization method and update the struct
file_system_type to utilize it. The initialization function is
responsible for working storage initialization, allocation and
initialization of file system private information storage and for
setting the operations in the fs context.

Also set struct file_system_type .parameters to the newly defined
struct fs_parameter_spec options parsing table for use by the fs
context methods and remove unused code.

Signed-off-by: Ian Kent <raven@themaw.net>
---
 fs/xfs/xfs_super.c |  408 ++++++++++++++++++++++------------------------------
 1 file changed, 171 insertions(+), 237 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 62dfc678c415..2d4edaaf934e 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -37,7 +37,8 @@
 #include "xfs_reflink.h"
 
 #include <linux/magic.h>
-#include <linux/parser.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 
 static const struct super_operations xfs_super_operations;
 
@@ -58,55 +59,57 @@ enum {
 	Opt_filestreams, Opt_quota, Opt_noquota, Opt_usrquota, Opt_grpquota,
 	Opt_prjquota, Opt_uquota, Opt_gquota, Opt_pquota,
 	Opt_uqnoenforce, Opt_gqnoenforce, Opt_pqnoenforce, Opt_qnoenforce,
-	Opt_discard, Opt_nodiscard, Opt_dax, Opt_err,
+	Opt_discard, Opt_nodiscard, Opt_dax,
 };
 
-static const match_table_t tokens = {
-	{Opt_logbufs,	"logbufs=%u"},	/* number of XFS log buffers */
-	{Opt_logbsize,	"logbsize=%s"},	/* size of XFS log buffers */
-	{Opt_logdev,	"logdev=%s"},	/* log device */
-	{Opt_rtdev,	"rtdev=%s"},	/* realtime I/O device */
-	{Opt_wsync,	"wsync"},	/* safe-mode nfs compatible mount */
-	{Opt_noalign,	"noalign"},	/* turn off stripe alignment */
-	{Opt_swalloc,	"swalloc"},	/* turn on stripe width allocation */
-	{Opt_sunit,	"sunit=%u"},	/* data volume stripe unit */
-	{Opt_swidth,	"swidth=%u"},	/* data volume stripe width */
-	{Opt_nouuid,	"nouuid"},	/* ignore filesystem UUID */
-	{Opt_grpid,	"grpid"},	/* group-ID from parent directory */
-	{Opt_nogrpid,	"nogrpid"},	/* group-ID from current process */
-	{Opt_bsdgroups,	"bsdgroups"},	/* group-ID from parent directory */
-	{Opt_sysvgroups,"sysvgroups"},	/* group-ID from current process */
-	{Opt_allocsize,	"allocsize=%s"},/* preferred allocation size */
-	{Opt_norecovery,"norecovery"},	/* don't run XFS recovery */
-	{Opt_inode64,	"inode64"},	/* inodes can be allocated anywhere */
-	{Opt_inode32,   "inode32"},	/* inode allocation limited to
-					 * XFS_MAXINUMBER_32 */
-	{Opt_ikeep,	"ikeep"},	/* do not free empty inode clusters */
-	{Opt_noikeep,	"noikeep"},	/* free empty inode clusters */
-	{Opt_largeio,	"largeio"},	/* report large I/O sizes in stat() */
-	{Opt_nolargeio,	"nolargeio"},	/* do not report large I/O sizes
-					 * in stat(). */
-	{Opt_attr2,	"attr2"},	/* do use attr2 attribute format */
-	{Opt_noattr2,	"noattr2"},	/* do not use attr2 attribute format */
-	{Opt_filestreams,"filestreams"},/* use filestreams allocator */
-	{Opt_quota,	"quota"},	/* disk quotas (user) */
-	{Opt_noquota,	"noquota"},	/* no quotas */
-	{Opt_usrquota,	"usrquota"},	/* user quota enabled */
-	{Opt_grpquota,	"grpquota"},	/* group quota enabled */
-	{Opt_prjquota,	"prjquota"},	/* project quota enabled */
-	{Opt_uquota,	"uquota"},	/* user quota (IRIX variant) */
-	{Opt_gquota,	"gquota"},	/* group quota (IRIX variant) */
-	{Opt_pquota,	"pquota"},	/* project quota (IRIX variant) */
-	{Opt_uqnoenforce,"uqnoenforce"},/* user quota limit enforcement */
-	{Opt_gqnoenforce,"gqnoenforce"},/* group quota limit enforcement */
-	{Opt_pqnoenforce,"pqnoenforce"},/* project quota limit enforcement */
-	{Opt_qnoenforce, "qnoenforce"},	/* same as uqnoenforce */
-	{Opt_discard,	"discard"},	/* Discard unused blocks */
-	{Opt_nodiscard,	"nodiscard"},	/* Do not discard unused blocks */
-	{Opt_dax,	"dax"},		/* Enable direct access to bdev pages */
-	{Opt_err,	NULL},
+static const struct fs_parameter_spec xfs_param_specs[] = {
+	fsparam_u32("logbufs",		Opt_logbufs),
+	fsparam_string("logbsize",	Opt_logbsize),
+	fsparam_string("logdev",	Opt_logdev),
+	fsparam_string("rtdev",		Opt_rtdev),
+	fsparam_flag("wsync",		Opt_wsync),
+	fsparam_flag("noalign",		Opt_noalign),
+	fsparam_flag("swalloc",		Opt_swalloc),
+	fsparam_u32("sunit",		Opt_sunit),
+	fsparam_u32("swidth",		Opt_swidth),
+	fsparam_flag("nouuid",		Opt_nouuid),
+	fsparam_flag("grpid",		Opt_grpid),
+	fsparam_flag("nogrpid",		Opt_nogrpid),
+	fsparam_flag("bsdgroups",	Opt_bsdgroups),
+	fsparam_flag("sysvgroups",	Opt_sysvgroups),
+	fsparam_string("allocsize",	Opt_allocsize),
+	fsparam_flag("norecovery",	Opt_norecovery),
+	fsparam_flag("inode64",		Opt_inode64),
+	fsparam_flag("inode32",		Opt_inode32),
+	fsparam_flag("ikeep",		Opt_ikeep),
+	fsparam_flag("noikeep",		Opt_noikeep),
+	fsparam_flag("largeio",		Opt_largeio),
+	fsparam_flag("nolargeio",	Opt_nolargeio),
+	fsparam_flag("attr2",		Opt_attr2),
+	fsparam_flag("noattr2",		Opt_noattr2),
+	fsparam_flag("filestreams",	Opt_filestreams),
+	fsparam_flag("quota",		Opt_quota),
+	fsparam_flag("noquota",		Opt_noquota),
+	fsparam_flag("usrquota",	Opt_usrquota),
+	fsparam_flag("grpquota",	Opt_grpquota),
+	fsparam_flag("prjquota",	Opt_prjquota),
+	fsparam_flag("uquota",		Opt_uquota),
+	fsparam_flag("gquota",		Opt_gquota),
+	fsparam_flag("pquota",		Opt_pquota),
+	fsparam_flag("uqnoenforce",	Opt_uqnoenforce),
+	fsparam_flag("gqnoenforce",	Opt_gqnoenforce),
+	fsparam_flag("pqnoenforce",	Opt_pqnoenforce),
+	fsparam_flag("qnoenforce",	Opt_qnoenforce),
+	fsparam_flag("discard",		Opt_discard),
+	fsparam_flag("nodiscard",	Opt_nodiscard),
+	fsparam_flag("dax",		Opt_dax),
+	{}
 };
 
+static const struct fs_parameter_description xfs_fs_parameters = {
+	.name		= "xfs",
+	.specs		= xfs_param_specs,
+};
 
 static int
 suffix_kstrtoint(
@@ -143,55 +146,42 @@ suffix_kstrtoint(
 	return ret;
 }
 
-static int
-match_kstrtoint(
-	const substring_t	*s,
-	unsigned int		base,
-	int			*res)
-{
-	const char		*value;
-	int			ret;
-
-	value = match_strdup(s);
-	if (!value)
-		return -ENOMEM;
-	ret = suffix_kstrtoint(value, base, res);
-	kfree(value);
-	return ret;
-}
-
 static int
 xfs_fc_parse_param(
-	int			token,
-	char			*p,
-	substring_t		*args,
-	struct xfs_mount	*mp)
+	struct fs_context	*fc,
+	struct fs_parameter	*param)
 {
+	struct xfs_mount	*mp = fc->s_fs_info;
+	struct fs_parse_result	result;
 	int			size = 0;
+	int			opt;
+
+	opt = fs_parse(fc, &xfs_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
 
-	switch (token) {
+	switch (opt) {
 	case Opt_logbufs:
-		if (match_int(args, &mp->m_logbufs))
-			return -EINVAL;
+		mp->m_logbufs = result.uint_32;
 		return 0;
 	case Opt_logbsize:
-		if (match_kstrtoint(args, 10, &mp->m_logbsize))
+		if (suffix_kstrtoint(param->string, 10, &mp->m_logbsize))
 			return -EINVAL;
 		return 0;
 	case Opt_logdev:
 		kfree(mp->m_logname);
-		mp->m_logname = match_strdup(args);
+		mp->m_logname = kstrdup(param->string, GFP_KERNEL);
 		if (!mp->m_logname)
 			return -ENOMEM;
 		return 0;
 	case Opt_rtdev:
 		kfree(mp->m_rtname);
-		mp->m_rtname = match_strdup(args);
+		mp->m_rtname = kstrdup(param->string, GFP_KERNEL);
 		if (!mp->m_rtname)
 			return -ENOMEM;
 		return 0;
 	case Opt_allocsize:
-		if (match_kstrtoint(args, 10, &size))
+		if (suffix_kstrtoint(param->string, 10, &size))
 			return -EINVAL;
 		mp->m_allocsize_log = ffs(size) - 1;
 		mp->m_flags |= XFS_MOUNT_ALLOCSIZE;
@@ -217,12 +207,10 @@ xfs_fc_parse_param(
 		mp->m_flags |= XFS_MOUNT_SWALLOC;
 		return 0;
 	case Opt_sunit:
-		if (match_int(args, &mp->m_dalign))
-			return -EINVAL;
+		mp->m_dalign = result.uint_32;
 		return 0;
 	case Opt_swidth:
-		if (match_int(args, &mp->m_swidth))
-			return -EINVAL;
+		mp->m_swidth = result.uint_32;
 		return 0;
 	case Opt_inode32:
 		mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
@@ -301,7 +289,7 @@ xfs_fc_parse_param(
 		return 0;
 #endif
 	default:
-		xfs_warn(mp, "unknown mount option [%s].", p);
+		xfs_warn(mp, "unknown mount option [%s].", param->key);
 		return -EINVAL;
 	}
 
@@ -376,62 +364,6 @@ xfs_fc_validate_params(
 	return 0;
 }
 
-/*
- * This function fills in xfs_mount_t fields based on mount args.
- * Note: the superblock has _not_ yet been read in.
- *
- * Note that this function leaks the various device name allocations on
- * failure.  The caller takes care of them.
- *
- * *sb is const because this is also used to test options on the remount
- * path, and we don't want this to have any side effects at remount time.
- * Today this function does not change *sb, but just to future-proof...
- */
-static int
-xfs_parseargs(
-	struct xfs_mount	*mp,
-	char			*options)
-{
-	const struct super_block *sb = mp->m_super;
-	char			*p;
-	substring_t		args[MAX_OPT_ARGS];
-
-	/*
-	 * Copy binary VFS mount flags we are interested in.
-	 */
-	if (sb_rdonly(sb))
-		mp->m_flags |= XFS_MOUNT_RDONLY;
-	if (sb->s_flags & SB_DIRSYNC)
-		mp->m_flags |= XFS_MOUNT_DIRSYNC;
-	if (sb->s_flags & SB_SYNCHRONOUS)
-		mp->m_flags |= XFS_MOUNT_WSYNC;
-
-	/*
-	 * These can be overridden by the mount option parsing.
-	 */
-	mp->m_logbufs = -1;
-	mp->m_logbsize = -1;
-	mp->m_allocsize_log = 16; /* 64k */
-
-	if (!options)
-		return 0;
-
-	while ((p = strsep(&options, ",")) != NULL) {
-		int		token;
-		int		ret;
-
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		ret = xfs_fc_parse_param(token, p, args, mp);
-		if (ret)
-			return ret;
-	}
-
-	return xfs_fc_validate_params(mp);
-}
-
 struct proc_xfs_info {
 	uint64_t	flag;
 	char		*str;
@@ -1207,25 +1139,6 @@ xfs_quiesce_attr(
 	xfs_log_quiesce(mp);
 }
 
-STATIC int
-xfs_test_remount_options(
-	struct super_block	*sb,
-	char			*options)
-{
-	int			error = 0;
-	struct xfs_mount	*tmp_mp;
-
-	tmp_mp = kmem_zalloc(sizeof(*tmp_mp), KM_MAYFAIL);
-	if (!tmp_mp)
-		return -ENOMEM;
-
-	tmp_mp->m_super = sb;
-	error = xfs_parseargs(tmp_mp, options);
-	xfs_mount_free(tmp_mp);
-
-	return error;
-}
-
 static int
 xfs_remount_rw(
 	struct xfs_mount	*mp)
@@ -1329,76 +1242,57 @@ xfs_remount_ro(
 	return 0;
 }
 
-STATIC int
-xfs_fs_remount(
-	struct super_block	*sb,
-	int			*flags,
-	char			*options)
+/*
+ * Logically we would return an error here to prevent users from believing
+ * they might have changed mount options using remount which can't be changed.
+ *
+ * But unfortunately mount(8) adds all options from mtab and fstab to the mount
+ * arguments in some cases so we can't blindly reject options, but have to
+ * check for each specified option if it actually differs from the currently
+ * set option and only reject it if that's the case.
+ *
+ * Until that is implemented we return success for every remount request, and
+ * silently ignore all options that we can't actually change.
+ */
+static int
+xfs_fc_reconfigure(
+	struct fs_context	*fc)
 {
-	struct xfs_mount	*mp = XFS_M(sb);
+	struct xfs_mount	*mp = XFS_M(fc->root->d_sb);
+	struct xfs_mount        *new_mp = fc->s_fs_info;
 	xfs_sb_t		*sbp = &mp->m_sb;
-	substring_t		args[MAX_OPT_ARGS];
-	char			*p;
+	int			flags = fc->sb_flags;
 	int			error;
 
-	/* First, check for complete junk; i.e. invalid options */
-	error = xfs_test_remount_options(sb, options);
+	error = xfs_fc_validate_params(new_mp);
 	if (error)
 		return error;
 
-	sync_filesystem(sb);
-	while ((p = strsep(&options, ",")) != NULL) {
-		int token;
-
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case Opt_inode64:
-			mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
-			mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
-			break;
-		case Opt_inode32:
-			mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
-			mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
-			break;
-		default:
-			/*
-			 * Logically we would return an error here to prevent
-			 * users from believing they might have changed
-			 * mount options using remount which can't be changed.
-			 *
-			 * But unfortunately mount(8) adds all options from
-			 * mtab and fstab to the mount arguments in some cases
-			 * so we can't blindly reject options, but have to
-			 * check for each specified option if it actually
-			 * differs from the currently set option and only
-			 * reject it if that's the case.
-			 *
-			 * Until that is implemented we return success for
-			 * every remount request, and silently ignore all
-			 * options that we can't actually change.
-			 */
-#if 0
-			xfs_info(mp,
-		"mount option \"%s\" not supported for remount", p);
-			return -EINVAL;
-#else
-			break;
-#endif
-		}
+	sync_filesystem(mp->m_super);
+
+	/* inode32 -> inode64 */
+	if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) &&
+	    !(new_mp->m_flags & XFS_MOUNT_SMALL_INUMS)) {
+		mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
+		mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
+	}
+
+	/* inode64 -> inode32 */
+	if (!(mp->m_flags & XFS_MOUNT_SMALL_INUMS) &&
+	    (new_mp->m_flags & XFS_MOUNT_SMALL_INUMS)) {
+		mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
+		mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
 	}
 
 	/* ro -> rw */
-	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & SB_RDONLY)) {
+	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(flags & SB_RDONLY)) {
 		error = xfs_remount_rw(mp);
 		if (error)
 			return error;
 	}
 
 	/* rw -> ro */
-	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (*flags & SB_RDONLY)) {
+	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (flags & SB_RDONLY)) {
 		error = xfs_remount_ro(mp);
 		if (error)
 			return error;
@@ -1588,28 +1482,18 @@ xfs_mount_alloc(void)
 	return mp;
 }
 
-
-STATIC int
-xfs_fs_fill_super(
+static int
+xfs_fc_fill_super(
 	struct super_block	*sb,
-	void			*data,
-	int			silent)
+	struct fs_context	*fc)
 {
+	struct xfs_mount	*mp = sb->s_fs_info;
 	struct inode		*root;
-	struct xfs_mount	*mp = NULL;
 	int			flags = 0, error = -ENOMEM;
 
-	/*
-	 * allocate mp and do all low-level struct initializations before we
-	 * attach it to the super
-	 */
-	mp = xfs_mount_alloc();
-	if (!mp)
-		goto out;
 	mp->m_super = sb;
-	sb->s_fs_info = mp;
 
-	error = xfs_parseargs(mp, (char *)data);
+	error = xfs_fc_validate_params(mp);
 	if (error)
 		goto out_free_names;
 
@@ -1633,7 +1517,7 @@ xfs_fs_fill_super(
 		msleep(xfs_globals.mount_delay * 1000);
 	}
 
-	if (silent)
+	if (fc->sb_flags & SB_SILENT)
 		flags |= XFS_MFSI_QUIET;
 
 	error = xfs_open_devices(mp);
@@ -1778,7 +1662,6 @@ xfs_fs_fill_super(
  out_free_names:
 	sb->s_fs_info = NULL;
 	xfs_mount_free(mp);
- out:
 	return error;
 
  out_unmount:
@@ -1787,6 +1670,13 @@ xfs_fs_fill_super(
 	goto out_free_sb;
 }
 
+static int
+xfs_fc_get_tree(
+	struct fs_context	*fc)
+{
+	return get_tree_bdev(fc, xfs_fc_fill_super);
+}
+
 STATIC void
 xfs_fs_put_super(
 	struct super_block	*sb)
@@ -1811,16 +1701,6 @@ xfs_fs_put_super(
 	xfs_mount_free(mp);
 }
 
-STATIC struct dentry *
-xfs_fs_mount(
-	struct file_system_type	*fs_type,
-	int			flags,
-	const char		*dev_name,
-	void			*data)
-{
-	return mount_bdev(fs_type, flags, dev_name, data, xfs_fs_fill_super);
-}
-
 static long
 xfs_fs_nr_cached_objects(
 	struct super_block	*sb,
@@ -1850,16 +1730,70 @@ static const struct super_operations xfs_super_operations = {
 	.freeze_fs		= xfs_fs_freeze,
 	.unfreeze_fs		= xfs_fs_unfreeze,
 	.statfs			= xfs_fs_statfs,
-	.remount_fs		= xfs_fs_remount,
 	.show_options		= xfs_fs_show_options,
 	.nr_cached_objects	= xfs_fs_nr_cached_objects,
 	.free_cached_objects	= xfs_fs_free_cached_objects,
 };
 
+static void xfs_fc_free(
+	struct fs_context	*fc)
+{
+	struct xfs_mount	*mp = fc->s_fs_info;
+
+	/*
+	 * mp is stored in the fs_context when it is initialized.
+	 * mp is transferred to the superblock on a successful mount,
+	 * but if an error occurs before the transfer we have to free
+	 * it here.
+	 */
+	if (mp)
+		xfs_mount_free(mp);
+}
+
+static const struct fs_context_operations xfs_context_ops = {
+	.parse_param = xfs_fc_parse_param,
+	.get_tree    = xfs_fc_get_tree,
+	.reconfigure = xfs_fc_reconfigure,
+	.free        = xfs_fc_free,
+};
+
+static int xfs_init_fs_context(
+	struct fs_context	*fc)
+{
+	struct xfs_mount	*mp;
+
+	mp = xfs_mount_alloc();
+	if (!mp)
+		return -ENOMEM;
+
+	/*
+	 * These can be overridden by the mount option parsing.
+	 */
+	mp->m_logbufs = -1;
+	mp->m_logbsize = -1;
+	mp->m_allocsize_log = 16; /* 64k */
+
+	/*
+	 * Copy binary VFS mount flags we are interested in.
+	 */
+	if (fc->sb_flags & SB_RDONLY)
+		mp->m_flags |= XFS_MOUNT_RDONLY;
+	if (fc->sb_flags & SB_DIRSYNC)
+		mp->m_flags |= XFS_MOUNT_DIRSYNC;
+	if (fc->sb_flags & SB_SYNCHRONOUS)
+		mp->m_flags |= XFS_MOUNT_WSYNC;
+
+	fc->s_fs_info = mp;
+	fc->ops = &xfs_context_ops;
+
+	return 0;
+}
+
 static struct file_system_type xfs_fs_type = {
 	.owner			= THIS_MODULE,
 	.name			= "xfs",
-	.mount			= xfs_fs_mount,
+	.init_fs_context	= xfs_init_fs_context,
+	.parameters		= &xfs_fs_parameters,
 	.kill_sb		= kill_block_super,
 	.fs_flags		= FS_REQUIRES_DEV,
 };