gfs2: Convert gfs2 to fs_context

Convert gfs2 and gfs2meta to fs_context. Removes the duplicated vfs code
from gfs2_mount and instead uses the new vfs_get_block_super() before
switching the ->root to the appropriate dentry.

The mount option parsing has been converted to the new API and error
reporting for invalid options has been made more precise at the same
time.

All of the mount/remount code has been moved into ops_fstype.c

Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: cluster-devel@redhat.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 374 insertions, 121 deletions

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 4a8e5a7310f0..0856f3c6ed8b 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -21,6 +21,7 @@
 #include <linux/lockdep.h>
 #include <linux/module.h>
 #include <linux/backing-dev.h>
+#include <linux/fs_parser.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -1030,16 +1031,17 @@ void gfs2_online_uevent(struct gfs2_sbd *sdp)
 }
 
 /**
- * fill_super - Read in superblock
+ * gfs2_fill_super - Read in superblock
  * @sb: The VFS superblock
- * @data: Mount options
+ * @args: Mount options
  * @silent: Don't complain if it's not a GFS2 filesystem
  *
- * Returns: errno
+ * Returns: -errno
  */
-
-static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent)
+static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc)
 {
+	struct gfs2_args *args = fc->fs_private;
+	int silent = fc->sb_flags & SB_SILENT;
 	struct gfs2_sbd *sdp;
 	struct gfs2_holder mount_gh;
 	int error;
@@ -1204,161 +1206,411 @@ fail_debug:
 	return error;
 }
 
-static int set_gfs2_super(struct super_block *s, void *data)
+/**
+ * gfs2_get_tree - Get the GFS2 superblock and root directory
+ * @fc: The filesystem context
+ *
+ * Returns: 0 or -errno on error
+ */
+static int gfs2_get_tree(struct fs_context *fc)
 {
-	s->s_bdev = data;
-	s->s_dev = s->s_bdev->bd_dev;
-	s->s_bdi = bdi_get(s->s_bdev->bd_bdi);
+	struct gfs2_args *args = fc->fs_private;
+	struct gfs2_sbd *sdp;
+	int error;
+
+	error = get_tree_bdev(fc, gfs2_fill_super);
+	if (error)
+		return error;
+
+	sdp = fc->root->d_sb->s_fs_info;
+	dput(fc->root);
+	if (args->ar_meta)
+		fc->root = dget(sdp->sd_master_dir);
+	else
+		fc->root = dget(sdp->sd_root_dir);
 	return 0;
 }
 
-static int test_gfs2_super(struct super_block *s, void *ptr)
+static void gfs2_fc_free(struct fs_context *fc)
 {
-	struct block_device *bdev = ptr;
-	return (bdev == s->s_bdev);
+	struct gfs2_args *args = fc->fs_private;
+
+	kfree(args);
 }
 
-/**
- * gfs2_mount - Get the GFS2 superblock
- * @fs_type: The GFS2 filesystem type
- * @flags: Mount flags
- * @dev_name: The name of the device
- * @data: The mount arguments
- *
- * Q. Why not use get_sb_bdev() ?
- * A. We need to select one of two root directories to mount, independent
- *    of whether this is the initial, or subsequent, mount of this sb
- *
- * Returns: 0 or -ve on error
- */
+enum gfs2_param {
+	Opt_lockproto,
+	Opt_locktable,
+	Opt_hostdata,
+	Opt_spectator,
+	Opt_ignore_local_fs,
+	Opt_localflocks,
+	Opt_localcaching,
+	Opt_debug,
+	Opt_upgrade,
+	Opt_acl,
+	Opt_quota,
+	Opt_suiddir,
+	Opt_data,
+	Opt_meta,
+	Opt_discard,
+	Opt_commit,
+	Opt_errors,
+	Opt_statfs_quantum,
+	Opt_statfs_percent,
+	Opt_quota_quantum,
+	Opt_barrier,
+	Opt_rgrplvb,
+	Opt_loccookie,
+};
 
-static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
-		       const char *dev_name, void *data)
-{
-	struct block_device *bdev;
-	struct super_block *s;
-	fmode_t mode = FMODE_READ | FMODE_EXCL;
-	int error;
-	struct gfs2_args args;
-	struct gfs2_sbd *sdp;
+enum opt_quota {
+	Opt_quota_unset = 0,
+	Opt_quota_off,
+	Opt_quota_account,
+	Opt_quota_on,
+};
+
+static const unsigned int opt_quota_values[] = {
+	[Opt_quota_off]     = GFS2_QUOTA_OFF,
+	[Opt_quota_account] = GFS2_QUOTA_ACCOUNT,
+	[Opt_quota_on]      = GFS2_QUOTA_ON,
+};
 
-	if (!(flags & SB_RDONLY))
-		mode |= FMODE_WRITE;
+enum opt_data {
+	Opt_data_writeback = GFS2_DATA_WRITEBACK,
+	Opt_data_ordered   = GFS2_DATA_ORDERED,
+};
 
-	bdev = blkdev_get_by_path(dev_name, mode, fs_type);
-	if (IS_ERR(bdev))
-		return ERR_CAST(bdev);
+enum opt_errors {
+	Opt_errors_withdraw = GFS2_ERRORS_WITHDRAW,
+	Opt_errors_panic    = GFS2_ERRORS_PANIC,
+};
 
-	/*
-	 * once the super is inserted into the list by sget, s_umount
-	 * will protect the lockfs code from trying to start a snapshot
-	 * while we are mounting
-	 */
-	mutex_lock(&bdev->bd_fsfreeze_mutex);
-	if (bdev->bd_fsfreeze_count > 0) {
-		mutex_unlock(&bdev->bd_fsfreeze_mutex);
-		error = -EBUSY;
-		goto error_bdev;
-	}
-	s = sget(fs_type, test_gfs2_super, set_gfs2_super, flags, bdev);
-	mutex_unlock(&bdev->bd_fsfreeze_mutex);
-	error = PTR_ERR(s);
-	if (IS_ERR(s))
-		goto error_bdev;
-
-	if (s->s_root) {
-		/*
-		 * s_umount nests inside bd_mutex during
-		 * __invalidate_device().  blkdev_put() acquires
-		 * bd_mutex and can't be called under s_umount.  Drop
-		 * s_umount temporarily.  This is safe as we're
-		 * holding an active reference.
-		 */
-		up_write(&s->s_umount);
-		blkdev_put(bdev, mode);
-		down_write(&s->s_umount);
-	} else {
-		/* s_mode must be set before deactivate_locked_super calls */
-		s->s_mode = mode;
-	}
+static const struct fs_parameter_spec gfs2_param_specs[] = {
+	fsparam_string ("lockproto",          Opt_lockproto),
+	fsparam_string ("locktable",          Opt_locktable),
+	fsparam_string ("hostdata",           Opt_hostdata),
+	fsparam_flag   ("spectator",          Opt_spectator),
+	fsparam_flag   ("norecovery",         Opt_spectator),
+	fsparam_flag   ("ignore_local_fs",    Opt_ignore_local_fs),
+	fsparam_flag   ("localflocks",        Opt_localflocks),
+	fsparam_flag   ("localcaching",       Opt_localcaching),
+	fsparam_flag_no("debug",              Opt_debug),
+	fsparam_flag   ("upgrade",            Opt_upgrade),
+	fsparam_flag_no("acl",                Opt_acl),
+	fsparam_flag_no("suiddir",            Opt_suiddir),
+	fsparam_enum   ("data",               Opt_data),
+	fsparam_flag   ("meta",               Opt_meta),
+	fsparam_flag_no("discard",            Opt_discard),
+	fsparam_s32    ("commit",             Opt_commit),
+	fsparam_enum   ("errors",             Opt_errors),
+	fsparam_s32    ("statfs_quantum",     Opt_statfs_quantum),
+	fsparam_s32    ("statfs_percent",     Opt_statfs_percent),
+	fsparam_s32    ("quota_quantum",      Opt_quota_quantum),
+	fsparam_flag_no("barrier",            Opt_barrier),
+	fsparam_flag_no("rgrplvb",            Opt_rgrplvb),
+	fsparam_flag_no("loccookie",          Opt_loccookie),
+	/* quota can be a flag or an enum so it gets special treatment */
+	__fsparam(fs_param_is_enum, "quota", Opt_quota, fs_param_neg_with_no|fs_param_v_optional),
+	{}
+};
 
-	memset(&args, 0, sizeof(args));
-	args.ar_quota = GFS2_QUOTA_DEFAULT;
-	args.ar_data = GFS2_DATA_DEFAULT;
-	args.ar_commit = 30;
-	args.ar_statfs_quantum = 30;
-	args.ar_quota_quantum = 60;
-	args.ar_errors = GFS2_ERRORS_DEFAULT;
+static const struct fs_parameter_enum gfs2_param_enums[] = {
+	{ Opt_quota,    "off",        Opt_quota_off },
+	{ Opt_quota,    "account",    Opt_quota_account },
+	{ Opt_quota,    "on",         Opt_quota_on },
+	{ Opt_data,     "writeback",  Opt_data_writeback },
+	{ Opt_data,     "ordered",    Opt_data_ordered },
+	{ Opt_errors,   "withdraw",   Opt_errors_withdraw },
+	{ Opt_errors,   "panic",      Opt_errors_panic },
+	{}
+};
 
-	error = gfs2_mount_args(&args, data);
-	if (error) {
-		pr_warn("can't parse mount arguments\n");
-		goto error_super;
+const struct fs_parameter_description gfs2_fs_parameters = {
+	.name = "gfs2",
+	.specs = gfs2_param_specs,
+	.enums = gfs2_param_enums,
+};
+
+/* Parse a single mount parameter */
+static int gfs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct gfs2_args *args = fc->fs_private;
+	struct fs_parse_result result;
+	int o;
+
+	o = fs_parse(fc, &gfs2_fs_parameters, param, &result);
+	if (o < 0)
+		return o;
+
+	switch (o) {
+	case Opt_lockproto:
+		strlcpy(args->ar_lockproto, param->string, GFS2_LOCKNAME_LEN);
+		break;
+	case Opt_locktable:
+		strlcpy(args->ar_locktable, param->string, GFS2_LOCKNAME_LEN);
+		break;
+	case Opt_hostdata:
+		strlcpy(args->ar_hostdata, param->string, GFS2_LOCKNAME_LEN);
+		break;
+	case Opt_spectator:
+		args->ar_spectator = 1;
+		break;
+	case Opt_ignore_local_fs:
+		/* Retained for backwards compat only */
+		break;
+	case Opt_localflocks:
+		args->ar_localflocks = 1;
+		break;
+	case Opt_localcaching:
+		/* Retained for backwards compat only */
+		break;
+	case Opt_debug:
+		if (result.boolean && args->ar_errors == GFS2_ERRORS_PANIC)
+			return invalf(fc, "gfs2: -o debug and -o errors=panic are mutually exclusive");
+		args->ar_debug = result.boolean;
+		break;
+	case Opt_upgrade:
+		/* Retained for backwards compat only */
+		break;
+	case Opt_acl:
+		args->ar_posix_acl = result.boolean;
+		break;
+	case Opt_quota:
+		/* The quota option can be a flag or an enum. A non-zero int_32
+		   result means that we have an enum index. Otherwise we have
+		   to rely on the 'negated' flag to tell us whether 'quota' or
+		   'noquota' was specified. */
+		if (result.negated)
+			args->ar_quota = GFS2_QUOTA_OFF;
+		else if (result.int_32 > 0)
+			args->ar_quota = opt_quota_values[result.int_32];
+		else
+			args->ar_quota = GFS2_QUOTA_ON;
+		break;
+	case Opt_suiddir:
+		args->ar_suiddir = result.boolean;
+		break;
+	case Opt_data:
+		/* The uint_32 result maps directly to GFS2_DATA_* */
+		args->ar_data = result.uint_32;
+		break;
+	case Opt_meta:
+		args->ar_meta = 1;
+		break;
+	case Opt_discard:
+		args->ar_discard = result.boolean;
+		break;
+	case Opt_commit:
+		if (result.int_32 <= 0)
+			return invalf(fc, "gfs2: commit mount option requires a positive numeric argument");
+		args->ar_commit = result.int_32;
+		break;
+	case Opt_statfs_quantum:
+		if (result.int_32 < 0)
+			return invalf(fc, "gfs2: statfs_quantum mount option requires a non-negative numeric argument");
+		args->ar_statfs_quantum = result.int_32;
+		break;
+	case Opt_quota_quantum:
+		if (result.int_32 <= 0)
+			return invalf(fc, "gfs2: quota_quantum mount option requires a positive numeric argument");
+		args->ar_quota_quantum = result.int_32;
+		break;
+	case Opt_statfs_percent:
+		if (result.int_32 < 0 || result.int_32 > 100)
+			return invalf(fc, "gfs2: statfs_percent mount option requires a numeric argument between 0 and 100");
+		args->ar_statfs_percent = result.int_32;
+		break;
+	case Opt_errors:
+		if (args->ar_debug && result.uint_32 == GFS2_ERRORS_PANIC)
+			return invalf(fc, "gfs2: -o debug and -o errors=panic are mutually exclusive");
+		args->ar_errors = result.uint_32;
+		break;
+	case Opt_barrier:
+		args->ar_nobarrier = result.boolean;
+		break;
+	case Opt_rgrplvb:
+		args->ar_rgrplvb = result.boolean;
+		break;
+	case Opt_loccookie:
+		args->ar_loccookie = result.boolean;
+		break;
+	default:
+		return invalf(fc, "gfs2: invalid mount option: %s", param->key);
 	}
+	return 0;
+}
 
-	if (s->s_root) {
-		error = -EBUSY;
-		if ((flags ^ s->s_flags) & SB_RDONLY)
-			goto error_super;
-	} else {
-		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
-		sb_set_blocksize(s, block_size(bdev));
-		error = fill_super(s, &args, flags & SB_SILENT ? 1 : 0);
-		if (error)
-			goto error_super;
-		s->s_flags |= SB_ACTIVE;
-		bdev->bd_super = s;
+static int gfs2_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+	struct gfs2_sbd *sdp = sb->s_fs_info;
+	struct gfs2_args *oldargs = &sdp->sd_args;
+	struct gfs2_args *newargs = fc->fs_private;
+	struct gfs2_tune *gt = &sdp->sd_tune;
+	int error = 0;
+
+	sync_filesystem(sb);
+
+	spin_lock(&gt->gt_spin);
+	oldargs->ar_commit = gt->gt_logd_secs;
+	oldargs->ar_quota_quantum = gt->gt_quota_quantum;
+	if (gt->gt_statfs_slow)
+		oldargs->ar_statfs_quantum = 0;
+	else
+		oldargs->ar_statfs_quantum = gt->gt_statfs_quantum;
+	spin_unlock(&gt->gt_spin);
+
+	if (strcmp(newargs->ar_lockproto, oldargs->ar_lockproto)) {
+		errorf(fc, "gfs2: reconfiguration of locking protocol not allowed");
+		return -EINVAL;
+	}
+	if (strcmp(newargs->ar_locktable, oldargs->ar_locktable)) {
+		errorf(fc, "gfs2: reconfiguration of lock table not allowed");
+		return -EINVAL;
+	}
+	if (strcmp(newargs->ar_hostdata, oldargs->ar_hostdata)) {
+		errorf(fc, "gfs2: reconfiguration of host data not allowed");
+		return -EINVAL;
+	}
+	if (newargs->ar_spectator != oldargs->ar_spectator) {
+		errorf(fc, "gfs2: reconfiguration of spectator mode not allowed");
+		return -EINVAL;
+	}
+	if (newargs->ar_localflocks != oldargs->ar_localflocks) {
+		errorf(fc, "gfs2: reconfiguration of localflocks not allowed");
+		return -EINVAL;
+	}
+	if (newargs->ar_meta != oldargs->ar_meta) {
+		errorf(fc, "gfs2: switching between gfs2 and gfs2meta not allowed");
+		return -EINVAL;
+	}
+	if (oldargs->ar_spectator)
+		fc->sb_flags |= SB_RDONLY;
+
+	if ((sb->s_flags ^ fc->sb_flags) & SB_RDONLY) {
+		if (fc->sb_flags & SB_RDONLY) {
+			error = gfs2_make_fs_ro(sdp);
+			if (error)
+				errorf(fc, "gfs2: unable to remount read-only");
+		} else {
+			error = gfs2_make_fs_rw(sdp);
+			if (error)
+				errorf(fc, "gfs2: unable to remount read-write");
+		}
 	}
+	sdp->sd_args = *newargs;
 
-	sdp = s->s_fs_info;
-	if (args.ar_meta)
-		return dget(sdp->sd_master_dir);
+	if (sdp->sd_args.ar_posix_acl)
+		sb->s_flags |= SB_POSIXACL;
+	else
+		sb->s_flags &= ~SB_POSIXACL;
+	if (sdp->sd_args.ar_nobarrier)
+		set_bit(SDF_NOBARRIERS, &sdp->sd_flags);
 	else
-		return dget(sdp->sd_root_dir);
-
-error_super:
-	deactivate_locked_super(s);
-	return ERR_PTR(error);
-error_bdev:
-	blkdev_put(bdev, mode);
-	return ERR_PTR(error);
+		clear_bit(SDF_NOBARRIERS, &sdp->sd_flags);
+	spin_lock(&gt->gt_spin);
+	gt->gt_logd_secs = newargs->ar_commit;
+	gt->gt_quota_quantum = newargs->ar_quota_quantum;
+	if (newargs->ar_statfs_quantum) {
+		gt->gt_statfs_slow = 0;
+		gt->gt_statfs_quantum = newargs->ar_statfs_quantum;
+	}
+	else {
+		gt->gt_statfs_slow = 1;
+		gt->gt_statfs_quantum = 30;
+	}
+	spin_unlock(&gt->gt_spin);
+
+	gfs2_online_uevent(sdp);
+	return error;
+}
+
+static const struct fs_context_operations gfs2_context_ops = {
+	.free        = gfs2_fc_free,
+	.parse_param = gfs2_parse_param,
+	.get_tree    = gfs2_get_tree,
+	.reconfigure = gfs2_reconfigure,
+};
+
+/* Set up the filesystem mount context */
+static int gfs2_init_fs_context(struct fs_context *fc)
+{
+	struct gfs2_args *args;
+
+	args = kzalloc(sizeof(*args), GFP_KERNEL);
+	if (args == NULL)
+		return -ENOMEM;
+
+	args->ar_quota = GFS2_QUOTA_DEFAULT;
+	args->ar_data = GFS2_DATA_DEFAULT;
+	args->ar_commit = 30;
+	args->ar_statfs_quantum = 30;
+	args->ar_quota_quantum = 60;
+	args->ar_errors = GFS2_ERRORS_DEFAULT;
+
+	fc->fs_private = args;
+	fc->ops = &gfs2_context_ops;
+	return 0;
 }
 
-static int set_meta_super(struct super_block *s, void *ptr)
+static int set_meta_super(struct super_block *s, struct fs_context *fc)
 {
 	return -EINVAL;
 }
 
-static struct dentry *gfs2_mount_meta(struct file_system_type *fs_type,
-			int flags, const char *dev_name, void *data)
+static int test_meta_super(struct super_block *s, struct fs_context *fc)
+{
+	return (fc->sget_key == s->s_bdev);
+}
+
+static int gfs2_meta_get_tree(struct fs_context *fc)
 {
 	struct super_block *s;
 	struct gfs2_sbd *sdp;
 	struct path path;
 	int error;
 
-	if (!dev_name || !*dev_name)
-		return ERR_PTR(-EINVAL);
+	if (!fc->source || !*fc->source)
+		return -EINVAL;
 
-	error = kern_path(dev_name, LOOKUP_FOLLOW, &path);
+	error = kern_path(fc->source, LOOKUP_FOLLOW, &path);
 	if (error) {
 		pr_warn("path_lookup on %s returned error %d\n",
-			dev_name, error);
-		return ERR_PTR(error);
+		        fc->source, error);
+		return error;
 	}
-	s = sget(&gfs2_fs_type, test_gfs2_super, set_meta_super, flags,
-		 path.dentry->d_sb->s_bdev);
+	fc->fs_type = &gfs2_fs_type;
+	fc->sget_key = path.dentry->d_sb->s_bdev;
+	s = sget_fc(fc, test_meta_super, set_meta_super);
 	path_put(&path);
 	if (IS_ERR(s)) {
 		pr_warn("gfs2 mount does not exist\n");
-		return ERR_CAST(s);
+		return PTR_ERR(s);
 	}
-	if ((flags ^ s->s_flags) & SB_RDONLY) {
+	if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) {
 		deactivate_locked_super(s);
-		return ERR_PTR(-EBUSY);
+		return -EBUSY;
 	}
 	sdp = s->s_fs_info;
-	return dget(sdp->sd_master_dir);
+	fc->root = dget(sdp->sd_master_dir);
+	return 0;
+}
+
+static const struct fs_context_operations gfs2_meta_context_ops = {
+	.get_tree    = gfs2_meta_get_tree,
+};
+
+static int gfs2_meta_init_fs_context(struct fs_context *fc)
+{
+	int ret = gfs2_init_fs_context(fc);
+
+	if (ret)
+		return ret;
+
+	fc->ops = &gfs2_meta_context_ops;
+	return 0;
 }
 
 static void gfs2_kill_sb(struct super_block *sb)
@@ -1382,7 +1634,8 @@ static void gfs2_kill_sb(struct super_block *sb)
 struct file_system_type gfs2_fs_type = {
 	.name = "gfs2",
 	.fs_flags = FS_REQUIRES_DEV,
-	.mount = gfs2_mount,
+	.init_fs_context = gfs2_init_fs_context,
+	.parameters = &gfs2_fs_parameters,
 	.kill_sb = gfs2_kill_sb,
 	.owner = THIS_MODULE,
 };
@@ -1391,7 +1644,7 @@ MODULE_ALIAS_FS("gfs2");
 struct file_system_type gfs2meta_fs_type = {
 	.name = "gfs2meta",
 	.fs_flags = FS_REQUIRES_DEV,
-	.mount = gfs2_mount_meta,
+	.init_fs_context = gfs2_meta_init_fs_context,
 	.owner = THIS_MODULE,
 };
 MODULE_ALIAS_FS("gfs2meta");