1 files changed, 273 insertions, 329 deletions

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 5729ee86da9a..badc2cbc895e 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
- * super.c - NILFS module and super block management.
+ * NILFS module and super block management.
  *
  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
  *
@@ -29,12 +29,13 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/blkdev.h>
-#include <linux/parser.h>
 #include <linux/crc32.h>
 #include <linux/vfs.h>
 #include <linux/writeback.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include "nilfs.h"
 #include "export.h"
 #include "mdt.h"
@@ -60,21 +61,26 @@ struct kmem_cache *nilfs_segbuf_cachep;
 struct kmem_cache *nilfs_btree_path_cache;
 
 static int nilfs_setup_super(struct super_block *sb, int is_mount);
-static int nilfs_remount(struct super_block *sb, int *flags, char *data);
 
-void __nilfs_msg(struct super_block *sb, const char *level, const char *fmt,
-		 ...)
+void __nilfs_msg(struct super_block *sb, const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list args;
+	int level;
 
 	va_start(args, fmt);
-	vaf.fmt = fmt;
+
+	level = printk_get_level(fmt);
+	vaf.fmt = printk_skip_level(fmt);
 	vaf.va = &args;
+
 	if (sb)
-		printk("%sNILFS (%s): %pV\n", level, sb->s_id, &vaf);
+		printk("%c%cNILFS (%s): %pV\n",
+		       KERN_SOH_ASCII, level, sb->s_id, &vaf);
 	else
-		printk("%sNILFS: %pV\n", level, &vaf);
+		printk("%c%cNILFS: %pV\n",
+		       KERN_SOH_ASCII, level, &vaf);
+
 	va_end(args);
 }
 
@@ -99,6 +105,10 @@ static void nilfs_set_error(struct super_block *sb)
 
 /**
  * __nilfs_error() - report failure condition on a filesystem
+ * @sb:       super block instance
+ * @function: name of calling function
+ * @fmt:      format string for message to be output
+ * @...:      optional arguments to @fmt
  *
  * __nilfs_error() sets an ERROR_FS flag on the superblock as well as
  * reporting an error message.  This function should be called when
@@ -106,7 +116,7 @@ static void nilfs_set_error(struct super_block *sb)
  *
  * This implements the body of nilfs_error() macro.  Normally,
  * nilfs_error() should be used.  As for sustainable errors such as a
- * single-shot I/O error, nilfs_msg() should be used instead.
+ * single-shot I/O error, nilfs_err() should be used instead.
  *
  * Callers should not add a trailing newline since this will do it.
  */
@@ -145,13 +155,15 @@ struct inode *nilfs_alloc_inode(struct super_block *sb)
 {
 	struct nilfs_inode_info *ii;
 
-	ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
+	ii = alloc_inode_sb(sb, nilfs_inode_cachep, GFP_NOFS);
 	if (!ii)
 		return NULL;
 	ii->i_bh = NULL;
 	ii->i_state = 0;
+	ii->i_type = 0;
 	ii->i_cno = 0;
-	nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode);
+	ii->i_assoc_inode = NULL;
+	ii->i_bmap = &ii->i_bmap_data;
 	return &ii->vfs_inode;
 }
 
@@ -178,8 +190,7 @@ static int nilfs_sync_super(struct super_block *sb, int flag)
 	}
 
 	if (unlikely(err)) {
-		nilfs_msg(sb, KERN_ERR, "unable to write superblock: err=%d",
-			  err);
+		nilfs_err(sb, "unable to write superblock: err=%d", err);
 		if (err == -EIO && nilfs->ns_sbh[1]) {
 			/*
 			 * sbp[0] points to newer log than sbp[1],
@@ -249,7 +260,7 @@ struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 		    sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 			memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 		} else {
-			nilfs_msg(sb, KERN_CRIT, "superblock broke");
+			nilfs_crit(sb, "superblock broke");
 			return NULL;
 		}
 	} else if (sbp[1] &&
@@ -298,6 +309,8 @@ int nilfs_commit_super(struct super_block *sb, int flag)
  * This function restores state flags in the on-disk super block.
  * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
  * filesystem was not clean previously.
+ *
+ * Return: 0 on success, %-EIO if I/O error or superblock is corrupted.
  */
 int nilfs_cleanup_super(struct super_block *sb)
 {
@@ -328,6 +341,8 @@ int nilfs_cleanup_super(struct super_block *sb)
  * nilfs_move_2nd_super - relocate secondary super block
  * @sb: super block instance
  * @sb2off: new offset of the secondary super block (in bytes)
+ *
+ * Return: 0 on success, or a negative error code on failure.
  */
 static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 {
@@ -359,17 +374,38 @@ static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 	offset = sb2off & (nilfs->ns_blocksize - 1);
 	nsbh = sb_getblk(sb, newblocknr);
 	if (!nsbh) {
-		nilfs_msg(sb, KERN_WARNING,
-			  "unable to move secondary superblock to block %llu",
-			  (unsigned long long)newblocknr);
+		nilfs_warn(sb,
+			   "unable to move secondary superblock to block %llu",
+			   (unsigned long long)newblocknr);
 		ret = -EIO;
 		goto out;
 	}
 	nsbp = (void *)nsbh->b_data + offset;
-	memset(nsbp, 0, nilfs->ns_blocksize);
 
+	lock_buffer(nsbh);
 	if (sb2i >= 0) {
+		/*
+		 * The position of the second superblock only changes by 4KiB,
+		 * which is larger than the maximum superblock data size
+		 * (= 1KiB), so there is no need to use memmove() to allow
+		 * overlap between source and destination.
+		 */
 		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
+
+		/*
+		 * Zero fill after copy to avoid overwriting in case of move
+		 * within the same block.
+		 */
+		memset(nsbh->b_data, 0, offset);
+		memset((void *)nsbp + nilfs->ns_sbsize, 0,
+		       nsbh->b_size - offset - nilfs->ns_sbsize);
+	} else {
+		memset(nsbh->b_data, 0, nsbh->b_size);
+	}
+	set_buffer_uptodate(nsbh);
+	unlock_buffer(nsbh);
+
+	if (sb2i >= 0) {
 		brelse(nilfs->ns_sbh[sb2i]);
 		nilfs->ns_sbh[sb2i] = nsbh;
 		nilfs->ns_sbp[sb2i] = nsbp;
@@ -388,6 +424,8 @@ out:
  * nilfs_resize_fs - resize the filesystem
  * @sb: super block instance
  * @newsize: new size of the filesystem (in bytes)
+ *
+ * Return: 0 on success, or a negative error code on failure.
  */
 int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 {
@@ -398,11 +436,20 @@ int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 	int ret;
 
 	ret = -ERANGE;
-	devsize = i_size_read(sb->s_bdev->bd_inode);
+	devsize = bdev_nr_bytes(sb->s_bdev);
 	if (newsize > devsize)
 		goto out;
 
 	/*
+	 * Prevent underflow in second superblock position calculation.
+	 * The exact minimum size check is done in nilfs_sufile_resize().
+	 */
+	if (newsize < 4096) {
+		ret = -ENOSPC;
+		goto out;
+	}
+
+	/*
 	 * Write lock is required to protect some functions depending
 	 * on the number of segments, the number of reserved segments,
 	 * and so forth.
@@ -411,7 +458,7 @@ int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 
 	sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 	newnsegs = sb2off >> nilfs->ns_blocksize_bits;
-	do_div(newnsegs, nilfs->ns_blocks_per_segment);
+	newnsegs = div64_ul(newnsegs, nilfs->ns_blocks_per_segment);
 
 	ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 	up_write(&nilfs->ns_segctor_sem);
@@ -467,6 +514,7 @@ static void nilfs_put_super(struct super_block *sb)
 		up_write(&nilfs->ns_sem);
 	}
 
+	nilfs_sysfs_delete_device_group(nilfs);
 	iput(nilfs->ns_sufile);
 	iput(nilfs->ns_cpfile);
 	iput(nilfs->ns_dat);
@@ -506,8 +554,6 @@ int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 {
 	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct nilfs_root *root;
-	struct nilfs_checkpoint *raw_cp;
-	struct buffer_head *bh_cp;
 	int err = -ENOMEM;
 
 	root = nilfs_find_or_create_root(
@@ -519,38 +565,19 @@ int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 		goto reuse; /* already attached checkpoint */
 
 	down_read(&nilfs->ns_segctor_sem);
-	err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
-					  &bh_cp);
+	err = nilfs_ifile_read(sb, root, cno, nilfs->ns_inode_size);
 	up_read(&nilfs->ns_segctor_sem);
-	if (unlikely(err)) {
-		if (err == -ENOENT || err == -EINVAL) {
-			nilfs_msg(sb, KERN_ERR,
-				  "Invalid checkpoint (checkpoint number=%llu)",
-				  (unsigned long long)cno);
-			err = -EINVAL;
-		}
+	if (unlikely(err))
 		goto failed;
-	}
-
-	err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
-			       &raw_cp->cp_ifile_inode, &root->ifile);
-	if (err)
-		goto failed_bh;
-
-	atomic64_set(&root->inodes_count,
-			le64_to_cpu(raw_cp->cp_inodes_count));
-	atomic64_set(&root->blocks_count,
-			le64_to_cpu(raw_cp->cp_blocks_count));
-
-	nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 
  reuse:
 	*rootp = root;
 	return 0;
 
- failed_bh:
-	nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
  failed:
+	if (err == -EINVAL)
+		nilfs_err(sb, "Invalid checkpoint (checkpoint number=%llu)",
+			  (unsigned long long)cno);
 	nilfs_put_root(root);
 
 	return err;
@@ -622,8 +649,7 @@ static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	err = nilfs_ifile_count_free_inodes(root->ifile,
 					    &nmaxinodes, &nfreeinodes);
 	if (unlikely(err)) {
-		nilfs_msg(sb, KERN_WARNING,
-			  "failed to count free inodes: err=%d", err);
+		nilfs_warn(sb, "failed to count free inodes: err=%d", err);
 		if (err == -ERANGE) {
 			/*
 			 * If nilfs_palloc_count_max_entries() returns
@@ -647,8 +673,7 @@ static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_files = nmaxinodes;
 	buf->f_ffree = nfreeinodes;
 	buf->f_namelen = NILFS_NAME_LEN;
-	buf->f_fsid.val[0] = (u32)id;
-	buf->f_fsid.val[1] = (u32)(id >> 32);
+	buf->f_fsid = u64_to_fsid(id);
 
 	return 0;
 }
@@ -687,106 +712,98 @@ static const struct super_operations nilfs_sops = {
 	.freeze_fs	= nilfs_freeze,
 	.unfreeze_fs	= nilfs_unfreeze,
 	.statfs         = nilfs_statfs,
-	.remount_fs     = nilfs_remount,
 	.show_options = nilfs_show_options
 };
 
 enum {
-	Opt_err_cont, Opt_err_panic, Opt_err_ro,
-	Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
-	Opt_discard, Opt_nodiscard, Opt_err,
+	Opt_err, Opt_barrier, Opt_snapshot, Opt_order, Opt_norecovery,
+	Opt_discard,
 };
 
-static match_table_t tokens = {
-	{Opt_err_cont, "errors=continue"},
-	{Opt_err_panic, "errors=panic"},
-	{Opt_err_ro, "errors=remount-ro"},
-	{Opt_barrier, "barrier"},
-	{Opt_nobarrier, "nobarrier"},
-	{Opt_snapshot, "cp=%u"},
-	{Opt_order, "order=%s"},
-	{Opt_norecovery, "norecovery"},
-	{Opt_discard, "discard"},
-	{Opt_nodiscard, "nodiscard"},
-	{Opt_err, NULL}
+static const struct constant_table nilfs_param_err[] = {
+	{"continue",	NILFS_MOUNT_ERRORS_CONT},
+	{"panic",	NILFS_MOUNT_ERRORS_PANIC},
+	{"remount-ro",	NILFS_MOUNT_ERRORS_RO},
+	{}
 };
 
-static int parse_options(char *options, struct super_block *sb, int is_remount)
-{
-	struct the_nilfs *nilfs = sb->s_fs_info;
-	char *p;
-	substring_t args[MAX_OPT_ARGS];
-
-	if (!options)
-		return 1;
-
-	while ((p = strsep(&options, ",")) != NULL) {
-		int token;
+static const struct fs_parameter_spec nilfs_param_spec[] = {
+	fsparam_enum	("errors", Opt_err, nilfs_param_err),
+	fsparam_flag_no	("barrier", Opt_barrier),
+	fsparam_u64	("cp", Opt_snapshot),
+	fsparam_string	("order", Opt_order),
+	fsparam_flag	("norecovery", Opt_norecovery),
+	fsparam_flag_no	("discard", Opt_discard),
+	{}
+};
 
-		if (!*p)
-			continue;
+struct nilfs_fs_context {
+	unsigned long ns_mount_opt;
+	__u64 cno;
+};
 
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case Opt_barrier:
-			nilfs_set_opt(nilfs, BARRIER);
-			break;
-		case Opt_nobarrier:
+static int nilfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct nilfs_fs_context *nilfs = fc->fs_private;
+	int is_remount = fc->purpose == FS_CONTEXT_FOR_RECONFIGURE;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, nilfs_param_spec, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_barrier:
+		if (result.negated)
 			nilfs_clear_opt(nilfs, BARRIER);
-			break;
-		case Opt_order:
-			if (strcmp(args[0].from, "relaxed") == 0)
-				/* Ordered data semantics */
-				nilfs_clear_opt(nilfs, STRICT_ORDER);
-			else if (strcmp(args[0].from, "strict") == 0)
-				/* Strict in-order semantics */
-				nilfs_set_opt(nilfs, STRICT_ORDER);
-			else
-				return 0;
-			break;
-		case Opt_err_panic:
-			nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
-			break;
-		case Opt_err_ro:
-			nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
-			break;
-		case Opt_err_cont:
-			nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
-			break;
-		case Opt_snapshot:
-			if (is_remount) {
-				nilfs_msg(sb, KERN_ERR,
-					  "\"%s\" option is invalid for remount",
-					  p);
-				return 0;
-			}
-			break;
-		case Opt_norecovery:
-			nilfs_set_opt(nilfs, NORECOVERY);
-			break;
-		case Opt_discard:
-			nilfs_set_opt(nilfs, DISCARD);
-			break;
-		case Opt_nodiscard:
-			nilfs_clear_opt(nilfs, DISCARD);
-			break;
-		default:
-			nilfs_msg(sb, KERN_ERR,
-				  "unrecognized mount option \"%s\"", p);
-			return 0;
+		else
+			nilfs_set_opt(nilfs, BARRIER);
+		break;
+	case Opt_order:
+		if (strcmp(param->string, "relaxed") == 0)
+			/* Ordered data semantics */
+			nilfs_clear_opt(nilfs, STRICT_ORDER);
+		else if (strcmp(param->string, "strict") == 0)
+			/* Strict in-order semantics */
+			nilfs_set_opt(nilfs, STRICT_ORDER);
+		else
+			return -EINVAL;
+		break;
+	case Opt_err:
+		nilfs->ns_mount_opt &= ~NILFS_MOUNT_ERROR_MODE;
+		nilfs->ns_mount_opt |= result.uint_32;
+		break;
+	case Opt_snapshot:
+		if (is_remount) {
+			struct super_block *sb = fc->root->d_sb;
+
+			nilfs_err(sb,
+				  "\"%s\" option is invalid for remount",
+				  param->key);
+			return -EINVAL;
 		}
+		if (result.uint_64 == 0) {
+			nilfs_err(NULL,
+				  "invalid option \"cp=0\": invalid checkpoint number 0");
+			return -EINVAL;
+		}
+		nilfs->cno = result.uint_64;
+		break;
+	case Opt_norecovery:
+		nilfs_set_opt(nilfs, NORECOVERY);
+		break;
+	case Opt_discard:
+		if (result.negated)
+			nilfs_clear_opt(nilfs, DISCARD);
+		else
+			nilfs_set_opt(nilfs, DISCARD);
+		break;
+	default:
+		return -EINVAL;
 	}
-	return 1;
-}
 
-static inline void
-nilfs_set_default_options(struct super_block *sb,
-			  struct nilfs_super_block *sbp)
-{
-	struct the_nilfs *nilfs = sb->s_fs_info;
-
-	nilfs->ns_mount_opt =
-		NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
+	return 0;
 }
 
 static int nilfs_setup_super(struct super_block *sb, int is_mount)
@@ -808,10 +825,10 @@ static int nilfs_setup_super(struct super_block *sb, int is_mount)
 	mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 
 	if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
-		nilfs_msg(sb, KERN_WARNING, "mounting fs with errors");
+		nilfs_warn(sb, "mounting fs with errors");
 #if 0
 	} else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
-		nilfs_msg(sb, KERN_WARNING, "maximal mount count reached");
+		nilfs_warn(sb, "maximal mount count reached");
 #endif
 	}
 	if (!max_mnt_count)
@@ -843,9 +860,8 @@ struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 	return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 }
 
-int nilfs_store_magic_and_option(struct super_block *sb,
-				 struct nilfs_super_block *sbp,
-				 char *data)
+int nilfs_store_magic(struct super_block *sb,
+		      struct nilfs_super_block *sbp)
 {
 	struct the_nilfs *nilfs = sb->s_fs_info;
 
@@ -856,14 +872,12 @@ int nilfs_store_magic_and_option(struct super_block *sb,
 	sb->s_flags |= SB_NOATIME;
 #endif
 
-	nilfs_set_default_options(sb, sbp);
-
 	nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 	nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 	nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 	nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 
-	return !parse_options(data, sb, 0) ? -EINVAL : 0;
+	return 0;
 }
 
 int nilfs_check_feature_compatibility(struct super_block *sb,
@@ -874,7 +888,7 @@ int nilfs_check_feature_compatibility(struct super_block *sb,
 	features = le64_to_cpu(sbp->s_feature_incompat) &
 		~NILFS_FEATURE_INCOMPAT_SUPP;
 	if (features) {
-		nilfs_msg(sb, KERN_ERR,
+		nilfs_err(sb,
 			  "couldn't mount because of unsupported optional features (%llx)",
 			  (unsigned long long)features);
 		return -EINVAL;
@@ -882,7 +896,7 @@ int nilfs_check_feature_compatibility(struct super_block *sb,
 	features = le64_to_cpu(sbp->s_feature_compat_ro) &
 		~NILFS_FEATURE_COMPAT_RO_SUPP;
 	if (!sb_rdonly(sb) && features) {
-		nilfs_msg(sb, KERN_ERR,
+		nilfs_err(sb,
 			  "couldn't mount RDWR because of unsupported optional features (%llx)",
 			  (unsigned long long)features);
 		return -EINVAL;
@@ -901,12 +915,12 @@ static int nilfs_get_root_dentry(struct super_block *sb,
 	inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 	if (IS_ERR(inode)) {
 		ret = PTR_ERR(inode);
-		nilfs_msg(sb, KERN_ERR, "error %d getting root inode", ret);
+		nilfs_err(sb, "error %d getting root inode", ret);
 		goto out;
 	}
 	if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 		iput(inode);
-		nilfs_msg(sb, KERN_ERR, "corrupt root inode");
+		nilfs_err(sb, "corrupt root inode");
 		ret = -EINVAL;
 		goto out;
 	}
@@ -934,7 +948,7 @@ static int nilfs_get_root_dentry(struct super_block *sb,
 	return ret;
 
  failed_dentry:
-	nilfs_msg(sb, KERN_ERR, "error %d getting root dentry", ret);
+	nilfs_err(sb, "error %d getting root dentry", ret);
 	goto out;
 }
 
@@ -954,7 +968,7 @@ static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 		ret = (ret == -ENOENT) ? -EINVAL : ret;
 		goto out;
 	} else if (!ret) {
-		nilfs_msg(s, KERN_ERR,
+		nilfs_err(s,
 			  "The specified checkpoint is not a snapshot (checkpoint number=%llu)",
 			  (unsigned long long)cno);
 		ret = -EINVAL;
@@ -963,7 +977,7 @@ static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 
 	ret = nilfs_attach_checkpoint(s, cno, false, &root);
 	if (ret) {
-		nilfs_msg(s, KERN_ERR,
+		nilfs_err(s,
 			  "error %d while loading snapshot (checkpoint number=%llu)",
 			  ret, (unsigned long long)cno);
 		goto out;
@@ -979,7 +993,7 @@ static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
  * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
  * @root_dentry: root dentry of the tree to be shrunk
  *
- * This function returns true if the tree was in-use.
+ * Return: true if the tree was in-use, false otherwise.
  */
 static bool nilfs_tree_is_busy(struct dentry *root_dentry)
 {
@@ -1021,17 +1035,19 @@ int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 /**
  * nilfs_fill_super() - initialize a super block instance
  * @sb: super_block
- * @data: mount options
- * @silent: silent mode flag
+ * @fc: filesystem context
  *
  * This function is called exclusively by nilfs->ns_mount_mutex.
  * So, the recovery process is protected from other simultaneous mounts.
+ *
+ * Return: 0 on success, or a negative error code on failure.
  */
 static int
-nilfs_fill_super(struct super_block *sb, void *data, int silent)
+nilfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct the_nilfs *nilfs;
 	struct nilfs_root *fsroot;
+	struct nilfs_fs_context *ctx = fc->fs_private;
 	__u64 cno;
 	int err;
 
@@ -1041,26 +1057,33 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	sb->s_fs_info = nilfs;
 
-	err = init_nilfs(nilfs, sb, (char *)data);
+	err = init_nilfs(nilfs, sb);
 	if (err)
 		goto failed_nilfs;
 
+	/* Copy in parsed mount options */
+	nilfs->ns_mount_opt = ctx->ns_mount_opt;
+
 	sb->s_op = &nilfs_sops;
 	sb->s_export_op = &nilfs_export_ops;
 	sb->s_root = NULL;
 	sb->s_time_gran = 1;
 	sb->s_max_links = NILFS_LINK_MAX;
 
-	sb->s_bdi = bdi_get(sb->s_bdev->bd_bdi);
+	sb->s_bdi = bdi_get(sb->s_bdev->bd_disk->bdi);
 
 	err = load_nilfs(nilfs, sb);
 	if (err)
 		goto failed_nilfs;
 
+	super_set_uuid(sb, nilfs->ns_sbp[0]->s_uuid,
+		       sizeof(nilfs->ns_sbp[0]->s_uuid));
+	super_set_sysfs_name_bdev(sb);
+
 	cno = nilfs_last_cno(nilfs);
 	err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
 	if (err) {
-		nilfs_msg(sb, KERN_ERR,
+		nilfs_err(sb,
 			  "error %d while loading last checkpoint (checkpoint number=%llu)",
 			  err, (unsigned long long)cno);
 		goto failed_unload;
@@ -1093,6 +1116,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent)
 	nilfs_put_root(fsroot);
 
  failed_unload:
+	nilfs_sysfs_delete_device_group(nilfs);
 	iput(nilfs->ns_sufile);
 	iput(nilfs->ns_cpfile);
 	iput(nilfs->ns_dat);
@@ -1102,36 +1126,25 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent)
 	return err;
 }
 
-static int nilfs_remount(struct super_block *sb, int *flags, char *data)
+static int nilfs_reconfigure(struct fs_context *fc)
 {
+	struct nilfs_fs_context *ctx = fc->fs_private;
+	struct super_block *sb = fc->root->d_sb;
 	struct the_nilfs *nilfs = sb->s_fs_info;
-	unsigned long old_sb_flags;
-	unsigned long old_mount_opt;
 	int err;
 
 	sync_filesystem(sb);
-	old_sb_flags = sb->s_flags;
-	old_mount_opt = nilfs->ns_mount_opt;
-
-	if (!parse_options(data, sb, 1)) {
-		err = -EINVAL;
-		goto restore_opts;
-	}
-	sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
 
 	err = -EINVAL;
 
 	if (!nilfs_valid_fs(nilfs)) {
-		nilfs_msg(sb, KERN_WARNING,
-			  "couldn't remount because the filesystem is in an incomplete recovery state");
-		goto restore_opts;
+		nilfs_warn(sb,
+			   "couldn't remount because the filesystem is in an incomplete recovery state");
+		goto ignore_opts;
 	}
-
-	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
+	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
 		goto out;
-	if (*flags & SB_RDONLY) {
-		/* Shutting down log writer */
-		nilfs_detach_log_writer(sb);
+	if (fc->sb_flags & SB_RDONLY) {
 		sb->s_flags |= SB_RDONLY;
 
 		/*
@@ -1155,171 +1168,72 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data)
 			~NILFS_FEATURE_COMPAT_RO_SUPP;
 		up_read(&nilfs->ns_sem);
 		if (features) {
-			nilfs_msg(sb, KERN_WARNING,
-				  "couldn't remount RDWR because of unsupported optional features (%llx)",
-				  (unsigned long long)features);
+			nilfs_warn(sb,
+				   "couldn't remount RDWR because of unsupported optional features (%llx)",
+				   (unsigned long long)features);
 			err = -EROFS;
-			goto restore_opts;
+			goto ignore_opts;
 		}
 
 		sb->s_flags &= ~SB_RDONLY;
 
 		root = NILFS_I(d_inode(sb->s_root))->i_root;
 		err = nilfs_attach_log_writer(sb, root);
-		if (err)
-			goto restore_opts;
+		if (err) {
+			sb->s_flags |= SB_RDONLY;
+			goto ignore_opts;
+		}
 
 		down_write(&nilfs->ns_sem);
 		nilfs_setup_super(sb, true);
 		up_write(&nilfs->ns_sem);
 	}
  out:
+	sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
+	/* Copy over parsed remount options */
+	nilfs->ns_mount_opt = ctx->ns_mount_opt;
+
 	return 0;
 
- restore_opts:
-	sb->s_flags = old_sb_flags;
-	nilfs->ns_mount_opt = old_mount_opt;
+ ignore_opts:
 	return err;
 }
 
-struct nilfs_super_data {
-	struct block_device *bdev;
-	__u64 cno;
-	int flags;
-};
-
-static int nilfs_parse_snapshot_option(const char *option,
-				       const substring_t *arg,
-				       struct nilfs_super_data *sd)
+static int
+nilfs_get_tree(struct fs_context *fc)
 {
-	unsigned long long val;
-	const char *msg = NULL;
+	struct nilfs_fs_context *ctx = fc->fs_private;
+	struct super_block *s;
+	dev_t dev;
 	int err;
 
-	if (!(sd->flags & SB_RDONLY)) {
-		msg = "read-only option is not specified";
-		goto parse_error;
-	}
-
-	err = kstrtoull(arg->from, 0, &val);
-	if (err) {
-		if (err == -ERANGE)
-			msg = "too large checkpoint number";
-		else
-			msg = "malformed argument";
-		goto parse_error;
-	} else if (val == 0) {
-		msg = "invalid checkpoint number 0";
-		goto parse_error;
+	if (ctx->cno && !(fc->sb_flags & SB_RDONLY)) {
+		nilfs_err(NULL,
+			  "invalid option \"cp=%llu\": read-only option is not specified",
+			  ctx->cno);
+		return -EINVAL;
 	}
-	sd->cno = val;
-	return 0;
-
-parse_error:
-	nilfs_msg(NULL, KERN_ERR, "invalid option \"%s\": %s", option, msg);
-	return 1;
-}
-
-/**
- * nilfs_identify - pre-read mount options needed to identify mount instance
- * @data: mount options
- * @sd: nilfs_super_data
- */
-static int nilfs_identify(char *data, struct nilfs_super_data *sd)
-{
-	char *p, *options = data;
-	substring_t args[MAX_OPT_ARGS];
-	int token;
-	int ret = 0;
-
-	do {
-		p = strsep(&options, ",");
-		if (p != NULL && *p) {
-			token = match_token(p, tokens, args);
-			if (token == Opt_snapshot)
-				ret = nilfs_parse_snapshot_option(p, &args[0],
-								  sd);
-		}
-		if (!options)
-			break;
-		BUG_ON(options == data);
-		*(options - 1) = ',';
-	} while (!ret);
-	return ret;
-}
-
-static int nilfs_set_bdev_super(struct super_block *s, void *data)
-{
-	s->s_bdev = data;
-	s->s_dev = s->s_bdev->bd_dev;
-	return 0;
-}
-
-static int nilfs_test_bdev_super(struct super_block *s, void *data)
-{
-	return (void *)s->s_bdev == data;
-}
-
-static struct dentry *
-nilfs_mount(struct file_system_type *fs_type, int flags,
-	     const char *dev_name, void *data)
-{
-	struct nilfs_super_data sd;
-	struct super_block *s;
-	fmode_t mode = FMODE_READ | FMODE_EXCL;
-	struct dentry *root_dentry;
-	int err, s_new = false;
-
-	if (!(flags & SB_RDONLY))
-		mode |= FMODE_WRITE;
-
-	sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
-	if (IS_ERR(sd.bdev))
-		return ERR_CAST(sd.bdev);
 
-	sd.cno = 0;
-	sd.flags = flags;
-	if (nilfs_identify((char *)data, &sd)) {
-		err = -EINVAL;
-		goto failed;
-	}
+	err = lookup_bdev(fc->source, &dev);
+	if (err)
+		return err;
 
-	/*
-	 * 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(&sd.bdev->bd_fsfreeze_mutex);
-	if (sd.bdev->bd_fsfreeze_count > 0) {
-		mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
-		err = -EBUSY;
-		goto failed;
-	}
-	s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
-		 sd.bdev);
-	mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
-	if (IS_ERR(s)) {
-		err = PTR_ERR(s);
-		goto failed;
-	}
+	s = sget_dev(fc, dev);
+	if (IS_ERR(s))
+		return PTR_ERR(s);
 
 	if (!s->s_root) {
-		s_new = true;
-
-		/* New superblock instance created */
-		s->s_mode = mode;
-		snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
-		sb_set_blocksize(s, block_size(sd.bdev));
-
-		err = nilfs_fill_super(s, data, flags & SB_SILENT ? 1 : 0);
+		err = setup_bdev_super(s, fc->sb_flags, fc);
+		if (!err)
+			err = nilfs_fill_super(s, fc);
 		if (err)
 			goto failed_super;
 
 		s->s_flags |= SB_ACTIVE;
-	} else if (!sd.cno) {
+	} else if (!ctx->cno) {
 		if (nilfs_tree_is_busy(s->s_root)) {
-			if ((flags ^ s->s_flags) & SB_RDONLY) {
-				nilfs_msg(s, KERN_ERR,
+			if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) {
+				nilfs_err(s,
 					  "the device already has a %s mount.",
 					  sb_rdonly(s) ? "read-only" : "read/write");
 				err = -EBUSY;
@@ -1327,43 +1241,75 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 			}
 		} else {
 			/*
-			 * Try remount to setup mount states if the current
+			 * Try reconfigure to setup mount states if the current
 			 * tree is not mounted and only snapshots use this sb.
+			 *
+			 * Since nilfs_reconfigure() requires fc->root to be
+			 * set, set it first and release it on failure.
 			 */
-			err = nilfs_remount(s, &flags, data);
-			if (err)
+			fc->root = dget(s->s_root);
+			err = nilfs_reconfigure(fc);
+			if (err) {
+				dput(fc->root);
+				fc->root = NULL;  /* prevent double release */
 				goto failed_super;
+			}
+			return 0;
 		}
 	}
 
-	if (sd.cno) {
-		err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
+	if (ctx->cno) {
+		struct dentry *root_dentry;
+
+		err = nilfs_attach_snapshot(s, ctx->cno, &root_dentry);
 		if (err)
 			goto failed_super;
-	} else {
-		root_dentry = dget(s->s_root);
+		fc->root = root_dentry;
+		return 0;
 	}
 
-	if (!s_new)
-		blkdev_put(sd.bdev, mode);
-
-	return root_dentry;
+	fc->root = dget(s->s_root);
+	return 0;
 
  failed_super:
 	deactivate_locked_super(s);
+	return err;
+}
 
- failed:
-	if (!s_new)
-		blkdev_put(sd.bdev, mode);
-	return ERR_PTR(err);
+static void nilfs_free_fc(struct fs_context *fc)
+{
+	kfree(fc->fs_private);
+}
+
+static const struct fs_context_operations nilfs_context_ops = {
+	.parse_param	= nilfs_parse_param,
+	.get_tree	= nilfs_get_tree,
+	.reconfigure	= nilfs_reconfigure,
+	.free		= nilfs_free_fc,
+};
+
+static int nilfs_init_fs_context(struct fs_context *fc)
+{
+	struct nilfs_fs_context *ctx;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->ns_mount_opt = NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
+	fc->fs_private = ctx;
+	fc->ops = &nilfs_context_ops;
+
+	return 0;
 }
 
 struct file_system_type nilfs_fs_type = {
 	.owner    = THIS_MODULE,
 	.name     = "nilfs2",
-	.mount    = nilfs_mount,
 	.kill_sb  = kill_block_super,
 	.fs_flags = FS_REQUIRES_DEV,
+	.init_fs_context = nilfs_init_fs_context,
+	.parameters = nilfs_param_spec,
 };
 MODULE_ALIAS_FS("nilfs2");
 
@@ -1375,8 +1321,6 @@ static void nilfs_inode_init_once(void *obj)
 #ifdef CONFIG_NILFS_XATTR
 	init_rwsem(&ii->xattr_sem);
 #endif
-	address_space_init_once(&ii->i_btnode_cache);
-	ii->i_bmap = &ii->i_bmap_data;
 	inode_init_once(&ii->vfs_inode);
 }