Description for this pull request:

- several bug fixes(broken mount discard option, remount failure, memory leak)
 - add missing MODULE_ALIAS_FS for automatically loading exfat module.
 - set s_time_gran and truncate atime with exfat timestamp granularity.
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Merge tag 'for-5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

Pull exfat fixes from Namjae Jeon:

 - several bug fixes(broken mount discard option, remount failure,
   memory leak)

 - add missing MODULE_ALIAS_FS for automatically loading exfat module.

 - set s_time_gran and truncate atime with exfat timestamp granularity.

* tag 'for-5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: truncate atimes to 2s granularity
  exfat: properly set s_time_gran
  exfat: remove 'bps' mount-option
  exfat: Unify access to the boot sector
  exfat: add missing MODULE_ALIAS_FS()
  exfat: Fix discard support

fs/exfat/balloc.c

@@ -91,7 +91,6 @@ static int exfat_allocate_bitmap(struct super_block *sb,
 		}
 	}
 
-	sbi->pbr_bh = NULL;
 	return 0;
 }
 
@@ -137,8 +136,6 @@ void exfat_free_bitmap(struct exfat_sb_info *sbi)
 {
 	int i;
 
-	brelse(sbi->pbr_bh);
-
 	for (i = 0; i < sbi->map_sectors; i++)
 		__brelse(sbi->vol_amap[i]);
 

fs/exfat/exfat_fs.h

@@ -507,6 +507,7 @@ void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)
 		__printf(3, 4) __cold;
 void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 		u8 tz, __le16 time, __le16 date, u8 time_ms);
+void exfat_truncate_atime(struct timespec64 *ts);
 void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 		u8 *tz, __le16 *time, __le16 *date, u8 *time_ms);
 unsigned short exfat_calc_chksum_2byte(void *data, int len,

fs/exfat/file.c

@@ -273,6 +273,7 @@ int exfat_getattr(const struct path *path, struct kstat *stat,
 	struct exfat_inode_info *ei = EXFAT_I(inode);
 
 	generic_fillattr(inode, stat);
+	exfat_truncate_atime(&stat->atime);
 	stat->result_mask |= STATX_BTIME;
 	stat->btime.tv_sec = ei->i_crtime.tv_sec;
 	stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
@@ -339,6 +340,7 @@ int exfat_setattr(struct dentry *dentry, struct iattr *attr)
 	}
 
 	setattr_copy(inode, attr);
+	exfat_truncate_atime(&inode->i_atime);
 	mark_inode_dirty(inode);
 
 out:

fs/exfat/misc.c

@@ -88,7 +88,8 @@ void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 	if (time_ms) {
 		ts->tv_sec += time_ms / 100;
 		ts->tv_nsec = (time_ms % 100) * 10 * NSEC_PER_MSEC;
-	}
+	} else
+		ts->tv_nsec = 0;
 
 	if (tz & EXFAT_TZ_VALID)
 		/* Adjust timezone to UTC0. */
@@ -124,6 +125,17 @@ void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 	*tz = EXFAT_TZ_VALID;
 }
 
+/*
+ * The timestamp for access_time has double seconds granularity.
+ * (There is no 10msIncrement field for access_time unlike create/modify_time)
+ * atime also has only a 2-second resolution.
+ */
+void exfat_truncate_atime(struct timespec64 *ts)
+{
+	ts->tv_sec = round_down(ts->tv_sec, 2);
+	ts->tv_nsec = 0;
+}
+
 unsigned short exfat_calc_chksum_2byte(void *data, int len,
 		unsigned short chksum, int type)
 {

fs/exfat/namei.c

@@ -595,6 +595,7 @@ static int exfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	inode_inc_iversion(inode);
 	inode->i_mtime = inode->i_atime = inode->i_ctime =
 		EXFAT_I(inode)->i_crtime = current_time(inode);
+	exfat_truncate_atime(&inode->i_atime);
 	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
 
 	d_instantiate(dentry, inode);
@@ -854,6 +855,7 @@ static int exfat_unlink(struct inode *dir, struct dentry *dentry)
 
 	inode_inc_iversion(dir);
 	dir->i_mtime = dir->i_atime = current_time(dir);
+	exfat_truncate_atime(&dir->i_atime);
 	if (IS_DIRSYNC(dir))
 		exfat_sync_inode(dir);
 	else
@@ -861,6 +863,7 @@ static int exfat_unlink(struct inode *dir, struct dentry *dentry)
 
 	clear_nlink(inode);
 	inode->i_mtime = inode->i_atime = current_time(inode);
+	exfat_truncate_atime(&inode->i_atime);
 	exfat_unhash_inode(inode);
 	exfat_d_version_set(dentry, inode_query_iversion(dir));
 unlock:
@@ -903,6 +906,7 @@ static int exfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	inode_inc_iversion(inode);
 	inode->i_mtime = inode->i_atime = inode->i_ctime =
 		EXFAT_I(inode)->i_crtime = current_time(inode);
+	exfat_truncate_atime(&inode->i_atime);
 	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
 
 	d_instantiate(dentry, inode);
@@ -1019,6 +1023,7 @@ static int exfat_rmdir(struct inode *dir, struct dentry *dentry)
 
 	inode_inc_iversion(dir);
 	dir->i_mtime = dir->i_atime = current_time(dir);
+	exfat_truncate_atime(&dir->i_atime);
 	if (IS_DIRSYNC(dir))
 		exfat_sync_inode(dir);
 	else
@@ -1027,6 +1032,7 @@ static int exfat_rmdir(struct inode *dir, struct dentry *dentry)
 
 	clear_nlink(inode);
 	inode->i_mtime = inode->i_atime = current_time(inode);
+	exfat_truncate_atime(&inode->i_atime);
 	exfat_unhash_inode(inode);
 	exfat_d_version_set(dentry, inode_query_iversion(dir));
 unlock:
@@ -1387,6 +1393,7 @@ static int exfat_rename(struct inode *old_dir, struct dentry *old_dentry,
 	inode_inc_iversion(new_dir);
 	new_dir->i_ctime = new_dir->i_mtime = new_dir->i_atime =
 		EXFAT_I(new_dir)->i_crtime = current_time(new_dir);
+	exfat_truncate_atime(&new_dir->i_atime);
 	if (IS_DIRSYNC(new_dir))
 		exfat_sync_inode(new_dir);
 	else

fs/exfat/super.c

@@ -49,6 +49,7 @@ static void exfat_put_super(struct super_block *sb)
 		sync_blockdev(sb->s_bdev);
 	exfat_set_vol_flags(sb, VOL_CLEAN);
 	exfat_free_bitmap(sbi);
+	brelse(sbi->pbr_bh);
 	mutex_unlock(&sbi->s_lock);
 
 	call_rcu(&sbi->rcu, exfat_delayed_free);
@@ -100,7 +101,7 @@ static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
 int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
 {
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
-	struct pbr64 *bpb;
+	struct pbr64 *bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
 	bool sync = 0;
 
 	/* flags are not changed */
@@ -115,15 +116,6 @@ int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
 	if (sb_rdonly(sb))
 		return 0;
 
-	if (!sbi->pbr_bh) {
-		sbi->pbr_bh = sb_bread(sb, 0);
-		if (!sbi->pbr_bh) {
-			exfat_msg(sb, KERN_ERR, "failed to read boot sector");
-			return -ENOMEM;
-		}
-	}
-
-	bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
 	bpb->bsx.vol_flags = cpu_to_le16(new_flag);
 
 	if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->pbr_bh))
@@ -159,7 +151,6 @@ static int exfat_show_options(struct seq_file *m, struct dentry *root)
 		seq_puts(m, ",iocharset=utf8");
 	else if (sbi->nls_io)
 		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
-	seq_printf(m, ",bps=%ld", sb->s_blocksize);
 	if (opts->errors == EXFAT_ERRORS_CONT)
 		seq_puts(m, ",errors=continue");
 	else if (opts->errors == EXFAT_ERRORS_PANIC)
@@ -351,14 +342,15 @@ static int exfat_read_root(struct inode *inode)
 	exfat_save_attr(inode, ATTR_SUBDIR);
 	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 		current_time(inode);
+	exfat_truncate_atime(&inode->i_atime);
 	exfat_cache_init_inode(inode);
 	return 0;
 }
 
-static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb,
-		struct buffer_head **prev_bh)
+static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb)
 {
-	struct pbr *p_pbr = (struct pbr *) (*prev_bh)->b_data;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct pbr *p_pbr = (struct pbr *) (sbi->pbr_bh)->b_data;
 	unsigned short logical_sect = 0;
 
 	logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
@@ -378,26 +370,23 @@ static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb,
 	}
 
 	if (logical_sect > sb->s_blocksize) {
-		struct buffer_head *bh = NULL;
-
-		__brelse(*prev_bh);
-		*prev_bh = NULL;
+		brelse(sbi->pbr_bh);
+		sbi->pbr_bh = NULL;
 
 		if (!sb_set_blocksize(sb, logical_sect)) {
 			exfat_msg(sb, KERN_ERR,
 				"unable to set blocksize %u", logical_sect);
 			return NULL;
 		}
-		bh = sb_bread(sb, 0);
-		if (!bh) {
+		sbi->pbr_bh = sb_bread(sb, 0);
+		if (!sbi->pbr_bh) {
 			exfat_msg(sb, KERN_ERR,
 				"unable to read boot sector (logical sector size = %lu)",
 				sb->s_blocksize);
 			return NULL;
 		}
 
-		*prev_bh = bh;
-		p_pbr = (struct pbr *) bh->b_data;
+		p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
 	}
 	return p_pbr;
 }
@@ -408,21 +397,20 @@ static int __exfat_fill_super(struct super_block *sb)
 	int ret;
 	struct pbr *p_pbr;
 	struct pbr64 *p_bpb;
-	struct buffer_head *bh;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 
 	/* set block size to read super block */
 	sb_min_blocksize(sb, 512);
 
 	/* read boot sector */
-	bh = sb_bread(sb, 0);
-	if (!bh) {
+	sbi->pbr_bh = sb_bread(sb, 0);
+	if (!sbi->pbr_bh) {
 		exfat_msg(sb, KERN_ERR, "unable to read boot sector");
 		return -EIO;
 	}
 
 	/* PRB is read */
-	p_pbr = (struct pbr *)bh->b_data;
+	p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
 
 	/* check the validity of PBR */
 	if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
@@ -433,7 +421,7 @@ static int __exfat_fill_super(struct super_block *sb)
 
 
 	/* check logical sector size */
-	p_pbr = exfat_read_pbr_with_logical_sector(sb, &bh);
+	p_pbr = exfat_read_pbr_with_logical_sector(sb);
 	if (!p_pbr) {
 		ret = -EIO;
 		goto free_bh;
@@ -514,7 +502,7 @@ static int __exfat_fill_super(struct super_block *sb)
 free_upcase_table:
 	exfat_free_upcase_table(sbi);
 free_bh:
-	brelse(bh);
+	brelse(sbi->pbr_bh);
 	return ret;
 }
 
@@ -531,17 +519,18 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (opts->discard) {
 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
 
-		if (!blk_queue_discard(q))
+		if (!blk_queue_discard(q)) {
 			exfat_msg(sb, KERN_WARNING,
 				"mounting with \"discard\" option, but the device does not support discard");
-		opts->discard = 0;
+			opts->discard = 0;
+		}
 	}
 
 	sb->s_flags |= SB_NODIRATIME;
 	sb->s_magic = EXFAT_SUPER_MAGIC;
 	sb->s_op = &exfat_sops;
 
-	sb->s_time_gran = 1;
+	sb->s_time_gran = 10 * NSEC_PER_MSEC;
 	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
 	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
 
@@ -605,6 +594,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 free_table:
 	exfat_free_upcase_table(sbi);
 	exfat_free_bitmap(sbi);
+	brelse(sbi->pbr_bh);
 
 check_nls_io:
 	unload_nls(sbi->nls_io);
@@ -717,6 +707,7 @@ static void __exit exit_exfat_fs(void)
 module_init(init_exfat_fs);
 module_exit(exit_exfat_fs);
 
+MODULE_ALIAS_FS("exfat");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("exFAT filesystem support");
 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");