From 181a9e8009a8a8bdb19c2e24eeeae7d8e77c8c47 Mon Sep 17 00:00:00 2001

From: Tetsuhiro Kohada <kohada.t2@gmail.com>

Date: Fri, 29 May 2020 19:14:56 +0900

Subject: [Backport 181a9e8009a8] exfat: redefine PBR as boot_sector

Aggregate PBR related definitions and redefine as "boot_sector" to comply

with the exFAT specification.

And, rename variable names including 'pbr'.

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>

Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

---

 src/exfat_fs.h  |  2 +-

 src/exfat_raw.h | 79 +++++++++++++++--------------------------

 src/super.c     | 84 ++++++++++++++++++++++----------------------

 3 files changed, 72 insertions(+), 93 deletions(-)

diff --git a/src/exfat_fs.h b/src/exfat_fs.h

index c84ae9e605085e0a5b19a2dbe8a9c36ab7efdce6..911f58b93f3d257bce04b645a2ada62d0f51a3c0 100644

--- a/src/exfat_fs.h

+++ b/src/exfat_fs.h

@@ -227,7 +227,7 @@ struct exfat_sb_info {

 	unsigned int root_dir; /* root dir cluster */

 	unsigned int dentries_per_clu; /* num of dentries per cluster */

 	unsigned int vol_flag; /* volume dirty flag */

-	struct buffer_head *pbr_bh; /* buffer_head of PBR sector */

+	struct buffer_head *boot_bh; /* buffer_head of BOOT sector */

 	unsigned int map_clu; /* allocation bitmap start cluster */

 	unsigned int map_sectors; /* num of allocation bitmap sectors */

diff --git a/src/exfat_raw.h b/src/exfat_raw.h

index 8d6c64a7546d8bc8899e677bfd7f9d91f4e0cb4d..07f74190df44b215128d4dcf2a8ee33d32a7cf21 100644

--- a/src/exfat_raw.h

+++ b/src/exfat_raw.h

@@ -8,7 +8,8 @@

 #include <linux/types.h>

-#define PBR_SIGNATURE		0xAA55

+#define BOOT_SIGNATURE		0xAA55

+#define EXBOOT_SIGNATURE	0xAA550000

 #define EXFAT_MAX_FILE_LEN	255

@@ -55,7 +56,7 @@

 /* checksum types */

 #define CS_DIR_ENTRY		0

-#define CS_PBR_SECTOR		1

+#define CS_BOOT_SECTOR		1

 #define CS_DEFAULT		2

 /* file attributes */

@@ -69,57 +70,35 @@

 #define ATTR_RWMASK		(ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME | \

 				 ATTR_SUBDIR | ATTR_ARCHIVE)

-#define PBR64_JUMP_BOOT_LEN		3

-#define PBR64_OEM_NAME_LEN		8

-#define PBR64_RESERVED_LEN		53

+#define BOOTSEC_JUMP_BOOT_LEN		3

+#define BOOTSEC_FS_NAME_LEN		8

+#define BOOTSEC_OLDBPB_LEN		53

 #define EXFAT_FILE_NAME_LEN		15

-/* EXFAT BIOS parameter block (64 bytes) */

-struct bpb64 {

-	__u8 jmp_boot[PBR64_JUMP_BOOT_LEN];

-	__u8 oem_name[PBR64_OEM_NAME_LEN];

-	__u8 res_zero[PBR64_RESERVED_LEN];

-} __packed;

-

-/* EXFAT EXTEND BIOS parameter block (56 bytes) */

-struct bsx64 {

-	__le64 vol_offset;

-	__le64 vol_length;

-	__le32 fat_offset;

-	__le32 fat_length;

-	__le32 clu_offset;

-	__le32 clu_count;

-	__le32 root_cluster;

-	__le32 vol_serial;

-	__u8 fs_version[2];

-	__le16 vol_flags;

-	__u8 sect_size_bits;

-	__u8 sect_per_clus_bits;

-	__u8 num_fats;

-	__u8 phy_drv_no;

-	__u8 perc_in_use;

-	__u8 reserved2[7];

-} __packed;

-

-/* EXFAT PBR[BPB+BSX] (120 bytes) */

-struct pbr64 {

-	struct bpb64 bpb;

-	struct bsx64 bsx;

-} __packed;

-

-/* Common PBR[Partition Boot Record] (512 bytes) */

-struct pbr {

-	union {

-		__u8 raw[64];

-		struct bpb64 f64;

-	} bpb;

-	union {

-		__u8 raw[56];

-		struct bsx64 f64;

-	} bsx;

-	__u8 boot_code[390];

-	__le16 signature;

+/* EXFAT: Main and Backup Boot Sector (512 bytes) */

+struct boot_sector {

+	__u8	jmp_boot[BOOTSEC_JUMP_BOOT_LEN];

+	__u8	fs_name[BOOTSEC_FS_NAME_LEN];

+	__u8	must_be_zero[BOOTSEC_OLDBPB_LEN];

+	__le64	partition_offset;

+	__le64	vol_length;

+	__le32	fat_offset;

+	__le32	fat_length;

+	__le32	clu_offset;

+	__le32	clu_count;

+	__le32	root_cluster;

+	__le32	vol_serial;

+	__u8	fs_revision[2];

+	__le16	vol_flags;

+	__u8	sect_size_bits;

+	__u8	sect_per_clus_bits;

+	__u8	num_fats;

+	__u8	drv_sel;

+	__u8	percent_in_use;

+	__u8	reserved[7];

+	__u8	boot_code[390];

+	__le16	signature;

 } __packed;

 struct exfat_dentry {

diff --git a/src/super.c b/src/super.c

index c1f47f4071a80449d7fbbdf81d4f1d7079419d56..e60d28e73ff007b85eafc751693d332911fbcfd3 100644

--- a/src/super.c

+++ b/src/super.c

@@ -49,7 +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);

+	brelse(sbi->boot_bh);

 	mutex_unlock(&sbi->s_lock);

 	call_rcu(&sbi->rcu, exfat_delayed_free);

@@ -101,7 +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 *)sbi->pbr_bh->b_data;

+	struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;

 	bool sync;

 	/* flags are not changed */

@@ -116,18 +116,18 @@ int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)

 	if (sb_rdonly(sb))

 		return 0;

-	bpb->bsx.vol_flags = cpu_to_le16(new_flag);

+	p_boot->vol_flags = cpu_to_le16(new_flag);

-	if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->pbr_bh))

+	if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->boot_bh))

 		sync = true;

 	else

 		sync = false;

-	set_buffer_uptodate(sbi->pbr_bh);

-	mark_buffer_dirty(sbi->pbr_bh);

+	set_buffer_uptodate(sbi->boot_bh);

+	mark_buffer_dirty(sbi->boot_bh);

 	if (sync)

-		sync_dirty_buffer(sbi->pbr_bh);

+		sync_dirty_buffer(sbi->boot_bh);

 	return 0;

 }

@@ -366,13 +366,14 @@ static int exfat_read_root(struct inode *inode)

 	return 0;

 }

-static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb)

+static struct boot_sector *exfat_read_boot_with_logical_sector(

+		struct super_block *sb)

 {

 	struct exfat_sb_info *sbi = EXFAT_SB(sb);

-	struct pbr *p_pbr = (struct pbr *) (sbi->pbr_bh)->b_data;

+	struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;

 	unsigned short logical_sect = 0;

-	logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;

+	logical_sect = 1 << p_boot->sect_size_bits;

 	if (!is_power_of_2(logical_sect) ||

 	    logical_sect < 512 || logical_sect > 4096) {

@@ -387,49 +388,48 @@ static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb)

 	}

 	if (logical_sect > sb->s_blocksize) {

-		brelse(sbi->pbr_bh);

-		sbi->pbr_bh = NULL;

+		brelse(sbi->boot_bh);

+		sbi->boot_bh = NULL;

 		if (!sb_set_blocksize(sb, logical_sect)) {

 			exfat_err(sb, "unable to set blocksize %u",

 				  logical_sect);

 			return NULL;

 		}

-		sbi->pbr_bh = sb_bread(sb, 0);

-		if (!sbi->pbr_bh) {

+		sbi->boot_bh = sb_bread(sb, 0);

+		if (!sbi->boot_bh) {

 			exfat_err(sb, "unable to read boot sector (logical sector size = %lu)",

 				  sb->s_blocksize);

 			return NULL;

 		}

-		p_pbr = (struct pbr *)sbi->pbr_bh->b_data;

+		p_boot = (struct boot_sector *)sbi->boot_bh->b_data;

 	}

-	return p_pbr;

+	return p_boot;

 }

 /* mount the file system volume */

 static int __exfat_fill_super(struct super_block *sb)

 {

 	int ret;

-	struct pbr *p_pbr;

-	struct pbr64 *p_bpb;

+	struct boot_sector *p_boot;

 	struct exfat_sb_info *sbi = EXFAT_SB(sb);

 	/* set block size to read super block */

 	sb_min_blocksize(sb, 512);

 	/* read boot sector */

-	sbi->pbr_bh = sb_bread(sb, 0);

-	if (!sbi->pbr_bh) {

+	sbi->boot_bh = sb_bread(sb, 0);

+	if (!sbi->boot_bh) {

 		exfat_err(sb, "unable to read boot sector");

 		return -EIO;

 	}

 	/* PRB is read */

-	p_pbr = (struct pbr *)sbi->pbr_bh->b_data;

+	p_boot = (struct boot_sector *)sbi->boot_bh->b_data;

-	/* check the validity of PBR */

-	if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {

+	/* check the validity of BOOT */

+	if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {

 		exfat_err(sb, "invalid boot record signature");

 		ret = -EINVAL;

 		goto free_bh;

@@ -437,8 +437,8 @@ static int __exfat_fill_super(struct super_block *sb)

 	/* check logical sector size */

-	p_pbr = exfat_read_pbr_with_logical_sector(sb);

-	if (!p_pbr) {

+	p_boot = exfat_read_boot_with_logical_sector(sb);

+	if (!p_boot) {

 		ret = -EIO;

 		goto free_bh;

 	}

@@ -447,43 +447,43 @@ static int __exfat_fill_super(struct super_block *sb)

 	 * res_zero field must be filled with zero to prevent mounting

 	 * from FAT volume.

 	 */

-	if (memchr_inv(p_pbr->bpb.f64.res_zero, 0,

-			sizeof(p_pbr->bpb.f64.res_zero))) {

+	if (memchr_inv(p_boot->must_be_zero, 0,

+			sizeof(p_boot->must_be_zero))) {

 		ret = -EINVAL;

 		goto free_bh;

 	}

-	p_bpb = (struct pbr64 *)p_pbr;

-	if (!p_bpb->bsx.num_fats) {

+	p_boot = (struct boot_sector *)p_boot;

+	if (!p_boot->num_fats) {

 		exfat_err(sb, "bogus number of FAT structure");

 		ret = -EINVAL;

 		goto free_bh;

 	}

-	sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;

-	sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;

+	sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;

+	sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;

 	sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits;

 	sbi->cluster_size = 1 << sbi->cluster_size_bits;

-	sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);

-	sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);

-	sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?

+	sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);

+	sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);

+	sbi->FAT2_start_sector = p_boot->num_fats == 1 ?

 		sbi->FAT1_start_sector :

 			sbi->FAT1_start_sector + sbi->num_FAT_sectors;

-	sbi->data_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);

-	sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);

+	sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);

+	sbi->num_sectors = le64_to_cpu(p_boot->vol_length);

 	/* because the cluster index starts with 2 */

-	sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) +

+	sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +

 		EXFAT_RESERVED_CLUSTERS;

-	sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);

+	sbi->root_dir = le32_to_cpu(p_boot->root_cluster);

 	sbi->dentries_per_clu = 1 <<

 		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);

-	sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);

+	sbi->vol_flag = le16_to_cpu(p_boot->vol_flags);

 	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;

 	sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;

-	if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {

+	if (le16_to_cpu(p_boot->vol_flags) & VOL_DIRTY) {

 		sbi->vol_flag |= VOL_DIRTY;

 		exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");

 	}

@@ -517,7 +517,7 @@ static int __exfat_fill_super(struct super_block *sb)

 free_upcase_table:

 	exfat_free_upcase_table(sbi);

 free_bh:

-	brelse(sbi->pbr_bh);

+	brelse(sbi->boot_bh);

 	return ret;

 }

@@ -608,7 +608,7 @@ 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);

+	brelse(sbi->boot_bh);

 check_nls_io:

 	unload_nls(sbi->nls_io);

-- 

2.31.1