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Subject[PATCH 1/4 v2] exfat: redefine PBR as boot_sector
Date
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>
---
Changes in v2:
- rebase with patch 'optimize dir-cache' applied

fs/exfat/exfat_fs.h | 2 +-
fs/exfat/exfat_raw.h | 79 +++++++++++++++--------------------------
fs/exfat/super.c | 84 ++++++++++++++++++++++----------------------
3 files changed, 72 insertions(+), 93 deletions(-)

diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 5caad1380818..9673e2d31045 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/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/fs/exfat/exfat_raw.h b/fs/exfat/exfat_raw.h
index 8d6c64a7546d..b373dc4e099f 100644
--- a/fs/exfat/exfat_raw.h
+++ b/fs/exfat/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_OEM_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 oem_name[BOOTSEC_OEM_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/fs/exfat/super.c b/fs/exfat/super.c
index c1f47f4071a8..e60d28e73ff0 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/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);
--
2.25.1
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