From 181a9e8009a8a8bdb19c2e24eeeae7d8e77c8c47 Mon Sep 17 00:00:00 2001 From: Tetsuhiro Kohada Date: Fri, 29 May 2020 19:14:56 +0900 Subject: [PATCH] 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 Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon --- 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 c84ae9e..911f58b 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 8d6c64a..07f7419 100644 --- a/fs/exfat/exfat_raw.h +++ b/fs/exfat/exfat_raw.h @@ -8,7 +8,8 @@ #include -#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/fs/exfat/super.c b/fs/exfat/super.c index c1f47f4..e60d28e 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 @@ free_alloc_bitmap: free_upcase_table: exfat_free_upcase_table(sbi); free_bh: - brelse(sbi->pbr_bh); + brelse(sbi->boot_bh); return ret; } @@ -608,7 +608,7 @@ put_inode: 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); -- 2.7.4