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Message-Id: <20171227091714.4566-2-chen.chenchacha@foxmail.com> Date: Wed, 27 Dec 2017 17:17:13 +0800 From: ChenGuanqiao <chen.chenchacha@...mail.com> To: hirofumi@...l.parknet.co.jp Cc: linux-kernel@...r.kernel.org, ChenGuanqiao <chen.chenchacha@...mail.com> Subject: [PATCH v5 1/2] fs: fat: Add fat filesystem partition volume label in local structure 1. Read volume label whe the fat system driver load. 2. Add interface to scan volume label entry. Signed-off-by: ChenGuanqiao <chen.chenchacha@...mail.com> --- fs/fat/dir.c | 29 +++++++++++++++++++++++++++++ fs/fat/fat.h | 2 ++ fs/fat/inode.c | 15 ++++++++++++--- include/uapi/linux/msdos_fs.h | 2 ++ 4 files changed, 45 insertions(+), 3 deletions(-) diff --git a/fs/fat/dir.c b/fs/fat/dir.c index 81cecbe6d7cf..b369953979e3 100644 --- a/fs/fat/dir.c +++ b/fs/fat/dir.c @@ -881,6 +881,35 @@ static int fat_get_short_entry(struct inode *dir, loff_t *pos, return -ENOENT; } +static int fat_get_volume_label_entry(struct inode *dir, loff_t *pos, + struct buffer_head **bh, + struct msdos_dir_entry **de) +{ + while (fat_get_entry(dir, pos, bh, de) >= 0) + if (((*de)->attr & ATTR_VOLUME) && (*de)->attr != ATTR_EXT) + return 0; + return -ENOENT; +} + +int fat_scan_volume_label(struct inode *dir, struct fat_slot_info *sinfo) +{ + struct super_block *sb = dir->i_sb; + + sinfo->slot_off = 0; + sinfo->bh = NULL; + while (fat_get_volume_label_entry(dir, &sinfo->slot_off, + &sinfo->bh, &sinfo->de) >= 0) { + sinfo->slot_off -= sizeof(*sinfo->de); + sinfo->nr_slots = 1; + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); + + return 0; + } + + return -ENOENT; +} +EXPORT_SYMBOL_GPL(fat_scan_volume_label); + /* * The ".." entry can not provide the "struct fat_slot_info" information * for inode, nor a usable i_pos. So, this function provides some information diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 051dac1ce3be..9e8d525d52c9 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -85,6 +85,7 @@ struct msdos_sb_info { int dir_per_block; /* dir entries per block */ int dir_per_block_bits; /* log2(dir_per_block) */ unsigned int vol_id; /*volume ID*/ + char vol_label[11]; /*volume label*/ int fatent_shift; const struct fatent_operations *fatent_ops; @@ -299,6 +300,7 @@ extern int fat_dir_empty(struct inode *dir); extern int fat_subdirs(struct inode *dir); extern int fat_scan(struct inode *dir, const unsigned char *name, struct fat_slot_info *sinfo); +extern int fat_scan_volume_label(struct inode *dir, struct fat_slot_info *sinfo); extern int fat_scan_logstart(struct inode *dir, int i_logstart, struct fat_slot_info *sinfo); extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh, diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 30c52394a7ad..e73379a41d49 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -45,12 +45,14 @@ struct fat_bios_param_block { u8 fat16_state; u32 fat16_vol_id; + u8 fat16_vol_label[11]; u32 fat32_length; u32 fat32_root_cluster; u16 fat32_info_sector; u8 fat32_state; u32 fat32_vol_id; + u8 fat32_vol_label[11]; }; static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; @@ -1460,12 +1462,16 @@ static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b, bpb->fat16_state = b->fat16.state; bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id); + memcpy(bpb->fat16_vol_label, b->fat16.vol_label, + sizeof(bpb->fat16_vol_label)); bpb->fat32_length = le32_to_cpu(b->fat32.length); bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster); bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector); bpb->fat32_state = b->fat32.state; bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id); + memcpy(bpb->fat32_vol_label, b->fat32.vol_label, + sizeof(bpb->fat32_vol_label)); /* Validate this looks like a FAT filesystem BPB */ if (!bpb->fat_reserved) { @@ -1723,11 +1729,14 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, brelse(fsinfo_bh); } - /* interpret volume ID as a little endian 32 bit integer */ - if (sbi->fat_bits == 32) + /* interpret volume ID and label as a little endian 32 bit integer */ + if (sbi->fat_bits == 32) { sbi->vol_id = bpb.fat32_vol_id; - else /* fat 16 or 12 */ + memcpy(sbi->vol_label, bpb.fat32_vol_label, sizeof(sbi->vol_label)); + } else { /* fat 16 or 12 */ sbi->vol_id = bpb.fat16_vol_id; + memcpy(sbi->vol_label, bpb.fat16_vol_label, sizeof(sbi->vol_label)); + } sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; diff --git a/include/uapi/linux/msdos_fs.h b/include/uapi/linux/msdos_fs.h index e956704f5fb1..b4fced0988a9 100644 --- a/include/uapi/linux/msdos_fs.h +++ b/include/uapi/linux/msdos_fs.h @@ -106,6 +106,8 @@ struct __fat_dirent { #define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u32) /*Android kernel has used 0x12, so we use 0x13*/ #define FAT_IOCTL_GET_VOLUME_ID _IOR('r', 0x13, __u32) +#define FAT_IOCTL_GET_VOLUME_LABEL _IOR('r', 0x14, __u8[11]) +#define FAT_IOCTL_SET_VOLUME_LABEL _IOW('r', 0x15, __u8[11]) struct fat_boot_sector { __u8 ignored[3]; /* Boot strap short or near jump */ -- 2.11.0
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