diff options
| -rw-r--r-- | fs/exfat/super.c | 728 |
1 files changed, 728 insertions, 0 deletions
diff --git a/fs/exfat/super.c b/fs/exfat/super.c new file mode 100644 index 000000000000..f06e0b53e393 --- /dev/null +++ b/fs/exfat/super.c @@ -0,0 +1,728 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. + */ + +#include <linux/fs_context.h> +#include <linux/fs_parser.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/time.h> +#include <linux/mount.h> +#include <linux/cred.h> +#include <linux/statfs.h> +#include <linux/seq_file.h> +#include <linux/blkdev.h> +#include <linux/fs_struct.h> +#include <linux/iversion.h> +#include <linux/nls.h> +#include <linux/buffer_head.h> + +#include "exfat_raw.h" +#include "exfat_fs.h" + +static char exfat_default_iocharset[] = CONFIG_EXFAT_DEFAULT_IOCHARSET; +static struct kmem_cache *exfat_inode_cachep; + +static void exfat_free_iocharset(struct exfat_sb_info *sbi) +{ + if (sbi->options.iocharset != exfat_default_iocharset) + kfree(sbi->options.iocharset); +} + +static void exfat_delayed_free(struct rcu_head *p) +{ + struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu); + + unload_nls(sbi->nls_io); + exfat_free_iocharset(sbi); + exfat_free_upcase_table(sbi); + kfree(sbi); +} + +static void exfat_put_super(struct super_block *sb) +{ + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + mutex_lock(&sbi->s_lock); + if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) + sync_blockdev(sb->s_bdev); + exfat_set_vol_flags(sb, VOL_CLEAN); + exfat_free_bitmap(sbi); + mutex_unlock(&sbi->s_lock); + + call_rcu(&sbi->rcu, exfat_delayed_free); +} + +static int exfat_sync_fs(struct super_block *sb, int wait) +{ + struct exfat_sb_info *sbi = EXFAT_SB(sb); + int err = 0; + + /* If there are some dirty buffers in the bdev inode */ + mutex_lock(&sbi->s_lock); + if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) { + sync_blockdev(sb->s_bdev); + if (exfat_set_vol_flags(sb, VOL_CLEAN)) + err = -EIO; + } + mutex_unlock(&sbi->s_lock); + return err; +} + +static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + struct super_block *sb = dentry->d_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev); + + if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) { + mutex_lock(&sbi->s_lock); + if (exfat_count_used_clusters(sb, &sbi->used_clusters)) { + mutex_unlock(&sbi->s_lock); + return -EIO; + } + mutex_unlock(&sbi->s_lock); + } + + buf->f_type = sb->s_magic; + buf->f_bsize = sbi->cluster_size; + buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */ + buf->f_bfree = buf->f_blocks - sbi->used_clusters; + buf->f_bavail = buf->f_bfree; + buf->f_fsid.val[0] = (unsigned int)id; + buf->f_fsid.val[1] = (unsigned int)(id >> 32); + /* Unicode utf16 255 characters */ + buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE; + return 0; +} + +int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag) +{ + struct exfat_sb_info *sbi = EXFAT_SB(sb); + struct pbr64 *bpb; + bool sync = 0; + + /* flags are not changed */ + if (sbi->vol_flag == new_flag) + return 0; + + sbi->vol_flag = new_flag; + + /* skip updating volume dirty flag, + * if this volume has been mounted with read-only + */ + 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)) + sync = true; + else + sync = false; + + set_buffer_uptodate(sbi->pbr_bh); + mark_buffer_dirty(sbi->pbr_bh); + + if (sync) + sync_dirty_buffer(sbi->pbr_bh); + return 0; +} + +static int exfat_show_options(struct seq_file *m, struct dentry *root) +{ + struct super_block *sb = root->d_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + struct exfat_mount_options *opts = &sbi->options; + + /* Show partition info */ + if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID)) + seq_printf(m, ",uid=%u", + from_kuid_munged(&init_user_ns, opts->fs_uid)); + if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID)) + seq_printf(m, ",gid=%u", + from_kgid_munged(&init_user_ns, opts->fs_gid)); + seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask); + if (opts->allow_utime) + seq_printf(m, ",allow_utime=%04o", opts->allow_utime); + if (opts->utf8) + 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) + seq_puts(m, ",errors=panic"); + else + seq_puts(m, ",errors=remount-ro"); + if (opts->discard) + seq_puts(m, ",discard"); + if (opts->time_offset) + seq_printf(m, ",time_offset=%d", opts->time_offset); + return 0; +} + +static struct inode *exfat_alloc_inode(struct super_block *sb) +{ + struct exfat_inode_info *ei; + + ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS); + if (!ei) + return NULL; + + init_rwsem(&ei->truncate_lock); + return &ei->vfs_inode; +} + +static void exfat_free_inode(struct inode *inode) +{ + kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode)); +} + +static const struct super_operations exfat_sops = { + .alloc_inode = exfat_alloc_inode, + .free_inode = exfat_free_inode, + .write_inode = exfat_write_inode, + .evict_inode = exfat_evict_inode, + .put_super = exfat_put_super, + .sync_fs = exfat_sync_fs, + .statfs = exfat_statfs, + .show_options = exfat_show_options, +}; + +enum { + Opt_uid, + Opt_gid, + Opt_umask, + Opt_dmask, + Opt_fmask, + Opt_allow_utime, + Opt_charset, + Opt_errors, + Opt_discard, + Opt_time_offset, +}; + +static const struct fs_parameter_spec exfat_param_specs[] = { + fsparam_u32("uid", Opt_uid), + fsparam_u32("gid", Opt_gid), + fsparam_u32oct("umask", Opt_umask), + fsparam_u32oct("dmask", Opt_dmask), + fsparam_u32oct("fmask", Opt_fmask), + fsparam_u32oct("allow_utime", Opt_allow_utime), + fsparam_string("iocharset", Opt_charset), + fsparam_enum("errors", Opt_errors), + fsparam_flag("discard", Opt_discard), + fsparam_s32("time_offset", Opt_time_offset), + {} +}; + +static const struct fs_parameter_enum exfat_param_enums[] = { + { Opt_errors, "continue", EXFAT_ERRORS_CONT }, + { Opt_errors, "panic", EXFAT_ERRORS_PANIC }, + { Opt_errors, "remount-ro", EXFAT_ERRORS_RO }, + {} +}; + +static const struct fs_parameter_description exfat_parameters = { + .name = "exfat", + .specs = exfat_param_specs, + .enums = exfat_param_enums, +}; + +static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param) +{ + struct exfat_sb_info *sbi = fc->s_fs_info; + struct exfat_mount_options *opts = &sbi->options; + struct fs_parse_result result; + int opt; + + opt = fs_parse(fc, &exfat_parameters, param, &result); + if (opt < 0) + return opt; + + switch (opt) { + case Opt_uid: + opts->fs_uid = make_kuid(current_user_ns(), result.uint_32); + break; + case Opt_gid: + opts->fs_gid = make_kgid(current_user_ns(), result.uint_32); + break; + case Opt_umask: + opts->fs_fmask = result.uint_32; + opts->fs_dmask = result.uint_32; + break; + case Opt_dmask: + opts->fs_dmask = result.uint_32; + break; + case Opt_fmask: + opts->fs_fmask = result.uint_32; + break; + case Opt_allow_utime: + opts->allow_utime = result.uint_32 & 0022; + break; + case Opt_charset: + exfat_free_iocharset(sbi); + opts->iocharset = kstrdup(param->string, GFP_KERNEL); + if (!opts->iocharset) + return -ENOMEM; + break; + case Opt_errors: + opts->errors = result.uint_32; + break; + case Opt_discard: + opts->discard = 1; + break; + case Opt_time_offset: + /* + * Make the limit 24 just in case someone invents something + * unusual. + */ + if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60) + return -EINVAL; + opts->time_offset = result.int_32; + break; + default: + return -EINVAL; + } + + return 0; +} + +static void exfat_hash_init(struct super_block *sb) +{ + struct exfat_sb_info *sbi = EXFAT_SB(sb); + int i; + + spin_lock_init(&sbi->inode_hash_lock); + for (i = 0; i < EXFAT_HASH_SIZE; i++) + INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); +} + +static int exfat_read_root(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + struct exfat_inode_info *ei = EXFAT_I(inode); + struct exfat_chain cdir; + int num_subdirs, num_clu = 0; + + exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN); + ei->entry = -1; + ei->start_clu = sbi->root_dir; + ei->flags = ALLOC_FAT_CHAIN; + ei->type = TYPE_DIR; + ei->version = 0; + ei->rwoffset = 0; + ei->hint_bmap.off = EXFAT_EOF_CLUSTER; + ei->hint_stat.eidx = 0; + ei->hint_stat.clu = sbi->root_dir; + ei->hint_femp.eidx = EXFAT_HINT_NONE; + + exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN); + if (exfat_count_num_clusters(sb, &cdir, &num_clu)) + return -EIO; + i_size_write(inode, num_clu << sbi->cluster_size_bits); + + num_subdirs = exfat_count_dir_entries(sb, &cdir); + if (num_subdirs < 0) + return -EIO; + set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR); + + inode->i_uid = sbi->options.fs_uid; + inode->i_gid = sbi->options.fs_gid; + inode_inc_iversion(inode); + inode->i_generation = 0; + inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777); + inode->i_op = &exfat_dir_inode_operations; + inode->i_fop = &exfat_dir_operations; + + inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) + & ~(sbi->cluster_size - 1)) >> inode->i_blkbits; + EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff; + EXFAT_I(inode)->i_size_aligned = i_size_read(inode); + EXFAT_I(inode)->i_size_ondisk = i_size_read(inode); + + exfat_save_attr(inode, ATTR_SUBDIR); + inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime = + current_time(inode); + 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) +{ + struct pbr *p_pbr = (struct pbr *) (*prev_bh)->b_data; + unsigned short logical_sect = 0; + + logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits; + + if (!is_power_of_2(logical_sect) || + logical_sect < 512 || logical_sect > 4096) { + exfat_msg(sb, KERN_ERR, "bogus logical sector size %u", + logical_sect); + return NULL; + } + + if (logical_sect < sb->s_blocksize) { + exfat_msg(sb, KERN_ERR, + "logical sector size too small for device (logical sector size = %u)", + logical_sect); + return NULL; + } + + if (logical_sect > sb->s_blocksize) { + struct buffer_head *bh = NULL; + + __brelse(*prev_bh); + *prev_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) { + 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; + } + return p_pbr; +} + +/* 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 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) { + exfat_msg(sb, KERN_ERR, "unable to read boot sector"); + return -EIO; + } + + /* PRB is read */ + p_pbr = (struct pbr *)bh->b_data; + + /* check the validity of PBR */ + if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) { + exfat_msg(sb, KERN_ERR, "invalid boot record signature"); + ret = -EINVAL; + goto free_bh; + } + + + /* check logical sector size */ + p_pbr = exfat_read_pbr_with_logical_sector(sb, &bh); + if (!p_pbr) { + ret = -EIO; + goto free_bh; + } + + /* + * 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))) { + ret = -EINVAL; + goto free_bh; + } + + p_bpb = (struct pbr64 *)p_pbr; + if (!p_bpb->bsx.num_fats) { + exfat_msg(sb, KERN_ERR, "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->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->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); + /* because the cluster index starts with 2 */ + sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) + + EXFAT_RESERVED_CLUSTERS; + + sbi->root_dir = le32_to_cpu(p_bpb->bsx.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->clu_srch_ptr = EXFAT_FIRST_CLUSTER; + sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED; + + if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) { + sbi->vol_flag |= VOL_DIRTY; + exfat_msg(sb, KERN_WARNING, + "Volume was not properly unmounted. Some data may be corrupt. Please run fsck."); + } + + /* exFAT file size is limited by a disk volume size */ + sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) << + sbi->cluster_size_bits; + + ret = exfat_create_upcase_table(sb); + if (ret) { + exfat_msg(sb, KERN_ERR, "failed to load upcase table"); + goto free_bh; + } + + ret = exfat_load_bitmap(sb); + if (ret) { + exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap"); + goto free_upcase_table; + } + + ret = exfat_count_used_clusters(sb, &sbi->used_clusters); + if (ret) { + exfat_msg(sb, KERN_ERR, "failed to scan clusters"); + goto free_alloc_bitmap; + } + + return 0; + +free_alloc_bitmap: + exfat_free_bitmap(sbi); +free_upcase_table: + exfat_free_upcase_table(sbi); +free_bh: + brelse(bh); + return ret; +} + +static int exfat_fill_super(struct super_block *sb, struct fs_context *fc) +{ + struct exfat_sb_info *sbi = sb->s_fs_info; + struct exfat_mount_options *opts = &sbi->options; + struct inode *root_inode; + int err; + + if (opts->allow_utime == (unsigned short)-1) + opts->allow_utime = ~opts->fs_dmask & 0022; + + if (opts->discard) { + struct request_queue *q = bdev_get_queue(sb->s_bdev); + + if (!blk_queue_discard(q)) + exfat_msg(sb, KERN_WARNING, + "mounting with \"discard\" option, but the device does not support discard"); + 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_min = EXFAT_MIN_TIMESTAMP_SECS; + sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS; + + err = __exfat_fill_super(sb); + if (err) { + exfat_msg(sb, KERN_ERR, "failed to recognize exfat type"); + goto check_nls_io; + } + + /* set up enough so that it can read an inode */ + exfat_hash_init(sb); + + if (!strcmp(sbi->options.iocharset, "utf8")) + opts->utf8 = 1; + else { + sbi->nls_io = load_nls(sbi->options.iocharset); + if (!sbi->nls_io) { + exfat_msg(sb, KERN_ERR, "IO charset %s not found", + sbi->options.iocharset); + err = -EINVAL; + goto free_table; + } + } + + if (sbi->options.utf8) + sb->s_d_op = &exfat_utf8_dentry_ops; + else + sb->s_d_op = &exfat_dentry_ops; + + root_inode = new_inode(sb); + if (!root_inode) { + exfat_msg(sb, KERN_ERR, "failed to allocate root inode."); + err = -ENOMEM; + goto free_table; + } + + root_inode->i_ino = EXFAT_ROOT_INO; + inode_set_iversion(root_inode, 1); + err = exfat_read_root(root_inode); + if (err) { + exfat_msg(sb, KERN_ERR, "failed to initialize root inode."); + goto put_inode; + } + + exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos); + insert_inode_hash(root_inode); + + sb->s_root = d_make_root(root_inode); + if (!sb->s_root) { + exfat_msg(sb, KERN_ERR, "failed to get the root dentry"); + err = -ENOMEM; + goto put_inode; + } + + return 0; + +put_inode: + iput(root_inode); + sb->s_root = NULL; + +free_table: + exfat_free_upcase_table(sbi); + exfat_free_bitmap(sbi); + +check_nls_io: + unload_nls(sbi->nls_io); + exfat_free_iocharset(sbi); + sb->s_fs_info = NULL; + kfree(sbi); + return err; +} + +static int exfat_get_tree(struct fs_context *fc) +{ + return get_tree_bdev(fc, exfat_fill_super); +} + +static void exfat_free(struct fs_context *fc) +{ + kfree(fc->s_fs_info); +} + +static const struct fs_context_operations exfat_context_ops = { + .parse_param = exfat_parse_param, + .get_tree = exfat_get_tree, + .free = exfat_free, +}; + +static int exfat_init_fs_context(struct fs_context *fc) +{ + struct exfat_sb_info *sbi; + + sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL); + if (!sbi) + return -ENOMEM; + + mutex_init(&sbi->s_lock); + ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + + sbi->options.fs_uid = current_uid(); + sbi->options.fs_gid = current_gid(); + sbi->options.fs_fmask = current->fs->umask; + sbi->options.fs_dmask = current->fs->umask; + sbi->options.allow_utime = -1; + sbi->options.iocharset = exfat_default_iocharset; + sbi->options.errors = EXFAT_ERRORS_RO; + + fc->s_fs_info = sbi; + fc->ops = &exfat_context_ops; + return 0; +} + +static struct file_system_type exfat_fs_type = { + .owner = THIS_MODULE, + .name = "exfat", + .init_fs_context = exfat_init_fs_context, + .parameters = &exfat_parameters, + .kill_sb = kill_block_super, + .fs_flags = FS_REQUIRES_DEV, +}; + +static void exfat_inode_init_once(void *foo) +{ + struct exfat_inode_info *ei = (struct exfat_inode_info *)foo; + + INIT_HLIST_NODE(&ei->i_hash_fat); + inode_init_once(&ei->vfs_inode); +} + +static int __init init_exfat_fs(void) +{ + int err; + + err = exfat_cache_init(); + if (err) + return err; + + exfat_inode_cachep = kmem_cache_create("exfat_inode_cache", + sizeof(struct exfat_inode_info), + 0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, + exfat_inode_init_once); + if (!exfat_inode_cachep) { + err = -ENOMEM; + goto shutdown_cache; + } + + err = register_filesystem(&exfat_fs_type); + if (err) + goto destroy_cache; + + return 0; + +destroy_cache: + kmem_cache_destroy(exfat_inode_cachep); +shutdown_cache: + exfat_cache_shutdown(); + return err; +} + +static void __exit exit_exfat_fs(void) +{ + /* + * Make sure all delayed rcu free inodes are flushed before we + * destroy cache. + */ + rcu_barrier(); + kmem_cache_destroy(exfat_inode_cachep); + unregister_filesystem(&exfat_fs_type); + exfat_cache_shutdown(); +} + +module_init(init_exfat_fs); +module_exit(exit_exfat_fs); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("exFAT filesystem support"); +MODULE_AUTHOR("Samsung Electronics Co., Ltd."); |