diff options
Diffstat (limited to 'lib/exfat_dir.c')
| -rw-r--r-- | lib/exfat_dir.c | 955 |
1 files changed, 955 insertions, 0 deletions
diff --git a/lib/exfat_dir.c b/lib/exfat_dir.c new file mode 100644 index 0000000..98e820f --- /dev/null +++ b/lib/exfat_dir.c @@ -0,0 +1,955 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2021 LG Electronics. + * + * Author(s): Hyunchul Lee <hyc.lee@gmail.com> + */ +#include <stdlib.h> +#include <stdio.h> +#include <errno.h> +#include <fcntl.h> +#include <string.h> +#include <time.h> + +#include "exfat_ondisk.h" +#include "libexfat.h" +#include "exfat_fs.h" +#include "exfat_dir.h" + +static struct path_resolve_ctx path_resolve_ctx; + +#define fsck_err(parent, inode, fmt, ...) \ +({ \ + exfat_resolve_path_parent(&path_resolve_ctx, \ + parent, inode); \ + exfat_err("ERROR: %s: " fmt, \ + path_resolve_ctx.local_path, \ + ##__VA_ARGS__); \ +}) + +static ssize_t write_block(struct exfat_de_iter *iter, unsigned int block) +{ + off_t device_offset; + struct exfat *exfat = iter->exfat; + struct buffer_desc *desc; + unsigned int i; + + desc = &iter->buffer_desc[block & 0x01]; + + for (i = 0; i < iter->read_size / iter->write_size; i++) { + if (desc->dirty[i]) { + device_offset = exfat_c2o(exfat, desc->p_clus) + + desc->offset; + if (exfat_write(exfat->blk_dev->dev_fd, + desc->buffer + i * iter->write_size, + iter->write_size, + device_offset + i * iter->write_size) + != (ssize_t)iter->write_size) + return -EIO; + desc->dirty[i] = 0; + } + } + return 0; +} + +static int read_ahead_first_blocks(struct exfat_de_iter *iter) +{ +#ifdef POSIX_FADV_WILLNEED + struct exfat *exfat = iter->exfat; + clus_t clus_count; + unsigned int size; + + clus_count = iter->parent->size / exfat->clus_size; + + if (clus_count > 1) { + iter->ra_begin_offset = 0; + iter->ra_next_clus = 1; + size = exfat->clus_size; + } else { + iter->ra_begin_offset = 0; + iter->ra_next_clus = 0; + size = iter->ra_partial_size; + } + return posix_fadvise(exfat->blk_dev->dev_fd, + exfat_c2o(exfat, iter->parent->first_clus), size, + POSIX_FADV_WILLNEED); +#else + return -ENOTSUP; +#endif +} + +/** + * read the next fragment in advance, and assume the fragment + * which covers @clus is already read. + */ +static int read_ahead_next_blocks(struct exfat_de_iter *iter, + clus_t clus, unsigned int offset, clus_t p_clus) +{ +#ifdef POSIX_FADV_WILLNEED + struct exfat *exfat = iter->exfat; + off_t device_offset; + clus_t clus_count, ra_clus, ra_p_clus; + unsigned int size; + int ret = 0; + + clus_count = iter->parent->size / exfat->clus_size; + if (clus + 1 < clus_count) { + ra_clus = clus + 1; + if (ra_clus == iter->ra_next_clus && + offset >= iter->ra_begin_offset) { + ret = exfat_get_inode_next_clus(exfat, iter->parent, + p_clus, &ra_p_clus); + if (ret) + return ret; + + if (ra_p_clus == EXFAT_EOF_CLUSTER) + return -EIO; + + device_offset = exfat_c2o(exfat, ra_p_clus); + size = ra_clus + 1 < clus_count ? + exfat->clus_size : iter->ra_partial_size; + ret = posix_fadvise(exfat->blk_dev->dev_fd, + device_offset, size, + POSIX_FADV_WILLNEED); + iter->ra_next_clus = ra_clus + 1; + iter->ra_begin_offset = 0; + } + } else { + if (offset >= iter->ra_begin_offset && + offset + iter->ra_partial_size <= + exfat->clus_size) { + device_offset = exfat_c2o(exfat, p_clus) + + offset + iter->ra_partial_size; + ret = posix_fadvise(exfat->blk_dev->dev_fd, + device_offset, iter->ra_partial_size, + POSIX_FADV_WILLNEED); + iter->ra_begin_offset = + offset + iter->ra_partial_size; + } + } + + return ret; +#else + return -ENOTSUP; +#endif +} + +static int read_ahead_next_dir_blocks(struct exfat_de_iter *iter) +{ +#ifdef POSIX_FADV_WILLNEED + struct exfat *exfat = iter->exfat; + struct list_head *current; + struct exfat_inode *next_inode; + off_t offset; + + if (list_empty(&exfat->dir_list)) + return -EINVAL; + + current = exfat->dir_list.next; + if (iter->parent == list_entry(current, struct exfat_inode, list) && + current->next != &exfat->dir_list) { + next_inode = list_entry(current->next, struct exfat_inode, + list); + offset = exfat_c2o(exfat, next_inode->first_clus); + return posix_fadvise(exfat->blk_dev->dev_fd, offset, + iter->ra_partial_size, + POSIX_FADV_WILLNEED); + } + + return 0; +#else + return -ENOTSUP; +#endif +} + +static ssize_t read_block(struct exfat_de_iter *iter, unsigned int block) +{ + struct exfat *exfat = iter->exfat; + struct buffer_desc *desc, *prev_desc; + off_t device_offset; + ssize_t ret; + + desc = &iter->buffer_desc[block & 0x01]; + if (block == 0) { + desc->p_clus = iter->parent->first_clus; + desc->offset = 0; + } + + /* if the buffer already contains dirty dentries, write it */ + if (write_block(iter, block)) + return -EIO; + + if (block > 0) { + if (block > iter->parent->size / iter->read_size) + return EOF; + + prev_desc = &iter->buffer_desc[(block-1) & 0x01]; + if (prev_desc->offset + 2 * iter->read_size <= + exfat->clus_size) { + desc->p_clus = prev_desc->p_clus; + desc->offset = prev_desc->offset + iter->read_size; + } else { + ret = exfat_get_inode_next_clus(exfat, iter->parent, + prev_desc->p_clus, &desc->p_clus); + desc->offset = 0; + if (ret) + return ret; + else if (desc->p_clus == EXFAT_EOF_CLUSTER) + return EOF; + } + } + + device_offset = exfat_c2o(exfat, desc->p_clus) + desc->offset; + ret = exfat_read(exfat->blk_dev->dev_fd, desc->buffer, + iter->read_size, device_offset); + if (ret <= 0) + return ret; + + /* + * if a buffer is filled with dentries, read blocks ahead of time, + * otherwise read blocks of the next directory in advance. + */ + if (desc->buffer[iter->read_size - 32] != EXFAT_LAST) + read_ahead_next_blocks(iter, + (block * iter->read_size) / exfat->clus_size, + (block * iter->read_size) % exfat->clus_size, + desc->p_clus); + else + read_ahead_next_dir_blocks(iter); + return ret; +} + +int exfat_de_iter_init(struct exfat_de_iter *iter, struct exfat *exfat, + struct exfat_inode *dir, struct buffer_desc *bd) +{ + iter->exfat = exfat; + iter->parent = dir; + iter->write_size = exfat->sect_size; + iter->read_size = exfat->clus_size <= 4*KB ? exfat->clus_size : 4*KB; + if (exfat->clus_size <= 32 * KB) + iter->ra_partial_size = MAX(4 * KB, exfat->clus_size / 2); + else + iter->ra_partial_size = exfat->clus_size / 4; + iter->ra_partial_size = MIN(iter->ra_partial_size, 8 * KB); + + iter->buffer_desc = bd; + + iter->de_file_offset = 0; + iter->next_read_offset = iter->read_size; + iter->max_skip_dentries = 0; + iter->invalid_name_num = 0; + + if (iter->parent->size == 0) + return EOF; + + read_ahead_first_blocks(iter); + if (read_block(iter, 0) != (ssize_t)iter->read_size) { + exfat_err("failed to read directory entries.\n"); + return -EIO; + } + + return 0; +} + +int exfat_de_iter_get(struct exfat_de_iter *iter, + int ith, struct exfat_dentry **dentry) +{ + off_t next_de_file_offset; + ssize_t ret; + unsigned int block; + + next_de_file_offset = iter->de_file_offset + + ith * sizeof(struct exfat_dentry); + block = (unsigned int)(next_de_file_offset / iter->read_size); + + if (next_de_file_offset + sizeof(struct exfat_dentry) > + iter->parent->size) + return EOF; + /* the dentry must be in current, or next block which will be read */ + if (block > iter->de_file_offset / iter->read_size + 1) + return -ERANGE; + + /* read next cluster if needed */ + if (next_de_file_offset >= iter->next_read_offset) { + ret = read_block(iter, block); + if (ret != (ssize_t)iter->read_size) + return ret; + iter->next_read_offset += iter->read_size; + } + + if (ith + 1 > iter->max_skip_dentries) + iter->max_skip_dentries = ith + 1; + + *dentry = (struct exfat_dentry *) + (iter->buffer_desc[block & 0x01].buffer + + next_de_file_offset % iter->read_size); + return 0; +} + +int exfat_de_iter_get_dirty(struct exfat_de_iter *iter, + int ith, struct exfat_dentry **dentry) +{ + off_t next_file_offset; + unsigned int block; + int ret, sect_idx; + + ret = exfat_de_iter_get(iter, ith, dentry); + if (!ret) { + next_file_offset = iter->de_file_offset + + ith * sizeof(struct exfat_dentry); + block = (unsigned int)(next_file_offset / iter->read_size); + sect_idx = (int)((next_file_offset % iter->read_size) / + iter->write_size); + iter->buffer_desc[block & 0x01].dirty[sect_idx] = 1; + } + + return ret; +} + +int exfat_de_iter_flush(struct exfat_de_iter *iter) +{ + if (write_block(iter, 0) || write_block(iter, 1)) + return -EIO; + return 0; +} + +int exfat_de_iter_advance(struct exfat_de_iter *iter, int skip_dentries) +{ + if (skip_dentries > iter->max_skip_dentries) + return -EINVAL; + + iter->max_skip_dentries = 0; + iter->de_file_offset = iter->de_file_offset + + skip_dentries * sizeof(struct exfat_dentry); + return 0; +} + +off_t exfat_de_iter_device_offset(struct exfat_de_iter *iter) +{ + struct buffer_desc *bd; + unsigned int block; + + if ((uint64_t)iter->de_file_offset >= iter->parent->size) + return EOF; + + block = iter->de_file_offset / iter->read_size; + bd = &iter->buffer_desc[block & 0x01]; + return exfat_c2o(iter->exfat, bd->p_clus) + bd->offset + + iter->de_file_offset % iter->read_size; +} + +off_t exfat_de_iter_file_offset(struct exfat_de_iter *iter) +{ + return iter->de_file_offset; +} + +/* + * try to find the dentry set matched with @filter. this function + * doesn't verify the dentry set. + * + * if found, return 0. if not found, return EOF. otherwise return errno. + */ +int exfat_lookup_dentry_set(struct exfat *exfat, struct exfat_inode *parent, + struct exfat_lookup_filter *filter) +{ + struct buffer_desc *bd = NULL; + struct exfat_dentry *dentry = NULL; + off_t free_file_offset = 0, free_dev_offset = 0; + struct exfat_de_iter de_iter; + int dentry_count, empty_dentry_count = 0; + int retval; + + bd = exfat_alloc_buffer(2, exfat->clus_size, exfat->sect_size); + if (!bd) + return -ENOMEM; + + retval = exfat_de_iter_init(&de_iter, exfat, parent, bd); + if (retval == EOF || retval) + goto out; + + filter->out.dentry_set = NULL; + while (1) { + retval = exfat_de_iter_get(&de_iter, 0, &dentry); + if (retval == EOF) { + break; + } else if (retval) { + fsck_err(parent->parent, parent, + "failed to get a dentry. %d\n", retval); + goto out; + } + + if (!IS_EXFAT_DELETED(dentry->type)) { + if (filter->in.dentry_count == 0 || + empty_dentry_count < filter->in.dentry_count) + empty_dentry_count = 0; + } + + dentry_count = 1; + if (dentry->type == filter->in.type) { + retval = 0; + if (filter->in.filter) + retval = filter->in.filter(&de_iter, + filter->in.param, + &dentry_count); + + if (retval == 0) { + struct exfat_dentry *d; + int i; + + filter->out.dentry_set = calloc(dentry_count, + sizeof(struct exfat_dentry)); + if (!filter->out.dentry_set) { + retval = -ENOMEM; + goto out; + } + for (i = 0; i < dentry_count; i++) { + exfat_de_iter_get(&de_iter, i, &d); + memcpy(filter->out.dentry_set + i, d, + sizeof(struct exfat_dentry)); + } + filter->out.dentry_count = dentry_count; + goto out; + } else if (retval < 0) { + goto out; + } + } else if (IS_EXFAT_DELETED(dentry->type)) { + if (empty_dentry_count == 0) { + free_file_offset = + exfat_de_iter_file_offset(&de_iter); + free_dev_offset = + exfat_de_iter_device_offset(&de_iter); + } + + if (filter->in.dentry_count == 0 || + empty_dentry_count < filter->in.dentry_count) + empty_dentry_count++; + } + + exfat_de_iter_advance(&de_iter, dentry_count); + } + +out: + if (retval == 0) { + filter->out.file_offset = + exfat_de_iter_file_offset(&de_iter); + filter->out.dev_offset = + exfat_de_iter_device_offset(&de_iter); + } else if (retval == EOF && empty_dentry_count) { + filter->out.file_offset = free_file_offset; + filter->out.dev_offset = free_dev_offset; + } else { + filter->out.file_offset = exfat_de_iter_file_offset(&de_iter); + filter->out.dev_offset = EOF; + } + if (bd) + exfat_free_buffer(bd, 2); + return retval; +} + +static int filter_lookup_file(struct exfat_de_iter *de_iter, + void *param, int *dentry_count) +{ + struct exfat_dentry *file_de, *stream_de, *name_de; + __le16 *name; + int retval, name_len; + int i; + + retval = exfat_de_iter_get(de_iter, 0, &file_de); + if (retval || file_de->type != EXFAT_FILE) + return 1; + + retval = exfat_de_iter_get(de_iter, 1, &stream_de); + if (retval || stream_de->type != EXFAT_STREAM) + return 1; + + name = (__le16 *)param; + name_len = (int)exfat_utf16_len(name, PATH_MAX); + + if (file_de->dentry.file.num_ext < + 1 + (name_len + ENTRY_NAME_MAX - 1) / ENTRY_NAME_MAX) + return 1; + + for (i = 2; i <= file_de->dentry.file.num_ext && name_len > 0; i++) { + int len; + + retval = exfat_de_iter_get(de_iter, i, &name_de); + if (retval || name_de->type != EXFAT_NAME) + return 1; + + len = MIN(name_len + 1, ENTRY_NAME_MAX); + if (memcmp(name_de->dentry.name.unicode_0_14, + name, len * 2) != 0) + return 1; + + name += len; + name_len -= len; + } + + *dentry_count = i; + return 0; +} + +int exfat_lookup_file_by_utf16name(struct exfat *exfat, + struct exfat_inode *parent, + __le16 *utf16_name, + struct exfat_lookup_filter *filter_out) +{ + int retval; + + filter_out->in.type = EXFAT_FILE; + filter_out->in.filter = filter_lookup_file; + filter_out->in.param = utf16_name; + filter_out->in.dentry_count = 0; + + retval = exfat_lookup_dentry_set(exfat, parent, filter_out); + if (retval < 0) + return retval; + + return 0; +} + +int exfat_lookup_file(struct exfat *exfat, struct exfat_inode *parent, + const char *name, struct exfat_lookup_filter *filter_out) +{ + int retval; + __le16 utf16_name[PATH_MAX + 2] = {0, }; + + retval = (int)exfat_utf16_enc(name, utf16_name, sizeof(utf16_name)); + if (retval < 0) + return retval; + + return exfat_lookup_file_by_utf16name(exfat, parent, utf16_name, + filter_out); +} + +void exfat_calc_dentry_checksum(struct exfat_dentry *dentry, + uint16_t *checksum, bool primary) +{ + unsigned int i; + uint8_t *bytes; + + bytes = (uint8_t *)dentry; + + /* use += to avoid promotion to int; UBSan complaints about signed overflow */ + *checksum = (*checksum << 15) | (*checksum >> 1); + *checksum += bytes[0]; + *checksum = (*checksum << 15) | (*checksum >> 1); + *checksum += bytes[1]; + + i = primary ? 4 : 2; + for (; i < sizeof(*dentry); i++) { + *checksum = (*checksum << 15) | (*checksum >> 1); + *checksum += bytes[i]; + } +} + +static uint16_t calc_dentry_set_checksum(struct exfat_dentry *dset, int dcount) +{ + uint16_t checksum; + int i; + + if (dcount < MIN_FILE_DENTRIES) + return 0; + + checksum = 0; + exfat_calc_dentry_checksum(&dset[0], &checksum, true); + for (i = 1; i < dcount; i++) + exfat_calc_dentry_checksum(&dset[i], &checksum, false); + return checksum; +} + +uint16_t exfat_calc_name_hash(struct exfat *exfat, + __le16 *name, int len) +{ + int i; + __le16 ch; + uint16_t chksum = 0; + + for (i = 0; i < len; i++) { + ch = exfat->upcase_table[le16_to_cpu(name[i])]; + ch = cpu_to_le16(ch); + + /* use += to avoid promotion to int; UBSan complaints about signed overflow */ + chksum = (chksum << 15) | (chksum >> 1); + chksum += ch & 0xFF; + chksum = (chksum << 15) | (chksum >> 1); + chksum += ch >> 8; + } + return chksum; +} + +static void unix_time_to_exfat_time(time_t unix_time, __u8 *tz, __le16 *date, + __le16 *time, __u8 *time_ms) +{ + struct tm tm; + __u16 t, d; + + gmtime_r(&unix_time, &tm); + d = ((tm.tm_year - 80) << 9) | ((tm.tm_mon + 1) << 5) | tm.tm_mday; + t = (tm.tm_hour << 11) | (tm.tm_min << 5) | (tm.tm_sec >> 1); + + *tz = 0x80; + *date = cpu_to_le16(d); + *time = cpu_to_le16(t); + if (time_ms) + *time_ms = (tm.tm_sec & 1) * 100; +} + +int exfat_build_file_dentry_set(struct exfat *exfat, const char *name, + unsigned short attr, struct exfat_dentry **dentry_set, + int *dentry_count) +{ + struct exfat_dentry *dset; + __le16 utf16_name[PATH_MAX + 2]; + int retval; + int dcount, name_len, i; + __le16 e_date, e_time; + __u8 tz, e_time_ms; + + memset(utf16_name, 0, sizeof(utf16_name)); + retval = exfat_utf16_enc(name, utf16_name, sizeof(utf16_name)); + if (retval < 0) + return retval; + + name_len = retval / 2; + dcount = 2 + DIV_ROUND_UP(name_len, ENTRY_NAME_MAX); + dset = calloc(1, dcount * DENTRY_SIZE); + if (!dset) + return -ENOMEM; + + dset[0].type = EXFAT_FILE; + dset[0].dentry.file.num_ext = dcount - 1; + dset[0].dentry.file.attr = cpu_to_le16(attr); + + unix_time_to_exfat_time(time(NULL), &tz, + &e_date, &e_time, &e_time_ms); + + dset[0].dentry.file.create_date = e_date; + dset[0].dentry.file.create_time = e_time; + dset[0].dentry.file.create_time_ms = e_time_ms; + dset[0].dentry.file.create_tz = tz; + + dset[0].dentry.file.modify_date = e_date; + dset[0].dentry.file.modify_time = e_time; + dset[0].dentry.file.modify_time_ms = e_time_ms; + dset[0].dentry.file.modify_tz = tz; + + dset[0].dentry.file.access_date = e_date; + dset[0].dentry.file.access_time = e_time; + dset[0].dentry.file.access_tz = tz; + + dset[1].type = EXFAT_STREAM; + dset[1].dentry.stream.flags = 0x01; + dset[1].dentry.stream.name_len = (__u8)name_len; + dset[1].dentry.stream.name_hash = + cpu_to_le16(exfat_calc_name_hash(exfat, utf16_name, name_len)); + + for (i = 2; i < dcount; i++) { + dset[i].type = EXFAT_NAME; + memcpy(dset[i].dentry.name.unicode_0_14, + utf16_name + (i - 2) * ENTRY_NAME_MAX, + ENTRY_NAME_MAX * 2); + } + + dset[0].dentry.file.checksum = + cpu_to_le16(calc_dentry_set_checksum(dset, dcount)); + + *dentry_set = dset; + *dentry_count = dcount; + return 0; +} + +int exfat_update_file_dentry_set(struct exfat *exfat, + struct exfat_dentry *dset, int dcount, + const char *name, + clus_t start_clu, clus_t ccount) +{ + int i, name_len; + __le16 utf16_name[PATH_MAX + 2]; + + if (dset[0].type != EXFAT_FILE || dcount < MIN_FILE_DENTRIES) + return -EINVAL; + + if (name) { + name_len = (int)exfat_utf16_enc(name, + utf16_name, sizeof(utf16_name)); + if (name_len < 0) + return name_len; + + name_len /= 2; + if (dcount != 2 + DIV_ROUND_UP(name_len, ENTRY_NAME_MAX)) + return -EINVAL; + + dset[1].dentry.stream.name_len = (__u8)name_len; + dset[1].dentry.stream.name_hash = + exfat_calc_name_hash(exfat, utf16_name, name_len); + + for (i = 2; i < dcount; i++) { + dset[i].type = EXFAT_NAME; + memcpy(dset[i].dentry.name.unicode_0_14, + utf16_name + (i - 2) * ENTRY_NAME_MAX, + ENTRY_NAME_MAX * 2); + } + } + + dset[1].dentry.stream.valid_size = cpu_to_le64(ccount * exfat->clus_size); + dset[1].dentry.stream.size = cpu_to_le64(ccount * exfat->clus_size); + if (start_clu) + dset[1].dentry.stream.start_clu = cpu_to_le32(start_clu); + + dset[0].dentry.file.checksum = + cpu_to_le16(calc_dentry_set_checksum(dset, dcount)); + return 0; +} + +static int find_free_cluster(struct exfat *exfat, + clus_t start, clus_t *new_clu) +{ + clus_t end = le32_to_cpu(exfat->bs->bsx.clu_count) + + EXFAT_FIRST_CLUSTER; + + if (!exfat_heap_clus(exfat, start)) + return -EINVAL; + + while (start < end) { + if (exfat_bitmap_find_zero(exfat, exfat->alloc_bitmap, + start, new_clu)) + break; + if (!exfat_bitmap_get(exfat->disk_bitmap, *new_clu)) + return 0; + start = *new_clu + 1; + } + + end = start; + start = EXFAT_FIRST_CLUSTER; + while (start < end) { + if (exfat_bitmap_find_zero(exfat, exfat->alloc_bitmap, + start, new_clu)) + goto out_nospc; + if (!exfat_bitmap_get(exfat->disk_bitmap, *new_clu)) + return 0; + start = *new_clu + 1; + } + +out_nospc: + *new_clu = EXFAT_EOF_CLUSTER; + return -ENOSPC; +} + +static int exfat_map_cluster(struct exfat *exfat, struct exfat_inode *inode, + off_t file_off, clus_t *mapped_clu) +{ + clus_t clu, next, count, last_count; + + if (!exfat_heap_clus(exfat, inode->first_clus)) + return -EINVAL; + + clu = inode->first_clus; + next = EXFAT_EOF_CLUSTER; + count = 1; + if (file_off == EOF) + last_count = DIV_ROUND_UP(inode->size, exfat->clus_size); + else + last_count = file_off / exfat->clus_size + 1; + + while (true) { + if (count * exfat->clus_size > inode->size) + return -EINVAL; + + if (count == last_count) { + *mapped_clu = clu; + return 0; + } + + if (exfat_get_inode_next_clus(exfat, inode, clu, &next)) + return -EINVAL; + + if (!exfat_heap_clus(exfat, clu)) + return -EINVAL; + + clu = next; + count++; + } + return -EINVAL; +} + +static int exfat_write_dentry_set(struct exfat *exfat, + struct exfat_dentry *dset, int dcount, + off_t dev_off, off_t *next_dev_off) +{ + clus_t clus; + unsigned int clus_off, dent_len, first_half_len, sec_half_len; + off_t first_half_off, sec_half_off = 0; + + if (exfat_o2c(exfat, dev_off, &clus, &clus_off)) + return -ERANGE; + + dent_len = dcount * DENTRY_SIZE; + first_half_len = MIN(dent_len, exfat->clus_size - clus_off); + sec_half_len = dent_len - first_half_len; + + first_half_off = dev_off; + if (sec_half_len) { + clus_t next_clus; + + if (exfat_get_next_clus(exfat, clus, &next_clus)) + return -EIO; + if (!exfat_heap_clus(exfat, next_clus)) + return -EINVAL; + sec_half_off = exfat_c2o(exfat, next_clus); + } + + if (exfat_write(exfat->blk_dev->dev_fd, dset, first_half_len, + first_half_off) != (ssize_t)first_half_len) + return -EIO; + + if (sec_half_len) { + dset = (struct exfat_dentry *)((char *)dset + first_half_len); + if (exfat_write(exfat->blk_dev->dev_fd, dset, sec_half_len, + sec_half_off) != (ssize_t)sec_half_len) + return -EIO; + } + + if (next_dev_off) { + if (sec_half_len) + *next_dev_off = sec_half_off + sec_half_len; + else + *next_dev_off = first_half_off + first_half_len; + } + return 0; +} + +static int exfat_alloc_cluster(struct exfat *exfat, struct exfat_inode *inode, + clus_t *new_clu) +{ + clus_t last_clu; + int err; + bool need_dset = inode != exfat->root; + + if ((need_dset && !inode->dentry_set) || inode->is_contiguous) + return -EINVAL; + + err = find_free_cluster(exfat, exfat->start_clu, new_clu); + if (err) { + exfat->start_clu = EXFAT_FIRST_CLUSTER; + exfat_err("failed to find an free cluster\n"); + return -ENOSPC; + } + exfat->start_clu = *new_clu; + + if (exfat_set_fat(exfat, *new_clu, EXFAT_EOF_CLUSTER)) + return -EIO; + + /* zero out the new cluster */ + if (exfat_write(exfat->blk_dev->dev_fd, exfat->zero_cluster, + exfat->clus_size, exfat_c2o(exfat, *new_clu)) != + (ssize_t)exfat->clus_size) { + exfat_err("failed to fill new cluster with zeroes\n"); + return -EIO; + } + + if (inode->size) { + err = exfat_map_cluster(exfat, inode, EOF, &last_clu); + if (err) { + exfat_err("failed to get the last cluster\n"); + return err; + } + + if (exfat_set_fat(exfat, last_clu, *new_clu)) + return -EIO; + + if (need_dset) { + err = exfat_update_file_dentry_set(exfat, + inode->dentry_set, + inode->dentry_count, + NULL, 0, + DIV_ROUND_UP(inode->size, + exfat->clus_size) + 1); + if (err) + return -EINVAL; + } + } else { + if (need_dset) { + err = exfat_update_file_dentry_set(exfat, + inode->dentry_set, + inode->dentry_count, + NULL, *new_clu, 1); + if (err) + return -EINVAL; + } + } + + if (need_dset && exfat_write_dentry_set(exfat, inode->dentry_set, + inode->dentry_count, + inode->dev_offset, NULL)) + return -EIO; + + exfat_bitmap_set(exfat->alloc_bitmap, *new_clu); + if (inode->size == 0) + inode->first_clus = *new_clu; + inode->size += exfat->clus_size; + return 0; +} + +int exfat_add_dentry_set(struct exfat *exfat, struct exfat_dentry_loc *loc, + struct exfat_dentry *dset, int dcount, + bool need_next_loc) +{ + struct exfat_inode *parent = loc->parent; + off_t dev_off, next_dev_off; + + if (parent->is_contiguous || + (uint64_t)loc->file_offset > parent->size || + (unsigned int)dcount * DENTRY_SIZE > exfat->clus_size) + return -EINVAL; + + dev_off = loc->dev_offset; + if ((uint64_t)loc->file_offset + dcount * DENTRY_SIZE > parent->size) { + clus_t new_clus; + + if (exfat_alloc_cluster(exfat, parent, &new_clus)) + return -EIO; + if ((uint64_t)loc->file_offset == parent->size - exfat->clus_size) + dev_off = exfat_c2o(exfat, new_clus); + } + + if (exfat_write_dentry_set(exfat, dset, dcount, dev_off, &next_dev_off)) + return -EIO; + + if (need_next_loc) { + loc->file_offset += dcount * DENTRY_SIZE; + loc->dev_offset = next_dev_off; + } + return 0; +} + +int exfat_create_file(struct exfat *exfat, struct exfat_inode *parent, + const char *name, unsigned short attr) +{ + struct exfat_dentry *dset; + int err, dcount; + struct exfat_lookup_filter filter; + struct exfat_dentry_loc loc; + + err = exfat_lookup_file(exfat, parent, name, &filter); + if (err == 0) { + dset = filter.out.dentry_set; + dcount = filter.out.dentry_count; + if ((le16_to_cpu(dset->dentry.file.attr) & attr) != attr) + err = -EEXIST; + goto out; + } + + err = exfat_build_file_dentry_set(exfat, name, attr, + &dset, &dcount); + if (err) + return err; + + loc.parent = parent; + loc.file_offset = filter.out.file_offset; + loc.dev_offset = filter.out.dev_offset; + err = exfat_add_dentry_set(exfat, &loc, dset, dcount, false); +out: + free(dset); + return err; +} |