diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c index 0cea9b9236d07..8a75d812ffdff 100644 --- a/fs/squashfs/block.c +++ b/fs/squashfs/block.c @@ -28,9 +28,12 @@ #include #include +#include #include #include +#include #include +#include #include "squashfs_fs.h" #include "squashfs_fs_sb.h" @@ -38,45 +41,355 @@ #include "decompressor.h" #include "page_actor.h" -/* - * Read the metadata block length, this is stored in the first two - * bytes of the metadata block. - */ -static struct buffer_head *get_block_length(struct super_block *sb, - u64 *cur_index, int *offset, int *length) +static struct workqueue_struct *squashfs_read_wq; + +struct squashfs_read_request { + struct super_block *sb; + u64 index; + int length; + int compressed; + int offset; + u64 read_end; + struct squashfs_page_actor *output; + enum { + SQUASHFS_COPY, + SQUASHFS_DECOMPRESS, + SQUASHFS_METADATA, + } data_processing; + bool synchronous; + + /* + * If the read is synchronous, it is possible to retrieve information + * about the request by setting these pointers. + */ + int *res; + int *bytes_read; + int *bytes_uncompressed; + + int nr_buffers; + struct buffer_head **bh; + struct work_struct offload; +}; + +struct squashfs_bio_request { + struct buffer_head **bh; + int nr_buffers; +}; + +static int squashfs_bio_submit(struct squashfs_read_request *req); + +int squashfs_init_read_wq(void) +{ + squashfs_read_wq = create_workqueue("SquashFS read wq"); + return !!squashfs_read_wq; +} + +void squashfs_destroy_read_wq(void) { - struct squashfs_sb_info *msblk = sb->s_fs_info; + flush_workqueue(squashfs_read_wq); + destroy_workqueue(squashfs_read_wq); +} + +static void free_read_request(struct squashfs_read_request *req, int error) +{ + if (!req->synchronous) + squashfs_page_actor_free(req->output, error); + if (req->res) + *(req->res) = error; + kfree(req->bh); + kfree(req); +} + +static void squashfs_process_blocks(struct squashfs_read_request *req) +{ + int error = 0; + int bytes, i, length; + struct squashfs_sb_info *msblk = req->sb->s_fs_info; + struct squashfs_page_actor *actor = req->output; + struct buffer_head **bh = req->bh; + int nr_buffers = req->nr_buffers; + + for (i = 0; i < nr_buffers; ++i) { + if (!bh[i]) + continue; + wait_on_buffer(bh[i]); + if (!buffer_uptodate(bh[i])) + error = -EIO; + } + if (error) + goto cleanup; + + if (req->data_processing == SQUASHFS_METADATA) { + /* Extract the length of the metadata block */ + if (req->offset != msblk->devblksize - 1) + length = *((u16 *)(bh[0]->b_data + req->offset)); + else { + length = bh[0]->b_data[req->offset]; + length |= bh[1]->b_data[0] << 8; + } + req->compressed = SQUASHFS_COMPRESSED(length); + req->data_processing = req->compressed ? SQUASHFS_DECOMPRESS + : SQUASHFS_COPY; + length = SQUASHFS_COMPRESSED_SIZE(length); + if (req->index + length + 2 > req->read_end) { + for (i = 0; i < nr_buffers; ++i) + put_bh(bh[i]); + kfree(bh); + req->length = length; + req->index += 2; + squashfs_bio_submit(req); + return; + } + req->length = length; + req->offset = (req->offset + 2) % PAGE_SIZE; + if (req->offset < 2) { + put_bh(bh[0]); + ++bh; + --nr_buffers; + } + } + if (req->bytes_read) + *(req->bytes_read) = req->length; + + if (req->data_processing == SQUASHFS_COPY) { + squashfs_bh_to_actor(bh, nr_buffers, req->output, req->offset, + req->length, msblk->devblksize); + } else if (req->data_processing == SQUASHFS_DECOMPRESS) { + req->length = squashfs_decompress(msblk, bh, nr_buffers, + req->offset, req->length, actor); + if (req->length < 0) { + error = -EIO; + goto cleanup; + } + } + + /* Last page may have trailing bytes not filled */ + bytes = req->length % PAGE_SIZE; + if (bytes && actor->page[actor->pages - 1]) + zero_user_segment(actor->page[actor->pages - 1], bytes, + PAGE_SIZE); + +cleanup: + if (req->bytes_uncompressed) + *(req->bytes_uncompressed) = req->length; + if (error) { + for (i = 0; i < nr_buffers; ++i) + if (bh[i]) + put_bh(bh[i]); + } + free_read_request(req, error); +} + +static void read_wq_handler(struct work_struct *work) +{ + squashfs_process_blocks(container_of(work, + struct squashfs_read_request, offload)); +} + +static void squashfs_bio_end_io(struct bio *bio) +{ + int i; + int error = bio->bi_error; + struct squashfs_bio_request *bio_req = bio->bi_private; + + bio_put(bio); + + for (i = 0; i < bio_req->nr_buffers; ++i) { + if (!bio_req->bh[i]) + continue; + if (!error) + set_buffer_uptodate(bio_req->bh[i]); + else + clear_buffer_uptodate(bio_req->bh[i]); + unlock_buffer(bio_req->bh[i]); + } + kfree(bio_req); +} + +static int actor_getblks(struct squashfs_read_request *req, u64 block) +{ + int i; + + req->bh = kmalloc_array(req->nr_buffers, sizeof(*(req->bh)), GFP_NOIO); + if (!req->bh) + return -ENOMEM; + + for (i = 0; i < req->nr_buffers; ++i) { + req->bh[i] = sb_getblk(req->sb, block + i); + if (!req->bh[i]) { + while (--i) { + if (req->bh[i]) + put_bh(req->bh[i]); + } + return -1; + } + } + return 0; +} + +static int squashfs_bio_submit(struct squashfs_read_request *req) +{ + struct bio *bio = NULL; struct buffer_head *bh; + struct squashfs_bio_request *bio_req = NULL; + int b = 0, prev_block = 0; + struct squashfs_sb_info *msblk = req->sb->s_fs_info; + + u64 read_start = round_down(req->index, msblk->devblksize); + u64 read_end = round_up(req->index + req->length, msblk->devblksize); + sector_t block = read_start >> msblk->devblksize_log2; + sector_t block_end = read_end >> msblk->devblksize_log2; + int offset = read_start - round_down(req->index, PAGE_SIZE); + int nr_buffers = block_end - block; + int blksz = msblk->devblksize; + int bio_max_pages = nr_buffers > BIO_MAX_PAGES ? BIO_MAX_PAGES + : nr_buffers; + + /* Setup the request */ + req->read_end = read_end; + req->offset = req->index - read_start; + req->nr_buffers = nr_buffers; + if (actor_getblks(req, block) < 0) + goto getblk_failed; - bh = sb_bread(sb, *cur_index); - if (bh == NULL) - return NULL; - - if (msblk->devblksize - *offset == 1) { - *length = (unsigned char) bh->b_data[*offset]; - put_bh(bh); - bh = sb_bread(sb, ++(*cur_index)); - if (bh == NULL) - return NULL; - *length |= (unsigned char) bh->b_data[0] << 8; - *offset = 1; - } else { - *length = (unsigned char) bh->b_data[*offset] | - (unsigned char) bh->b_data[*offset + 1] << 8; - *offset += 2; - - if (*offset == msblk->devblksize) { - put_bh(bh); - bh = sb_bread(sb, ++(*cur_index)); - if (bh == NULL) - return NULL; - *offset = 0; + /* Create and submit the BIOs */ + for (b = 0; b < nr_buffers; ++b, offset += blksz) { + bh = req->bh[b]; + if (!bh || !trylock_buffer(bh)) + continue; + if (buffer_uptodate(bh)) { + unlock_buffer(bh); + continue; } + offset %= PAGE_SIZE; + + /* Append the buffer to the current BIO if it is contiguous */ + if (bio && bio_req && prev_block + 1 == b) { + if (bio_add_page(bio, bh->b_page, blksz, offset)) { + bio_req->nr_buffers += 1; + prev_block = b; + continue; + } + } + + /* Otherwise, submit the current BIO and create a new one */ + if (bio) + submit_bio(READ, bio); + bio_req = kcalloc(1, sizeof(struct squashfs_bio_request), + GFP_NOIO); + if (!bio_req) + goto req_alloc_failed; + bio_req->bh = &req->bh[b]; + bio = bio_alloc(GFP_NOIO, bio_max_pages); + if (!bio) + goto bio_alloc_failed; + bio->bi_bdev = req->sb->s_bdev; + bio->bi_iter.bi_sector = (block + b) + << (msblk->devblksize_log2 - 9); + bio->bi_private = bio_req; + bio->bi_end_io = squashfs_bio_end_io; + + bio_add_page(bio, bh->b_page, blksz, offset); + bio_req->nr_buffers += 1; + prev_block = b; } + if (bio) + submit_bio(READ, bio); - return bh; + if (req->synchronous) + squashfs_process_blocks(req); + else { + INIT_WORK(&req->offload, read_wq_handler); + schedule_work(&req->offload); + } + return 0; + +bio_alloc_failed: + kfree(bio_req); +req_alloc_failed: + unlock_buffer(bh); + while (--nr_buffers >= b) + if (req->bh[nr_buffers]) + put_bh(req->bh[nr_buffers]); + while (--b >= 0) + if (req->bh[b]) + wait_on_buffer(req->bh[b]); +getblk_failed: + free_read_request(req, -ENOMEM); + return -ENOMEM; +} + +static int read_metadata_block(struct squashfs_read_request *req, + u64 *next_index) +{ + int ret, error, bytes_read = 0, bytes_uncompressed = 0; + struct squashfs_sb_info *msblk = req->sb->s_fs_info; + + if (req->index + 2 > msblk->bytes_used) { + free_read_request(req, -EINVAL); + return -EINVAL; + } + req->length = 2; + + /* Do not read beyond the end of the device */ + if (req->index + req->length > msblk->bytes_used) + req->length = msblk->bytes_used - req->index; + req->data_processing = SQUASHFS_METADATA; + + /* + * Reading metadata is always synchronous because we don't know the + * length in advance and the function is expected to update + * 'next_index' and return the length. + */ + req->synchronous = true; + req->res = &error; + req->bytes_read = &bytes_read; + req->bytes_uncompressed = &bytes_uncompressed; + + TRACE("Metadata block @ 0x%llx, %scompressed size %d, src size %d\n", + req->index, req->compressed ? "" : "un", bytes_read, + req->output->length); + + ret = squashfs_bio_submit(req); + if (ret) + return ret; + if (error) + return error; + if (next_index) + *next_index += 2 + bytes_read; + return bytes_uncompressed; } +static int read_data_block(struct squashfs_read_request *req, int length, + u64 *next_index, bool synchronous) +{ + int ret, error = 0, bytes_uncompressed = 0, bytes_read = 0; + + req->compressed = SQUASHFS_COMPRESSED_BLOCK(length); + req->length = length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length); + req->data_processing = req->compressed ? SQUASHFS_DECOMPRESS + : SQUASHFS_COPY; + + req->synchronous = synchronous; + if (synchronous) { + req->res = &error; + req->bytes_read = &bytes_read; + req->bytes_uncompressed = &bytes_uncompressed; + } + + TRACE("Data block @ 0x%llx, %scompressed size %d, src size %d\n", + req->index, req->compressed ? "" : "un", req->length, + req->output->length); + + ret = squashfs_bio_submit(req); + if (ret) + return ret; + if (synchronous) + ret = error ? error : bytes_uncompressed; + if (next_index) + *next_index += length; + return ret; +} /* * Read and decompress a metadata block or datablock. Length is non-zero @@ -87,128 +400,50 @@ static struct buffer_head *get_block_length(struct super_block *sb, * generated a larger block - this does occasionally happen with compression * algorithms). */ -int squashfs_read_data(struct super_block *sb, u64 index, int length, - u64 *next_index, struct squashfs_page_actor *output) +static int __squashfs_read_data(struct super_block *sb, u64 index, int length, + u64 *next_index, struct squashfs_page_actor *output, bool sync) { - struct squashfs_sb_info *msblk = sb->s_fs_info; - struct buffer_head **bh; - int offset = index & ((1 << msblk->devblksize_log2) - 1); - u64 cur_index = index >> msblk->devblksize_log2; - int bytes, compressed, b = 0, k = 0, avail, i; + struct squashfs_read_request *req; - bh = kcalloc(((output->length + msblk->devblksize - 1) - >> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL); - if (bh == NULL) + req = kcalloc(1, sizeof(struct squashfs_read_request), GFP_KERNEL); + if (!req) { + if (!sync) + squashfs_page_actor_free(output, -ENOMEM); return -ENOMEM; + } - if (length) { - /* - * Datablock. - */ - bytes = -offset; - compressed = SQUASHFS_COMPRESSED_BLOCK(length); - length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length); - if (next_index) - *next_index = index + length; - - TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n", - index, compressed ? "" : "un", length, output->length); - - if (length < 0 || length > output->length || - (index + length) > msblk->bytes_used) - goto read_failure; - - for (b = 0; bytes < length; b++, cur_index++) { - bh[b] = sb_getblk(sb, cur_index); - if (bh[b] == NULL) - goto block_release; - bytes += msblk->devblksize; - } - ll_rw_block(READ, b, bh); - } else { - /* - * Metadata block. - */ - if ((index + 2) > msblk->bytes_used) - goto read_failure; - - bh[0] = get_block_length(sb, &cur_index, &offset, &length); - if (bh[0] == NULL) - goto read_failure; - b = 1; - - bytes = msblk->devblksize - offset; - compressed = SQUASHFS_COMPRESSED(length); - length = SQUASHFS_COMPRESSED_SIZE(length); - if (next_index) - *next_index = index + length + 2; + req->sb = sb; + req->index = index; + req->output = output; - TRACE("Block @ 0x%llx, %scompressed size %d\n", index, - compressed ? "" : "un", length); + if (next_index) + *next_index = index; - if (length < 0 || length > output->length || - (index + length) > msblk->bytes_used) - goto block_release; + if (length) + length = read_data_block(req, length, next_index, sync); + else + length = read_metadata_block(req, next_index); - for (; bytes < length; b++) { - bh[b] = sb_getblk(sb, ++cur_index); - if (bh[b] == NULL) - goto block_release; - bytes += msblk->devblksize; - } - ll_rw_block(READ, b - 1, bh + 1); + if (length < 0) { + ERROR("squashfs_read_data failed to read block 0x%llx\n", + (unsigned long long)index); + return -EIO; } - for (i = 0; i < b; i++) { - wait_on_buffer(bh[i]); - if (!buffer_uptodate(bh[i])) - goto block_release; - } - - if (compressed) { - length = squashfs_decompress(msblk, bh, b, offset, length, - output); - if (length < 0) - goto read_failure; - } else { - /* - * Block is uncompressed. - */ - int in, pg_offset = 0; - void *data = squashfs_first_page(output); - - for (bytes = length; k < b; k++) { - in = min(bytes, msblk->devblksize - offset); - bytes -= in; - while (in) { - if (pg_offset == PAGE_CACHE_SIZE) { - data = squashfs_next_page(output); - pg_offset = 0; - } - avail = min_t(int, in, PAGE_CACHE_SIZE - - pg_offset); - memcpy(data + pg_offset, bh[k]->b_data + offset, - avail); - in -= avail; - pg_offset += avail; - offset += avail; - } - offset = 0; - put_bh(bh[k]); - } - squashfs_finish_page(output); - } - - kfree(bh); return length; +} + +int squashfs_read_data(struct super_block *sb, u64 index, int length, + u64 *next_index, struct squashfs_page_actor *output) +{ + return __squashfs_read_data(sb, index, length, next_index, output, + true); +} -block_release: - for (; k < b; k++) - put_bh(bh[k]); +int squashfs_read_data_async(struct super_block *sb, u64 index, int length, + u64 *next_index, struct squashfs_page_actor *output) +{ -read_failure: - ERROR("squashfs_read_data failed to read block 0x%llx\n", - (unsigned long long) index); - kfree(bh); - return -EIO; + return __squashfs_read_data(sb, index, length, next_index, output, + false); } diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c index 9d033ec0f133a..10fe1272535f6 100644 --- a/fs/squashfs/file_direct.c +++ b/fs/squashfs/file_direct.c @@ -20,157 +20,93 @@ #include "squashfs.h" #include "page_actor.h" -static int squashfs_read_cache(struct page *target_page, u64 block, int bsize, - int pages, struct page **page); +static void release_actor_pages(struct page **page, int pages, int error) +{ + int i; -/* Read separately compressed datablock directly into page cache */ -int squashfs_readpage_block(struct page *target_page, u64 block, int bsize) + for (i = 0; i < pages; i++) { + if (!page[i]) + continue; + flush_dcache_page(page[i]); + if (!error) + SetPageUptodate(page[i]); + else { + SetPageError(page[i]); + zero_user_segment(page[i], 0, PAGE_CACHE_SIZE); + } + unlock_page(page[i]); + put_page(page[i]); + } + kfree(page); +} +/* + * Create a "page actor" which will kmap and kunmap the + * page cache pages appropriately within the decompressor + */ +static struct squashfs_page_actor *actor_from_page_cache( + struct page *target_page, int start_index, int nr_pages) { - struct inode *inode = target_page->mapping->host; - struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info; - - int file_end = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; - int mask = (1 << (msblk->block_log - PAGE_CACHE_SHIFT)) - 1; - int start_index = target_page->index & ~mask; - int end_index = start_index | mask; - int i, n, pages, missing_pages, bytes, res = -ENOMEM; + int i, n; struct page **page; struct squashfs_page_actor *actor; - void *pageaddr; - - if (end_index > file_end) - end_index = file_end; - - pages = end_index - start_index + 1; - page = kmalloc_array(pages, sizeof(void *), GFP_KERNEL); - if (page == NULL) - return res; - - /* - * Create a "page actor" which will kmap and kunmap the - * page cache pages appropriately within the decompressor - */ - actor = squashfs_page_actor_init(page, pages, 0, NULL); - if (actor == NULL) - goto out; - - /* Try to grab all the pages covered by the Squashfs block */ - for (missing_pages = 0, i = 0, n = start_index; i < pages; i++, n++) { - page[i] = (n == target_page->index) ? target_page : - grab_cache_page_nowait(target_page->mapping, n); - - if (page[i] == NULL) { - missing_pages++; - continue; + page = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); + if (!page) + return NULL; + + /* Try to grab all the pages covered by the SquashFS block */ + for (i = 0, n = start_index; i < nr_pages; i++, n++) { + if (target_page->index == n) { + page[i] = target_page; + } else { + page[i] = grab_cache_page_nowait(target_page->mapping, + n); + if (page[i] == NULL) + continue; } if (PageUptodate(page[i])) { unlock_page(page[i]); - page_cache_release(page[i]); + put_page(page[i]); page[i] = NULL; - missing_pages++; } } - if (missing_pages) { - /* - * Couldn't get one or more pages, this page has either - * been VM reclaimed, but others are still in the page cache - * and uptodate, or we're racing with another thread in - * squashfs_readpage also trying to grab them. Fall back to - * using an intermediate buffer. - */ - res = squashfs_read_cache(target_page, block, bsize, pages, - page); - if (res < 0) - goto mark_errored; - - goto out; - } - - /* Decompress directly into the page cache buffers */ - res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor); - if (res < 0) - goto mark_errored; - - /* Last page may have trailing bytes not filled */ - bytes = res % PAGE_CACHE_SIZE; - if (bytes) { - pageaddr = kmap_atomic(page[pages - 1]); - memset(pageaddr + bytes, 0, PAGE_CACHE_SIZE - bytes); - kunmap_atomic(pageaddr); + actor = squashfs_page_actor_init(page, nr_pages, 0, + release_actor_pages); + if (!actor) { + release_actor_pages(page, nr_pages, -ENOMEM); + kfree(page); + return NULL; } - - /* Mark pages as uptodate, unlock and release */ - for (i = 0; i < pages; i++) { - flush_dcache_page(page[i]); - SetPageUptodate(page[i]); - unlock_page(page[i]); - if (page[i] != target_page) - page_cache_release(page[i]); - } - - kfree(actor); - kfree(page); - - return 0; - -mark_errored: - /* Decompression failed, mark pages as errored. Target_page is - * dealt with by the caller - */ - for (i = 0; i < pages; i++) { - if (page[i] == NULL || page[i] == target_page) - continue; - flush_dcache_page(page[i]); - SetPageError(page[i]); - unlock_page(page[i]); - page_cache_release(page[i]); - } - -out: - squashfs_page_actor_free(actor, 0); - kfree(page); - return res; + return actor; } +/* Read separately compressed datablock directly into page cache */ +int squashfs_readpage_block(struct page *target_page, u64 block, int bsize) -static int squashfs_read_cache(struct page *target_page, u64 block, int bsize, - int pages, struct page **page) { - struct inode *i = target_page->mapping->host; - struct squashfs_cache_entry *buffer = squashfs_get_datablock(i->i_sb, - block, bsize); - int bytes = buffer->length, res = buffer->error, n, offset = 0; - void *pageaddr; - - if (res) { - ERROR("Unable to read page, block %llx, size %x\n", block, - bsize); - goto out; - } + struct inode *inode = target_page->mapping->host; + struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info; - for (n = 0; n < pages && bytes > 0; n++, - bytes -= PAGE_CACHE_SIZE, offset += PAGE_CACHE_SIZE) { - int avail = min_t(int, bytes, PAGE_CACHE_SIZE); + int file_end = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; + int mask = (1 << (msblk->block_log - PAGE_CACHE_SHIFT)) - 1; + int start_index = target_page->index & ~mask; + int end_index = start_index | mask; + int pages, res = -ENOMEM; + struct squashfs_page_actor *actor; - if (page[n] == NULL) - continue; + if (end_index > file_end) + end_index = file_end; + pages = end_index - start_index + 1; - pageaddr = kmap_atomic(page[n]); - squashfs_copy_data(pageaddr, buffer, offset, avail); - memset(pageaddr + avail, 0, PAGE_CACHE_SIZE - avail); - kunmap_atomic(pageaddr); - flush_dcache_page(page[n]); - SetPageUptodate(page[n]); - unlock_page(page[n]); - if (page[n] != target_page) - page_cache_release(page[n]); - } + actor = actor_from_page_cache(target_page, start_index, pages); + if (!actor) + return -ENOMEM; -out: - squashfs_cache_put(buffer); - return res; + get_page(target_page); + res = squashfs_read_data_async(inode->i_sb, block, bsize, NULL, + actor); + return res < 0 ? res : 0; } diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h index 887d6d270080a..985317fbf6c2b 100644 --- a/fs/squashfs/squashfs.h +++ b/fs/squashfs/squashfs.h @@ -28,8 +28,14 @@ #define WARNING(s, args...) pr_warn("SQUASHFS: "s, ## args) /* block.c */ +extern int squashfs_init_read_wq(void); +extern void squashfs_destroy_read_wq(void); extern int squashfs_read_data(struct super_block *, u64, int, u64 *, struct squashfs_page_actor *); +extern int squashfs_read_data(struct super_block *, u64, int, u64 *, + struct squashfs_page_actor *); +extern int squashfs_read_data_async(struct super_block *, u64, int, u64 *, + struct squashfs_page_actor *); /* cache.c */ extern struct squashfs_cache *squashfs_cache_init(char *, int, int); diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c index 5056babe00df9..61cd0b39ed0ed 100644 --- a/fs/squashfs/super.c +++ b/fs/squashfs/super.c @@ -444,9 +444,15 @@ static int __init init_squashfs_fs(void) if (err) return err; + if (!squashfs_init_read_wq()) { + destroy_inodecache(); + return -ENOMEM; + } + err = register_filesystem(&squashfs_fs_type); if (err) { destroy_inodecache(); + squashfs_destroy_read_wq(); return err; } @@ -460,6 +466,7 @@ static void __exit exit_squashfs_fs(void) { unregister_filesystem(&squashfs_fs_type); destroy_inodecache(); + squashfs_destroy_read_wq(); }