diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/btrfs/compression.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/btrfs/compression.c | 1038 |
1 files changed, 0 insertions, 1038 deletions
diff --git a/ANDROID_3.4.5/fs/btrfs/compression.c b/ANDROID_3.4.5/fs/btrfs/compression.c deleted file mode 100644 index 86eff48d..00000000 --- a/ANDROID_3.4.5/fs/btrfs/compression.c +++ /dev/null @@ -1,1038 +0,0 @@ -/* - * Copyright (C) 2008 Oracle. All rights reserved. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public - * License v2 as published by the Free Software Foundation. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public - * License along with this program; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 021110-1307, USA. - */ - -#include <linux/kernel.h> -#include <linux/bio.h> -#include <linux/buffer_head.h> -#include <linux/file.h> -#include <linux/fs.h> -#include <linux/pagemap.h> -#include <linux/highmem.h> -#include <linux/time.h> -#include <linux/init.h> -#include <linux/string.h> -#include <linux/backing-dev.h> -#include <linux/mpage.h> -#include <linux/swap.h> -#include <linux/writeback.h> -#include <linux/bit_spinlock.h> -#include <linux/slab.h> -#include "compat.h" -#include "ctree.h" -#include "disk-io.h" -#include "transaction.h" -#include "btrfs_inode.h" -#include "volumes.h" -#include "ordered-data.h" -#include "compression.h" -#include "extent_io.h" -#include "extent_map.h" - -struct compressed_bio { - /* number of bios pending for this compressed extent */ - atomic_t pending_bios; - - /* the pages with the compressed data on them */ - struct page **compressed_pages; - - /* inode that owns this data */ - struct inode *inode; - - /* starting offset in the inode for our pages */ - u64 start; - - /* number of bytes in the inode we're working on */ - unsigned long len; - - /* number of bytes on disk */ - unsigned long compressed_len; - - /* the compression algorithm for this bio */ - int compress_type; - - /* number of compressed pages in the array */ - unsigned long nr_pages; - - /* IO errors */ - int errors; - int mirror_num; - - /* for reads, this is the bio we are copying the data into */ - struct bio *orig_bio; - - /* - * the start of a variable length array of checksums only - * used by reads - */ - u32 sums; -}; - -static inline int compressed_bio_size(struct btrfs_root *root, - unsigned long disk_size) -{ - u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); - - return sizeof(struct compressed_bio) + - ((disk_size + root->sectorsize - 1) / root->sectorsize) * - csum_size; -} - -static struct bio *compressed_bio_alloc(struct block_device *bdev, - u64 first_byte, gfp_t gfp_flags) -{ - int nr_vecs; - - nr_vecs = bio_get_nr_vecs(bdev); - return btrfs_bio_alloc(bdev, first_byte >> 9, nr_vecs, gfp_flags); -} - -static int check_compressed_csum(struct inode *inode, - struct compressed_bio *cb, - u64 disk_start) -{ - int ret; - struct btrfs_root *root = BTRFS_I(inode)->root; - struct page *page; - unsigned long i; - char *kaddr; - u32 csum; - u32 *cb_sum = &cb->sums; - - if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) - return 0; - - for (i = 0; i < cb->nr_pages; i++) { - page = cb->compressed_pages[i]; - csum = ~(u32)0; - - kaddr = kmap_atomic(page); - csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE); - btrfs_csum_final(csum, (char *)&csum); - kunmap_atomic(kaddr); - - if (csum != *cb_sum) { - printk(KERN_INFO "btrfs csum failed ino %llu " - "extent %llu csum %u " - "wanted %u mirror %d\n", - (unsigned long long)btrfs_ino(inode), - (unsigned long long)disk_start, - csum, *cb_sum, cb->mirror_num); - ret = -EIO; - goto fail; - } - cb_sum++; - - } - ret = 0; -fail: - return ret; -} - -/* when we finish reading compressed pages from the disk, we - * decompress them and then run the bio end_io routines on the - * decompressed pages (in the inode address space). - * - * This allows the checksumming and other IO error handling routines - * to work normally - * - * The compressed pages are freed here, and it must be run - * in process context - */ -static void end_compressed_bio_read(struct bio *bio, int err) -{ - struct compressed_bio *cb = bio->bi_private; - struct inode *inode; - struct page *page; - unsigned long index; - int ret; - - if (err) - cb->errors = 1; - - /* if there are more bios still pending for this compressed - * extent, just exit - */ - if (!atomic_dec_and_test(&cb->pending_bios)) - goto out; - - inode = cb->inode; - ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9); - if (ret) - goto csum_failed; - - /* ok, we're the last bio for this extent, lets start - * the decompression. - */ - ret = btrfs_decompress_biovec(cb->compress_type, - cb->compressed_pages, - cb->start, - cb->orig_bio->bi_io_vec, - cb->orig_bio->bi_vcnt, - cb->compressed_len); -csum_failed: - if (ret) - cb->errors = 1; - - /* release the compressed pages */ - index = 0; - for (index = 0; index < cb->nr_pages; index++) { - page = cb->compressed_pages[index]; - page->mapping = NULL; - page_cache_release(page); - } - - /* do io completion on the original bio */ - if (cb->errors) { - bio_io_error(cb->orig_bio); - } else { - int bio_index = 0; - struct bio_vec *bvec = cb->orig_bio->bi_io_vec; - - /* - * we have verified the checksum already, set page - * checked so the end_io handlers know about it - */ - while (bio_index < cb->orig_bio->bi_vcnt) { - SetPageChecked(bvec->bv_page); - bvec++; - bio_index++; - } - bio_endio(cb->orig_bio, 0); - } - - /* finally free the cb struct */ - kfree(cb->compressed_pages); - kfree(cb); -out: - bio_put(bio); -} - -/* - * Clear the writeback bits on all of the file - * pages for a compressed write - */ -static noinline void end_compressed_writeback(struct inode *inode, u64 start, - unsigned long ram_size) -{ - unsigned long index = start >> PAGE_CACHE_SHIFT; - unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; - struct page *pages[16]; - unsigned long nr_pages = end_index - index + 1; - int i; - int ret; - - while (nr_pages > 0) { - ret = find_get_pages_contig(inode->i_mapping, index, - min_t(unsigned long, - nr_pages, ARRAY_SIZE(pages)), pages); - if (ret == 0) { - nr_pages -= 1; - index += 1; - continue; - } - for (i = 0; i < ret; i++) { - end_page_writeback(pages[i]); - page_cache_release(pages[i]); - } - nr_pages -= ret; - index += ret; - } - /* the inode may be gone now */ -} - -/* - * do the cleanup once all the compressed pages hit the disk. - * This will clear writeback on the file pages and free the compressed - * pages. - * - * This also calls the writeback end hooks for the file pages so that - * metadata and checksums can be updated in the file. - */ -static void end_compressed_bio_write(struct bio *bio, int err) -{ - struct extent_io_tree *tree; - struct compressed_bio *cb = bio->bi_private; - struct inode *inode; - struct page *page; - unsigned long index; - - if (err) - cb->errors = 1; - - /* if there are more bios still pending for this compressed - * extent, just exit - */ - if (!atomic_dec_and_test(&cb->pending_bios)) - goto out; - - /* ok, we're the last bio for this extent, step one is to - * call back into the FS and do all the end_io operations - */ - inode = cb->inode; - tree = &BTRFS_I(inode)->io_tree; - cb->compressed_pages[0]->mapping = cb->inode->i_mapping; - tree->ops->writepage_end_io_hook(cb->compressed_pages[0], - cb->start, - cb->start + cb->len - 1, - NULL, 1); - cb->compressed_pages[0]->mapping = NULL; - - end_compressed_writeback(inode, cb->start, cb->len); - /* note, our inode could be gone now */ - - /* - * release the compressed pages, these came from alloc_page and - * are not attached to the inode at all - */ - index = 0; - for (index = 0; index < cb->nr_pages; index++) { - page = cb->compressed_pages[index]; - page->mapping = NULL; - page_cache_release(page); - } - - /* finally free the cb struct */ - kfree(cb->compressed_pages); - kfree(cb); -out: - bio_put(bio); -} - -/* - * worker function to build and submit bios for previously compressed pages. - * The corresponding pages in the inode should be marked for writeback - * and the compressed pages should have a reference on them for dropping - * when the IO is complete. - * - * This also checksums the file bytes and gets things ready for - * the end io hooks. - */ -int btrfs_submit_compressed_write(struct inode *inode, u64 start, - unsigned long len, u64 disk_start, - unsigned long compressed_len, - struct page **compressed_pages, - unsigned long nr_pages) -{ - struct bio *bio = NULL; - struct btrfs_root *root = BTRFS_I(inode)->root; - struct compressed_bio *cb; - unsigned long bytes_left; - struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; - int pg_index = 0; - struct page *page; - u64 first_byte = disk_start; - struct block_device *bdev; - int ret; - int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM; - - WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); - cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); - if (!cb) - return -ENOMEM; - atomic_set(&cb->pending_bios, 0); - cb->errors = 0; - cb->inode = inode; - cb->start = start; - cb->len = len; - cb->mirror_num = 0; - cb->compressed_pages = compressed_pages; - cb->compressed_len = compressed_len; - cb->orig_bio = NULL; - cb->nr_pages = nr_pages; - - bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; - - bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); - if(!bio) { - kfree(cb); - return -ENOMEM; - } - bio->bi_private = cb; - bio->bi_end_io = end_compressed_bio_write; - atomic_inc(&cb->pending_bios); - - /* create and submit bios for the compressed pages */ - bytes_left = compressed_len; - for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) { - page = compressed_pages[pg_index]; - page->mapping = inode->i_mapping; - if (bio->bi_size) - ret = io_tree->ops->merge_bio_hook(page, 0, - PAGE_CACHE_SIZE, - bio, 0); - else - ret = 0; - - page->mapping = NULL; - if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < - PAGE_CACHE_SIZE) { - bio_get(bio); - - /* - * inc the count before we submit the bio so - * we know the end IO handler won't happen before - * we inc the count. Otherwise, the cb might get - * freed before we're done setting it up - */ - atomic_inc(&cb->pending_bios); - ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); - BUG_ON(ret); /* -ENOMEM */ - - if (!skip_sum) { - ret = btrfs_csum_one_bio(root, inode, bio, - start, 1); - BUG_ON(ret); /* -ENOMEM */ - } - - ret = btrfs_map_bio(root, WRITE, bio, 0, 1); - BUG_ON(ret); /* -ENOMEM */ - - bio_put(bio); - - bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); - BUG_ON(!bio); - bio->bi_private = cb; - bio->bi_end_io = end_compressed_bio_write; - bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); - } - if (bytes_left < PAGE_CACHE_SIZE) { - printk("bytes left %lu compress len %lu nr %lu\n", - bytes_left, cb->compressed_len, cb->nr_pages); - } - bytes_left -= PAGE_CACHE_SIZE; - first_byte += PAGE_CACHE_SIZE; - cond_resched(); - } - bio_get(bio); - - ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); - BUG_ON(ret); /* -ENOMEM */ - - if (!skip_sum) { - ret = btrfs_csum_one_bio(root, inode, bio, start, 1); - BUG_ON(ret); /* -ENOMEM */ - } - - ret = btrfs_map_bio(root, WRITE, bio, 0, 1); - BUG_ON(ret); /* -ENOMEM */ - - bio_put(bio); - return 0; -} - -static noinline int add_ra_bio_pages(struct inode *inode, - u64 compressed_end, - struct compressed_bio *cb) -{ - unsigned long end_index; - unsigned long pg_index; - u64 last_offset; - u64 isize = i_size_read(inode); - int ret; - struct page *page; - unsigned long nr_pages = 0; - struct extent_map *em; - struct address_space *mapping = inode->i_mapping; - struct extent_map_tree *em_tree; - struct extent_io_tree *tree; - u64 end; - int misses = 0; - - page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; - last_offset = (page_offset(page) + PAGE_CACHE_SIZE); - em_tree = &BTRFS_I(inode)->extent_tree; - tree = &BTRFS_I(inode)->io_tree; - - if (isize == 0) - return 0; - - end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; - - while (last_offset < compressed_end) { - pg_index = last_offset >> PAGE_CACHE_SHIFT; - - if (pg_index > end_index) - break; - - rcu_read_lock(); - page = radix_tree_lookup(&mapping->page_tree, pg_index); - rcu_read_unlock(); - if (page) { - misses++; - if (misses > 4) - break; - goto next; - } - - page = __page_cache_alloc(mapping_gfp_mask(mapping) & - ~__GFP_FS); - if (!page) - break; - - if (add_to_page_cache_lru(page, mapping, pg_index, - GFP_NOFS)) { - page_cache_release(page); - goto next; - } - - end = last_offset + PAGE_CACHE_SIZE - 1; - /* - * at this point, we have a locked page in the page cache - * for these bytes in the file. But, we have to make - * sure they map to this compressed extent on disk. - */ - set_page_extent_mapped(page); - lock_extent(tree, last_offset, end); - read_lock(&em_tree->lock); - em = lookup_extent_mapping(em_tree, last_offset, - PAGE_CACHE_SIZE); - read_unlock(&em_tree->lock); - - if (!em || last_offset < em->start || - (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || - (em->block_start >> 9) != cb->orig_bio->bi_sector) { - free_extent_map(em); - unlock_extent(tree, last_offset, end); - unlock_page(page); - page_cache_release(page); - break; - } - free_extent_map(em); - - if (page->index == end_index) { - char *userpage; - size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); - - if (zero_offset) { - int zeros; - zeros = PAGE_CACHE_SIZE - zero_offset; - userpage = kmap_atomic(page); - memset(userpage + zero_offset, 0, zeros); - flush_dcache_page(page); - kunmap_atomic(userpage); - } - } - - ret = bio_add_page(cb->orig_bio, page, - PAGE_CACHE_SIZE, 0); - - if (ret == PAGE_CACHE_SIZE) { - nr_pages++; - page_cache_release(page); - } else { - unlock_extent(tree, last_offset, end); - unlock_page(page); - page_cache_release(page); - break; - } -next: - last_offset += PAGE_CACHE_SIZE; - } - return 0; -} - -/* - * for a compressed read, the bio we get passed has all the inode pages - * in it. We don't actually do IO on those pages but allocate new ones - * to hold the compressed pages on disk. - * - * bio->bi_sector points to the compressed extent on disk - * bio->bi_io_vec points to all of the inode pages - * bio->bi_vcnt is a count of pages - * - * After the compressed pages are read, we copy the bytes into the - * bio we were passed and then call the bio end_io calls - */ -int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, - int mirror_num, unsigned long bio_flags) -{ - struct extent_io_tree *tree; - struct extent_map_tree *em_tree; - struct compressed_bio *cb; - struct btrfs_root *root = BTRFS_I(inode)->root; - unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; - unsigned long compressed_len; - unsigned long nr_pages; - unsigned long pg_index; - struct page *page; - struct block_device *bdev; - struct bio *comp_bio; - u64 cur_disk_byte = (u64)bio->bi_sector << 9; - u64 em_len; - u64 em_start; - struct extent_map *em; - int ret = -ENOMEM; - u32 *sums; - - tree = &BTRFS_I(inode)->io_tree; - em_tree = &BTRFS_I(inode)->extent_tree; - - /* we need the actual starting offset of this extent in the file */ - read_lock(&em_tree->lock); - em = lookup_extent_mapping(em_tree, - page_offset(bio->bi_io_vec->bv_page), - PAGE_CACHE_SIZE); - read_unlock(&em_tree->lock); - if (!em) - return -EIO; - - compressed_len = em->block_len; - cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); - if (!cb) - goto out; - - atomic_set(&cb->pending_bios, 0); - cb->errors = 0; - cb->inode = inode; - cb->mirror_num = mirror_num; - sums = &cb->sums; - - cb->start = em->orig_start; - em_len = em->len; - em_start = em->start; - - free_extent_map(em); - em = NULL; - - cb->len = uncompressed_len; - cb->compressed_len = compressed_len; - cb->compress_type = extent_compress_type(bio_flags); - cb->orig_bio = bio; - - nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / - PAGE_CACHE_SIZE; - cb->compressed_pages = kzalloc(sizeof(struct page *) * nr_pages, - GFP_NOFS); - if (!cb->compressed_pages) - goto fail1; - - bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; - - for (pg_index = 0; pg_index < nr_pages; pg_index++) { - cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS | - __GFP_HIGHMEM); - if (!cb->compressed_pages[pg_index]) - goto fail2; - } - cb->nr_pages = nr_pages; - - add_ra_bio_pages(inode, em_start + em_len, cb); - - /* include any pages we added in add_ra-bio_pages */ - uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; - cb->len = uncompressed_len; - - comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); - if (!comp_bio) - goto fail2; - comp_bio->bi_private = cb; - comp_bio->bi_end_io = end_compressed_bio_read; - atomic_inc(&cb->pending_bios); - - for (pg_index = 0; pg_index < nr_pages; pg_index++) { - page = cb->compressed_pages[pg_index]; - page->mapping = inode->i_mapping; - page->index = em_start >> PAGE_CACHE_SHIFT; - - if (comp_bio->bi_size) - ret = tree->ops->merge_bio_hook(page, 0, - PAGE_CACHE_SIZE, - comp_bio, 0); - else - ret = 0; - - page->mapping = NULL; - if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < - PAGE_CACHE_SIZE) { - bio_get(comp_bio); - - ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); - BUG_ON(ret); /* -ENOMEM */ - - /* - * inc the count before we submit the bio so - * we know the end IO handler won't happen before - * we inc the count. Otherwise, the cb might get - * freed before we're done setting it up - */ - atomic_inc(&cb->pending_bios); - - if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { - ret = btrfs_lookup_bio_sums(root, inode, - comp_bio, sums); - BUG_ON(ret); /* -ENOMEM */ - } - sums += (comp_bio->bi_size + root->sectorsize - 1) / - root->sectorsize; - - ret = btrfs_map_bio(root, READ, comp_bio, - mirror_num, 0); - BUG_ON(ret); /* -ENOMEM */ - - bio_put(comp_bio); - - comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, - GFP_NOFS); - BUG_ON(!comp_bio); - comp_bio->bi_private = cb; - comp_bio->bi_end_io = end_compressed_bio_read; - - bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0); - } - cur_disk_byte += PAGE_CACHE_SIZE; - } - bio_get(comp_bio); - - ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); - BUG_ON(ret); /* -ENOMEM */ - - if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { - ret = btrfs_lookup_bio_sums(root, inode, comp_bio, sums); - BUG_ON(ret); /* -ENOMEM */ - } - - ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0); - BUG_ON(ret); /* -ENOMEM */ - - bio_put(comp_bio); - return 0; - -fail2: - for (pg_index = 0; pg_index < nr_pages; pg_index++) - free_page((unsigned long)cb->compressed_pages[pg_index]); - - kfree(cb->compressed_pages); -fail1: - kfree(cb); -out: - free_extent_map(em); - return ret; -} - -static struct list_head comp_idle_workspace[BTRFS_COMPRESS_TYPES]; -static spinlock_t comp_workspace_lock[BTRFS_COMPRESS_TYPES]; -static int comp_num_workspace[BTRFS_COMPRESS_TYPES]; -static atomic_t comp_alloc_workspace[BTRFS_COMPRESS_TYPES]; -static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES]; - -struct btrfs_compress_op *btrfs_compress_op[] = { - &btrfs_zlib_compress, - &btrfs_lzo_compress, -}; - -void __init btrfs_init_compress(void) -{ - int i; - - for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { - INIT_LIST_HEAD(&comp_idle_workspace[i]); - spin_lock_init(&comp_workspace_lock[i]); - atomic_set(&comp_alloc_workspace[i], 0); - init_waitqueue_head(&comp_workspace_wait[i]); - } -} - -/* - * this finds an available workspace or allocates a new one - * ERR_PTR is returned if things go bad. - */ -static struct list_head *find_workspace(int type) -{ - struct list_head *workspace; - int cpus = num_online_cpus(); - int idx = type - 1; - - struct list_head *idle_workspace = &comp_idle_workspace[idx]; - spinlock_t *workspace_lock = &comp_workspace_lock[idx]; - atomic_t *alloc_workspace = &comp_alloc_workspace[idx]; - wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx]; - int *num_workspace = &comp_num_workspace[idx]; -again: - spin_lock(workspace_lock); - if (!list_empty(idle_workspace)) { - workspace = idle_workspace->next; - list_del(workspace); - (*num_workspace)--; - spin_unlock(workspace_lock); - return workspace; - - } - if (atomic_read(alloc_workspace) > cpus) { - DEFINE_WAIT(wait); - - spin_unlock(workspace_lock); - prepare_to_wait(workspace_wait, &wait, TASK_UNINTERRUPTIBLE); - if (atomic_read(alloc_workspace) > cpus && !*num_workspace) - schedule(); - finish_wait(workspace_wait, &wait); - goto again; - } - atomic_inc(alloc_workspace); - spin_unlock(workspace_lock); - - workspace = btrfs_compress_op[idx]->alloc_workspace(); - if (IS_ERR(workspace)) { - atomic_dec(alloc_workspace); - wake_up(workspace_wait); - } - return workspace; -} - -/* - * put a workspace struct back on the list or free it if we have enough - * idle ones sitting around - */ -static void free_workspace(int type, struct list_head *workspace) -{ - int idx = type - 1; - struct list_head *idle_workspace = &comp_idle_workspace[idx]; - spinlock_t *workspace_lock = &comp_workspace_lock[idx]; - atomic_t *alloc_workspace = &comp_alloc_workspace[idx]; - wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx]; - int *num_workspace = &comp_num_workspace[idx]; - - spin_lock(workspace_lock); - if (*num_workspace < num_online_cpus()) { - list_add_tail(workspace, idle_workspace); - (*num_workspace)++; - spin_unlock(workspace_lock); - goto wake; - } - spin_unlock(workspace_lock); - - btrfs_compress_op[idx]->free_workspace(workspace); - atomic_dec(alloc_workspace); -wake: - if (waitqueue_active(workspace_wait)) - wake_up(workspace_wait); -} - -/* - * cleanup function for module exit - */ -static void free_workspaces(void) -{ - struct list_head *workspace; - int i; - - for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { - while (!list_empty(&comp_idle_workspace[i])) { - workspace = comp_idle_workspace[i].next; - list_del(workspace); - btrfs_compress_op[i]->free_workspace(workspace); - atomic_dec(&comp_alloc_workspace[i]); - } - } -} - -/* - * given an address space and start/len, compress the bytes. - * - * pages are allocated to hold the compressed result and stored - * in 'pages' - * - * out_pages is used to return the number of pages allocated. There - * may be pages allocated even if we return an error - * - * total_in is used to return the number of bytes actually read. It - * may be smaller then len if we had to exit early because we - * ran out of room in the pages array or because we cross the - * max_out threshold. - * - * total_out is used to return the total number of compressed bytes - * - * max_out tells us the max number of bytes that we're allowed to - * stuff into pages - */ -int btrfs_compress_pages(int type, struct address_space *mapping, - u64 start, unsigned long len, - struct page **pages, - unsigned long nr_dest_pages, - unsigned long *out_pages, - unsigned long *total_in, - unsigned long *total_out, - unsigned long max_out) -{ - struct list_head *workspace; - int ret; - - workspace = find_workspace(type); - if (IS_ERR(workspace)) - return -1; - - ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping, - start, len, pages, - nr_dest_pages, out_pages, - total_in, total_out, - max_out); - free_workspace(type, workspace); - return ret; -} - -/* - * pages_in is an array of pages with compressed data. - * - * disk_start is the starting logical offset of this array in the file - * - * bvec is a bio_vec of pages from the file that we want to decompress into - * - * vcnt is the count of pages in the biovec - * - * srclen is the number of bytes in pages_in - * - * The basic idea is that we have a bio that was created by readpages. - * The pages in the bio are for the uncompressed data, and they may not - * be contiguous. They all correspond to the range of bytes covered by - * the compressed extent. - */ -int btrfs_decompress_biovec(int type, struct page **pages_in, u64 disk_start, - struct bio_vec *bvec, int vcnt, size_t srclen) -{ - struct list_head *workspace; - int ret; - - workspace = find_workspace(type); - if (IS_ERR(workspace)) - return -ENOMEM; - - ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in, - disk_start, - bvec, vcnt, srclen); - free_workspace(type, workspace); - return ret; -} - -/* - * a less complex decompression routine. Our compressed data fits in a - * single page, and we want to read a single page out of it. - * start_byte tells us the offset into the compressed data we're interested in - */ -int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, - unsigned long start_byte, size_t srclen, size_t destlen) -{ - struct list_head *workspace; - int ret; - - workspace = find_workspace(type); - if (IS_ERR(workspace)) - return -ENOMEM; - - ret = btrfs_compress_op[type-1]->decompress(workspace, data_in, - dest_page, start_byte, - srclen, destlen); - - free_workspace(type, workspace); - return ret; -} - -void btrfs_exit_compress(void) -{ - free_workspaces(); -} - -/* - * Copy uncompressed data from working buffer to pages. - * - * buf_start is the byte offset we're of the start of our workspace buffer. - * - * total_out is the last byte of the buffer - */ -int btrfs_decompress_buf2page(char *buf, unsigned long buf_start, - unsigned long total_out, u64 disk_start, - struct bio_vec *bvec, int vcnt, - unsigned long *pg_index, - unsigned long *pg_offset) -{ - unsigned long buf_offset; - unsigned long current_buf_start; - unsigned long start_byte; - unsigned long working_bytes = total_out - buf_start; - unsigned long bytes; - char *kaddr; - struct page *page_out = bvec[*pg_index].bv_page; - - /* - * start byte is the first byte of the page we're currently - * copying into relative to the start of the compressed data. - */ - start_byte = page_offset(page_out) - disk_start; - - /* we haven't yet hit data corresponding to this page */ - if (total_out <= start_byte) - return 1; - - /* - * the start of the data we care about is offset into - * the middle of our working buffer - */ - if (total_out > start_byte && buf_start < start_byte) { - buf_offset = start_byte - buf_start; - working_bytes -= buf_offset; - } else { - buf_offset = 0; - } - current_buf_start = buf_start; - - /* copy bytes from the working buffer into the pages */ - while (working_bytes > 0) { - bytes = min(PAGE_CACHE_SIZE - *pg_offset, - PAGE_CACHE_SIZE - buf_offset); - bytes = min(bytes, working_bytes); - kaddr = kmap_atomic(page_out); - memcpy(kaddr + *pg_offset, buf + buf_offset, bytes); - kunmap_atomic(kaddr); - flush_dcache_page(page_out); - - *pg_offset += bytes; - buf_offset += bytes; - working_bytes -= bytes; - current_buf_start += bytes; - - /* check if we need to pick another page */ - if (*pg_offset == PAGE_CACHE_SIZE) { - (*pg_index)++; - if (*pg_index >= vcnt) - return 0; - - page_out = bvec[*pg_index].bv_page; - *pg_offset = 0; - start_byte = page_offset(page_out) - disk_start; - - /* - * make sure our new page is covered by this - * working buffer - */ - if (total_out <= start_byte) - return 1; - - /* - * the next page in the biovec might not be adjacent - * to the last page, but it might still be found - * inside this working buffer. bump our offset pointer - */ - if (total_out > start_byte && - current_buf_start < start_byte) { - buf_offset = start_byte - buf_start; - working_bytes = total_out - start_byte; - current_buf_start = buf_start + buf_offset; - } - } - } - - return 1; -} |