diff options
Diffstat (limited to 'fs/btrfs/compression.c')
-rw-r--r-- | fs/btrfs/compression.c | 169 |
1 files changed, 103 insertions, 66 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 3346cd8f9910..658c39b70fba 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -119,7 +119,7 @@ static int check_compressed_csum(struct inode *inode, csum = ~(u32)0; kaddr = kmap_atomic(page); - csum = btrfs_csum_data(kaddr, csum, PAGE_CACHE_SIZE); + csum = btrfs_csum_data(kaddr, csum, PAGE_SIZE); btrfs_csum_final(csum, (char *)&csum); kunmap_atomic(kaddr); @@ -190,7 +190,7 @@ csum_failed: for (index = 0; index < cb->nr_pages; index++) { page = cb->compressed_pages[index]; page->mapping = NULL; - page_cache_release(page); + put_page(page); } /* do io completion on the original bio */ @@ -224,8 +224,8 @@ out: static noinline void end_compressed_writeback(struct inode *inode, const struct compressed_bio *cb) { - unsigned long index = cb->start >> PAGE_CACHE_SHIFT; - unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_CACHE_SHIFT; + unsigned long index = cb->start >> PAGE_SHIFT; + unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_SHIFT; struct page *pages[16]; unsigned long nr_pages = end_index - index + 1; int i; @@ -247,7 +247,7 @@ static noinline void end_compressed_writeback(struct inode *inode, if (cb->errors) SetPageError(pages[i]); end_page_writeback(pages[i]); - page_cache_release(pages[i]); + put_page(pages[i]); } nr_pages -= ret; index += ret; @@ -304,7 +304,7 @@ static void end_compressed_bio_write(struct bio *bio) for (index = 0; index < cb->nr_pages; index++) { page = cb->compressed_pages[index]; page->mapping = NULL; - page_cache_release(page); + put_page(page); } /* finally free the cb struct */ @@ -341,7 +341,7 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start, int ret; int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM; - WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); + WARN_ON(start & ((u64)PAGE_SIZE - 1)); cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); if (!cb) return -ENOMEM; @@ -374,14 +374,14 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start, page->mapping = inode->i_mapping; if (bio->bi_iter.bi_size) ret = io_tree->ops->merge_bio_hook(WRITE, page, 0, - PAGE_CACHE_SIZE, + PAGE_SIZE, bio, 0); else ret = 0; page->mapping = NULL; - if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < - PAGE_CACHE_SIZE) { + if (ret || bio_add_page(bio, page, PAGE_SIZE, 0) < + PAGE_SIZE) { bio_get(bio); /* @@ -410,15 +410,15 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start, BUG_ON(!bio); bio->bi_private = cb; bio->bi_end_io = end_compressed_bio_write; - bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); + bio_add_page(bio, page, PAGE_SIZE, 0); } - if (bytes_left < PAGE_CACHE_SIZE) { + if (bytes_left < PAGE_SIZE) { btrfs_info(BTRFS_I(inode)->root->fs_info, "bytes left %lu compress len %lu nr %lu", bytes_left, cb->compressed_len, cb->nr_pages); } - bytes_left -= PAGE_CACHE_SIZE; - first_byte += PAGE_CACHE_SIZE; + bytes_left -= PAGE_SIZE; + first_byte += PAGE_SIZE; cond_resched(); } bio_get(bio); @@ -457,17 +457,17 @@ static noinline int add_ra_bio_pages(struct inode *inode, 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); + last_offset = (page_offset(page) + PAGE_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; + end_index = (i_size_read(inode) - 1) >> PAGE_SHIFT; while (last_offset < compressed_end) { - pg_index = last_offset >> PAGE_CACHE_SHIFT; + pg_index = last_offset >> PAGE_SHIFT; if (pg_index > end_index) break; @@ -488,11 +488,11 @@ static noinline int add_ra_bio_pages(struct inode *inode, break; if (add_to_page_cache_lru(page, mapping, pg_index, GFP_NOFS)) { - page_cache_release(page); + put_page(page); goto next; } - end = last_offset + PAGE_CACHE_SIZE - 1; + end = last_offset + PAGE_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 @@ -502,27 +502,27 @@ static noinline int add_ra_bio_pages(struct inode *inode, lock_extent(tree, last_offset, end); read_lock(&em_tree->lock); em = lookup_extent_mapping(em_tree, last_offset, - PAGE_CACHE_SIZE); + PAGE_SIZE); read_unlock(&em_tree->lock); if (!em || last_offset < em->start || - (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || + (last_offset + PAGE_SIZE > extent_map_end(em)) || (em->block_start >> 9) != cb->orig_bio->bi_iter.bi_sector) { free_extent_map(em); unlock_extent(tree, last_offset, end); unlock_page(page); - page_cache_release(page); + put_page(page); break; } free_extent_map(em); if (page->index == end_index) { char *userpage; - size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); + size_t zero_offset = isize & (PAGE_SIZE - 1); if (zero_offset) { int zeros; - zeros = PAGE_CACHE_SIZE - zero_offset; + zeros = PAGE_SIZE - zero_offset; userpage = kmap_atomic(page); memset(userpage + zero_offset, 0, zeros); flush_dcache_page(page); @@ -531,19 +531,19 @@ static noinline int add_ra_bio_pages(struct inode *inode, } ret = bio_add_page(cb->orig_bio, page, - PAGE_CACHE_SIZE, 0); + PAGE_SIZE, 0); - if (ret == PAGE_CACHE_SIZE) { + if (ret == PAGE_SIZE) { nr_pages++; - page_cache_release(page); + put_page(page); } else { unlock_extent(tree, last_offset, end); unlock_page(page); - page_cache_release(page); + put_page(page); break; } next: - last_offset += PAGE_CACHE_SIZE; + last_offset += PAGE_SIZE; } return 0; } @@ -567,7 +567,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, 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 uncompressed_len = bio->bi_vcnt * PAGE_SIZE; unsigned long compressed_len; unsigned long nr_pages; unsigned long pg_index; @@ -589,7 +589,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, read_lock(&em_tree->lock); em = lookup_extent_mapping(em_tree, page_offset(bio->bi_io_vec->bv_page), - PAGE_CACHE_SIZE); + PAGE_SIZE); read_unlock(&em_tree->lock); if (!em) return -EIO; @@ -617,7 +617,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, cb->compress_type = extent_compress_type(bio_flags); cb->orig_bio = bio; - nr_pages = DIV_ROUND_UP(compressed_len, PAGE_CACHE_SIZE); + nr_pages = DIV_ROUND_UP(compressed_len, PAGE_SIZE); cb->compressed_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); if (!cb->compressed_pages) @@ -640,7 +640,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, 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; + uncompressed_len = bio->bi_vcnt * PAGE_SIZE; cb->len = uncompressed_len; comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); @@ -653,18 +653,18 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, 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; + page->index = em_start >> PAGE_SHIFT; if (comp_bio->bi_iter.bi_size) ret = tree->ops->merge_bio_hook(READ, page, 0, - PAGE_CACHE_SIZE, + PAGE_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) { + if (ret || bio_add_page(comp_bio, page, PAGE_SIZE, 0) < + PAGE_SIZE) { bio_get(comp_bio); ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, @@ -702,9 +702,9 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *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); + bio_add_page(comp_bio, page, PAGE_SIZE, 0); } - cur_disk_byte += PAGE_CACHE_SIZE; + cur_disk_byte += PAGE_SIZE; } bio_get(comp_bio); @@ -743,8 +743,11 @@ out: static struct { struct list_head idle_ws; spinlock_t ws_lock; - int num_ws; - atomic_t alloc_ws; + /* Number of free workspaces */ + int free_ws; + /* Total number of allocated workspaces */ + atomic_t total_ws; + /* Waiters for a free workspace */ wait_queue_head_t ws_wait; } btrfs_comp_ws[BTRFS_COMPRESS_TYPES]; @@ -758,16 +761,34 @@ void __init btrfs_init_compress(void) int i; for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { + struct list_head *workspace; + INIT_LIST_HEAD(&btrfs_comp_ws[i].idle_ws); spin_lock_init(&btrfs_comp_ws[i].ws_lock); - atomic_set(&btrfs_comp_ws[i].alloc_ws, 0); + atomic_set(&btrfs_comp_ws[i].total_ws, 0); init_waitqueue_head(&btrfs_comp_ws[i].ws_wait); + + /* + * Preallocate one workspace for each compression type so + * we can guarantee forward progress in the worst case + */ + workspace = btrfs_compress_op[i]->alloc_workspace(); + if (IS_ERR(workspace)) { + printk(KERN_WARNING + "BTRFS: cannot preallocate compression workspace, will try later"); + } else { + atomic_set(&btrfs_comp_ws[i].total_ws, 1); + btrfs_comp_ws[i].free_ws = 1; + list_add(workspace, &btrfs_comp_ws[i].idle_ws); + } } } /* - * this finds an available workspace or allocates a new one - * ERR_PTR is returned if things go bad. + * This finds an available workspace or allocates a new one. + * If it's not possible to allocate a new one, waits until there's one. + * Preallocation makes a forward progress guarantees and we do not return + * errors. */ static struct list_head *find_workspace(int type) { @@ -777,36 +798,58 @@ static struct list_head *find_workspace(int type) struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws; spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock; - atomic_t *alloc_ws = &btrfs_comp_ws[idx].alloc_ws; + atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws; wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait; - int *num_ws = &btrfs_comp_ws[idx].num_ws; + int *free_ws = &btrfs_comp_ws[idx].free_ws; again: spin_lock(ws_lock); if (!list_empty(idle_ws)) { workspace = idle_ws->next; list_del(workspace); - (*num_ws)--; + (*free_ws)--; spin_unlock(ws_lock); return workspace; } - if (atomic_read(alloc_ws) > cpus) { + if (atomic_read(total_ws) > cpus) { DEFINE_WAIT(wait); spin_unlock(ws_lock); prepare_to_wait(ws_wait, &wait, TASK_UNINTERRUPTIBLE); - if (atomic_read(alloc_ws) > cpus && !*num_ws) + if (atomic_read(total_ws) > cpus && !*free_ws) schedule(); finish_wait(ws_wait, &wait); goto again; } - atomic_inc(alloc_ws); + atomic_inc(total_ws); spin_unlock(ws_lock); workspace = btrfs_compress_op[idx]->alloc_workspace(); if (IS_ERR(workspace)) { - atomic_dec(alloc_ws); + atomic_dec(total_ws); wake_up(ws_wait); + + /* + * Do not return the error but go back to waiting. There's a + * workspace preallocated for each type and the compression + * time is bounded so we get to a workspace eventually. This + * makes our caller's life easier. + * + * To prevent silent and low-probability deadlocks (when the + * initial preallocation fails), check if there are any + * workspaces at all. + */ + if (atomic_read(total_ws) == 0) { + static DEFINE_RATELIMIT_STATE(_rs, + /* once per minute */ 60 * HZ, + /* no burst */ 1); + + if (__ratelimit(&_rs)) { + printk(KERN_WARNING + "no compression workspaces, low memory, retrying"); + } + } + goto again; } return workspace; } @@ -820,21 +863,21 @@ static void free_workspace(int type, struct list_head *workspace) int idx = type - 1; struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws; spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock; - atomic_t *alloc_ws = &btrfs_comp_ws[idx].alloc_ws; + atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws; wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait; - int *num_ws = &btrfs_comp_ws[idx].num_ws; + int *free_ws = &btrfs_comp_ws[idx].free_ws; spin_lock(ws_lock); - if (*num_ws < num_online_cpus()) { + if (*free_ws < num_online_cpus()) { list_add(workspace, idle_ws); - (*num_ws)++; + (*free_ws)++; spin_unlock(ws_lock); goto wake; } spin_unlock(ws_lock); btrfs_compress_op[idx]->free_workspace(workspace); - atomic_dec(alloc_ws); + atomic_dec(total_ws); wake: /* * Make sure counter is updated before we wake up waiters. @@ -857,7 +900,7 @@ static void free_workspaces(void) workspace = btrfs_comp_ws[i].idle_ws.next; list_del(workspace); btrfs_compress_op[i]->free_workspace(workspace); - atomic_dec(&btrfs_comp_ws[i].alloc_ws); + atomic_dec(&btrfs_comp_ws[i].total_ws); } } } @@ -894,8 +937,6 @@ int btrfs_compress_pages(int type, struct address_space *mapping, int ret; workspace = find_workspace(type); - if (IS_ERR(workspace)) - return PTR_ERR(workspace); ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping, start, len, pages, @@ -930,8 +971,6 @@ static int btrfs_decompress_biovec(int type, struct page **pages_in, int ret; workspace = find_workspace(type); - if (IS_ERR(workspace)) - return PTR_ERR(workspace); ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in, disk_start, @@ -952,8 +991,6 @@ int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, int ret; workspace = find_workspace(type); - if (IS_ERR(workspace)) - return PTR_ERR(workspace); ret = btrfs_compress_op[type-1]->decompress(workspace, data_in, dest_page, start_byte, @@ -1013,8 +1050,8 @@ int btrfs_decompress_buf2page(char *buf, unsigned long 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(PAGE_SIZE - *pg_offset, + PAGE_SIZE - buf_offset); bytes = min(bytes, working_bytes); kaddr = kmap_atomic(page_out); memcpy(kaddr + *pg_offset, buf + buf_offset, bytes); @@ -1027,7 +1064,7 @@ int btrfs_decompress_buf2page(char *buf, unsigned long buf_start, current_buf_start += bytes; /* check if we need to pick another page */ - if (*pg_offset == PAGE_CACHE_SIZE) { + if (*pg_offset == PAGE_SIZE) { (*pg_index)++; if (*pg_index >= vcnt) return 0; |