From: Josef Bacik Date: Wed, 14 Aug 2013 18:02:47 +0000 (-0400) Subject: Btrfs: avoid starting a transaction in the write path X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=00361589d2eebd90fca022148c763e40d3e90871;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git Btrfs: avoid starting a transaction in the write path I noticed while looking at a deadlock that we are always starting a transaction in cow_file_range(). This isn't really needed since we only need a transaction if we are doing an inline extent, or if the allocator needs to allocate a chunk. So push down all the transaction start stuff to be closer to where we actually need a transaction in all of these cases. This will hopefully reduce our write latency when we are committing often. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 063e48587126..7c93d9f13812 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3165,11 +3165,9 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 root_objectid, u64 owner, u64 offset, struct btrfs_key *ins); -int btrfs_reserve_extent(struct btrfs_trans_handle *trans, - struct btrfs_root *root, - u64 num_bytes, u64 min_alloc_size, - u64 empty_size, u64 hint_byte, - struct btrfs_key *ins, int is_data); +int btrfs_reserve_extent(struct btrfs_root *root, u64 num_bytes, + u64 min_alloc_size, u64 empty_size, u64 hint_byte, + struct btrfs_key *ins, int is_data); int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, int full_backref, int for_cow); int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, @@ -3612,8 +3610,7 @@ void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work); struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page, size_t pg_offset, u64 start, u64 len, int create); -noinline int can_nocow_extent(struct btrfs_trans_handle *trans, - struct inode *inode, u64 offset, u64 *len, +noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len, u64 *orig_start, u64 *orig_block_len, u64 *ram_bytes); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 277d2c26b034..f1c1694d34b7 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -6121,8 +6121,7 @@ enum btrfs_loop_type { * ins->offset == number of blocks * Any available blocks before search_start are skipped. */ -static noinline int find_free_extent(struct btrfs_trans_handle *trans, - struct btrfs_root *orig_root, +static noinline int find_free_extent(struct btrfs_root *orig_root, u64 num_bytes, u64 empty_size, u64 hint_byte, struct btrfs_key *ins, u64 flags) @@ -6345,10 +6344,10 @@ refill_cluster: block_group->full_stripe_len); /* allocate a cluster in this block group */ - ret = btrfs_find_space_cluster(trans, root, - block_group, last_ptr, - search_start, num_bytes, - aligned_cluster); + ret = btrfs_find_space_cluster(root, block_group, + last_ptr, search_start, + num_bytes, + aligned_cluster); if (ret == 0) { /* * now pull our allocation out of this @@ -6479,17 +6478,28 @@ loop: index = 0; loop++; if (loop == LOOP_ALLOC_CHUNK) { + struct btrfs_trans_handle *trans; + + trans = btrfs_join_transaction(root); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out; + } + ret = do_chunk_alloc(trans, root, flags, CHUNK_ALLOC_FORCE); /* * Do not bail out on ENOSPC since we * can do more things. */ - if (ret < 0 && ret != -ENOSPC) { + if (ret < 0 && ret != -ENOSPC) btrfs_abort_transaction(trans, root, ret); + else + ret = 0; + btrfs_end_transaction(trans, root); + if (ret) goto out; - } } if (loop == LOOP_NO_EMPTY_SIZE) { @@ -6553,8 +6563,7 @@ again: up_read(&info->groups_sem); } -int btrfs_reserve_extent(struct btrfs_trans_handle *trans, - struct btrfs_root *root, +int btrfs_reserve_extent(struct btrfs_root *root, u64 num_bytes, u64 min_alloc_size, u64 empty_size, u64 hint_byte, struct btrfs_key *ins, int is_data) @@ -6566,8 +6575,8 @@ int btrfs_reserve_extent(struct btrfs_trans_handle *trans, flags = btrfs_get_alloc_profile(root, is_data); again: WARN_ON(num_bytes < root->sectorsize); - ret = find_free_extent(trans, root, num_bytes, empty_size, - hint_byte, ins, flags); + ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins, + flags); if (ret == -ENOSPC) { if (!final_tried) { @@ -6955,7 +6964,7 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans, if (IS_ERR(block_rsv)) return ERR_CAST(block_rsv); - ret = btrfs_reserve_extent(trans, root, blocksize, blocksize, + ret = btrfs_reserve_extent(root, blocksize, blocksize, empty_size, hint, &ins, 0); if (ret) { unuse_block_rsv(root->fs_info, block_rsv, blocksize); diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 8cc941e5b3e1..5e7ea996f105 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1339,7 +1339,6 @@ fail: static noinline int check_can_nocow(struct inode *inode, loff_t pos, size_t *write_bytes) { - struct btrfs_trans_handle *trans; struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_ordered_extent *ordered; u64 lockstart, lockend; @@ -1361,16 +1360,8 @@ static noinline int check_can_nocow(struct inode *inode, loff_t pos, btrfs_put_ordered_extent(ordered); } - trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) { - unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend); - return PTR_ERR(trans); - } - num_bytes = lockend - lockstart + 1; - ret = can_nocow_extent(trans, inode, lockstart, &num_bytes, NULL, NULL, - NULL); - btrfs_end_transaction(trans, root); + ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL); if (ret <= 0) { ret = 0; } else { diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index b21a3cd667d8..25f906fd0221 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -2525,8 +2525,7 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group, * returns zero and sets up cluster if things worked out, otherwise * it returns -enospc */ -int btrfs_find_space_cluster(struct btrfs_trans_handle *trans, - struct btrfs_root *root, +int btrfs_find_space_cluster(struct btrfs_root *root, struct btrfs_block_group_cache *block_group, struct btrfs_free_cluster *cluster, u64 offset, u64 bytes, u64 empty_size) diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h index 894116b71304..4acfb19ba4ee 100644 --- a/fs/btrfs/free-space-cache.h +++ b/fs/btrfs/free-space-cache.h @@ -98,8 +98,7 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group, u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root); void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, u64 bytes); -int btrfs_find_space_cluster(struct btrfs_trans_handle *trans, - struct btrfs_root *root, +int btrfs_find_space_cluster(struct btrfs_root *root, struct btrfs_block_group_cache *block_group, struct btrfs_free_cluster *cluster, u64 offset, u64 bytes, u64 empty_size); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index de7085bc28f6..264feefa0290 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -230,12 +230,13 @@ fail: * does the checks required to make sure the data is small enough * to fit as an inline extent. */ -static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans, - struct btrfs_root *root, - struct inode *inode, u64 start, u64 end, - size_t compressed_size, int compress_type, - struct page **compressed_pages) +static noinline int cow_file_range_inline(struct btrfs_root *root, + struct inode *inode, u64 start, + u64 end, size_t compressed_size, + int compress_type, + struct page **compressed_pages) { + struct btrfs_trans_handle *trans; u64 isize = i_size_read(inode); u64 actual_end = min(end + 1, isize); u64 inline_len = actual_end - start; @@ -256,9 +257,16 @@ static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans, return 1; } + trans = btrfs_join_transaction(root); + if (IS_ERR(trans)) + return PTR_ERR(trans); + trans->block_rsv = &root->fs_info->delalloc_block_rsv; + ret = btrfs_drop_extents(trans, root, inode, start, aligned_end, 1); - if (ret) - return ret; + if (ret) { + btrfs_abort_transaction(trans, root, ret); + goto out; + } if (isize > actual_end) inline_len = min_t(u64, isize, actual_end); @@ -267,15 +275,18 @@ static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans, compress_type, compressed_pages); if (ret && ret != -ENOSPC) { btrfs_abort_transaction(trans, root, ret); - return ret; + goto out; } else if (ret == -ENOSPC) { - return 1; + ret = 1; + goto out; } set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags); btrfs_delalloc_release_metadata(inode, end + 1 - start); btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0); - return 0; +out: + btrfs_end_transaction(trans, root); + return ret; } struct async_extent { @@ -343,7 +354,6 @@ static noinline int compress_file_range(struct inode *inode, int *num_added) { struct btrfs_root *root = BTRFS_I(inode)->root; - struct btrfs_trans_handle *trans; u64 num_bytes; u64 blocksize = root->sectorsize; u64 actual_end; @@ -461,25 +471,16 @@ again: } cont: if (start == 0) { - trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) { - ret = PTR_ERR(trans); - trans = NULL; - goto cleanup_and_out; - } - trans->block_rsv = &root->fs_info->delalloc_block_rsv; - /* lets try to make an inline extent */ if (ret || total_in < (actual_end - start)) { /* we didn't compress the entire range, try * to make an uncompressed inline extent. */ - ret = cow_file_range_inline(trans, root, inode, - start, end, 0, 0, NULL); + ret = cow_file_range_inline(root, inode, start, end, + 0, 0, NULL); } else { /* try making a compressed inline extent */ - ret = cow_file_range_inline(trans, root, inode, - start, end, + ret = cow_file_range_inline(root, inode, start, end, total_compressed, compress_type, pages); } @@ -498,10 +499,8 @@ cont: PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK); - btrfs_end_transaction(trans, root); goto free_pages_out; } - btrfs_end_transaction(trans, root); } if (will_compress) { @@ -592,18 +591,6 @@ free_pages_out: kfree(pages); goto out; - -cleanup_and_out: - extent_clear_unlock_delalloc(inode, start, end, NULL, - EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | - EXTENT_DEFRAG, PAGE_UNLOCK | - PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK | - PAGE_END_WRITEBACK); - if (!trans || IS_ERR(trans)) - btrfs_error(root->fs_info, ret, "Failed to join transaction"); - else - btrfs_abort_transaction(trans, root, ret); - goto free_pages_out; } /* @@ -617,7 +604,6 @@ static noinline int submit_compressed_extents(struct inode *inode, { struct async_extent *async_extent; u64 alloc_hint = 0; - struct btrfs_trans_handle *trans; struct btrfs_key ins; struct extent_map *em; struct btrfs_root *root = BTRFS_I(inode)->root; @@ -678,20 +664,10 @@ retry: lock_extent(io_tree, async_extent->start, async_extent->start + async_extent->ram_size - 1); - trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) { - ret = PTR_ERR(trans); - } else { - trans->block_rsv = &root->fs_info->delalloc_block_rsv; - ret = btrfs_reserve_extent(trans, root, + ret = btrfs_reserve_extent(root, async_extent->compressed_size, async_extent->compressed_size, 0, alloc_hint, &ins, 1); - if (ret && ret != -ENOSPC) - btrfs_abort_transaction(trans, root, ret); - btrfs_end_transaction(trans, root); - } - if (ret) { int i; @@ -850,14 +826,13 @@ static u64 get_extent_allocation_hint(struct inode *inode, u64 start, * required to start IO on it. It may be clean and already done with * IO when we return. */ -static noinline int __cow_file_range(struct btrfs_trans_handle *trans, - struct inode *inode, - struct btrfs_root *root, - struct page *locked_page, - u64 start, u64 end, int *page_started, - unsigned long *nr_written, - int unlock) +static noinline int cow_file_range(struct inode *inode, + struct page *locked_page, + u64 start, u64 end, int *page_started, + unsigned long *nr_written, + int unlock) { + struct btrfs_root *root = BTRFS_I(inode)->root; u64 alloc_hint = 0; u64 num_bytes; unsigned long ram_size; @@ -878,12 +853,12 @@ static noinline int __cow_file_range(struct btrfs_trans_handle *trans, /* if this is a small write inside eof, kick off defrag */ if (num_bytes < 64 * 1024 && (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size)) - btrfs_add_inode_defrag(trans, inode); + btrfs_add_inode_defrag(NULL, inode); if (start == 0) { /* lets try to make an inline extent */ - ret = cow_file_range_inline(trans, root, inode, - start, end, 0, 0, NULL); + ret = cow_file_range_inline(root, inode, start, end, 0, 0, + NULL); if (ret == 0) { extent_clear_unlock_delalloc(inode, start, end, NULL, EXTENT_LOCKED | EXTENT_DELALLOC | @@ -896,7 +871,6 @@ static noinline int __cow_file_range(struct btrfs_trans_handle *trans, *page_started = 1; goto out; } else if (ret < 0) { - btrfs_abort_transaction(trans, root, ret); goto out_unlock; } } @@ -911,13 +885,11 @@ static noinline int __cow_file_range(struct btrfs_trans_handle *trans, unsigned long op; cur_alloc_size = disk_num_bytes; - ret = btrfs_reserve_extent(trans, root, cur_alloc_size, + ret = btrfs_reserve_extent(root, cur_alloc_size, root->sectorsize, 0, alloc_hint, &ins, 1); - if (ret < 0) { - btrfs_abort_transaction(trans, root, ret); + if (ret < 0) goto out_unlock; - } em = alloc_extent_map(); if (!em) { @@ -963,10 +935,8 @@ static noinline int __cow_file_range(struct btrfs_trans_handle *trans, BTRFS_DATA_RELOC_TREE_OBJECTID) { ret = btrfs_reloc_clone_csums(inode, start, cur_alloc_size); - if (ret) { - btrfs_abort_transaction(trans, root, ret); + if (ret) goto out_reserve; - } } if (disk_num_bytes < cur_alloc_size) @@ -1005,37 +975,6 @@ out_unlock: goto out; } -static noinline int cow_file_range(struct inode *inode, - struct page *locked_page, - u64 start, u64 end, int *page_started, - unsigned long *nr_written, - int unlock) -{ - struct btrfs_trans_handle *trans; - struct btrfs_root *root = BTRFS_I(inode)->root; - int ret; - - trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) { - extent_clear_unlock_delalloc(inode, start, end, locked_page, - EXTENT_LOCKED | EXTENT_DELALLOC | - EXTENT_DO_ACCOUNTING | - EXTENT_DEFRAG, PAGE_UNLOCK | - PAGE_CLEAR_DIRTY | - PAGE_SET_WRITEBACK | - PAGE_END_WRITEBACK); - return PTR_ERR(trans); - } - trans->block_rsv = &root->fs_info->delalloc_block_rsv; - - ret = __cow_file_range(trans, inode, root, locked_page, start, end, - page_started, nr_written, unlock); - - btrfs_end_transaction(trans, root); - - return ret; -} - /* * work queue call back to started compression on a file and pages */ @@ -1347,9 +1286,9 @@ out_check: btrfs_release_path(path); if (cow_start != (u64)-1) { - ret = __cow_file_range(trans, inode, root, locked_page, - cow_start, found_key.offset - 1, - page_started, nr_written, 1); + ret = cow_file_range(inode, locked_page, + cow_start, found_key.offset - 1, + page_started, nr_written, 1); if (ret) { btrfs_abort_transaction(trans, root, ret); goto error; @@ -1423,9 +1362,8 @@ out_check: } if (cow_start != (u64)-1) { - ret = __cow_file_range(trans, inode, root, locked_page, - cow_start, end, - page_started, nr_written, 1); + ret = cow_file_range(inode, locked_page, cow_start, end, + page_started, nr_written, 1); if (ret) { btrfs_abort_transaction(trans, root, ret); goto error; @@ -6344,39 +6282,32 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode, u64 start, u64 len) { struct btrfs_root *root = BTRFS_I(inode)->root; - struct btrfs_trans_handle *trans; struct extent_map *em; struct btrfs_key ins; u64 alloc_hint; int ret; - trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) - return ERR_CAST(trans); - - trans->block_rsv = &root->fs_info->delalloc_block_rsv; - alloc_hint = get_extent_allocation_hint(inode, start, len); - ret = btrfs_reserve_extent(trans, root, len, root->sectorsize, 0, + ret = btrfs_reserve_extent(root, len, root->sectorsize, 0, alloc_hint, &ins, 1); - if (ret) { - em = ERR_PTR(ret); - goto out; - } + if (ret) + return ERR_PTR(ret); em = create_pinned_em(inode, start, ins.offset, start, ins.objectid, ins.offset, ins.offset, ins.offset, 0); - if (IS_ERR(em)) - goto out; + if (IS_ERR(em)) { + btrfs_free_reserved_extent(root, ins.objectid, ins.offset); + return em; + } ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid, ins.offset, ins.offset, 0); if (ret) { btrfs_free_reserved_extent(root, ins.objectid, ins.offset); - em = ERR_PTR(ret); + free_extent_map(em); + return ERR_PTR(ret); } -out: - btrfs_end_transaction(trans, root); + return em; } @@ -6384,11 +6315,11 @@ out: * returns 1 when the nocow is safe, < 1 on error, 0 if the * block must be cow'd */ -noinline int can_nocow_extent(struct btrfs_trans_handle *trans, - struct inode *inode, u64 offset, u64 *len, +noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len, u64 *orig_start, u64 *orig_block_len, u64 *ram_bytes) { + struct btrfs_trans_handle *trans; struct btrfs_path *path; int ret; struct extent_buffer *leaf; @@ -6406,7 +6337,7 @@ noinline int can_nocow_extent(struct btrfs_trans_handle *trans, if (!path) return -ENOMEM; - ret = btrfs_lookup_file_extent(trans, root, path, btrfs_ino(inode), + ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), offset, 0); if (ret < 0) goto out; @@ -6471,9 +6402,19 @@ noinline int can_nocow_extent(struct btrfs_trans_handle *trans, * look for other files referencing this extent, if we * find any we must cow */ - if (btrfs_cross_ref_exist(trans, root, btrfs_ino(inode), - key.offset - backref_offset, disk_bytenr)) + trans = btrfs_join_transaction(root); + if (IS_ERR(trans)) { + ret = 0; goto out; + } + + ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode), + key.offset - backref_offset, disk_bytenr); + btrfs_end_transaction(trans, root); + if (ret) { + ret = 0; + goto out; + } /* * adjust disk_bytenr and num_bytes to cover just the bytes @@ -6615,7 +6556,6 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock, u64 start = iblock << inode->i_blkbits; u64 lockstart, lockend; u64 len = bh_result->b_size; - struct btrfs_trans_handle *trans; int unlock_bits = EXTENT_LOCKED; int ret = 0; @@ -6697,16 +6637,7 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock, len = min(len, em->len - (start - em->start)); block_start = em->block_start + (start - em->start); - /* - * we're not going to log anything, but we do need - * to make sure the current transaction stays open - * while we look for nocow cross refs - */ - trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) - goto must_cow; - - if (can_nocow_extent(trans, inode, start, &len, &orig_start, + if (can_nocow_extent(inode, start, &len, &orig_start, &orig_block_len, &ram_bytes) == 1) { if (type == BTRFS_ORDERED_PREALLOC) { free_extent_map(em); @@ -6715,24 +6646,20 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock, block_start, len, orig_block_len, ram_bytes, type); - if (IS_ERR(em)) { - btrfs_end_transaction(trans, root); + if (IS_ERR(em)) goto unlock_err; - } } ret = btrfs_add_ordered_extent_dio(inode, start, block_start, len, len, type); - btrfs_end_transaction(trans, root); if (ret) { free_extent_map(em); goto unlock_err; } goto unlock; } - btrfs_end_transaction(trans, root); } -must_cow: + /* * this will cow the extent, reset the len in case we changed * it above @@ -8495,8 +8422,8 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode, cur_bytes = min(num_bytes, 256ULL * 1024 * 1024); cur_bytes = max(cur_bytes, min_size); - ret = btrfs_reserve_extent(trans, root, cur_bytes, - min_size, 0, *alloc_hint, &ins, 1); + ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0, + *alloc_hint, &ins, 1); if (ret) { if (own_trans) btrfs_end_transaction(trans, root);