From d4452bc526c431a882cc6ba854619e166cb7dfe4 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 19 May 2014 20:47:56 -0700 Subject: [PATCH] Btrfs: break up __btrfs_write_out_cache to cut down stack usage __btrfs_write_out_cache was one of our stack pigs. This breaks it up into helper functions and slims it down to 194 bytes. Signed-off-by: Chris Mason --- fs/btrfs/free-space-cache.c | 308 ++++++++++++++++++++++-------------- 1 file changed, 191 insertions(+), 117 deletions(-) diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index a6bd654dcd47..372b05ff1943 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -851,90 +851,44 @@ out: return ret; } -/** - * __btrfs_write_out_cache - write out cached info to an inode - * @root - the root the inode belongs to - * @ctl - the free space cache we are going to write out - * @block_group - the block_group for this cache if it belongs to a block_group - * @trans - the trans handle - * @path - the path to use - * @offset - the offset for the key we'll insert - * - * This function writes out a free space cache struct to disk for quick recovery - * on mount. This will return 0 if it was successfull in writing the cache out, - * and -1 if it was not. - */ -static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, - struct btrfs_free_space_ctl *ctl, - struct btrfs_block_group_cache *block_group, - struct btrfs_trans_handle *trans, - struct btrfs_path *path, u64 offset) +static noinline_for_stack +int write_cache_extent_entries(struct io_ctl *io_ctl, + struct btrfs_free_space_ctl *ctl, + struct btrfs_block_group_cache *block_group, + int *entries, int *bitmaps, + struct list_head *bitmap_list) { - struct btrfs_free_space_header *header; - struct extent_buffer *leaf; - struct rb_node *node; - struct list_head *pos, *n; - struct extent_state *cached_state = NULL; - struct btrfs_free_cluster *cluster = NULL; - struct extent_io_tree *unpin = NULL; - struct io_ctl io_ctl; - struct list_head bitmap_list; - struct btrfs_key key; - u64 start, extent_start, extent_end, len; - int entries = 0; - int bitmaps = 0; int ret; - int err = -1; - - INIT_LIST_HEAD(&bitmap_list); - - if (!i_size_read(inode)) - return -1; - - ret = io_ctl_init(&io_ctl, inode, root); - if (ret) - return -1; + struct btrfs_free_cluster *cluster = NULL; + struct rb_node *node = rb_first(&ctl->free_space_offset); /* Get the cluster for this block_group if it exists */ - if (block_group && !list_empty(&block_group->cluster_list)) + if (block_group && !list_empty(&block_group->cluster_list)) { cluster = list_entry(block_group->cluster_list.next, struct btrfs_free_cluster, block_group_list); + } - /* Lock all pages first so we can lock the extent safely. */ - io_ctl_prepare_pages(&io_ctl, inode, 0); - - lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, - 0, &cached_state); - - node = rb_first(&ctl->free_space_offset); if (!node && cluster) { node = rb_first(&cluster->root); cluster = NULL; } - /* Make sure we can fit our crcs into the first page */ - if (io_ctl.check_crcs && - (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE) - goto out_nospc; - - io_ctl_set_generation(&io_ctl, trans->transid); - /* Write out the extent entries */ while (node) { struct btrfs_free_space *e; e = rb_entry(node, struct btrfs_free_space, offset_index); - entries++; + *entries += 1; - ret = io_ctl_add_entry(&io_ctl, e->offset, e->bytes, + ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes, e->bitmap); if (ret) - goto out_nospc; + goto fail; if (e->bitmap) { - list_add_tail(&e->list, &bitmap_list); - bitmaps++; + list_add_tail(&e->list, bitmap_list); + *bitmaps += 1; } node = rb_next(node); if (!node && cluster) { @@ -942,13 +896,84 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, cluster = NULL; } } + return 0; +fail: + return -ENOSPC; +} + +static noinline_for_stack int +update_cache_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct inode *inode, + struct btrfs_path *path, u64 offset, + int entries, int bitmaps) +{ + struct btrfs_key key; + struct btrfs_free_space_header *header; + struct extent_buffer *leaf; + int ret; + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = offset; + key.type = 0; + + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); + if (ret < 0) { + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1, + EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL, + GFP_NOFS); + goto fail; + } + leaf = path->nodes[0]; + if (ret > 0) { + struct btrfs_key found_key; + ASSERT(path->slots[0]); + path->slots[0]--; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID || + found_key.offset != offset) { + clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, + inode->i_size - 1, + EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, + NULL, GFP_NOFS); + btrfs_release_path(path); + goto fail; + } + } + + BTRFS_I(inode)->generation = trans->transid; + header = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_free_space_header); + btrfs_set_free_space_entries(leaf, header, entries); + btrfs_set_free_space_bitmaps(leaf, header, bitmaps); + btrfs_set_free_space_generation(leaf, header, trans->transid); + btrfs_mark_buffer_dirty(leaf); + btrfs_release_path(path); + + return 0; + +fail: + return -1; +} + +static noinline_for_stack int +add_ioctl_entries(struct btrfs_root *root, + struct inode *inode, + struct btrfs_block_group_cache *block_group, + struct io_ctl *io_ctl, + struct extent_state **cached_state, + struct list_head *bitmap_list, + int *entries) +{ + u64 start, extent_start, extent_end, len; + struct list_head *pos, *n; + struct extent_io_tree *unpin = NULL; + int ret; /* * We want to add any pinned extents to our free space cache * so we don't leak the space - */ - - /* + * * We shouldn't have switched the pinned extents yet so this is the * right one */ @@ -977,8 +1002,8 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, block_group->key.offset, extent_end + 1); len = extent_end - extent_start; - entries++; - ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL); + *entries += 1; + ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL); if (ret) goto out_nospc; @@ -986,74 +1011,129 @@ static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, } /* Write out the bitmaps */ - list_for_each_safe(pos, n, &bitmap_list) { + list_for_each_safe(pos, n, bitmap_list) { struct btrfs_free_space *entry = list_entry(pos, struct btrfs_free_space, list); - ret = io_ctl_add_bitmap(&io_ctl, entry->bitmap); + ret = io_ctl_add_bitmap(io_ctl, entry->bitmap); if (ret) goto out_nospc; list_del_init(&entry->list); } /* Zero out the rest of the pages just to make sure */ - io_ctl_zero_remaining_pages(&io_ctl); + io_ctl_zero_remaining_pages(io_ctl); - ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages, - 0, i_size_read(inode), &cached_state); - io_ctl_drop_pages(&io_ctl); + ret = btrfs_dirty_pages(root, inode, io_ctl->pages, io_ctl->num_pages, + 0, i_size_read(inode), cached_state); + io_ctl_drop_pages(io_ctl); unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, - i_size_read(inode) - 1, &cached_state, GFP_NOFS); + i_size_read(inode) - 1, cached_state, GFP_NOFS); if (ret) - goto out; + goto fail; ret = btrfs_wait_ordered_range(inode, 0, (u64)-1); if (ret) { clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1, EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL, GFP_NOFS); - goto out; + goto fail; } + return 0; - key.objectid = BTRFS_FREE_SPACE_OBJECTID; - key.offset = offset; - key.type = 0; +fail: + return -1; - ret = btrfs_search_slot(trans, root, &key, path, 0, 1); - if (ret < 0) { - clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1, - EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL, - GFP_NOFS); - goto out; - } - leaf = path->nodes[0]; - if (ret > 0) { - struct btrfs_key found_key; - ASSERT(path->slots[0]); - path->slots[0]--; - btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); - if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID || - found_key.offset != offset) { - clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, - inode->i_size - 1, - EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, - NULL, GFP_NOFS); - btrfs_release_path(path); - goto out; - } +out_nospc: + return -ENOSPC; +} + +static void noinline_for_stack +cleanup_write_cache_enospc(struct inode *inode, + struct io_ctl *io_ctl, + struct extent_state **cached_state, + struct list_head *bitmap_list) +{ + struct list_head *pos, *n; + list_for_each_safe(pos, n, bitmap_list) { + struct btrfs_free_space *entry = + list_entry(pos, struct btrfs_free_space, list); + list_del_init(&entry->list); } + io_ctl_drop_pages(io_ctl); + unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, + i_size_read(inode) - 1, cached_state, + GFP_NOFS); +} - BTRFS_I(inode)->generation = trans->transid; - header = btrfs_item_ptr(leaf, path->slots[0], - struct btrfs_free_space_header); - btrfs_set_free_space_entries(leaf, header, entries); - btrfs_set_free_space_bitmaps(leaf, header, bitmaps); - btrfs_set_free_space_generation(leaf, header, trans->transid); - btrfs_mark_buffer_dirty(leaf); - btrfs_release_path(path); +/** + * __btrfs_write_out_cache - write out cached info to an inode + * @root - the root the inode belongs to + * @ctl - the free space cache we are going to write out + * @block_group - the block_group for this cache if it belongs to a block_group + * @trans - the trans handle + * @path - the path to use + * @offset - the offset for the key we'll insert + * + * This function writes out a free space cache struct to disk for quick recovery + * on mount. This will return 0 if it was successfull in writing the cache out, + * and -1 if it was not. + */ +static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode, + struct btrfs_free_space_ctl *ctl, + struct btrfs_block_group_cache *block_group, + struct btrfs_trans_handle *trans, + struct btrfs_path *path, u64 offset) +{ + struct extent_state *cached_state = NULL; + struct io_ctl io_ctl; + struct list_head bitmap_list; + int entries = 0; + int bitmaps = 0; + int ret; + int err = -1; + + INIT_LIST_HEAD(&bitmap_list); + + if (!i_size_read(inode)) + return -1; + + ret = io_ctl_init(&io_ctl, inode, root); + if (ret) + return -1; + + /* Lock all pages first so we can lock the extent safely. */ + io_ctl_prepare_pages(&io_ctl, inode, 0); + + lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1, + 0, &cached_state); + + + /* Make sure we can fit our crcs into the first page */ + if (io_ctl.check_crcs && + (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE) + goto out_nospc; + + io_ctl_set_generation(&io_ctl, trans->transid); + + ret = write_cache_extent_entries(&io_ctl, ctl, + block_group, &entries, &bitmaps, + &bitmap_list); + if (ret) + goto out_nospc; + + ret = add_ioctl_entries(root, inode, block_group, &io_ctl, + &cached_state, &bitmap_list, &entries); + + if (ret == -ENOSPC) + goto out_nospc; + else if (ret) + goto out; + + err = update_cache_item(trans, root, inode, path, offset, + entries, bitmaps); - err = 0; out: io_ctl_free(&io_ctl); if (err) { @@ -1064,14 +1144,8 @@ out: return err; out_nospc: - list_for_each_safe(pos, n, &bitmap_list) { - struct btrfs_free_space *entry = - list_entry(pos, struct btrfs_free_space, list); - list_del_init(&entry->list); - } - io_ctl_drop_pages(&io_ctl); - unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0, - i_size_read(inode) - 1, &cached_state, GFP_NOFS); + + cleanup_write_cache_enospc(inode, &io_ctl, &cached_state, &bitmap_list); goto out; } -- 2.20.1