X-Git-Url: https://bbs.cooldavid.org/git/?a=blobdiff_plain;f=fs%2Fbtrfs%2Fextent_io.c;h=eac10e3260a982e24149957981c3f2a7be792d09;hb=925d169f5b86fe57e2f5264ea574cce9a89b719d;hp=d74e6af9b53a598a26bf83357f1bed61d2103ef2;hpb=00527cc6bbcac05ab7d54c40bda1ff2a0625ab10;p=net-next-2.6.git diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index d74e6af9b53..eac10e3260a 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -104,7 +104,7 @@ void extent_io_tree_init(struct extent_io_tree *tree, struct address_space *mapping, gfp_t mask) { tree->state = RB_ROOT; - tree->buffer = RB_ROOT; + INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC); tree->ops = NULL; tree->dirty_bytes = 0; spin_lock_init(&tree->lock); @@ -235,50 +235,6 @@ static inline struct rb_node *tree_search(struct extent_io_tree *tree, return ret; } -static struct extent_buffer *buffer_tree_insert(struct extent_io_tree *tree, - u64 offset, struct rb_node *node) -{ - struct rb_root *root = &tree->buffer; - struct rb_node **p = &root->rb_node; - struct rb_node *parent = NULL; - struct extent_buffer *eb; - - while (*p) { - parent = *p; - eb = rb_entry(parent, struct extent_buffer, rb_node); - - if (offset < eb->start) - p = &(*p)->rb_left; - else if (offset > eb->start) - p = &(*p)->rb_right; - else - return eb; - } - - rb_link_node(node, parent, p); - rb_insert_color(node, root); - return NULL; -} - -static struct extent_buffer *buffer_search(struct extent_io_tree *tree, - u64 offset) -{ - struct rb_root *root = &tree->buffer; - struct rb_node *n = root->rb_node; - struct extent_buffer *eb; - - while (n) { - eb = rb_entry(n, struct extent_buffer, rb_node); - if (offset < eb->start) - n = n->rb_left; - else if (offset > eb->start) - n = n->rb_right; - else - return eb; - } - return NULL; -} - static void merge_cb(struct extent_io_tree *tree, struct extent_state *new, struct extent_state *other) { @@ -1901,10 +1857,8 @@ static int submit_one_bio(int rw, struct bio *bio, int mirror_num, struct page *page = bvec->bv_page; struct extent_io_tree *tree = bio->bi_private; u64 start; - u64 end; start = ((u64)page->index << PAGE_CACHE_SHIFT) + bvec->bv_offset; - end = start + bvec->bv_len - 1; bio->bi_private = NULL; @@ -2204,7 +2158,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, u64 last_byte = i_size_read(inode); u64 block_start; u64 iosize; - u64 unlock_start; sector_t sector; struct extent_state *cached_state = NULL; struct extent_map *em; @@ -2329,7 +2282,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, if (tree->ops && tree->ops->writepage_end_io_hook) tree->ops->writepage_end_io_hook(page, start, page_end, NULL, 1); - unlock_start = page_end + 1; goto done; } @@ -2340,7 +2292,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, if (tree->ops && tree->ops->writepage_end_io_hook) tree->ops->writepage_end_io_hook(page, cur, page_end, NULL, 1); - unlock_start = page_end + 1; break; } em = epd->get_extent(inode, page, pg_offset, cur, @@ -2387,7 +2338,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, cur += iosize; pg_offset += iosize; - unlock_start = cur; continue; } /* leave this out until we have a page_mkwrite call */ @@ -2473,7 +2423,6 @@ static int extent_write_cache_pages(struct extent_io_tree *tree, pgoff_t index; pgoff_t end; /* Inclusive */ int scanned = 0; - int range_whole = 0; pagevec_init(&pvec, 0); if (wbc->range_cyclic) { @@ -2482,8 +2431,6 @@ static int extent_write_cache_pages(struct extent_io_tree *tree, } else { index = wbc->range_start >> PAGE_CACHE_SHIFT; end = wbc->range_end >> PAGE_CACHE_SHIFT; - if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) - range_whole = 1; scanned = 1; } retry: @@ -2823,6 +2770,8 @@ int extent_prepare_write(struct extent_io_tree *tree, NULL, 1, end_bio_extent_preparewrite, 0, 0, 0); + if (ret && !err) + err = ret; iocount++; block_start = block_start + iosize; } else { @@ -3104,6 +3053,39 @@ static void __free_extent_buffer(struct extent_buffer *eb) kmem_cache_free(extent_buffer_cache, eb); } +/* + * Helper for releasing extent buffer page. + */ +static void btrfs_release_extent_buffer_page(struct extent_buffer *eb, + unsigned long start_idx) +{ + unsigned long index; + struct page *page; + + if (!eb->first_page) + return; + + index = num_extent_pages(eb->start, eb->len); + if (start_idx >= index) + return; + + do { + index--; + page = extent_buffer_page(eb, index); + if (page) + page_cache_release(page); + } while (index != start_idx); +} + +/* + * Helper for releasing the extent buffer. + */ +static inline void btrfs_release_extent_buffer(struct extent_buffer *eb) +{ + btrfs_release_extent_buffer_page(eb, 0); + __free_extent_buffer(eb); +} + struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree, u64 start, unsigned long len, struct page *page0, @@ -3117,16 +3099,16 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree, struct page *p; struct address_space *mapping = tree->mapping; int uptodate = 1; + int ret; - spin_lock(&tree->buffer_lock); - eb = buffer_search(tree, start); - if (eb) { - atomic_inc(&eb->refs); - spin_unlock(&tree->buffer_lock); + rcu_read_lock(); + eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT); + if (eb && atomic_inc_not_zero(&eb->refs)) { + rcu_read_unlock(); mark_page_accessed(eb->first_page); return eb; } - spin_unlock(&tree->buffer_lock); + rcu_read_unlock(); eb = __alloc_extent_buffer(tree, start, len, mask); if (!eb) @@ -3165,26 +3147,31 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree, if (uptodate) set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags); + ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM); + if (ret) + goto free_eb; + spin_lock(&tree->buffer_lock); - exists = buffer_tree_insert(tree, start, &eb->rb_node); - if (exists) { + ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb); + if (ret == -EEXIST) { + exists = radix_tree_lookup(&tree->buffer, + start >> PAGE_CACHE_SHIFT); /* add one reference for the caller */ atomic_inc(&exists->refs); spin_unlock(&tree->buffer_lock); + radix_tree_preload_end(); goto free_eb; } /* add one reference for the tree */ atomic_inc(&eb->refs); spin_unlock(&tree->buffer_lock); + radix_tree_preload_end(); return eb; free_eb: if (!atomic_dec_and_test(&eb->refs)) return exists; - for (index = 1; index < i; index++) - page_cache_release(extent_buffer_page(eb, index)); - page_cache_release(extent_buffer_page(eb, 0)); - __free_extent_buffer(eb); + btrfs_release_extent_buffer(eb); return exists; } @@ -3194,16 +3181,16 @@ struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree, { struct extent_buffer *eb; - spin_lock(&tree->buffer_lock); - eb = buffer_search(tree, start); - if (eb) - atomic_inc(&eb->refs); - spin_unlock(&tree->buffer_lock); - - if (eb) + rcu_read_lock(); + eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT); + if (eb && atomic_inc_not_zero(&eb->refs)) { + rcu_read_unlock(); mark_page_accessed(eb->first_page); + return eb; + } + rcu_read_unlock(); - return eb; + return NULL; } void free_extent_buffer(struct extent_buffer *eb) @@ -3833,34 +3820,45 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset, } } +static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head) +{ + struct extent_buffer *eb = + container_of(head, struct extent_buffer, rcu_head); + + btrfs_release_extent_buffer(eb); +} + int try_release_extent_buffer(struct extent_io_tree *tree, struct page *page) { u64 start = page_offset(page); struct extent_buffer *eb; int ret = 1; - unsigned long i; - unsigned long num_pages; spin_lock(&tree->buffer_lock); - eb = buffer_search(tree, start); + eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT); if (!eb) goto out; - if (atomic_read(&eb->refs) > 1) { + if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) { ret = 0; goto out; } - if (test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) { + + /* + * set @eb->refs to 0 if it is already 1, and then release the @eb. + * Or go back. + */ + if (atomic_cmpxchg(&eb->refs, 1, 0) != 1) { ret = 0; goto out; } - /* at this point we can safely release the extent buffer */ - num_pages = num_extent_pages(eb->start, eb->len); - for (i = 0; i < num_pages; i++) - page_cache_release(extent_buffer_page(eb, i)); - rb_erase(&eb->rb_node, &tree->buffer); - __free_extent_buffer(eb); + + radix_tree_delete(&tree->buffer, start >> PAGE_CACHE_SHIFT); out: spin_unlock(&tree->buffer_lock); + + /* at this point we can safely release the extent buffer */ + if (atomic_read(&eb->refs) == 0) + call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu); return ret; }