From 42dc7babdcc99feadb04d461592ce5898a362550 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 15 Dec 2008 11:44:56 -0500 Subject: [PATCH] Btrfs: Fix compressed writes on truncated pages The compression code was using isize to limit the amount of data it sent through zlib. But, it wasn't properly limiting the looping to just the pages inside i_size. The end result was trying to compress too many pages, including those that had not been setup and properly locked down. This made the compression code oops while trying find_get_page on a page that didn't exist. Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 2 +- fs/btrfs/inode.c | 8 +++++--- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index c0c95cccbb5b..f6f7a6af0357 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2887,8 +2887,8 @@ int btrfs_split_item(struct btrfs_trans_handle *trans, path->keep_locks = 0; BUG_ON(ret); - BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item)); leaf = path->nodes[0]; + BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item)); split: item = btrfs_item_nr(leaf, path->slots[0]); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index e64a4fe19a60..5313a13a998d 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -332,6 +332,7 @@ static noinline int compress_file_range(struct inode *inode, u64 disk_num_bytes; u64 blocksize = root->sectorsize; u64 actual_end; + u64 isize = i_size_read(inode); int ret = 0; struct page **pages = NULL; unsigned long nr_pages; @@ -345,12 +346,12 @@ static noinline int compress_file_range(struct inode *inode, orig_start = start; + actual_end = min_t(u64, isize, end + 1); again: will_compress = 0; nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1; nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE); - actual_end = min_t(u64, i_size_read(inode), end + 1); total_compressed = actual_end - start; /* we want to make sure that amount of ram required to uncompress @@ -488,7 +489,7 @@ again: add_async_extent(async_cow, start, num_bytes, total_compressed, pages, nr_pages_ret); - if (start + num_bytes < end) { + if (start + num_bytes < end && start + num_bytes < actual_end) { start += num_bytes; pages = NULL; cond_resched(); @@ -696,6 +697,7 @@ static noinline int cow_file_range(struct inode *inode, u64 cur_alloc_size; u64 blocksize = root->sectorsize; u64 actual_end; + u64 isize = i_size_read(inode); struct btrfs_key ins; struct extent_map *em; struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; @@ -705,7 +707,7 @@ static noinline int cow_file_range(struct inode *inode, BUG_ON(!trans); btrfs_set_trans_block_group(trans, inode); - actual_end = min_t(u64, i_size_read(inode), end + 1); + actual_end = min_t(u64, isize, end + 1); num_bytes = (end - start + blocksize) & ~(blocksize - 1); num_bytes = max(blocksize, num_bytes); -- 2.20.1