From: David Sterba dsterba@suse.com
stable inclusion from linux-4.19.199 commit a91010f5e28c95309bd0e35903728fab654b7ea5
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commit f2165627319ffd33a6217275e5690b1ab5c45763 upstream
The early check if we should attempt compression does not take into account the number of input pages. It can happen that there's only one page, eg. a tail page after some ranges of the BTRFS_MAX_UNCOMPRESSED have been processed, or an isolated page that won't be converted to an inline extent.
The single page would be compressed but a later check would drop it again because the result size must be at least one block shorter than the input. That can never work with just one page.
CC: stable@vger.kernel.org # 4.4+ Signed-off-by: David Sterba dsterba@suse.com [sudip: adjust context] Signed-off-by: Sudip Mukherjee sudipm.mukherjee@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/btrfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 9e3e003e4488e..6f024c7100ab7 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -530,7 +530,7 @@ static noinline void compress_file_range(struct inode *inode, * inode has not been flagged as nocompress. This flag can * change at any time if we discover bad compression ratios. */ - if (inode_need_compress(inode, start, end)) { + if (nr_pages > 1 && inode_need_compress(inode, start, end)) { WARN_ON(pages); pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); if (!pages) {