From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB1C88F70 for ; Sun, 16 Jul 2023 19:56:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40AE5C433C7; Sun, 16 Jul 2023 19:56:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689537403; bh=162XbSXobg2Aw/MEUmG7ePp+WzV77Grj7ynQn8BUJE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sT6zrprQ7m2Bk3h9cnLVu+aTqk13u2jj0dFFQzQzf+hIsNQuGZUjXG9zutKhS1du4 K7bjLZQPGLequUqffGZGqRl/64a82MZ3b2qNF9slVzPMZgbh7xKwpIaEQxeHSLuofr lkqiIxQ1OHvAnmp5LKTi5FGG1o5FV6B9DC/EfiS0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josef Bacik , Christoph Hellwig , David Sterba , Sasha Levin Subject: [PATCH 6.4 056/800] btrfs: dont fail writeback when allocating the compression context fails Date: Sun, 16 Jul 2023 21:38:29 +0200 Message-ID: <20230716194950.391411359@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230716194949.099592437@linuxfoundation.org> References: <20230716194949.099592437@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Christoph Hellwig [ Upstream commit 973fb26e81a9f59dfe45b079a698c0e238f7bf69 ] If cow_file_range_async fails to allocate the asynchronous writeback context, it currently returns an error and entirely fails the writeback. This is not a good idea as a writeback failure is a non-temporary error condition that will make the file system unusable. Just fall back to synchronous uncompressed writeback instead. This requires us to delay setting the BTRFS_INODE_HAS_ASYNC_EXTENT flag until we've committed to the async writeback. The compression checks INODE_NOCOMPRESS and FORCE_COMPRESS are moved from cow_file_range_async to the preceding checks btrfs_run_delalloc_range(). Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba Stable-dep-of: 7027f87108ce ("btrfs: don't treat zoned writeback as being from an async helper thread") Signed-off-by: Sasha Levin --- fs/btrfs/inode.c | 74 ++++++++++++++++++------------------------------ 1 file changed, 28 insertions(+), 46 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 7fcafcc5292c8..3d12dba145152 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1521,58 +1521,36 @@ static noinline void async_cow_free(struct btrfs_work *work) kvfree(async_cow); } -static int cow_file_range_async(struct btrfs_inode *inode, - struct writeback_control *wbc, - struct page *locked_page, - u64 start, u64 end, int *page_started, - unsigned long *nr_written) +static bool cow_file_range_async(struct btrfs_inode *inode, + struct writeback_control *wbc, + struct page *locked_page, + u64 start, u64 end, int *page_started, + unsigned long *nr_written) { struct btrfs_fs_info *fs_info = inode->root->fs_info; struct cgroup_subsys_state *blkcg_css = wbc_blkcg_css(wbc); struct async_cow *ctx; struct async_chunk *async_chunk; unsigned long nr_pages; - u64 cur_end; u64 num_chunks = DIV_ROUND_UP(end - start, SZ_512K); int i; - bool should_compress; unsigned nofs_flag; const blk_opf_t write_flags = wbc_to_write_flags(wbc); - unlock_extent(&inode->io_tree, start, end, NULL); - - if (inode->flags & BTRFS_INODE_NOCOMPRESS && - !btrfs_test_opt(fs_info, FORCE_COMPRESS)) { - num_chunks = 1; - should_compress = false; - } else { - should_compress = true; - } - nofs_flag = memalloc_nofs_save(); ctx = kvmalloc(struct_size(ctx, chunks, num_chunks), GFP_KERNEL); memalloc_nofs_restore(nofs_flag); + if (!ctx) + return false; - if (!ctx) { - unsigned clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | - EXTENT_DELALLOC_NEW | EXTENT_DEFRAG | - EXTENT_DO_ACCOUNTING; - unsigned long page_ops = PAGE_UNLOCK | PAGE_START_WRITEBACK | - PAGE_END_WRITEBACK | PAGE_SET_ERROR; - - extent_clear_unlock_delalloc(inode, start, end, locked_page, - clear_bits, page_ops); - return -ENOMEM; - } + unlock_extent(&inode->io_tree, start, end, NULL); + set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT, &inode->runtime_flags); async_chunk = ctx->chunks; atomic_set(&ctx->num_chunks, num_chunks); for (i = 0; i < num_chunks; i++) { - if (should_compress) - cur_end = min(end, start + SZ_512K - 1); - else - cur_end = end; + u64 cur_end = min(end, start + SZ_512K - 1); /* * igrab is called higher up in the call chain, take only the @@ -1633,7 +1611,7 @@ static int cow_file_range_async(struct btrfs_inode *inode, start = cur_end + 1; } *page_started = 1; - return 0; + return true; } static noinline int run_delalloc_zoned(struct btrfs_inode *inode, @@ -2214,7 +2192,7 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct page *locked_page u64 start, u64 end, int *page_started, unsigned long *nr_written, struct writeback_control *wbc) { - int ret; + int ret = 0; const bool zoned = btrfs_is_zoned(inode->root->fs_info); /* @@ -2235,19 +2213,23 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct page *locked_page ASSERT(!zoned || btrfs_is_data_reloc_root(inode->root)); ret = run_delalloc_nocow(inode, locked_page, start, end, page_started, nr_written); - } else if (!btrfs_inode_can_compress(inode) || - !inode_need_compress(inode, start, end)) { - if (zoned) - ret = run_delalloc_zoned(inode, locked_page, start, end, - page_started, nr_written); - else - ret = cow_file_range(inode, locked_page, start, end, - page_started, nr_written, 1, NULL); - } else { - set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT, &inode->runtime_flags); - ret = cow_file_range_async(inode, wbc, locked_page, start, end, - page_started, nr_written); + goto out; } + + if (btrfs_inode_can_compress(inode) && + inode_need_compress(inode, start, end) && + cow_file_range_async(inode, wbc, locked_page, start, + end, page_started, nr_written)) + goto out; + + if (zoned) + ret = run_delalloc_zoned(inode, locked_page, start, end, + page_started, nr_written); + else + ret = cow_file_range(inode, locked_page, start, end, + page_started, nr_written, 1, NULL); + +out: ASSERT(ret <= 0); if (ret) btrfs_cleanup_ordered_extents(inode, locked_page, start, -- 2.39.2