From: Christoph Hellwig hch@lst.de
[ 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 josef@toxicpanda.com Signed-off-by: Christoph Hellwig hch@lst.de Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Stable-dep-of: 7027f87108ce ("btrfs: don't treat zoned writeback as being from an async helper thread") Signed-off-by: Sasha Levin sashal@kernel.org --- 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,