From a54aa76108619e5d8290b49081c2aaaeff5be9a2 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 27 Feb 2011 16:43:24 -0500 Subject: [PATCH] ext4: don't leave PageWriteback set after memory failure In ext4_bio_write_page(), if the memory allocation for the struct ext4_io_page fails, it returns with the page's PageWriteback flag set. This will end up causing the page not to skip writeback in WB_SYNC_NONE mode, and in WB_SYNC_ALL mode (i.e., on a sync, fsync, or umount) the writeback daemon will get stuck forever on the wait_on_page_writeback() function in write_cache_pages_da(). Or, if journalling is enabled and the file gets deleted, it the journal thread can get stuck in journal_finish_inode_data_buffers() call to filemap_fdatawait(). Another place where things can get hung up is in truncate_inode_pages(), called out of ext4_evict_inode(). Fix this by not setting PageWriteback until after we have successfully allocated the struct ext4_io_page. Signed-off-by: "Theodore Ts'o" --- fs/ext4/page-io.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index 68d92a8..d5c391f 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -381,8 +381,6 @@ int ext4_bio_write_page(struct ext4_io_submit *io, BUG_ON(!PageLocked(page)); BUG_ON(PageWriteback(page)); - set_page_writeback(page); - ClearPageError(page); io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS); if (!io_page) { @@ -393,6 +391,8 @@ int ext4_bio_write_page(struct ext4_io_submit *io, io_page->p_page = page; atomic_set(&io_page->p_count, 1); get_page(page); + set_page_writeback(page); + ClearPageError(page); for (bh = head = page_buffers(page), block_start = 0; bh != head || !block_start; -- 2.7.4