From 01f28610a1691078d0f7ba62b365567f8799f07c Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 29 Apr 2015 11:18:42 -0700 Subject: [PATCH] f2fs: fix race on allocating and deallocating a dentry block There are two threads: f2fs_delete_entry() get_new_data_page() f2fs_reserve_block() dn.blkaddr = XXX lock_page(dentry_block) truncate_hole() dn.blkaddr = NULL unlock_page(dentry_block) lock_page(dentry_block) fill the block from XXX address add new dentries unlock_page(dentry_block) Later, f2fs_write_data_page() will truncate the dentry_block, since its block address is NULL. The reason for this was due to the wrong lock order. In this case, we should do f2fs_reserve_block() after locking its dentry block. Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 81d1fd581078..9ba30b435a5a 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1076,20 +1076,22 @@ struct page *get_new_data_page(struct inode *inode, struct page *page; struct dnode_of_data dn; int err; +repeat: + page = grab_cache_page(mapping, index); + if (!page) + return ERR_PTR(-ENOMEM); set_new_dnode(&dn, inode, ipage, NULL, 0); err = f2fs_reserve_block(&dn, index); - if (err) + if (err) { + f2fs_put_page(page, 1); return ERR_PTR(err); -repeat: - page = grab_cache_page(mapping, index); - if (!page) { - err = -ENOMEM; - goto put_err; } + if (!ipage) + f2fs_put_dnode(&dn); if (PageUptodate(page)) - return page; + goto got_it; if (dn.data_blkaddr == NEW_ADDR) { zero_user_segment(page, 0, PAGE_CACHE_SIZE); @@ -1104,20 +1106,19 @@ repeat: }; err = f2fs_submit_page_bio(&fio); if (err) - goto put_err; + return ERR_PTR(err); lock_page(page); if (unlikely(!PageUptodate(page))) { f2fs_put_page(page, 1); - err = -EIO; - goto put_err; + return ERR_PTR(-EIO); } if (unlikely(page->mapping != mapping)) { f2fs_put_page(page, 1); goto repeat; } } - +got_it: if (new_i_size && i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) { i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT)); @@ -1125,10 +1126,6 @@ repeat: set_inode_flag(F2FS_I(inode), FI_UPDATE_DIR); } return page; - -put_err: - f2fs_put_dnode(&dn); - return ERR_PTR(err); } static int __allocate_data_block(struct dnode_of_data *dn) -- 2.20.1