In get_lock_data_page, if there is a data race between get_dnode_of_data for node and grab_cache_page for data, f2fs is able to face with the following BUG_ON(dn.data_blkaddr == NEW_ADDR).
kernel BUG at /home/zeus/f2fs_test/src/fs/f2fs/data.c:251! [<ffffffffa044966c>] get_lock_data_page+0x1ec/0x210 [f2fs] Call Trace: [<ffffffffa043b089>] f2fs_readdir+0x89/0x210 [f2fs] [<ffffffff811a0920>] ? fillonedir+0x100/0x100 [<ffffffff811a0920>] ? fillonedir+0x100/0x100 [<ffffffff811a07f8>] vfs_readdir+0xb8/0xe0 [<ffffffff811a0b4f>] sys_getdents+0x8f/0x110 [<ffffffff816d7999>] system_call_fastpath+0x16/0x1b This bug is able to be occurred when the block address of the data block is changed after f2fs_put_dnode(). In order to avoid that, this patch fixes the lock order of node and data blocks in which the node block lock is covered by the data block lock. Signed-off-by: Jaegeuk Kim <[email protected]> --- fs/f2fs/data.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 91ff93b..05fb5c6 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -233,18 +233,23 @@ struct page *get_lock_data_page(struct inode *inode, pgoff_t index) struct page *page; int err; +repeat: + page = grab_cache_page(mapping, index); + if (!page) + return ERR_PTR(-ENOMEM); + set_new_dnode(&dn, inode, NULL, NULL, 0); err = get_dnode_of_data(&dn, index, LOOKUP_NODE); - if (err) + if (err) { + f2fs_put_page(page, 1); return ERR_PTR(err); + } f2fs_put_dnode(&dn); - if (dn.data_blkaddr == NULL_ADDR) + if (dn.data_blkaddr == NULL_ADDR) { + f2fs_put_page(page, 1); return ERR_PTR(-ENOENT); -repeat: - page = grab_cache_page(mapping, index); - if (!page) - return ERR_PTR(-ENOMEM); + } if (PageUptodate(page)) return page; -- 1.8.1.3.566.gaa39828 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
