3.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Sandeen <[email protected]> commit c1bb05a657fb3d8c6179a4ef7980261fae4521d7 upstream. Processes hang forever on a sync-mounted ext2 file system that is mounted with the ext4 module (default in Fedora 16). I can reproduce this reliably by mounting an ext2 partition with "-o sync" and opening a new file an that partition with vim. vim will hang in "D" state forever. The same happens on ext4 without a journal. I am attaching a small patch here that solves this issue for me. In the sync mounted case without a journal, ext4_handle_dirty_metadata() may call sync_dirty_buffer(), which can't be called with buffer lock held. Also move mb_cache_entry_release inside lock to avoid race fixed previously by 8a2bfdcb ext[34]: EA block reference count racing fix Note too that ext2 fixed this same problem in 2006 with b2f49033 [PATCH] fix deadlock in ext2 Signed-off-by: [email protected] [[email protected]: move mb_cache_entry_release before unlock, edit commit msg] Signed-off-by: Eric Sandeen <[email protected]> Signed-off-by: "Theodore Ts'o" <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/ext4/xattr.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -487,18 +487,19 @@ ext4_xattr_release_block(handle_t *handl ext4_free_blocks(handle, inode, bh, 0, 1, EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET); + unlock_buffer(bh); } else { le32_add_cpu(&BHDR(bh)->h_refcount, -1); + if (ce) + mb_cache_entry_release(ce); + unlock_buffer(bh); error = ext4_handle_dirty_metadata(handle, inode, bh); if (IS_SYNC(inode)) ext4_handle_sync(handle); dquot_free_block(inode, 1); ea_bdebug(bh, "refcount now=%d; releasing", le32_to_cpu(BHDR(bh)->h_refcount)); - if (ce) - mb_cache_entry_release(ce); } - unlock_buffer(bh); out: ext4_std_error(inode->i_sb, error); return; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
