From: "Darrick J. Wong" Subject: [PATCH 04/34] libext2fs: ext2fs_new_block2() should call alloc_block hook Date: Sat, 13 Sep 2014 15:11:39 -0700 Message-ID: <20140913221139.13646.58932.stgit@birch.djwong.org> References: <20140913221112.13646.3873.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: tytso@mit.edu, darrick.wong@oracle.com Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:32131 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752186AbaIMWLo (ORCPT ); Sat, 13 Sep 2014 18:11:44 -0400 In-Reply-To: <20140913221112.13646.3873.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: If ext2fs_new_block2() is called without a specific block map, we should call the alloc_block hook before checking fs->block_map. This helps us to avoid a bug in e2fsck where we need to allocate a block but instead of consulting block_found_map, we use the FS bitmaps, which (prior to pass 5) could be wrong. Signed-off-by: Darrick J. Wong --- e2fsck/pass1.c | 2 +- lib/ext2fs/alloc.c | 15 +++++++++++++++ 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c index db5273e..04bb465 100644 --- a/e2fsck/pass1.c +++ b/e2fsck/pass1.c @@ -3725,7 +3725,7 @@ static errcode_t e2fsck_get_alloc_block(ext2_filsys fs, blk64_t goal, return retval; } - retval = ext2fs_new_block2(fs, goal, 0, &new_block); + retval = ext2fs_new_block2(fs, goal, fs->block_map, &new_block); if (retval) return retval; } diff --git a/lib/ext2fs/alloc.c b/lib/ext2fs/alloc.c index 578fd7f..d1c1a84 100644 --- a/lib/ext2fs/alloc.c +++ b/lib/ext2fs/alloc.c @@ -137,9 +137,23 @@ errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal, { errcode_t retval; blk64_t b = 0; + errcode_t (*gab)(ext2_filsys fs, blk64_t goal, blk64_t *ret); EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + if (!map && fs->get_alloc_block) { + /* + * In case there are clients out there whose get_alloc_block + * handlers call ext2fs_new_block2 with a NULL block map, + * temporarily swap out the function pointer so that we don't + * end up in an infinite loop. + */ + gab = fs->get_alloc_block; + fs->get_alloc_block = NULL; + retval = gab(fs, goal, &b); + fs->get_alloc_block = gab; + goto allocated; + } if (!map) map = fs->block_map; if (!map) @@ -153,6 +167,7 @@ errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal, if ((retval == ENOENT) && (goal != fs->super->s_first_data_block)) retval = ext2fs_find_first_zero_block_bitmap2(map, fs->super->s_first_data_block, goal - 1, &b); +allocated: if (retval == ENOENT) return EXT2_ET_BLOCK_ALLOC_FAIL; if (retval)