From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxim Patlasov Subject: [PATCH] ext4: ext4_free_blocks() fix Date: Fri, 10 Jun 2011 14:07:54 +0400 Message-ID: <1307700474-25743-1-git-send-email-maxim.patlasov@gmail.com> Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org To: tytso@mit.edu Return-path: Received: from mailhub.sw.ru ([195.214.232.25]:35693 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753445Ab1FJKIF (ORCPT ); Fri, 10 Jun 2011 06:08:05 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: Existent implementation of ext4_free_blocks() always calls vfs_dq_free_block This looks quite sensible in the most cases: blocks to be freed are associated with inode and were accounted in quota and i_blocks some time ago. However, there is a case when blocks to free were not accounted by the time calling ext4_free_blocks() yet: 1. delalloc is on, write_begin pre-allocated some space in quota 2. write-back happens, ext4 allocates some blocks in ext4_ext_get_blocks() 3. then ext4_ext_get_blocks() gets an error (e.g. ENOSPC) from ext4_ext_insert_extent() and calls ext4_free_blocks(). In this scenario, ext4_free_blocks() calls vfs_dq_free_block() who, in turn, decrements i_blocks for blocks which were not accounted yet (due to delalloc) After clean umount, e2fsck reports something like: > Inode 21, i_blocks is 5080, should be 5128. Fix? because i_blocks was erroneously decremented as explained above. The patch fixes the problem by passing EXT4_FREE_BLOCKS_SKIP_QUPD flag to ext4_free_blocks(). This flag forces ext4_free_blocks() to skip vfs_dq_free_block() call. Signed-off-by: Maxim Patlasov --- fs/ext4/ext4.h | 1 + fs/ext4/extents.c | 4 +++- fs/ext4/mballoc.c | 2 +- 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 1921392..2cff50c 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -526,6 +526,7 @@ struct ext4_new_group_data { #define EXT4_FREE_BLOCKS_METADATA 0x0001 #define EXT4_FREE_BLOCKS_FORGET 0x0002 #define EXT4_FREE_BLOCKS_VALIDATED 0x0004 +#define EXT4_FREE_BLOCKS_SKIP_QUPD 0x0008 /* * ioctl commands diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 5199bac..4d17497 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3601,12 +3601,14 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); if (err) { + int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ? + EXT4_FREE_BLOCKS_SKIP_QUPD : 0; /* free data blocks we just allocated */ /* not a good idea to call discard here directly, * but otherwise we'd need to call it every free() */ ext4_discard_preallocations(inode); ext4_free_blocks(handle, inode, NULL, ext4_ext_pblock(&newex), - ext4_ext_get_actual_len(&newex), 0); + ext4_ext_get_actual_len(&newex), fb_flags); goto out2; } diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 859f2ae..ba391c6 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4637,7 +4637,7 @@ do_more: } ext4_mark_super_dirty(sb); error_return: - if (freed) + if (freed && !(flags & EXT4_FREE_BLOCKS_SKIP_QUPD)) dquot_free_block(inode, freed); brelse(bitmap_bh); ext4_std_error(sb, err); -- 1.7.4.4