From patchwork Mon May 24 22:28:00 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: gregkh@suse.de X-Patchwork-Id: 53478 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id A1309B7D61 for ; Tue, 25 May 2010 08:43:04 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757044Ab0EXWiO (ORCPT ); Mon, 24 May 2010 18:38:14 -0400 Received: from kroah.org ([198.145.64.141]:35987 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751593Ab0EXWiN (ORCPT ); Mon, 24 May 2010 18:38:13 -0400 Received: from localhost (c-24-16-163-131.hsd1.wa.comcast.net [24.16.163.131]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by coco.kroah.org (Postfix) with ESMTPSA id BB05A484A8; Mon, 24 May 2010 15:38:12 -0700 (PDT) X-Mailbox-Line: From gregkh@clark.site Mon May 24 15:30:14 2010 Message-Id: <20100524223014.777274118@clark.site> User-Agent: quilt/0.48-8.10 Date: Mon, 24 May 2010 15:28:00 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ext4 Developers List , "Theodore Tso" , "Jayson R. King" , "Aneesh Kumar K.V" Subject: [04/24] ext4: Make sure all the block allocation paths reserve blocks In-Reply-To: <20100524223544.GA13721@kroah.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org 2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Aneesh Kumar K.V commit a30d542a0035b886ffaafd0057ced0a2b28c3a4f upstream. With delayed allocation we need to make sure block are reserved before we attempt to allocate them. Otherwise we get block allocation failure (ENOSPC) during writepages which cannot be handled. This would mean silent data loss (We do a printk stating data will be lost). This patch updates the DIO and fallocate code path to do block reservation before block allocation. This is needed to make sure parallel DIO and fallocate request doesn't take block out of delayed reserve space. When free blocks count go below a threshold we switch to a slow patch which looks at other CPU's accumulated percpu counter values. Signed-off-by: Aneesh Kumar K.V Signed-off-by: "Theodore Ts'o" Signed-off-by: Jayson R. King Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/balloc.c | 58 +++++++++++++++++++++++++++++++++++++++--------------- fs/ext4/ext4.h | 13 ++++++++++++ fs/ext4/inode.c | 5 ---- fs/ext4/mballoc.c | 23 ++++++++++++--------- 4 files changed, 69 insertions(+), 30 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -1754,6 +1754,32 @@ out: return ret; } +int ext4_claim_free_blocks(struct ext4_sb_info *sbi, + ext4_fsblk_t nblocks) +{ + s64 free_blocks; + ext4_fsblk_t root_blocks = 0; + struct percpu_counter *fbc = &sbi->s_freeblocks_counter; + + free_blocks = percpu_counter_read(fbc); + + if (!capable(CAP_SYS_RESOURCE) && + sbi->s_resuid != current->fsuid && + (sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid))) + root_blocks = ext4_r_blocks_count(sbi->s_es); + + if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK) + free_blocks = percpu_counter_sum(&sbi->s_freeblocks_counter); + + if (free_blocks < (root_blocks + nblocks)) + /* we don't have free space */ + return -ENOSPC; + + /* reduce fs free blocks counter */ + percpu_counter_sub(fbc, nblocks); + return 0; +} + /** * ext4_has_free_blocks() * @sbi: in-core super block structure. @@ -1775,18 +1801,17 @@ ext4_fsblk_t ext4_has_free_blocks(struct sbi->s_resuid != current->fsuid && (sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid))) root_blocks = ext4_r_blocks_count(sbi->s_es); -#ifdef CONFIG_SMP - if (free_blocks - root_blocks < FBC_BATCH) - free_blocks = - percpu_counter_sum(&sbi->s_freeblocks_counter); -#endif + + if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK) + free_blocks = percpu_counter_sum_positive(&sbi->s_freeblocks_counter); + if (free_blocks <= root_blocks) /* we don't have free space */ return 0; if (free_blocks - root_blocks < nblocks) return free_blocks - root_blocks; return nblocks; - } +} /** @@ -1865,14 +1890,11 @@ ext4_fsblk_t ext4_old_new_blocks(handle_ /* * With delalloc we already reserved the blocks */ - *count = ext4_has_free_blocks(sbi, *count); - } - if (*count == 0) { - *errp = -ENOSPC; - return 0; /*return with ENOSPC error */ + if (ext4_claim_free_blocks(sbi, *count)) { + *errp = -ENOSPC; + return 0; /*return with ENOSPC error */ + } } - num = *count; - /* * Check quota for allocation of this block. */ @@ -2067,9 +2089,13 @@ allocated: le16_add_cpu(&gdp->bg_free_blocks_count, -num); gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp); spin_unlock(sb_bgl_lock(sbi, group_no)); - if (!EXT4_I(inode)->i_delalloc_reserved_flag) - percpu_counter_sub(&sbi->s_freeblocks_counter, num); - + if (!EXT4_I(inode)->i_delalloc_reserved_flag && (*count != num)) { + /* + * we allocated less blocks than we + * claimed. Add the difference back. + */ + percpu_counter_add(&sbi->s_freeblocks_counter, *count - num); + } if (sbi->s_log_groups_per_flex) { ext4_group_t flex_group = ext4_flex_group(sbi, group_no); spin_lock(sb_bgl_lock(sbi, flex_group)); --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1015,6 +1015,8 @@ extern ext4_fsblk_t ext4_new_blocks(hand unsigned long *count, int *errp); extern ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode, ext4_fsblk_t goal, unsigned long *count, int *errp); +extern int ext4_claim_free_blocks(struct ext4_sb_info *sbi, + ext4_fsblk_t nblocks); extern ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi, ext4_fsblk_t nblocks); extern void ext4_free_blocks (handle_t *handle, struct inode *inode, @@ -1245,6 +1247,17 @@ do { \ __ext4_std_error((sb), __func__, (errno)); \ } while (0) +#ifdef CONFIG_SMP +/* Each CPU can accumulate FBC_BATCH blocks in their local + * counters. So we need to make sure we have free blocks more + * than FBC_BATCH * nr_cpu_ids. Also add a window of 4 times. + */ +#define EXT4_FREEBLOCKS_WATERMARK (4 * (FBC_BATCH * nr_cpu_ids)) +#else +#define EXT4_FREEBLOCKS_WATERMARK 0 +#endif + + /* * Inodes and files operations */ --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1564,13 +1564,10 @@ static int ext4_da_reserve_space(struct md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks; total = md_needed + nrblocks; - if (ext4_has_free_blocks(sbi, total) < total) { + if (ext4_claim_free_blocks(sbi, total)) { spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); return -ENOSPC; } - /* reduce fs free blocks counter */ - percpu_counter_sub(&sbi->s_freeblocks_counter, total); - EXT4_I(inode)->i_reserved_data_blocks += nrblocks; EXT4_I(inode)->i_reserved_meta_blocks = mdblocks; --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3194,9 +3194,15 @@ ext4_mb_mark_diskspace_used(struct ext4_ * at write_begin() time for delayed allocation * do not double accounting */ - if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED)) - percpu_counter_sub(&sbi->s_freeblocks_counter, - ac->ac_b_ex.fe_len); + if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED) && + ac->ac_o_ex.fe_len != ac->ac_b_ex.fe_len) { + /* + * we allocated less blocks than we calimed + * Add the difference back + */ + percpu_counter_add(&sbi->s_freeblocks_counter, + ac->ac_o_ex.fe_len - ac->ac_b_ex.fe_len); + } if (sbi->s_log_groups_per_flex) { ext4_group_t flex_group = ext4_flex_group(sbi, @@ -4649,14 +4655,11 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t /* * With delalloc we already reserved the blocks */ - ar->len = ext4_has_free_blocks(sbi, ar->len); - } - - if (ar->len == 0) { - *errp = -ENOSPC; - return 0; + if (ext4_claim_free_blocks(sbi, ar->len)) { + *errp = -ENOSPC; + return 0; + } } - while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) { ar->flags |= EXT4_MB_HINT_NOPREALLOC; ar->len--;