Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967900Ab0B0HXZ (ORCPT ); Sat, 27 Feb 2010 02:23:25 -0500 Received: from bosmailout07.eigbox.net ([66.96.187.7]:50444 "EHLO bosmailout07.eigbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967882Ab0B0HXN (ORCPT ); Sat, 27 Feb 2010 02:23:13 -0500 X-EN-OrigOutIP: 10.20.18.4 X-EN-IMPSID: muqV1d00205GATN01uqV3z Message-ID: <4B88BC7A.4020005@jaysonking.com> Date: Sat, 27 Feb 2010 00:32:26 -0600 From: "Jayson R. King" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Thunderbird/3.0.1 MIME-Version: 1.0 To: LKML , Stable team , Greg Kroah-Hartman CC: "Aneesh Kumar K.V" , Mingming Cao , "Theodore Ts'o" , linux-ext4@vger.kernel.org, Andrew Morton , Jayson King Subject: [03/11] ext4: Make sure all the block allocation paths reserve blocks References: <4B88BA1B.4050500@jaysonking.com> In-Reply-To: <4B88BA1B.4050500@jaysonking.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-EN-UserInfo: 06af1bc540adb20c3d2d7097199478a6:08dd1976e651f6e3791fbe97eaa5f898 X-EN-AuthUser: jaysonking@jaysonking.com X-EN-OrigIP: 69.150.131.230 X-EN-OrigHost: unknown Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7680 Lines: 218 From: Aneesh Kumar K.V Date: Thu Oct 9 10:56:23 2008 -0400 Subject: ext4: Make sure all the block allocation paths reserve blocks 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 --- 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(-) diff -urNp linux-2.6.27.orig/fs/ext4/balloc.c linux-2.6.27/fs/ext4/balloc.c --- linux-2.6.27.orig/fs/ext4/balloc.c 2010-02-26 14:19:37.651252924 -0600 +++ linux-2.6.27/fs/ext4/balloc.c 2010-02-26 14:20:04.172252779 -0600 @@ -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)); diff -urNp linux-2.6.27.orig/fs/ext4/ext4.h linux-2.6.27/fs/ext4/ext4.h --- linux-2.6.27.orig/fs/ext4/ext4.h 2010-02-26 14:10:41.167252303 -0600 +++ linux-2.6.27/fs/ext4/ext4.h 2010-02-26 14:20:04.172252779 -0600 @@ -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 */ diff -urNp linux-2.6.27.orig/fs/ext4/inode.c linux-2.6.27/fs/ext4/inode.c --- linux-2.6.27.orig/fs/ext4/inode.c 2010-02-26 14:15:33.187252503 -0600 +++ linux-2.6.27/fs/ext4/inode.c 2010-02-26 14:20:04.173252623 -0600 @@ -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; diff -urNp linux-2.6.27.orig/fs/ext4/mballoc.c linux-2.6.27/fs/ext4/mballoc.c --- linux-2.6.27.orig/fs/ext4/mballoc.c 2010-02-26 14:10:41.169252348 -0600 +++ linux-2.6.27/fs/ext4/mballoc.c 2010-02-26 14:20:04.174252546 -0600 @@ -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--; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/