From patchwork Tue Nov 10 19:50:56 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 542577 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 1B98E141431 for ; Wed, 11 Nov 2015 06:55:02 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751561AbbKJTwd (ORCPT ); Tue, 10 Nov 2015 14:52:33 -0500 Received: from mx2.suse.de ([195.135.220.15]:52903 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751731AbbKJTvR (ORCPT ); Tue, 10 Nov 2015 14:51:17 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 90D97ADA5; Tue, 10 Nov 2015 19:50:54 +0000 (UTC) Received: by quack.suse.cz (Postfix, from userid 1000) id BD42C82832; Tue, 10 Nov 2015 20:51:11 +0100 (CET) From: Jan Kara To: Ted Tso Cc: linux-ext4@vger.kernel.org, Ross Zwisler , dan.j.williams@intel.com, brian.boylston@hpe.com, Jan Kara Subject: [PATCH 6/9] ext4: Get rid of EXT4_GET_BLOCKS_NO_LOCK flag Date: Tue, 10 Nov 2015 20:50:56 +0100 Message-Id: <1447185059-16166-7-git-send-email-jack@suse.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1447185059-16166-1-git-send-email-jack@suse.com> References: <1447185059-16166-1-git-send-email-jack@suse.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org When dioread_nolock mode is enabled, we grab i_data_sem in ext4_ext_direct_IO() and therefore we need to instruct _ext4_get_block() not to grab i_data_sem again using EXT4_GET_BLOCKS_NO_LOCK. However holding i_data_sem over overwrite direct IO isn't needed these days. We have exclusion against truncate / hole punching because we increase i_dio_count under i_mutex in ext4_ext_direct_IO() so once ext4_file_write_iter() verifies blocks are allocated & written, they are guaranteed to stay so during the whole direct IO even after we drop i_mutex. So we can just remove this locking abuse and the no longer necessary EXT4_GET_BLOCKS_NO_LOCK flag. Signed-off-by: Jan Kara --- fs/ext4/ext4.h | 4 +--- fs/ext4/inode.c | 43 ++++++++++++++++++++----------------------- include/trace/events/ext4.h | 3 +-- 3 files changed, 22 insertions(+), 28 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index d049fc76efcd..1d09345c9793 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -554,10 +554,8 @@ enum { #define EXT4_GET_BLOCKS_NO_NORMALIZE 0x0040 /* Request will not result in inode size update (user for fallocate) */ #define EXT4_GET_BLOCKS_KEEP_SIZE 0x0080 - /* Do not take i_data_sem locking in ext4_map_blocks */ -#define EXT4_GET_BLOCKS_NO_LOCK 0x0100 /* Convert written extents to unwritten */ -#define EXT4_GET_BLOCKS_CONVERT_UNWRITTEN 0x0200 +#define EXT4_GET_BLOCKS_CONVERT_UNWRITTEN 0x0100 /* * The bit position of these flags must not overlap with any of the diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index fcd4ab065e4a..528d1a0aebff 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -403,8 +403,7 @@ static void ext4_map_blocks_es_recheck(handle_t *handle, * out taking i_data_sem. So at the time the unwritten extent * could be converted. */ - if (!(flags & EXT4_GET_BLOCKS_NO_LOCK)) - down_read(&EXT4_I(inode)->i_data_sem); + down_read(&EXT4_I(inode)->i_data_sem); if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { retval = ext4_ext_map_blocks(handle, inode, map, flags & EXT4_GET_BLOCKS_KEEP_SIZE); @@ -412,8 +411,7 @@ static void ext4_map_blocks_es_recheck(handle_t *handle, retval = ext4_ind_map_blocks(handle, inode, map, flags & EXT4_GET_BLOCKS_KEEP_SIZE); } - if (!(flags & EXT4_GET_BLOCKS_NO_LOCK)) - up_read((&EXT4_I(inode)->i_data_sem)); + up_read((&EXT4_I(inode)->i_data_sem)); /* * We don't check m_len because extent will be collpased in status @@ -509,8 +507,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode, * Try to see if we can get the block without requesting a new * file system block. */ - if (!(flags & EXT4_GET_BLOCKS_NO_LOCK)) - down_read(&EXT4_I(inode)->i_data_sem); + down_read(&EXT4_I(inode)->i_data_sem); if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { retval = ext4_ext_map_blocks(handle, inode, map, flags & EXT4_GET_BLOCKS_KEEP_SIZE); @@ -541,8 +538,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode, if (ret < 0) retval = ret; } - if (!(flags & EXT4_GET_BLOCKS_NO_LOCK)) - up_read((&EXT4_I(inode)->i_data_sem)); + up_read((&EXT4_I(inode)->i_data_sem)); found: if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) { @@ -674,7 +670,7 @@ static int _ext4_get_block(struct inode *inode, sector_t iblock, map.m_lblk = iblock; map.m_len = bh->b_size >> inode->i_blkbits; - if (flags && !(flags & EXT4_GET_BLOCKS_NO_LOCK) && !handle) { + if (flags && !handle) { /* Direct IO write... */ if (map.m_len > DIO_MAX_BLOCKS) map.m_len = DIO_MAX_BLOCKS; @@ -879,9 +875,6 @@ int do_journal_get_write_access(handle_t *handle, return ret; } -static int ext4_get_block_write_nolock(struct inode *inode, sector_t iblock, - struct buffer_head *bh_result, int create); - #ifdef CONFIG_EXT4_FS_ENCRYPTION static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len, get_block_t *get_block) @@ -3054,13 +3047,21 @@ int ext4_get_block_write(struct inode *inode, sector_t iblock, EXT4_GET_BLOCKS_IO_CREATE_EXT); } -static int ext4_get_block_write_nolock(struct inode *inode, sector_t iblock, +static int ext4_get_block_overwrite(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { - ext4_debug("ext4_get_block_write_nolock: inode %lu, create flag %d\n", + int ret; + + ext4_debug("ext4_get_block_overwrite: inode %lu, create flag %d\n", inode->i_ino, create); - return _ext4_get_block(inode, iblock, bh_result, - EXT4_GET_BLOCKS_NO_LOCK); + ret = _ext4_get_block(inode, iblock, bh_result, 0); + /* + * Blocks should have been preallocated! ext4_file_write_iter() checks + * that. + */ + WARN_ON_ONCE(!buffer_mapped(bh_result)); + + return ret; } int ext4_get_block_dax(struct inode *inode, sector_t iblock, @@ -3143,10 +3144,8 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter, /* If we do a overwrite dio, i_mutex locking can be released */ overwrite = *((int *)iocb->private); - if (overwrite) { - down_read(&EXT4_I(inode)->i_data_sem); + if (overwrite) mutex_unlock(&inode->i_mutex); - } /* * We could direct write to holes and fallocate. @@ -3189,7 +3188,7 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter, } if (overwrite) { - get_block_func = ext4_get_block_write_nolock; + get_block_func = ext4_get_block_overwrite; } else { get_block_func = ext4_get_block_write; dio_flags = DIO_LOCKING; @@ -3245,10 +3244,8 @@ retake_lock: if (iov_iter_rw(iter) == WRITE) inode_dio_end(inode); /* take i_mutex locking again if we do a ovewrite dio */ - if (overwrite) { - up_read(&EXT4_I(inode)->i_data_sem); + if (overwrite) mutex_lock(&inode->i_mutex); - } return ret; } diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h index 594b4b29a224..5f2ace56efc5 100644 --- a/include/trace/events/ext4.h +++ b/include/trace/events/ext4.h @@ -42,8 +42,7 @@ struct extent_status; { EXT4_GET_BLOCKS_CONVERT, "CONVERT" }, \ { EXT4_GET_BLOCKS_METADATA_NOFAIL, "METADATA_NOFAIL" }, \ { EXT4_GET_BLOCKS_NO_NORMALIZE, "NO_NORMALIZE" }, \ - { EXT4_GET_BLOCKS_KEEP_SIZE, "KEEP_SIZE" }, \ - { EXT4_GET_BLOCKS_NO_LOCK, "NO_LOCK" }) + { EXT4_GET_BLOCKS_KEEP_SIZE, "KEEP_SIZE" }) #define show_mflags(flags) __print_flags(flags, "", \ { EXT4_MAP_NEW, "N" }, \