From patchwork Mon Sep 21 14:43:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Goldwyn Rodrigues X-Patchwork-Id: 11790245 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EE4046CA for ; Mon, 21 Sep 2020 14:45:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD9E42311D for ; Mon, 21 Sep 2020 14:45:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728293AbgIUOoc (ORCPT ); Mon, 21 Sep 2020 10:44:32 -0400 Received: from mx2.suse.de ([195.135.220.15]:56006 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727760AbgIUOo3 (ORCPT ); Mon, 21 Sep 2020 10:44:29 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3A0CAAD6B; Mon, 21 Sep 2020 14:45:04 +0000 (UTC) From: Goldwyn Rodrigues To: linux-fsdevel@vger.kernel.org Cc: linux-btrfs@vger.kernel.org, david@fromorbit.com, hch@lst.de, johannes.thumshirn@wdc.com, dsterba@suse.com, darrick.wong@oracle.com, josef@toxicpanda.com, Goldwyn Rodrigues Subject: [PATCH 08/15] btrfs: Introduce btrfs_write_check() Date: Mon, 21 Sep 2020 09:43:46 -0500 Message-Id: <20200921144353.31319-9-rgoldwyn@suse.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200921144353.31319-1-rgoldwyn@suse.de> References: <20200921144353.31319-1-rgoldwyn@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Goldwyn Rodrigues btrfs_write_check() checks for all parameters in one place before beginning a write. This does away with inode_unlock() after every check. In the later patches, it will help push inode_lock/unlock() in buffered and direct write functions respectively. Signed-off-by: Goldwyn Rodrigues --- fs/btrfs/file.c | 159 ++++++++++++++++++++++++------------------------ 1 file changed, 81 insertions(+), 78 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index ca374cb5ffc9..0f961ce1fa98 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1615,6 +1615,85 @@ void btrfs_check_nocow_unlock(struct btrfs_inode *inode) btrfs_drew_write_unlock(&inode->root->snapshot_lock); } +static void update_time_for_write(struct inode *inode) +{ + struct timespec64 now; + + if (IS_NOCMTIME(inode)) + return; + + now = current_time(inode); + if (!timespec64_equal(&inode->i_mtime, &now)) + inode->i_mtime = now; + + if (!timespec64_equal(&inode->i_ctime, &now)) + inode->i_ctime = now; + + if (IS_I_VERSION(inode)) + inode_inc_iversion(inode); +} + +static size_t btrfs_write_check(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + loff_t pos = iocb->ki_pos; + size_t count = iov_iter_count(from); + int err; + loff_t oldsize; + loff_t start_pos; + + err = generic_write_checks(iocb, from); + if (err <= 0) + return err; + + if (iocb->ki_flags & IOCB_NOWAIT) { + size_t nocow_bytes = count; + + /* + * We will allocate space in case nodatacow is not set, + * so bail + */ + if (check_nocow_nolock(BTRFS_I(inode), pos, &nocow_bytes) + <= 0) + return -EAGAIN; + /* + * There are holes in the range or parts of the range that must + * be COWed (shared extents, RO block groups, etc), so just bail + * out. + */ + if (nocow_bytes < count) + return -EAGAIN; + } + + current->backing_dev_info = inode_to_bdi(inode); + err = file_remove_privs(file); + if (err) + return err; + + /* + * We reserve space for updating the inode when we reserve space for the + * extent we are going to write, so we will enospc out there. We don't + * need to start yet another transaction to update the inode as we will + * update the inode when we finish writing whatever data we write. + */ + update_time_for_write(inode); + + start_pos = round_down(pos, fs_info->sectorsize); + oldsize = i_size_read(inode); + if (start_pos > oldsize) { + /* Expand hole size to cover write data, preventing empty gap */ + loff_t end_pos = round_up(pos + count, + fs_info->sectorsize); + err = btrfs_cont_expand(inode, oldsize, end_pos); + if (err) + return err; + } + + return count; +} + static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i) { @@ -1947,24 +2026,6 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from) return written ? written : err; } -static void update_time_for_write(struct inode *inode) -{ - struct timespec64 now; - - if (IS_NOCMTIME(inode)) - return; - - now = current_time(inode); - if (!timespec64_equal(&inode->i_mtime, &now)) - inode->i_mtime = now; - - if (!timespec64_equal(&inode->i_ctime, &now)) - inode->i_ctime = now; - - if (IS_I_VERSION(inode)) - inode_inc_iversion(inode); -} - static ssize_t btrfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { @@ -1972,14 +2033,9 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, struct inode *inode = file_inode(file); struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct btrfs_root *root = BTRFS_I(inode)->root; - u64 start_pos; - u64 end_pos; ssize_t num_written = 0; const bool sync = iocb->ki_flags & IOCB_DSYNC; ssize_t err; - loff_t pos; - size_t count; - loff_t oldsize; /* * If BTRFS flips readonly due to some impossible error @@ -2001,65 +2057,12 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, inode_lock(inode); } - err = generic_write_checks(iocb, from); + err = btrfs_write_check(iocb, from); if (err <= 0) { inode_unlock(inode); return err; } - pos = iocb->ki_pos; - count = iov_iter_count(from); - if (iocb->ki_flags & IOCB_NOWAIT) { - size_t nocow_bytes = count; - - /* - * We will allocate space in case nodatacow is not set, - * so bail - */ - if (check_nocow_nolock(BTRFS_I(inode), pos, &nocow_bytes) - <= 0) { - inode_unlock(inode); - return -EAGAIN; - } - /* - * There are holes in the range or parts of the range that must - * be COWed (shared extents, RO block groups, etc), so just bail - * out. - */ - if (nocow_bytes < count) { - inode_unlock(inode); - return -EAGAIN; - } - } - - current->backing_dev_info = inode_to_bdi(inode); - err = file_remove_privs(file); - if (err) { - inode_unlock(inode); - goto out; - } - - /* - * We reserve space for updating the inode when we reserve space for the - * extent we are going to write, so we will enospc out there. We don't - * need to start yet another transaction to update the inode as we will - * update the inode when we finish writing whatever data we write. - */ - update_time_for_write(inode); - - start_pos = round_down(pos, fs_info->sectorsize); - oldsize = i_size_read(inode); - if (start_pos > oldsize) { - /* Expand hole size to cover write data, preventing empty gap */ - end_pos = round_up(pos + count, - fs_info->sectorsize); - err = btrfs_cont_expand(inode, oldsize, end_pos); - if (err) { - inode_unlock(inode); - goto out; - } - } - if (sync) atomic_inc(&BTRFS_I(inode)->sync_writers); @@ -2117,7 +2120,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, if (sync) atomic_dec(&BTRFS_I(inode)->sync_writers); -out: + current->backing_dev_info = NULL; return num_written ? num_written : err; }