From patchwork Wed May 12 13:46:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 12253651 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8ED42C43460 for ; Wed, 12 May 2021 13:46:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74274613E6 for ; Wed, 12 May 2021 13:46:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231283AbhELNrq (ORCPT ); Wed, 12 May 2021 09:47:46 -0400 Received: from mx2.suse.de ([195.135.220.15]:41626 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231163AbhELNro (ORCPT ); Wed, 12 May 2021 09:47:44 -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 BC448B186; Wed, 12 May 2021 13:46:32 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 055701F2B6A; Wed, 12 May 2021 15:46:32 +0200 (CEST) From: Jan Kara To: Cc: Christoph Hellwig , Dave Chinner , ceph-devel@vger.kernel.org, Chao Yu , Damien Le Moal , "Darrick J. Wong" , Jaegeuk Kim , Jeff Layton , Johannes Thumshirn , linux-cifs@vger.kernel.org, , linux-f2fs-devel@lists.sourceforge.net, , , Miklos Szeredi , Steve French , Ted Tso , Matthew Wilcox , Jan Kara Subject: [PATCH 09/11] fuse: Convert to using invalidate_lock Date: Wed, 12 May 2021 15:46:17 +0200 Message-Id: <20210512134631.4053-9-jack@suse.cz> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210512101639.22278-1-jack@suse.cz> References: <20210512101639.22278-1-jack@suse.cz> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Use invalidate_lock instead of fuse's private i_mmap_sem. The intended purpose is exactly the same. By this conversion we fix a long standing race between hole punching and read(2) / readahead(2) paths that can lead to stale page cache contents. CC: Miklos Szeredi Signed-off-by: Jan Kara --- fs/fuse/dax.c | 50 +++++++++++++++++++++++------------------------- fs/fuse/dir.c | 11 ++++++----- fs/fuse/file.c | 10 +++++----- fs/fuse/fuse_i.h | 7 ------- fs/fuse/inode.c | 1 - 5 files changed, 35 insertions(+), 44 deletions(-) diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c index ff99ab2a3c43..03e5477ee913 100644 --- a/fs/fuse/dax.c +++ b/fs/fuse/dax.c @@ -443,12 +443,12 @@ static int fuse_setup_new_dax_mapping(struct inode *inode, loff_t pos, /* * Can't do inline reclaim in fault path. We call * dax_layout_busy_page() before we free a range. And - * fuse_wait_dax_page() drops fi->i_mmap_sem lock and requires it. - * In fault path we enter with fi->i_mmap_sem held and can't drop - * it. Also in fault path we hold fi->i_mmap_sem shared and not - * exclusive, so that creates further issues with fuse_wait_dax_page(). - * Hence return -EAGAIN and fuse_dax_fault() will wait for a memory - * range to become free and retry. + * fuse_wait_dax_page() drops mapping->invalidate_lock and requires it. + * In fault path we enter with mapping->invalidate_lock held and can't + * drop it. Also in fault path we hold mapping->invalidate_lock shared + * and not exclusive, so that creates further issues with + * fuse_wait_dax_page(). Hence return -EAGAIN and fuse_dax_fault() + * will wait for a memory range to become free and retry. */ if (flags & IOMAP_FAULT) { alloc_dmap = alloc_dax_mapping(fcd); @@ -512,7 +512,7 @@ static int fuse_upgrade_dax_mapping(struct inode *inode, loff_t pos, down_write(&fi->dax->sem); node = interval_tree_iter_first(&fi->dax->tree, idx, idx); - /* We are holding either inode lock or i_mmap_sem, and that should + /* We are holding either inode lock or invalidate_lock, and that should * ensure that dmap can't be truncated. We are holding a reference * on dmap and that should make sure it can't be reclaimed. So dmap * should still be there in tree despite the fact we dropped and @@ -659,14 +659,12 @@ static const struct iomap_ops fuse_iomap_ops = { static void fuse_wait_dax_page(struct inode *inode) { - struct fuse_inode *fi = get_fuse_inode(inode); - - up_write(&fi->i_mmap_sem); + up_write(&inode->i_mapping->invalidate_lock); schedule(); - down_write(&fi->i_mmap_sem); + down_write(&inode->i_mapping->invalidate_lock); } -/* Should be called with fi->i_mmap_sem lock held exclusively */ +/* Should be called with mapping->invalidate_lock held exclusively */ static int __fuse_dax_break_layouts(struct inode *inode, bool *retry, loff_t start, loff_t end) { @@ -812,18 +810,18 @@ static vm_fault_t __fuse_dax_fault(struct vm_fault *vmf, * we do not want any read/write/mmap to make progress and try * to populate page cache or access memory we are trying to free. */ - down_read(&get_fuse_inode(inode)->i_mmap_sem); + down_read(&inode->i_mapping->invalidate_lock); ret = dax_iomap_fault(vmf, pe_size, &pfn, &error, &fuse_iomap_ops); if ((ret & VM_FAULT_ERROR) && error == -EAGAIN) { error = 0; retry = true; - up_read(&get_fuse_inode(inode)->i_mmap_sem); + up_read(&inode->i_mapping->invalidate_lock); goto retry; } if (ret & VM_FAULT_NEEDDSYNC) ret = dax_finish_sync_fault(vmf, pe_size, pfn); - up_read(&get_fuse_inode(inode)->i_mmap_sem); + up_read(&inode->i_mapping->invalidate_lock); if (write) sb_end_pagefault(sb); @@ -959,7 +957,7 @@ inode_inline_reclaim_one_dmap(struct fuse_conn_dax *fcd, struct inode *inode, int ret; struct interval_tree_node *node; - down_write(&fi->i_mmap_sem); + down_write(&inode->i_mapping->invalidate_lock); /* Lookup a dmap and corresponding file offset to reclaim. */ down_read(&fi->dax->sem); @@ -1020,7 +1018,7 @@ inode_inline_reclaim_one_dmap(struct fuse_conn_dax *fcd, struct inode *inode, out_write_dmap_sem: up_write(&fi->dax->sem); out_mmap_sem: - up_write(&fi->i_mmap_sem); + up_write(&inode->i_mapping->invalidate_lock); return dmap; } @@ -1049,10 +1047,10 @@ alloc_dax_mapping_reclaim(struct fuse_conn_dax *fcd, struct inode *inode) * had a reference or some other temporary failure, * Try again. We want to give up inline reclaim only * if there is no range assigned to this node. Otherwise - * if a deadlock is possible if we sleep with fi->i_mmap_sem - * held and worker to free memory can't make progress due - * to unavailability of fi->i_mmap_sem lock. So sleep - * only if fi->dax->nr=0 + * if a deadlock is possible if we sleep with + * mapping->invalidate_lock held and worker to free memory + * can't make progress due to unavailability of + * mapping->invalidate_lock. So sleep only if fi->dax->nr=0 */ if (retry) continue; @@ -1060,8 +1058,8 @@ alloc_dax_mapping_reclaim(struct fuse_conn_dax *fcd, struct inode *inode) * There are no mappings which can be reclaimed. Wait for one. * We are not holding fi->dax->sem. So it is possible * that range gets added now. But as we are not holding - * fi->i_mmap_sem, worker should still be able to free up - * a range and wake us up. + * mapping->invalidate_lock, worker should still be able to + * free up a range and wake us up. */ if (!fi->dax->nr && !(fcd->nr_free_ranges > 0)) { if (wait_event_killable_exclusive(fcd->range_waitq, @@ -1107,7 +1105,7 @@ static int lookup_and_reclaim_dmap_locked(struct fuse_conn_dax *fcd, /* * Free a range of memory. * Locking: - * 1. Take fi->i_mmap_sem to block dax faults. + * 1. Take mapping->invalidate_lock to block dax faults. * 2. Take fi->dax->sem to protect interval tree and also to make sure * read/write can not reuse a dmap which we might be freeing. */ @@ -1121,7 +1119,7 @@ static int lookup_and_reclaim_dmap(struct fuse_conn_dax *fcd, loff_t dmap_start = start_idx << FUSE_DAX_SHIFT; loff_t dmap_end = (dmap_start + FUSE_DAX_SZ) - 1; - down_write(&fi->i_mmap_sem); + down_write(&inode->i_mapping->invalidate_lock); ret = fuse_dax_break_layouts(inode, dmap_start, dmap_end); if (ret) { pr_debug("virtio_fs: fuse_dax_break_layouts() failed. err=%d\n", @@ -1133,7 +1131,7 @@ static int lookup_and_reclaim_dmap(struct fuse_conn_dax *fcd, ret = lookup_and_reclaim_dmap_locked(fcd, inode, start_idx); up_write(&fi->dax->sem); out_mmap_sem: - up_write(&fi->i_mmap_sem); + up_write(&inode->i_mapping->invalidate_lock); return ret; } diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 1b6c001a7dd1..0ab27170da11 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1601,6 +1601,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, struct fuse_mount *fm = get_fuse_mount(inode); struct fuse_conn *fc = fm->fc; struct fuse_inode *fi = get_fuse_inode(inode); + struct address_space *mapping = inode->i_mapping; FUSE_ARGS(args); struct fuse_setattr_in inarg; struct fuse_attr_out outarg; @@ -1625,11 +1626,11 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, } if (FUSE_IS_DAX(inode) && is_truncate) { - down_write(&fi->i_mmap_sem); + down_write(&mapping->invalidate_lock); fault_blocked = true; err = fuse_dax_break_layouts(inode, 0, 0); if (err) { - up_write(&fi->i_mmap_sem); + up_write(&mapping->invalidate_lock); return err; } } @@ -1739,13 +1740,13 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, if ((is_truncate || !is_wb) && S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) { truncate_pagecache(inode, outarg.attr.size); - invalidate_inode_pages2(inode->i_mapping); + invalidate_inode_pages2(mapping); } clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); out: if (fault_blocked) - up_write(&fi->i_mmap_sem); + up_write(&mapping->invalidate_lock); return 0; @@ -1756,7 +1757,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); if (fault_blocked) - up_write(&fi->i_mmap_sem); + up_write(&mapping->invalidate_lock); return err; } diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 09ef2a4d25ed..22be837169a7 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -243,7 +243,7 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir) } if (dax_truncate) { - down_write(&get_fuse_inode(inode)->i_mmap_sem); + down_write(&inode->i_mapping->invalidate_lock); err = fuse_dax_break_layouts(inode, 0, 0); if (err) goto out; @@ -255,7 +255,7 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir) out: if (dax_truncate) - up_write(&get_fuse_inode(inode)->i_mmap_sem); + up_write(&inode->i_mapping->invalidate_lock); if (is_wb_truncate | dax_truncate) { fuse_release_nowrite(inode); @@ -2920,7 +2920,7 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset, if (lock_inode) { inode_lock(inode); if (block_faults) { - down_write(&fi->i_mmap_sem); + down_write(&inode->i_mapping->invalidate_lock); err = fuse_dax_break_layouts(inode, 0, 0); if (err) goto out; @@ -2976,7 +2976,7 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset, clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); if (block_faults) - up_write(&fi->i_mmap_sem); + up_write(&inode->i_mapping->invalidate_lock); if (lock_inode) inode_unlock(inode); @@ -3045,7 +3045,7 @@ static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in, * modifications. Yet this does give less guarantees than if the * copying was performed with write(2). * - * To fix this a i_mmap_sem style lock could be used to prevent new + * To fix this a mapping->invalidate_lock could be used to prevent new * faults while the copy is ongoing. */ err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1); diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 7e463e220053..5130e88f811e 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -149,13 +149,6 @@ struct fuse_inode { /** Lock to protect write related fields */ spinlock_t lock; - /** - * Can't take inode lock in fault path (leads to circular dependency). - * Introduce another semaphore which can be taken in fault path and - * then other filesystem paths can take this to block faults. - */ - struct rw_semaphore i_mmap_sem; - #ifdef CONFIG_FUSE_DAX /* * Dax specific inode data diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 393e36b74dc4..f73bab71a0a0 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -85,7 +85,6 @@ static struct inode *fuse_alloc_inode(struct super_block *sb) fi->orig_ino = 0; fi->state = 0; mutex_init(&fi->mutex); - init_rwsem(&fi->i_mmap_sem); spin_lock_init(&fi->lock); fi->forget = fuse_alloc_forget(); if (!fi->forget)