From: Jan Kara <jack@suse.cz> To: <linux-fsdevel@vger.kernel.org> Cc: Christoph Hellwig <hch@infradead.org>, Dave Chinner <david@fromorbit.com>, ceph-devel@vger.kernel.org, Chao Yu <yuchao0@huawei.com>, Damien Le Moal <damien.lemoal@wdc.com>, "Darrick J. Wong" <darrick.wong@oracle.com>, Jaegeuk Kim <jaegeuk@kernel.org>, Jeff Layton <jlayton@kernel.org>, Johannes Thumshirn <jth@kernel.org>, linux-cifs@vger.kernel.org, <linux-ext4@vger.kernel.org>, linux-f2fs-devel@lists.sourceforge.net, <linux-mm@kvack.org>, <linux-xfs@vger.kernel.org>, Miklos Szeredi <miklos@szeredi.hu>, Steve French <sfrench@samba.org>, Ted Tso <tytso@mit.edu>, Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz> Subject: [PATCH 11/13] fuse: Convert to using invalidate_lock Date: Tue, 25 May 2021 15:50:48 +0200 [thread overview] Message-ID: <20210525135100.11221-11-jack@suse.cz> (raw) In-Reply-To: <20210525125652.20457-1-jack@suse.cz> 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 <miklos@szeredi.hu> Signed-off-by: Jan Kara <jack@suse.cz> --- 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) -- 2.26.2
next prev parent reply other threads:[~2021-05-25 13:51 UTC|newest] Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-25 13:50 [PATCH 0/13 v6] fs: Hole punch vs page cache filling races Jan Kara 2021-05-25 13:50 ` [PATCH 01/13] mm: Fix comments mentioning i_mutex Jan Kara 2021-05-25 13:50 ` [PATCH 02/13] documentation: Sync file_operations members with reality Jan Kara 2021-05-25 20:43 ` Darrick J. Wong 2021-05-25 13:50 ` [PATCH 03/13] mm: Protect operations adding pages to page cache with invalidate_lock Jan Kara 2021-05-25 21:01 ` Darrick J. Wong 2021-05-26 10:00 ` Jan Kara 2021-05-25 13:50 ` [PATCH 04/13] mm: Add functions to lock invalidate_lock for two mappings Jan Kara 2021-05-25 20:48 ` Darrick J. Wong 2021-05-26 10:07 ` Jan Kara 2021-05-26 12:11 ` Damien Le Moal 2021-05-26 13:45 ` Jan Kara 2021-05-26 15:25 ` Darrick J. Wong 2021-05-25 13:50 ` [PATCH 05/13] ext4: Convert to use mapping->invalidate_lock Jan Kara 2021-05-25 13:50 ` [PATCH 06/13] ext2: Convert to using invalidate_lock Jan Kara 2021-05-25 13:50 ` [PATCH 07/13] xfs: Convert to use invalidate_lock Jan Kara 2021-05-25 21:37 ` Darrick J. Wong 2021-05-26 10:18 ` Jan Kara 2021-05-26 15:32 ` Darrick J. Wong 2021-05-27 12:01 ` Jan Kara 2021-05-25 21:40 ` Dave Chinner 2021-05-26 10:20 ` Jan Kara 2021-05-26 13:42 ` Jan Kara 2021-05-25 13:50 ` [PATCH 08/13] xfs: Convert double locking of MMAPLOCK to use VFS helpers Jan Kara 2021-05-25 21:41 ` Darrick J. Wong 2021-05-25 13:50 ` [PATCH 09/13] zonefs: Convert to using invalidate_lock Jan Kara 2021-05-25 13:50 ` [PATCH 10/13] f2fs: " Jan Kara 2021-05-26 9:55 ` Chao Yu 2021-05-25 13:50 ` Jan Kara [this message] 2021-05-25 13:50 ` [PATCH 12/13] ceph: Fix race between hole punch and page fault Jan Kara 2021-05-25 13:50 ` [PATCH 13/13] cifs: " Jan Kara
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20210525135100.11221-11-jack@suse.cz \ --to=jack@suse.cz \ --cc=ceph-devel@vger.kernel.org \ --cc=damien.lemoal@wdc.com \ --cc=darrick.wong@oracle.com \ --cc=david@fromorbit.com \ --cc=hch@infradead.org \ --cc=jaegeuk@kernel.org \ --cc=jlayton@kernel.org \ --cc=jth@kernel.org \ --cc=linux-cifs@vger.kernel.org \ --cc=linux-ext4@vger.kernel.org \ --cc=linux-f2fs-devel@lists.sourceforge.net \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=linux-xfs@vger.kernel.org \ --cc=miklos@szeredi.hu \ --cc=sfrench@samba.org \ --cc=tytso@mit.edu \ --cc=willy@infradead.org \ --cc=yuchao0@huawei.com \ --subject='Re: [PATCH 11/13] fuse: Convert to using invalidate_lock' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).