From: Jan Kara <jack@suse.cz>
To: <linux-fsdevel@vger.kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>,
Amir Goldstein <amir73il@gmail.com>,
Dave Chinner <david@fromorbit.com>, Ted Tso <tytso@mit.edu>,
Jan Kara <jack@suse.cz>, Jeff Layton <jlayton@kernel.org>,
ceph-devel@vger.kernel.org
Subject: [PATCH 11/12] ceph: Fix race between hole punch and page fault
Date: Fri, 23 Apr 2021 19:29:40 +0200 [thread overview]
Message-ID: <20210423173018.23133-11-jack@suse.cz> (raw)
In-Reply-To: <20210423171010.12-1-jack@suse.cz>
Ceph has a following race between hole punching and page fault:
CPU1 CPU2
ceph_fallocate()
...
ceph_zero_pagecache_range()
ceph_filemap_fault()
faults in page in the range being
punched
ceph_zero_objects()
And now we have a page in punched range with invalid data. Fix the
problem by using mapping->invalidate_lock similarly to other
filesystems. Note that using invalidate_lock also fixes a similar race
wrt ->readpage().
CC: Jeff Layton <jlayton@kernel.org>
CC: ceph-devel@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/ceph/addr.c | 9 ++++++---
fs/ceph/file.c | 2 ++
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 26e66436f005..4f45e9754b5a 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1519,9 +1519,11 @@ static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
ret = VM_FAULT_SIGBUS;
} else {
struct address_space *mapping = inode->i_mapping;
- struct page *page = find_or_create_page(mapping, 0,
- mapping_gfp_constraint(mapping,
- ~__GFP_FS));
+ struct page *page;
+
+ down_read(&mapping->invalidate_lock);
+ page = find_or_create_page(mapping, 0,
+ mapping_gfp_constraint(mapping, ~__GFP_FS));
if (!page) {
ret = VM_FAULT_OOM;
goto out_inline;
@@ -1542,6 +1544,7 @@ static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
vmf->page = page;
ret = VM_FAULT_MAJOR | VM_FAULT_LOCKED;
out_inline:
+ up_read(&mapping->invalidate_lock);
dout("filemap_fault %p %llu~%zd read inline data ret %x\n",
inode, off, (size_t)PAGE_SIZE, ret);
}
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 209535d5b8d3..40fee8ff5cf9 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -2087,6 +2087,7 @@ static long ceph_fallocate(struct file *file, int mode,
if (ret < 0)
goto unlock;
+ down_write(&inode->i_mapping->invalidate_lock);
ceph_zero_pagecache_range(inode, offset, length);
ret = ceph_zero_objects(inode, offset, length);
@@ -2099,6 +2100,7 @@ static long ceph_fallocate(struct file *file, int mode,
if (dirty)
__mark_inode_dirty(inode, dirty);
}
+ up_write(&inode->i_mapping->invalidate_lock);
ceph_put_cap_refs(ci, got);
unlock:
--
2.26.2
next prev parent reply other threads:[~2021-04-23 17:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 17:29 [PATCH 0/12 v4] fs: Hole punch vs page cache filling races Jan Kara
2021-04-23 17:29 ` [PATCH 02/12] mm: Protect operations adding pages to page cache with invalidate_lock Jan Kara
2021-04-23 18:30 ` Matthew Wilcox
2021-04-23 23:04 ` Dave Chinner
2021-04-26 15:46 ` Jan Kara
2021-04-23 17:29 ` Jan Kara [this message]
2021-04-23 22:07 ` [PATCH 0/12 v4] fs: Hole punch vs page cache filling races Dave Chinner
2021-04-23 23:51 ` Matthew Wilcox
2021-04-24 6:11 ` Christoph Hellwig
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