diff options
| author | Jan Kara <jack@suse.cz> | 2021-04-22 16:38:26 +0200 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2021-07-13 14:29:01 +0200 |
| commit | 057ba5b24532aca202cb1ae8c246bde27de12763 (patch) | |
| tree | 3abff803cddcd5ef21b135f6c31cb1d05f908e6a | |
| parent | 8bcbbe9c7c8e49281fc2e0a6c5455b87c85a9c2a (diff) | |
| download | linux-057ba5b24532aca202cb1ae8c246bde27de12763.tar.gz | |
ceph: Fix race between hole punch and page fault
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
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
| -rw-r--r-- | fs/ceph/addr.c | 9 | ||||
| -rw-r--r-- | 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 a1e2813731d1..7e7a897ae0d3 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -1395,9 +1395,11 @@ 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; + + filemap_invalidate_lock_shared(mapping); + page = find_or_create_page(mapping, 0, + mapping_gfp_constraint(mapping, ~__GFP_FS)); if (!page) { ret = VM_FAULT_OOM; goto out_inline; @@ -1418,6 +1420,7 @@ static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf) vmf->page = page; ret = VM_FAULT_MAJOR | VM_FAULT_LOCKED; out_inline: + filemap_invalidate_unlock_shared(mapping); dout("filemap_fault %p %llu read inline data ret %x\n", inode, off, ret); } diff --git a/fs/ceph/file.c b/fs/ceph/file.c index d1755ac1d964..e1d605a02d4a 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -2088,6 +2088,7 @@ static long ceph_fallocate(struct file *file, int mode, if (ret < 0) goto unlock; + filemap_invalidate_lock(inode->i_mapping); ceph_zero_pagecache_range(inode, offset, length); ret = ceph_zero_objects(inode, offset, length); @@ -2100,6 +2101,7 @@ static long ceph_fallocate(struct file *file, int mode, if (dirty) __mark_inode_dirty(inode, dirty); } + filemap_invalidate_unlock(inode->i_mapping); ceph_put_cap_refs(ci, got); unlock: |