On 4/7/22 11:38 PM, Jeff Layton wrote:
On Thu, 2022-04-07 at 11:33 -0400, Jeff Layton wrote:
On Thu, 2022-04-07 at 22:41 +0800, xiubli@xxxxxxxxxx wrote:
From: Xiubo Li <xiubli@xxxxxxxxxx>
When truncating the file size the MDS will help update the last
encrypted block, and during this we need to make sure the client
won't fill the pagecaches.
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---
fs/ceph/inode.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index f4059d73edd5..cc1829ab497d 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -2647,9 +2647,12 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr, struct ceph_iattr *c
req->r_num_caps = 1;
req->r_stamp = attr->ia_ctime;
if (fill_fscrypt) {
+ filemap_invalidate_lock(inode->i_mapping);
err = fill_fscrypt_truncate(inode, req, attr);
- if (err)
+ if (err) {
+ filemap_invalidate_unlock(inode->i_mapping);
goto out;
+ }
}
/*
@@ -2660,6 +2663,8 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr, struct ceph_iattr *c
* it.
*/
err = ceph_mdsc_do_request(mdsc, NULL, req);
+ if (fill_fscrypt)
+ filemap_invalidate_unlock(inode->i_mapping);
if (err == -EAGAIN && truncate_retry--) {
dout("setattr %p result=%d (%s locally, %d remote), retry it!\n",
inode, err, ceph_cap_string(dirtied), mask);
Looks reasonable. Is there any reason we shouldn't do this in the non-
encrypted case too? I suppose it doesn't make as much difference in that
case.
We only need this in encrypted case, which will do the RMW for the last
block.
I'll plan to pull this and the other patch into the wip-fscrypt branch.
Should I just fold them into your earlier patches?
Yeah, certainly.
OTOH...do we really need this? I'm not sure I understand the race you're
trying to prevent. Can you lay it out for me?
I am thinking during the RMW for the last block, the page fault still
could happen because the page fault function doesn't prevent that.
And we should prevent it during the RMW is going on.
-- Xiubo
Thanks,
