Re: Kernel 6.0.5 breaks virtual machines that boot from nfs mounted qcow2 images

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 2022-11-23 18:51, Chuck Lever III wrote:

On Nov 23, 2022, at 12:49 PM, Benjamin Coddington <bcodding@xxxxxxxxxx> wrote:

On 23 Nov 2022, at 5:08, Anders Blomdell wrote:

Our problems turned out to be a fallout of Al Viros's splice rework, where nfsd reads with non-zero offsets and not ending
on a page boundary failed to remap the last page. I belive that this is a decent fix for that problem (tested on v6.1-rc6,
6.0.7 and 6.0.9)

---- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -873,7 +873,7 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
        unsigned offset = buf->offset;
         page += offset / PAGE_SIZE;
-       for (int i = sd->len; i > 0; i -= PAGE_SIZE)
+       for (int i = sd->len + offset % PAGE_SIZE; i > 0; i -= PAGE_SIZE)
                svc_rqst_replace_page(rqstp, page++);
        if (rqstp->rq_res.page_len == 0)        // first call
                rqstp->rq_res.page_base = offset % PAGE_SIZE;


Does anyone have insight into how we could possibly have caught this in testing?

Was also wondering this. I had though fstests (via fsx) would have exercised
this usage scenario.
My guess is that one has to look very hard at qcow2 handling in qemu...

/Anders


--
Anders Blomdell                  Email: anders.blomdell@xxxxxxxxxxxxxx
Department of Automatic Control
Lund University                  Phone:    +46 46 222 4625
P.O. Box 118
SE-221 00 Lund, Sweden



[Index of Archives]     [Linux Filesystem Development]     [Linux USB Development]     [Linux Media Development]     [Video for Linux]     [Linux NILFS]     [Linux Audio Users]     [Yosemite Info]     [Linux SCSI]

  Powered by Linux