merged into cifs-2.6.git for-next On Wed, Apr 20, 2022 at 8:15 PM Ronnie Sahlberg <lsahlber@xxxxxxxxxx> wrote: > > because the copychunk_write might cover a region of the file that has not yet > been sent to the server and thus fail. > > A simple way to reproduce this is: > truncate -s 0 /mnt/testfile; strace -f -o x -ttT xfs_io -i -f -c 'pwrite 0k 128k' -c 'fcollapse 16k 24k' /mnt/testfile > > the issue is that the 'pwrite 0k 128k' becomes rearranged on the wire with > the 'fcollapse 16k 24k' due to write-back caching. > > fcollapse is implemented in cifs.ko as a SMB2 IOCTL(COPYCHUNK_WRITE) call > and it will fail serverside since the file is still 0b in size serverside > until the writes have been destaged. > To avoid this we must ensure that we destage any unwritten data to the > server before calling COPYCHUNK_WRITE. > > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1997373 > Reported-by: Xiaoli Feng <xifeng@xxxxxxxxxx> > Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx> > --- > fs/cifs/smb2ops.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c > index a67df8eaf702..d6aaeff4a30a 100644 > --- a/fs/cifs/smb2ops.c > +++ b/fs/cifs/smb2ops.c > @@ -1858,9 +1858,17 @@ smb2_copychunk_range(const unsigned int xid, > int chunks_copied = 0; > bool chunk_sizes_updated = false; > ssize_t bytes_written, total_bytes_written = 0; > + struct inode *inode; > > pcchunk = kmalloc(sizeof(struct copychunk_ioctl), GFP_KERNEL); > > + /* > + * We need to flush all unwritten data before we can send the > + * copychunk ioctl to the server. > + */ > + inode = d_inode(trgtfile->dentry); > + filemap_write_and_wait(inode->i_mapping); > + > if (pcchunk == NULL) > return -ENOMEM; > > -- > 2.30.2 > -- Thanks, Steve
