23.07.2014, в 10:15, Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> написал(а):
> On Mon, Jul 21, 2014 at 10:45 AM, Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:
>> If a server change maximum buffer size for write (wsize) requests
>> on reconnect we can fail on repeating with a big size buffer on
>> -EAGAIN error in iovec write. Fix this by checking wsize all the
>> time before repeating request in iovec write.
>>
>> Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
>> ---
>> fs/cifs/cifssmb.c | 4 ----
>> fs/cifs/file.c | 63 ++++++++++++++++++++++++++++++++++---------------------
>> fs/cifs/smb2pdu.c | 4 ----
>> 3 files changed, 39 insertions(+), 32 deletions(-)
>>
>> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
>> index e273ded..784f105 100644
>> --- a/fs/cifs/cifssmb.c
>> +++ b/fs/cifs/cifssmb.c
>> @@ -196,10 +196,6 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
>> if (rc)
>> goto out;
>>
>> - /*
>> - * FIXME: check if wsize needs updated due to negotiated smb buffer
>> - * size shrinking
>> - */
>> atomic_inc(&tconInfoReconnectCount);
>>
>> /* tell server Unix caps we support */
>> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
>> index 6660698..c9c4f5a 100644
>> --- a/fs/cifs/file.c
>> +++ b/fs/cifs/file.c
>> @@ -2401,28 +2401,6 @@ cifs_uncached_writev_complete(struct work_struct *work)
>> kref_put(&wdata->refcount, cifs_uncached_writedata_release);
>> }
>>
>> -/* attempt to send write to server, retry on any -EAGAIN errors */
>> -static int
>> -cifs_uncached_retry_writev(struct cifs_writedata *wdata)
>> -{
>> - int rc;
>> - struct TCP_Server_Info *server;
>> -
>> - server = tlink_tcon(wdata->cfile->tlink)->ses->server;
>> -
>> - do {
>> - if (wdata->cfile->invalidHandle) {
>> - rc = cifs_reopen_file(wdata->cfile, false);
>> - if (rc != 0)
>> - continue;
>> - }
>> - rc = server->ops->async_writev(wdata,
>> - cifs_uncached_writedata_release);
>> - } while (rc == -EAGAIN);
>> -
>> - return rc;
>> -}
>> -
>> static int
>> wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
>> size_t *len, unsigned long *num_pages)
>> @@ -2474,13 +2452,19 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
>> size_t cur_len;
>> unsigned long nr_pages, num_pages, i;
>> struct cifs_writedata *wdata;
>> + struct iov_iter saved_from;
>> + loff_t saved_offset = offset;
>> pid_t pid;
>> + struct TCP_Server_Info *server;
>>
>> if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
>> pid = open_file->pid;
>> else
>> pid = current->tgid;
>>
>> + server = tlink_tcon(open_file->tlink)->ses->server;
>> + memcpy(&saved_from, from, sizeof(struct iov_iter));
>> +
>> do {
>> nr_pages = get_numpages(cifs_sb->wsize, len, &cur_len);
>> wdata = cifs_writedata_alloc(nr_pages,
>> @@ -2520,10 +2504,20 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
>> wdata->bytes = cur_len;
>> wdata->pagesz = PAGE_SIZE;
>> wdata->tailsz = cur_len - ((nr_pages - 1) * PAGE_SIZE);
>> - rc = cifs_uncached_retry_writev(wdata);
>> +
>> + if (!wdata->cfile->invalidHandle ||
>> + !cifs_reopen_file(wdata->cfile, false))
>> + rc = server->ops->async_writev(wdata,
>> + cifs_uncached_writedata_release);
>> if (rc) {
>> kref_put(&wdata->refcount,
>> cifs_uncached_writedata_release);
>> + if (rc == -EAGAIN) {
>> + memcpy(from, &saved_from,
>> + sizeof(struct iov_iter));
>> + iov_iter_advance(from, offset - saved_offset);
>> + continue;
>> + }
>> break;
>> }
>>
>> @@ -2545,6 +2539,7 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
>> struct cifs_sb_info *cifs_sb;
>> struct cifs_writedata *wdata, *tmp;
>> struct list_head wdata_list;
>> + struct iov_iter saved_from;
>> int rc;
>>
>> len = iov_iter_count(from);
>> @@ -2565,6 +2560,8 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
>> if (!tcon->ses->server->ops->async_writev)
>> return -ENOSYS;
>>
>> + memcpy(&saved_from, from, sizeof(struct iov_iter));
>> +
>> rc = cifs_write_from_iter(*poffset, len, from, open_file, cifs_sb,
>> &wdata_list);
>>
>> @@ -2596,7 +2593,25 @@ restart_loop:
>>
>> /* resend call if it's a retryable error */
>> if (rc == -EAGAIN) {
>> - rc = cifs_uncached_retry_writev(wdata);
>> + struct list_head tmp_list;
>> + struct iov_iter tmp_from;
>> +
>> + INIT_LIST_HEAD(&tmp_list);
>> + list_del_init(&wdata->list);
>> +
>> + memcpy(&tmp_from, &saved_from,
>> + sizeof(struct iov_iter));
>> + iov_iter_advance(&tmp_from,
>> + wdata->offset - *poffset);
>> +
>> + rc = cifs_write_from_iter(wdata->offset,
>> + wdata->bytes, &tmp_from,
>> + open_file, cifs_sb, &tmp_list);
>> +
>> + list_splice(&tmp_list, &wdata_list);
>
> Do we list_splice unconditionally or do we list splice only if e.g.
> if (!list_empty(&tmp_list)) i.e. could tmp_list be empty if
> cifs_write_from_iter returned with non-zero rc (thus we did not
> add a wdata to the list)?
Yes. The check is done inside the list_splice().
--
Best regards,
Pavel Shilovsky.
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