Reviewed-by: Shirish Pargaonkar <spargaonkar@xxxxxxxx>
On Mon, Jul 21, 2014 at 10:45 AM, Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:
> If a server changes maximum buffer size for read (rsize) requests
> on reconnect we can fail on repeating with a big size buffer on
> -EAGAIN error in readpages. Fix this by checking rsize all the
> time before repeating requests.
>
> Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
> ---
> fs/cifs/file.c | 41 ++++++++++++++++++++++++++---------------
> 1 file changed, 26 insertions(+), 15 deletions(-)
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index bec48f1..d627918 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -3349,6 +3349,8 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
> unsigned int expected_index;
> int rc;
>
> + INIT_LIST_HEAD(tmplist);
> +
> page = list_entry(page_list->prev, struct page, lru);
>
> /*
> @@ -3404,19 +3406,10 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> struct list_head tmplist;
> struct cifsFileInfo *open_file = file->private_data;
> struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
> - unsigned int rsize = cifs_sb->rsize;
> + struct TCP_Server_Info *server;
> pid_t pid;
>
> /*
> - * Give up immediately if rsize is too small to read an entire page.
> - * The VFS will fall back to readpage. We should never reach this
> - * point however since we set ra_pages to 0 when the rsize is smaller
> - * than a cache page.
> - */
> - if (unlikely(rsize < PAGE_CACHE_SIZE))
> - return 0;
> -
> - /*
> * Reads as many pages as possible from fscache. Returns -ENOBUFS
> * immediately if the cookie is negative
> *
> @@ -3434,7 +3427,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> pid = current->tgid;
>
> rc = 0;
> - INIT_LIST_HEAD(&tmplist);
> + server = tlink_tcon(open_file->tlink)->ses->server;
>
> cifs_dbg(FYI, "%s: file=%p mapping=%p num_pages=%u\n",
> __func__, file, mapping, num_pages);
> @@ -3456,8 +3449,17 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> struct page *page, *tpage;
> struct cifs_readdata *rdata;
>
> - rc = readpages_get_pages(mapping, page_list, rsize, &tmplist,
> - &nr_pages, &offset, &bytes);
> + /*
> + * Give up immediately if rsize is too small to read an entire
> + * page. The VFS will fall back to readpage. We should never
> + * reach this point however since we set ra_pages to 0 when the
> + * rsize is smaller than a cache page.
> + */
> + if (unlikely(cifs_sb->rsize < PAGE_CACHE_SIZE))
> + return 0;
> +
> + rc = readpages_get_pages(mapping, page_list, cifs_sb->rsize,
> + &tmplist, &nr_pages, &offset, &bytes);
> if (rc)
> break;
>
> @@ -3487,15 +3489,24 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> rdata->pages[rdata->nr_pages++] = page;
> }
>
> - rc = cifs_retry_async_readv(rdata);
> - if (rc != 0) {
> + if (!rdata->cfile->invalidHandle ||
> + !cifs_reopen_file(rdata->cfile, true))
> + rc = server->ops->async_readv(rdata);
> + if (rc) {
> for (i = 0; i < rdata->nr_pages; i++) {
> page = rdata->pages[i];
> lru_cache_add_file(page);
> unlock_page(page);
> page_cache_release(page);
> + if (rc == -EAGAIN)
> + list_add_tail(&page->lru, &tmplist);
> }
> kref_put(&rdata->refcount, cifs_readdata_release);
> + if (rc == -EAGAIN) {
> + /* Re-add pages to the page_list and retry */
> + list_splice(&tmplist, page_list);
> + continue;
> + }
> break;
> }
>
> --
> 1.8.1.2
>
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