Commit 69cebd75 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Fix rsize usage in readpages 



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.

Reviewed-by: default avatarShirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: default avatarPavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent 387eb92a

fs/cifs/file.c

+26 −15
Original line number Diff line number Diff line
@@ -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);



	/*
@@ -3404,18 +3406,9 @@ 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;

		}