CIFS: Fix rsize usage in user read

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 user read. Fix this by checking rsize all the
time before repeating requests.

Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 22 insertions, 23 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 7df4e4658d74..bbc38594b39a 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2828,26 +2828,6 @@ cifs_uncached_readdata_release(struct kref *refcount)
         cifs_readdata_release(refcount);
 }
 
-static int
-cifs_retry_async_readv(struct cifs_readdata *rdata)
-{
-        int rc;
-        struct TCP_Server_Info *server;
-
-        server = tlink_tcon(rdata->cfile->tlink)->ses->server;
-
-        do {
-                if (rdata->cfile->invalidHandle) {
-                        rc = cifs_reopen_file(rdata->cfile, true);
-                        if (rc != 0)
-                                continue;
-                }
-                rc = server->ops->async_readv(rdata);
-        } while (rc == -EAGAIN);
-
-        return rc;
-}
-
 /**
  * cifs_readdata_to_iov - copy data from pages in response to an iovec
  * @rdata:      the readdata response with list of pages holding data
@@ -2941,6 +2921,9 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
         size_t cur_len;
         int rc;
         pid_t pid;
+        struct TCP_Server_Info *server;
+
+        server = tlink_tcon(open_file->tlink)->ses->server;
 
         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
                 pid = open_file->pid;
@@ -2971,11 +2954,15 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
                 rdata->pagesz = PAGE_SIZE;
                 rdata->read_into_pages = cifs_uncached_read_into_pages;
 
-                rc = cifs_retry_async_readv(rdata);
+                if (!rdata->cfile->invalidHandle ||
+                    !cifs_reopen_file(rdata->cfile, true))
+                        rc = server->ops->async_readv(rdata);
 error:
                 if (rc) {
                         kref_put(&rdata->refcount,
                                  cifs_uncached_readdata_release);
+                        if (rc == -EAGAIN)
+                                continue;
                         break;
                 }
 
@@ -3023,8 +3010,8 @@ ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to)
 
         len = iov_iter_count(to);
         /* the loop below should proceed in the order of increasing offsets */
+again:
         list_for_each_entry_safe(rdata, tmp, &rdata_list, list) {
-        again:
                 if (!rc) {
                         /* FIXME: freezable sleep too? */
                         rc = wait_for_completion_killable(&rdata->done);
@@ -3034,7 +3021,19 @@ ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to)
                                 rc = rdata->result;
                                 /* resend call if it's a retryable error */
                                 if (rc == -EAGAIN) {
-                                        rc = cifs_retry_async_readv(rdata);
+                                        struct list_head tmp_list;
+
+                                        list_del_init(&rdata->list);
+                                        INIT_LIST_HEAD(&tmp_list);
+
+                                        rc = cifs_send_async_read(rdata->offset,
+                                                rdata->bytes, rdata->cfile,
+                                                cifs_sb, &tmp_list);
+
+                                        list_splice(&tmp_list, &rdata_list);
+
+                                        kref_put(&rdata->refcount,
+                                                cifs_uncached_readdata_release);
                                         goto again;
                                 }
                         } else {