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SubjectRe: [PATCH] CIFS: Avoid returning EBUSY to upper layer VFS
Tentatively pushed to cifs-2.6.git for-next
On Wed, Dec 5, 2018 at 10:52 PM Long Li <longli@linuxonhyperv.com> wrote:
>
> From: Long Li <longli@microsoft.com>
>
> EBUSY is not handled by VFS, and will be passed to user-mode. This is not
> correct as we need to wait for more credits.
>
> This patch also fixes a bug where rsize or wsize is used uninitialized when
> the call to server->ops->wait_mtu_credits() fails.
>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Long Li <longli@microsoft.com>
> ---
> fs/cifs/file.c | 31 ++++++-------------------------
> 1 file changed, 6 insertions(+), 25 deletions(-)
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 74c33d5..c9bc56b 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2541,14 +2541,13 @@ static int
> cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
> struct cifs_aio_ctx *ctx)
> {
> - int wait_retry = 0;
> unsigned int wsize, credits;
> int rc;
> struct TCP_Server_Info *server =
> tlink_tcon(wdata->cfile->tlink)->ses->server;
>
> /*
> - * Try to resend this wdata, waiting for credits up to 3 seconds.
> + * Wait for credits to resend this wdata.
> * Note: we are attempting to resend the whole wdata not in segments
> */
> do {
> @@ -2556,19 +2555,13 @@ cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
> server, wdata->bytes, &wsize, &credits);
>
> if (rc)
> - break;
> + goto out;
>
> if (wsize < wdata->bytes) {
> add_credits_and_wake_if(server, credits, 0);
> msleep(1000);
> - wait_retry++;
> }
> - } while (wsize < wdata->bytes && wait_retry < 3);
> -
> - if (wsize < wdata->bytes) {
> - rc = -EBUSY;
> - goto out;
> - }
> + } while (wsize < wdata->bytes);
>
> rc = -EAGAIN;
> while (rc == -EAGAIN) {
> @@ -3234,14 +3227,13 @@ static int cifs_resend_rdata(struct cifs_readdata *rdata,
> struct list_head *rdata_list,
> struct cifs_aio_ctx *ctx)
> {
> - int wait_retry = 0;
> unsigned int rsize, credits;
> int rc;
> struct TCP_Server_Info *server =
> tlink_tcon(rdata->cfile->tlink)->ses->server;
>
> /*
> - * Try to resend this rdata, waiting for credits up to 3 seconds.
> + * Wait for credits to resend this rdata.
> * Note: we are attempting to resend the whole rdata not in segments
> */
> do {
> @@ -3249,24 +3241,13 @@ static int cifs_resend_rdata(struct cifs_readdata *rdata,
> &rsize, &credits);
>
> if (rc)
> - break;
> + goto out;
>
> if (rsize < rdata->bytes) {
> add_credits_and_wake_if(server, credits, 0);
> msleep(1000);
> - wait_retry++;
> }
> - } while (rsize < rdata->bytes && wait_retry < 3);
> -
> - /*
> - * If we can't find enough credits to send this rdata
> - * release the rdata and return failure, this will pass
> - * whatever I/O amount we have finished to VFS.
> - */
> - if (rsize < rdata->bytes) {
> - rc = -EBUSY;
> - goto out;
> - }
> + } while (rsize < rdata->bytes);
>
> rc = -EAGAIN;
> while (rc == -EAGAIN) {
> --
> 2.7.4
>


--
Thanks,

Steve

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