2017-04-07 4:29 GMT-07:00 Germano Percossi <germano.percossi@xxxxxxxxxx>:
> This fixes Continuous Availability when errors during
> file reopen are encountered.
>
> cifs_user_readv and cifs_user_writev would wait for ever if
> results of cifs_reopen_file are not stored and for later inspection.
>
> In fact, results are checked and, in case of errors, a chain
> of function calls leading to reads and writes to be scheduled in
> a separate thread is skipped.
> These threads will wake up the corresponding waiters once reads
> and writes are done.
>
> However, given the return value is not stored, when rc is checked
> for errors a previous one (always zero) is inspected instead.
> This leads to pending reads/writes added to the list, making
> cifs_user_readv and cifs_user_writev wait for ever.
>
> Signed-off-by: Germano Percossi <germano.percossi@xxxxxxxxxx>
> ---
> fs/cifs/file.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index aa3debb..21d4045 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2597,7 +2597,7 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
> wdata->credits = credits;
>
> if (!wdata->cfile->invalidHandle ||
> - !cifs_reopen_file(wdata->cfile, false))
> + !(rc = cifs_reopen_file(wdata->cfile, false)))
> rc = server->ops->async_writev(wdata,
> cifs_uncached_writedata_release);
> if (rc) {
> @@ -3022,7 +3022,7 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
> rdata->credits = credits;
>
> if (!rdata->cfile->invalidHandle ||
> - !cifs_reopen_file(rdata->cfile, true))
> + !(rc = cifs_reopen_file(rdata->cfile, true)))
> rc = server->ops->async_readv(rdata);
> error:
> if (rc) {
> @@ -3617,7 +3617,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> }
>
> if (!rdata->cfile->invalidHandle ||
> - !cifs_reopen_file(rdata->cfile, true))
> + !(rc = cifs_reopen_file(rdata->cfile, true)))
> rc = server->ops->async_readv(rdata);
> if (rc) {
> add_credits_and_wake_if(server, rdata->credits, 0);
> --
> git-series 0.9.1
> --
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Nice catch! This one should probably go to stable.
Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
--
Best regards,
Pavel Shilovsky
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