Reviewed-by: Shirish Pargaonkar <spargaonkar@xxxxxxxx>
On Mon, Jul 21, 2014 at 10:45 AM, Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:
> If we negotiate SMB 2.1 and higher version of the protocol and
> a server supports large read buffer size, we need to consume 1
> credit per 65536 bytes. So, we need to know how many credits
> we have and obtain the required number of them before constructing
> a readdata structure in readpages and user read.
>
> Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
> ---
> fs/cifs/cifsglob.h | 1 +
> fs/cifs/file.c | 35 ++++++++++++++++++++++++++++-------
> fs/cifs/smb2ops.c | 2 --
> fs/cifs/smb2pdu.c | 30 +++++++++++++++++++++++++++---
> 4 files changed, 56 insertions(+), 12 deletions(-)
>
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 54ca2b9..f33ff4c 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -1068,6 +1068,7 @@ struct cifs_readdata {
> struct kvec iov;
> unsigned int pagesz;
> unsigned int tailsz;
> + unsigned int credits;
> unsigned int nr_pages;
> struct page *pages[];
> };
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 00b2a25..ebdeb56 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2917,7 +2917,7 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
> struct cifs_sb_info *cifs_sb, struct list_head *rdata_list)
> {
> struct cifs_readdata *rdata;
> - unsigned int npages;
> + unsigned int npages, rsize, credits;
> size_t cur_len;
> int rc;
> pid_t pid;
> @@ -2931,13 +2931,19 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
> pid = current->tgid;
>
> do {
> - cur_len = min_t(const size_t, len, cifs_sb->rsize);
> + rc = server->ops->wait_mtu_credits(server, cifs_sb->rsize,
> + &rsize, &credits);
> + if (rc)
> + break;
> +
> + cur_len = min_t(const size_t, len, rsize);
> npages = DIV_ROUND_UP(cur_len, PAGE_SIZE);
>
> /* allocate a readdata struct */
> rdata = cifs_readdata_alloc(npages,
> cifs_uncached_readv_complete);
> if (!rdata) {
> + add_credits_and_wake_if(server, credits, 0);
> rc = -ENOMEM;
> break;
> }
> @@ -2953,12 +2959,14 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
> rdata->pid = pid;
> rdata->pagesz = PAGE_SIZE;
> rdata->read_into_pages = cifs_uncached_read_into_pages;
> + rdata->credits = credits;
>
> if (!rdata->cfile->invalidHandle ||
> !cifs_reopen_file(rdata->cfile, true))
> rc = server->ops->async_readv(rdata);
> error:
> if (rc) {
> + add_credits_and_wake_if(server, rdata->credits, 0);
> kref_put(&rdata->refcount,
> cifs_uncached_readdata_release);
> if (rc == -EAGAIN)
> @@ -3458,10 +3466,16 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> * the rdata->pages, then we want them in increasing order.
> */
> while (!list_empty(page_list)) {
> - unsigned int i, nr_pages, bytes;
> + unsigned int i, nr_pages, bytes, rsize;
> loff_t offset;
> struct page *page, *tpage;
> struct cifs_readdata *rdata;
> + unsigned credits;
> +
> + rc = server->ops->wait_mtu_credits(server, cifs_sb->rsize,
> + &rsize, &credits);
> + if (rc)
> + break;
>
> /*
> * Give up immediately if rsize is too small to read an entire
> @@ -3469,13 +3483,17 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> * 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))
> + if (unlikely(rsize < PAGE_CACHE_SIZE)) {
> + add_credits_and_wake_if(server, credits, 0);
> return 0;
> + }
>
> - rc = readpages_get_pages(mapping, page_list, cifs_sb->rsize,
> - &tmplist, &nr_pages, &offset, &bytes);
> - if (rc)
> + rc = readpages_get_pages(mapping, page_list, rsize, &tmplist,
> + &nr_pages, &offset, &bytes);
> + if (rc) {
> + add_credits_and_wake_if(server, credits, 0);
> break;
> + }
>
> rdata = cifs_readdata_alloc(nr_pages, cifs_readv_complete);
> if (!rdata) {
> @@ -3487,6 +3505,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> page_cache_release(page);
> }
> rc = -ENOMEM;
> + add_credits_and_wake_if(server, credits, 0);
> break;
> }
>
> @@ -3497,6 +3516,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> rdata->pid = pid;
> rdata->pagesz = PAGE_CACHE_SIZE;
> rdata->read_into_pages = cifs_readpages_read_into_pages;
> + rdata->credits = credits;
>
> list_for_each_entry_safe(page, tpage, &tmplist, lru) {
> list_del(&page->lru);
> @@ -3507,6 +3527,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
> !cifs_reopen_file(rdata->cfile, true))
> rc = server->ops->async_readv(rdata);
> if (rc) {
> + add_credits_and_wake_if(server, rdata->credits, 0);
> for (i = 0; i < rdata->nr_pages; i++) {
> page = rdata->pages[i];
> lru_cache_add_file(page);
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index fecc2de..081529f 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -242,8 +242,6 @@ smb2_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
> /* start with specified rsize, or default */
> rsize = volume_info->rsize ? volume_info->rsize : CIFS_DEFAULT_IOSIZE;
> rsize = min_t(unsigned int, rsize, server->max_read);
> - /* set it to the maximum buffer size value we can send with 1 credit */
> - rsize = min_t(unsigned int, rsize, SMB2_MAX_BUFFER_SIZE);
>
> return rsize;
> }
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index a1d89b7..26624ee 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -1758,11 +1758,12 @@ smb2_readv_callback(struct mid_q_entry *mid)
> int
> smb2_async_readv(struct cifs_readdata *rdata)
> {
> - int rc;
> + int rc, flags = 0;
> struct smb2_hdr *buf;
> struct cifs_io_parms io_parms;
> struct smb_rqst rqst = { .rq_iov = &rdata->iov,
> .rq_nvec = 1 };
> + struct TCP_Server_Info *server;
>
> cifs_dbg(FYI, "%s: offset=%llu bytes=%u\n",
> __func__, rdata->offset, rdata->bytes);
> @@ -1773,18 +1774,41 @@ smb2_async_readv(struct cifs_readdata *rdata)
> io_parms.persistent_fid = rdata->cfile->fid.persistent_fid;
> io_parms.volatile_fid = rdata->cfile->fid.volatile_fid;
> io_parms.pid = rdata->pid;
> +
> + server = io_parms.tcon->ses->server;
> +
> rc = smb2_new_read_req(&rdata->iov, &io_parms, 0, 0);
> - if (rc)
> + if (rc) {
> + if (rc == -EAGAIN && rdata->credits) {
> + /* credits was reseted by reconnect */
> + rdata->credits = 0;
> + /* reduce in_flight value since we won't send the req */
> + spin_lock(&server->req_lock);
> + server->in_flight--;
> + spin_unlock(&server->req_lock);
> + }
> return rc;
> + }
>
> buf = (struct smb2_hdr *)rdata->iov.iov_base;
> /* 4 for rfc1002 length field */
> rdata->iov.iov_len = get_rfc1002_length(rdata->iov.iov_base) + 4;
>
> + if (rdata->credits) {
> + buf->CreditCharge = cpu_to_le16(DIV_ROUND_UP(rdata->bytes,
> + SMB2_MAX_BUFFER_SIZE));
> + spin_lock(&server->req_lock);
> + server->credits += rdata->credits -
> + le16_to_cpu(buf->CreditCharge);
> + spin_unlock(&server->req_lock);
> + wake_up(&server->request_q);
> + flags = CIFS_HAS_CREDITS;
> + }
> +
> kref_get(&rdata->refcount);
> rc = cifs_call_async(io_parms.tcon->ses->server, &rqst,
> cifs_readv_receive, smb2_readv_callback,
> - rdata, 0);
> + rdata, flags);
> if (rc) {
> kref_put(&rdata->refcount, cifs_readdata_release);
> cifs_stats_fail_inc(io_parms.tcon, SMB2_READ_HE);
> --
> 1.8.1.2
>
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