CIFS: Use multicredits for SMB 2.1/3 reads
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.
Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
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 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 @@
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 @@
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 @@
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 @@
* 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 @@
* 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 @@
page_cache_release(page);
}
rc = -ENOMEM;
+ add_credits_and_wake_if(server, credits, 0);
break;
}
@@ -3497,6 +3516,7 @@
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 @@
!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 3427c1f..d0210a8 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -245,8 +245,9 @@
/* 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);
+
+ if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
+ 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 be7b2eb..c31e5a0 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1747,11 +1747,12 @@
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);
@@ -1762,18 +1763,41 @@
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 reset 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);