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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>
This commit is contained in:
Pavel Shilovsky 2014-06-25 11:28:57 +04:00 committed by Steve French
parent e374d90f8a
commit bed9da0213
4 changed files with 59 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/cifs/cifsglob.h
View File

@ -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[];
};

35
fs/cifs/file.c
View File

@ -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);

5
fs/cifs/smb2ops.c
View File

@ -245,8 +245,9 @@ 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);
if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
rsize = min_t(unsigned int, rsize, SMB2_MAX_BUFFER_SIZE);
return rsize;
}

30
fs/cifs/smb2pdu.c
View File

@ -1747,11 +1747,12 @@ 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);
@ -1762,18 +1763,41 @@ 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 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);