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CIFS: Adjust MTU credits before reopening a file
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Currently we adjust MTU credits before sending an IO request
and after reopening a file. This approach doesn't allow the
reopen routine to use existing credits that are not needed
for IO. Reorder credit adjustment and reopening a file to
use credits available to the client more efficiently. Also
unwrap complex if statement into few pieces to improve
readability.

Signed-off-by: Pavel Shilovsky <[email protected]>
Signed-off-by: Steve French <[email protected]>
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@piastry
piastry authored and Steve French committed Mar 6, 2019
1 parent 97ea499 commit 9a1c67e
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Showing 4 changed files with 94 additions and 42 deletions.
12 changes: 12 additions & 0 deletions fs/cifs/cifsglob.h
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Original file line number Diff line number Diff line change
Expand Up @@ -457,6 +457,10 @@ struct smb_version_operations {
/* get mtu credits */
int (*wait_mtu_credits)(struct TCP_Server_Info *, unsigned int,
unsigned int *, struct cifs_credits *);
/* adjust previously taken mtu credits to request size */
int (*adjust_credits)(struct TCP_Server_Info *server,
struct cifs_credits *credits,
const unsigned int payload_size);
/* check if we need to issue closedir */
bool (*dir_needs_close)(struct cifsFileInfo *);
long (*fallocate)(struct file *, struct cifs_tcon *, int, loff_t,
Expand Down Expand Up @@ -763,6 +767,14 @@ set_credits(struct TCP_Server_Info *server, const int val)
server->ops->set_credits(server, val);
}

static inline int
adjust_credits(struct TCP_Server_Info *server, struct cifs_credits *credits,
const unsigned int payload_size)
{
return server->ops->adjust_credits ?
server->ops->adjust_credits(server, credits, payload_size) : 0;
}

static inline __le64
get_next_mid64(struct TCP_Server_Info *server)
{
Expand Down
53 changes: 39 additions & 14 deletions fs/cifs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2076,11 +2076,11 @@ wdata_prepare_pages(struct cifs_writedata *wdata, unsigned int found_pages,
}

static int
wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
struct address_space *mapping, struct writeback_control *wbc)
wdata_send_pages(struct TCP_Server_Info *server, struct cifs_writedata *wdata,
unsigned int nr_pages, struct address_space *mapping,
struct writeback_control *wbc)
{
int rc = 0;
struct TCP_Server_Info *server;
unsigned int i;

wdata->sync_mode = wbc->sync_mode;
Expand All @@ -2092,6 +2092,10 @@ wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
(loff_t)PAGE_SIZE);
wdata->bytes = ((nr_pages - 1) * PAGE_SIZE) + wdata->tailsz;

rc = adjust_credits(server, &wdata->credits, wdata->bytes);
if (rc)
goto send_pages_out;

if (wdata->cfile != NULL)
cifsFileInfo_put(wdata->cfile);
wdata->cfile = find_writable_file(CIFS_I(mapping->host), false);
Expand All @@ -2100,10 +2104,10 @@ wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
rc = -EBADF;
} else {
wdata->pid = wdata->cfile->pid;
server = tlink_tcon(wdata->cfile->tlink)->ses->server;
rc = server->ops->async_writev(wdata, cifs_writedata_release);
}

send_pages_out:
for (i = 0; i < nr_pages; ++i)
unlock_page(wdata->pages[i]);

Expand Down Expand Up @@ -2184,7 +2188,7 @@ static int cifs_writepages(struct address_space *mapping,

wdata->credits = credits_on_stack;

rc = wdata_send_pages(wdata, nr_pages, mapping, wbc);
rc = wdata_send_pages(server, wdata, nr_pages, mapping, wbc);

/* send failure -- clean up the mess */
if (rc != 0) {
Expand Down Expand Up @@ -2743,10 +2747,17 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
wdata->ctx = ctx;
kref_get(&ctx->refcount);

if (!wdata->cfile->invalidHandle ||
!(rc = cifs_reopen_file(wdata->cfile, false)))
rc = server->ops->async_writev(wdata,
rc = adjust_credits(server, &wdata->credits, wdata->bytes);

if (!rc) {
if (wdata->cfile->invalidHandle)
rc = cifs_reopen_file(wdata->cfile, false);

if (!rc)
rc = server->ops->async_writev(wdata,
cifs_uncached_writedata_release);
}

if (rc) {
add_credits_and_wake_if(server, &wdata->credits, 0);
kref_put(&wdata->refcount,
Expand Down Expand Up @@ -3423,9 +3434,16 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
rdata->ctx = ctx;
kref_get(&ctx->refcount);

if (!rdata->cfile->invalidHandle ||
!(rc = cifs_reopen_file(rdata->cfile, true)))
rc = server->ops->async_readv(rdata);
rc = adjust_credits(server, &rdata->credits, rdata->bytes);

if (!rc) {
if (rdata->cfile->invalidHandle)
rc = cifs_reopen_file(rdata->cfile, true);

if (!rc)
rc = server->ops->async_readv(rdata);
}

if (rc) {
add_credits_and_wake_if(server, &rdata->credits, 0);
kref_put(&rdata->refcount,
Expand Down Expand Up @@ -4163,9 +4181,16 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
rdata->pages[rdata->nr_pages++] = page;
}

if (!rdata->cfile->invalidHandle ||
!(rc = cifs_reopen_file(rdata->cfile, true)))
rc = server->ops->async_readv(rdata);
rc = adjust_credits(server, &rdata->credits, rdata->bytes);

if (!rc) {
if (rdata->cfile->invalidHandle)
rc = cifs_reopen_file(rdata->cfile, true);

if (!rc)
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++) {
Expand Down
35 changes: 35 additions & 0 deletions fs/cifs/smb2ops.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -222,6 +222,38 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
return rc;
}

static int
smb2_adjust_credits(struct TCP_Server_Info *server,
struct cifs_credits *credits,
const unsigned int payload_size)
{
int new_val = DIV_ROUND_UP(payload_size, SMB2_MAX_BUFFER_SIZE);

if (!credits->value || credits->value == new_val)
return 0;

if (credits->value < new_val) {
WARN_ONCE(1, "request has less credits (%d) than required (%d)",
credits->value, new_val);
return -ENOTSUPP;
}

spin_lock(&server->req_lock);

if (server->reconnect_instance != credits->instance) {
spin_unlock(&server->req_lock);
cifs_dbg(VFS, "trying to return %d credits to old session\n",
credits->value - new_val);
return -EAGAIN;
}

server->credits += credits->value - new_val;
spin_unlock(&server->req_lock);
wake_up(&server->request_q);
credits->value = new_val;
return 0;
}

static __u64
smb2_get_next_mid(struct TCP_Server_Info *server)
{
Expand Down Expand Up @@ -3678,6 +3710,7 @@ struct smb_version_operations smb21_operations = {
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
.wait_mtu_credits = smb2_wait_mtu_credits,
.adjust_credits = smb2_adjust_credits,
.get_next_mid = smb2_get_next_mid,
.revert_current_mid = smb2_revert_current_mid,
.read_data_offset = smb2_read_data_offset,
Expand Down Expand Up @@ -3775,6 +3808,7 @@ struct smb_version_operations smb30_operations = {
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
.wait_mtu_credits = smb2_wait_mtu_credits,
.adjust_credits = smb2_adjust_credits,
.get_next_mid = smb2_get_next_mid,
.revert_current_mid = smb2_revert_current_mid,
.read_data_offset = smb2_read_data_offset,
Expand Down Expand Up @@ -3881,6 +3915,7 @@ struct smb_version_operations smb311_operations = {
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
.wait_mtu_credits = smb2_wait_mtu_credits,
.adjust_credits = smb2_adjust_credits,
.get_next_mid = smb2_get_next_mid,
.revert_current_mid = smb2_revert_current_mid,
.read_data_offset = smb2_read_data_offset,
Expand Down
36 changes: 8 additions & 28 deletions fs/cifs/smb2pdu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3322,21 +3322,11 @@ smb2_async_readv(struct cifs_readdata *rdata)
SMB2_MAX_BUFFER_SIZE));
shdr->CreditRequest =
cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 1);
spin_lock(&server->req_lock);
if (server->reconnect_instance == rdata->credits.instance)
server->credits += rdata->credits.value -
le16_to_cpu(shdr->CreditCharge);
else {
spin_unlock(&server->req_lock);
cifs_dbg(VFS, "trying to return %u credits to old session\n",
rdata->credits.value
- le16_to_cpu(shdr->CreditCharge));
rc = -EAGAIN;

rc = adjust_credits(server, &rdata->credits, rdata->bytes);
if (rc)
goto async_readv_out;
}
spin_unlock(&server->req_lock);
wake_up(&server->request_q);
rdata->credits.value = le16_to_cpu(shdr->CreditCharge);

flags |= CIFS_HAS_CREDITS;
}

Expand Down Expand Up @@ -3626,21 +3616,11 @@ smb2_async_writev(struct cifs_writedata *wdata,
SMB2_MAX_BUFFER_SIZE));
shdr->CreditRequest =
cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 1);
spin_lock(&server->req_lock);
if (server->reconnect_instance == wdata->credits.instance)
server->credits += wdata->credits.value -
le16_to_cpu(shdr->CreditCharge);
else {
spin_unlock(&server->req_lock);
cifs_dbg(VFS, "trying to return %d credits to old session\n",
wdata->credits.value
- le16_to_cpu(shdr->CreditCharge));
rc = -EAGAIN;

rc = adjust_credits(server, &wdata->credits, wdata->bytes);
if (rc)
goto async_writev_out;
}
spin_unlock(&server->req_lock);
wake_up(&server->request_q);
wdata->credits.value = le16_to_cpu(shdr->CreditCharge);

flags |= CIFS_HAS_CREDITS;
}

Expand Down

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