Add the ability for CIFS to do an asynchronous write. The kernel will
set the frame up as it would for a "normal" SMBWrite2 request, and use
cifs_call_async to send it. The mid callback will then be configured to
handle the result.
Reviewed-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/cifs/cifsproto.h | 18 ++++
fs/cifs/cifssmb.c | 238 +++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 256 insertions(+), 0 deletions(-)
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index c621b45..d35019b 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -433,4 +433,22 @@ extern int mdfour(unsigned char *, unsigned char *, int);
extern int E_md4hash(const unsigned char *passwd, unsigned char *p16);
extern int SMBencrypt(unsigned char *passwd, const unsigned char *c8,
unsigned char *p24);
+
+/* asynchronous write support */
+struct cifs_writedata {
+ struct kref refcount;
+ enum writeback_sync_modes sync_mode;
+ struct work_struct work;
+ struct cifsFileInfo *cfile;
+ __u64 offset;
+ unsigned int bytes;
+ int result;
+ unsigned int nr_pages;
+ struct page *pages[1];
+};
+
+int cifs_async_writev(struct cifs_writedata *wdata);
+struct cifs_writedata *cifs_writedata_alloc(unsigned int nr_pages);
+void cifs_writedata_release(struct kref *refcount);
+
#endif /* _CIFSPROTO_H */
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index d4698b9..6ff9b0a 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -32,6 +32,7 @@
#include <linux/vfs.h>
#include <linux/slab.h>
#include <linux/posix_acl_xattr.h>
+#include <linux/pagemap.h>
#include <asm/uaccess.h>
#include "cifspdu.h"
#include "cifsglob.h"
@@ -1604,6 +1605,243 @@ CIFSSMBWrite(const int xid, struct cifs_tcon *tcon,
return rc;
}
+void
+cifs_writedata_release(struct kref *refcount)
+{
+ struct cifs_writedata *wdata = container_of(refcount,
+ struct cifs_writedata, refcount);
+
+ if (wdata->cfile)
+ cifsFileInfo_put(wdata->cfile);
+
+ kfree(wdata);
+}
+
+/*
+ * Write failed with a retryable error. Resend the write request. It's also
+ * possible that the page was redirtied so re-clean the page.
+ */
+static void
+cifs_writev_requeue(struct cifs_writedata *wdata)
+{
+ int i, rc;
+ struct inode *inode = wdata->cfile->dentry->d_inode;
+
+ for (i = 0; i < wdata->nr_pages; i++) {
+ lock_page(wdata->pages[i]);
+ clear_page_dirty_for_io(wdata->pages[i]);
+ }
+
+ do {
+ rc = cifs_async_writev(wdata);
+ } while(rc != -EAGAIN);
+
+ for (i = 0; i < wdata->nr_pages; i++) {
+ if (rc != 0)
+ SetPageError(wdata->pages[i]);
+ unlock_page(wdata->pages[i]);
+ }
+
+ if (rc != 0)
+ mapping_set_error(inode->i_mapping, rc);
+
+ kref_put(&wdata->refcount, cifs_writedata_release);
+}
+
+static void
+cifs_writev_complete(struct work_struct *work)
+{
+ struct cifs_writedata *wdata = container_of(work,
+ struct cifs_writedata, work);
+ struct inode *inode = wdata->cfile->dentry->d_inode;
+ int i = 0;
+
+ if (wdata->result == 0) {
+ cifs_update_eof(CIFS_I(inode), wdata->offset, wdata->bytes);
+ cifs_stats_bytes_written(tlink_tcon(wdata->cfile->tlink),
+ wdata->bytes);
+ } else if (wdata->sync_mode == WB_SYNC_ALL && wdata->result == -EAGAIN)
+ return cifs_writev_requeue(wdata);
+
+ for (i = 0; i < wdata->nr_pages; i++) {
+ struct page *page = wdata->pages[i];
+ if (wdata->result == -EAGAIN)
+ __set_page_dirty_nobuffers(page);
+ else if (wdata->result < 0)
+ SetPageError(page);
+ end_page_writeback(page);
+ page_cache_release(page);
+ }
+ if (wdata->result != -EAGAIN)
+ mapping_set_error(inode->i_mapping, wdata->result);
+ kref_put(&wdata->refcount, cifs_writedata_release);
+}
+
+struct cifs_writedata *
+cifs_writedata_alloc(unsigned int nr_pages)
+{
+ struct cifs_writedata *wdata;
+
+ /* this would overflow */
+ if (nr_pages == 0) {
+ cERROR(1, "%s: called with nr_pages == 0!", __func__);
+ return NULL;
+ }
+
+ /* writedata + number of page pointers */
+ wdata = kzalloc(sizeof(*wdata) +
+ sizeof(struct page *) * (nr_pages - 1), GFP_NOFS);
+ if (wdata != NULL) {
+ INIT_WORK(&wdata->work, cifs_writev_complete);
+ kref_init(&wdata->refcount);
+ }
+ return wdata;
+}
+
+/*
+ * Check the midState and signature on received buffer (if any), and queue the
+ * workqueue completion task.
+ */
+static void
+cifs_writev_callback(struct mid_q_entry *mid)
+{
+ struct cifs_writedata *wdata = mid->callback_data;
+ struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
+ unsigned int written;
+ WRITE_RSP *smb = (WRITE_RSP *)mid->resp_buf;
+
+ switch(mid->midState) {
+ case MID_RESPONSE_RECEIVED:
+ wdata->result = cifs_check_receive(mid, tcon->ses->server, 0);
+ if (wdata->result != 0)
+ break;
+
+ written = le16_to_cpu(smb->CountHigh);
+ written <<= 16;
+ written += le16_to_cpu(smb->Count);
+ /*
+ * Mask off high 16 bits when bytes written as returned
+ * by the server is greater than bytes requested by the
+ * client. OS/2 servers are known to set incorrect
+ * CountHigh values.
+ */
+ if (written > wdata->bytes)
+ written &= 0xFFFF;
+
+ if (written < wdata->bytes)
+ wdata->result = -ENOSPC;
+ else
+ wdata->bytes = written;
+ break;
+ case MID_REQUEST_SUBMITTED:
+ case MID_RETRY_NEEDED:
+ wdata->result = -EAGAIN;
+ break;
+ default:
+ wdata->result = -EIO;
+ break;
+ }
+
+ queue_work(system_nrt_wq, &wdata->work);
+ DeleteMidQEntry(mid);
+ atomic_dec(&tcon->ses->server->inFlight);
+ wake_up(&tcon->ses->server->request_q);
+}
+
+/* cifs_async_writev - send an async write, and set up mid to handle result */
+int
+cifs_async_writev(struct cifs_writedata *wdata)
+{
+ int i, rc = -EACCES;
+ WRITE_REQ *smb = NULL;
+ int wct;
+ struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
+ struct inode *inode = wdata->cfile->dentry->d_inode;
+ struct kvec *iov = NULL;
+
+ if (tcon->ses->capabilities & CAP_LARGE_FILES) {
+ wct = 14;
+ } else {
+ wct = 12;
+ if (wdata->offset >> 32 > 0) {
+ /* can not handle big offset for old srv */
+ return -EIO;
+ }
+ }
+
+ rc = small_smb_init(SMB_COM_WRITE_ANDX, wct, tcon, (void **)&smb);
+ if (rc)
+ goto async_writev_out;
+
+ /* 1 iov per page + 1 for header */
+ iov = kzalloc((wdata->nr_pages + 1) * sizeof(*iov), GFP_NOFS);
+ if (iov == NULL) {
+ rc = -ENOMEM;
+ goto async_writev_out;
+ }
+
+ smb->AndXCommand = 0xFF; /* none */
+ smb->Fid = wdata->cfile->netfid;
+ smb->OffsetLow = cpu_to_le32(wdata->offset & 0xFFFFFFFF);
+ if (wct == 14)
+ smb->OffsetHigh = cpu_to_le32(wdata->offset >> 32);
+ smb->Reserved = 0xFFFFFFFF;
+ smb->WriteMode = 0;
+ smb->Remaining = 0;
+
+ smb->DataOffset =
+ cpu_to_le16(offsetof(struct smb_com_write_req, Data) - 4);
+
+ /* 4 for RFC1001 length + 1 for BCC */
+ iov[0].iov_len = be32_to_cpu(smb->hdr.smb_buf_length) + 4 + 1;
+ iov[0].iov_base = smb;
+
+ /* marshal up the pages into iov array */
+ wdata->bytes = 0;
+ for (i = 0; i < wdata->nr_pages; i++) {
+ iov[i + 1].iov_len = min(inode->i_size -
+ page_offset(wdata->pages[i]),
+ (loff_t)PAGE_CACHE_SIZE);
+ iov[i + 1].iov_base = kmap(wdata->pages[i]);
+ wdata->bytes += iov[i + 1].iov_len;
+ }
+
+ cFYI(1, "async write at %llu %u bytes", wdata->offset, wdata->bytes);
+
+ smb->DataLengthLow = cpu_to_le16(wdata->bytes & 0xFFFF);
+ smb->DataLengthHigh = cpu_to_le16(wdata->bytes >> 16);
+
+ if (wct == 14) {
+ inc_rfc1001_len(&smb->hdr, wdata->bytes + 1);
+ put_bcc(wdata->bytes + 1, &smb->hdr);
+ } else {
+ /* wct == 12 */
+ struct smb_com_writex_req *smbw =
+ (struct smb_com_writex_req *)smb;
+ inc_rfc1001_len(&smbw->hdr, wdata->bytes + 5);
+ put_bcc(wdata->bytes + 5, &smbw->hdr);
+ iov[0].iov_len += 4; /* pad bigger by four bytes */
+ }
+
+ kref_get(&wdata->refcount);
+ rc = cifs_call_async(tcon->ses->server, iov, wdata->nr_pages + 1,
+ cifs_writev_callback, wdata, false);
+
+ if (rc == 0)
+ cifs_stats_inc(&tcon->stats.cifs_stats.num_writes);
+ else
+ kref_put(&wdata->refcount, cifs_writedata_release);
+
+ /* send is done, unmap pages */
+ for (i = 0; i < wdata->nr_pages; i++)
+ kunmap(wdata->pages[i]);
+
+async_writev_out:
+ cifs_small_buf_release(smb);
+ kfree(iov);
+ return rc;
+}
+
int
CIFSSMBWrite2(const int xid, struct cifs_tcon *tcon,
const int netfid, const unsigned int count,
--
1.7.4.4
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