2011/4/2 Jeff Layton <jlayton@xxxxxxxxxx>:
> 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.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/cifsproto.h | 19 +++++
> fs/cifs/cifssmb.c | 219 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 238 insertions(+), 0 deletions(-)
Looks good too, except two small notes.
>
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index e255a2b..7b964df 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -21,6 +21,7 @@
> #ifndef _CIFSPROTO_H
> #define _CIFSPROTO_H
> #include <linux/nls.h>
> +#include <linux/pagevec.h>
>
> struct statfs;
> struct smb_vol;
> @@ -433,4 +434,22 @@ 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 list_head pending;
> + struct kref refcount;
> + struct completion completion;
> + struct work_struct work;
> + struct cifsFileInfo *cfile;
> + __u64 offset;
> + unsigned int bytes;
> + int result;
> + struct page *pages[PAGEVEC_SIZE];
> +};
> +
> +int cifs_async_writev(struct cifs_writedata *wdata);
> +struct cifs_writedata *cifs_writedata_alloc(void);
> +void cifs_writedata_release(struct kref *refcount);
> +
> #endif /* _CIFSPROTO_H */
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index 8de7e79..b308605 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 +1605,224 @@ 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);
> + struct address_space *mapping;
> +
> + if (wdata->cfile) {
> + mapping = wdata->cfile->dentry->d_inode->i_mapping;
> +
> + spin_lock(&mapping->private_lock);
> + list_del(&wdata->pending);
> + spin_unlock(&mapping->private_lock);
> +
> + cifsFileInfo_put(wdata->cfile);
> + }
> +
> + kfree(wdata);
> +}
> +
> +static void
> +cifs_writev_complete(struct work_struct *work)
> +{
> + struct cifs_writedata *wdata = container_of(work,
> + struct cifs_writedata, work);
> + struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
^^^ this variable is unused.
> + struct inode *inode = wdata->cfile->dentry->d_inode;
> + struct page *page;
> + int i = 0;
> +
> + if (wdata->result == 0) {
> + cifs_update_eof(CIFS_I(inode), wdata->offset, wdata->bytes);
> + cifs_stats_bytes_written(tcon, wdata->bytes);
> + }
> +
> + for (i = 0; i < ARRAY_SIZE(wdata->pages) && (page = wdata->pages[i]);
> + 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);
> + complete(&wdata->completion);
> + kref_put(&wdata->refcount, cifs_writedata_release);
> +}
> +
> +struct cifs_writedata *
> +cifs_writedata_alloc(void)
> +{
> + struct cifs_writedata *wdata;
> +
> + wdata = kzalloc(sizeof(*wdata), GFP_NOFS);
> + if (wdata != NULL) {
> + INIT_LIST_HEAD(&wdata->pending);
> + INIT_WORK(&wdata->work, cifs_writev_complete);
> + kref_init(&wdata->refcount);
> + init_completion(&wdata->completion);
> + }
> + 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;
> + unsigned int npages = ARRAY_SIZE(wdata->pages);
> + struct kvec *iov = NULL;
> +
> + cFYI(1, "async write at %llu %u bytes", wdata->offset, wdata->bytes);
^^^^ bytes is
zero here. You calculate it next - I suggest to move this info message
after you get right bytes value.
> +
> + 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;
> +
> + /* FIXME: only allocate number of kvecs we need */
> + iov = kzalloc((npages + 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 */
> + npages = 0;
> + wdata->bytes = 0;
> + for (i = 0; i < ARRAY_SIZE(wdata->pages) && wdata->pages[i]; i++) {
> + if (wdata->bytes + PAGE_CACHE_SIZE <=
> + CIFS_SB(inode->i_sb)->wsize) {
> + 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;
> + npages++;
> + } else {
> + /* if we're beyond wsize, then re-mark page dirty */
> + __set_page_dirty_nobuffers(wdata->pages[i]);
> + }
> + }
> +
> + 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, npages + 1,
> + cifs_writev_callback, wdata);
> +
> + 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 < npages; 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
>
> --
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>
Anyway, it's good. You can my "Reviewed-by: Pavel Shilovsky
<piastry@xxxxxxxxxxx>" tag when you fix the notes above.
--
Best regards,
Pavel Shilovsky.
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