From c28c89fc43e3f81436efc4748837534d4d46f90c Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 19 May 2011 16:22:56 -0400 Subject: [PATCH] cifs: add cifs_async_writev 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 Signed-off-by: Jeff Layton Signed-off-by: Steve French --- fs/cifs/cifsproto.h | 18 ++++ fs/cifs/cifssmb.c | 236 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 254 insertions(+) diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index fdc0dc2c083..8aea8850ffe 100644 --- a/fs/cifs/cifsproto.h +++ b/fs/cifs/cifsproto.h @@ -442,4 +442,22 @@ 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 e0d24135b3c..136df013b0a 100644 --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include "cifspdu.h" #include "cifsglob.h" @@ -1604,6 +1605,241 @@ CIFSSMBWrite(const int xid, struct cifsTconInfo *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]); + } + + 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 cifsTconInfo *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 cifsTconInfo *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->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 cifsTconInfo *tcon, const int netfid, const unsigned int count, -- 2.20.1