On Fri, 17 Dec 2010 15:49:14 +0300 Pavel Shilovsky <[email protected]> wrote:
> If we don't have Exclusive oplock we write a data to the server through > CISSMBWrite2. Also set invalidate_mapping flag on the inode if we wrote > something to the server. > > Signed-off-by: Pavel Shilovsky <[email protected]> > --- > fs/cifs/cifsfs.c | 228 > ++++++++++++++++++++++++++++++++++++++++++++++++++- > fs/cifs/cifsproto.h | 2 + > fs/cifs/file.c | 2 +- > 3 files changed, 227 insertions(+), 5 deletions(-) > > diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c > index bcb4d2c..fb50883 100644 > --- a/fs/cifs/cifsfs.c > +++ b/fs/cifs/cifsfs.c > @@ -606,15 +606,235 @@ static ssize_t cifs_strict_read(struct kiocb *iocb, > const struct iovec *iov, > return read; > } > > +/* Assume that dest points to memory area that is enough for source data */ > +static int cifs_copy_iovs(struct kvec *dst, const struct iovec **source, > + unsigned long *lastlen, unsigned long len) > +{ > + const struct iovec *src = *source; > + unsigned long dst_lastlen, src_lastlen; > + unsigned long cur_len; > + > + dst_lastlen = dst->iov_len; > + src_lastlen = *lastlen; > + > + while (len > 0) { > + cur_len = min_t(unsigned long, dst_lastlen, src_lastlen); > + cur_len = min_t(unsigned long, cur_len, len); > + > + if (copy_from_user(dst->iov_base + dst->iov_len - dst_lastlen, > + src->iov_base + src->iov_len - src_lastlen, > + cur_len)) > + return -EFAULT; > + > + dst_lastlen -= cur_len; > + if (!dst_lastlen) { > + dst++; > + dst_lastlen = dst->iov_len; > + } > + > + src_lastlen -= cur_len; > + if (!src_lastlen) { > + src++; > + src_lastlen = src->iov_len; > + } > + > + len -= cur_len; > + } > + > + /* update length of the last element in dest */ > + if (dst_lastlen) > + dst->iov_len -= dst_lastlen; > + > + /* save offset and length of the last element in source */ > + *lastlen = src_lastlen; > + *source = src; > + > + return 0; > +} > + > +static int > +cifs_strict_write_helper(struct page ***ppages, struct kvec **pto_send, ^^^^ Wow, a triple pointer? Ugly... > + unsigned long num_pages) > +{ > + int rc = 0; > + unsigned long i; > + struct page **pages; > + struct kvec *to_send; > + > + *ppages = kmalloc(sizeof(struct pages *)*num_pages, GFP_KERNEL); > + if (!ppages) > + return -ENOMEM; > + > + *pto_send = kmalloc(sizeof(struct kvec)*(num_pages + 1), > + GFP_KERNEL); > + if (!pto_send) { > + kfree(ppages); > + return -ENOMEM; > + } > + > + pages = *ppages; > + to_send = *pto_send; > + > + for (i = 0; i < num_pages; i++) { > + pages[i] = alloc_page(__GFP_HIGHMEM); > + if (!pages[i]) { > + /* > + * save number of pages we have already allocated and > + * return with ENOMEM error > + */ > + num_pages = i; > + rc = -ENOMEM; > + goto error; > + } > + to_send[i+1].iov_base = kmap(pages[i]); > + to_send[i+1].iov_len = PAGE_CACHE_SIZE; ^^^^^^^^^^^ kmap space is limited on 32-bit architectures. You really want to limit the amount of pages that you have simultaneously mapped. What's going to happen if someone passes down a massive write this way? I expect that it would fail badly. I think that you really only want to allocate the memory needed to perform just the write that you're getting ready to perform, and then free it when that's done. > + } > + > + return rc; > + > +error: > + for (i = 0; i < num_pages; i++) { > + kunmap(pages[i]); > + put_page(pages[i]); > + } > + kfree(to_send); > + kfree(pages); > + return rc; > +} > + Instead of rolling your own functions for this, might it be better to try and use the iov_iter infrastructure? Look at what generic_perform_write does, IOW. This situation is a little different, but there are similarities. > +static ssize_t cifs_strict_write(struct kiocb *iocb, const struct iovec *iov, > + unsigned long nr_segs, loff_t pos) > +{ > + struct inode *inode; > + struct cifs_sb_info *cifs_sb; > + ssize_t written = 0, total_written = 0; > + unsigned long i, num_pages, cur_numpages; > + unsigned long len, cur_len, last_len; > + struct kvec *to_send; > + const struct iovec *offset; > + struct page **pages; > + struct cifsFileInfo *open_file; > + struct cifsTconInfo *pTcon; > + int xid, rc; > + > + inode = iocb->ki_filp->f_path.dentry->d_inode; > + > + if (CIFS_I(inode)->clientCanCacheAll) > + return generic_file_aio_write(iocb, iov, nr_segs, pos); > + > + cifs_sb = CIFS_SB(iocb->ki_filp->f_path.dentry->d_sb); > + > + /* > + * In strict cache mode we need to write the data to the server exactly > + * from the pos to pos+len-1 rather than flush all affected pages > + * because it may cause a error with mandatory locks on these pages but > + * not on the region from pos to ppos+len-1. > + */ > + > + len = 0; > + for (i = 0; i < nr_segs; i++) > + len += iov[i].iov_len; > + > + if (!len) > + return 0; > + > + /* > + * BB - optimize the way when signing is disabled. We can drop this > + * extra memory-to-memory copying and use iovec buffers for constructing > + * write request. > + */ > + > + xid = GetXid(); > + open_file = iocb->ki_filp->private_data; > + pTcon = tlink_tcon(open_file->tlink); > + > + /* calculate number of pages we need for process this write */ > + cur_len = min_t(unsigned long, len, cifs_sb->wsize); > + num_pages = cur_len / PAGE_CACHE_SIZE; > + if (cur_len % PAGE_CACHE_SIZE) > + num_pages++; > + > + rc = cifs_strict_write_helper(&pages, &to_send, num_pages); > + if (rc) { > + total_written = rc; > + goto error; > + } > + > + last_len = iov->iov_len; > + offset = iov; > + cur_numpages = num_pages; > + > + do { > + rc = cifs_copy_iovs(to_send+1, &offset, &last_len, cur_len); > + if (rc) { > + total_written = -EFAULT; > + goto exit; > + } > + > + do { > + rc = CIFSSMBWrite2(xid, pTcon, open_file->netfid, > + cur_len, pos, &written, to_send, > + cur_numpages, 0); > + } while (rc == -EAGAIN); > + > + if (written) { > + len -= written; > + total_written += written; > + cifs_update_eof(CIFS_I(inode), pos, written); > + pos += written; > + } else if (rc < 0) { > + if (!total_written) > + total_written = rc; > + goto exit; > + } > + > + /* get length and number of kvecs of the next write */ > + cur_len = min_t(unsigned long, len, cifs_sb->wsize); > + cur_numpages = cur_len / PAGE_CACHE_SIZE; > + if (cur_len % PAGE_CACHE_SIZE) > + cur_numpages++; > + } while (len > 0); > + > +exit: > + if (total_written > 0) { > + CIFS_I(inode)->invalid_mapping = true; > + iocb->ki_pos += total_written; > + spin_lock(&inode->i_lock); > + if (pos > inode->i_size) > + i_size_write(inode, pos); > + spin_unlock(&inode->i_lock); > + } > + > + cifs_stats_bytes_written(pTcon, total_written); > + mark_inode_dirty_sync(inode); > + > + for (i = 0; i < num_pages; i++) { > + kunmap(pages[i]); > + put_page(pages[i]); > + } > + kfree(to_send); > + kfree(pages); > +error: > + FreeXid(xid); > + return total_written; > +} > + > static ssize_t cifs_file_aio_write(struct kiocb *iocb, const struct iovec > *iov, > unsigned long nr_segs, loff_t pos) > { > struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode; > ssize_t written; > + int rc; > > written = generic_file_aio_write(iocb, iov, nr_segs, pos); > - if (!CIFS_I(inode)->clientCanCacheAll) > - filemap_fdatawrite(inode->i_mapping); > + > + if (CIFS_I(inode)->clientCanCacheAll) > + return written; > + > + rc = filemap_fdatawrite(inode->i_mapping); > + if (rc) > + cFYI(1, "cifs_file_aio_write: %d rc on %p inode", rc, inode); > + > return written; > } > > @@ -748,7 +968,7 @@ const struct file_operations cifs_file_strict_ops = { > .read = do_sync_read, > .write = do_sync_write, > .aio_read = cifs_strict_read, > - .aio_write = cifs_file_aio_write, > + .aio_write = cifs_strict_write, > .open = cifs_open, > .release = cifs_close, > .lock = cifs_lock, > @@ -804,7 +1024,7 @@ const struct file_operations cifs_file_strict_nobrl_ops > = { > .read = do_sync_read, > .write = do_sync_write, > .aio_read = cifs_strict_read, > - .aio_write = cifs_file_aio_write, > + .aio_write = cifs_strict_write, > .open = cifs_open, > .release = cifs_close, > .fsync = cifs_strict_fsync, > diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h > index e6d1481..e7d6c24 100644 > --- a/fs/cifs/cifsproto.h > +++ b/fs/cifs/cifsproto.h > @@ -79,6 +79,8 @@ extern int checkSMB(struct smb_hdr *smb, __u16 mid, > unsigned int length); > extern bool is_valid_oplock_break(struct smb_hdr *smb, > struct TCP_Server_Info *); > extern bool is_size_safe_to_change(struct cifsInodeInfo *, __u64 eof); > +extern void cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset, > + unsigned int bytes_written); > extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *, bool); > extern struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *, bool); > extern unsigned int smbCalcSize(struct smb_hdr *ptr); > diff --git a/fs/cifs/file.c b/fs/cifs/file.c > index bc53e9e..8260f53 100644 > --- a/fs/cifs/file.c > +++ b/fs/cifs/file.c > @@ -924,7 +924,7 @@ cifs_write_timeout(struct cifsInodeInfo *cifsi, loff_t > offset) > } > > /* update the file size (if needed) after a write */ > -static void > +void > cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset, > unsigned int bytes_written) > { -- Jeff Layton <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
