CIFS: Implement cifs_strict_writev (try #4)

If we don't have Exclusive oplock we write a data to the server.
Also set invalidate_mapping flag on the inode if we wrote something
to the server. Add cifs_iovec_write to let the client write iovec
buffers through CIFSSMBWrite2.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index a8323f1..f297013 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -600,10 +600,17 @@ static ssize_t cifs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 {
        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;
 }
 
@@ -737,7 +744,7 @@ const struct file_operations cifs_file_strict_ops = {
        .read = do_sync_read,
        .write = do_sync_write,
        .aio_read = cifs_strict_readv,
-       .aio_write = cifs_file_aio_write,
+       .aio_write = cifs_strict_writev,
        .open = cifs_open,
        .release = cifs_close,
        .lock = cifs_lock,
@@ -793,7 +800,7 @@ const struct file_operations cifs_file_strict_nobrl_ops = {
        .read = do_sync_read,
        .write = do_sync_write,
        .aio_read = cifs_strict_readv,
-       .aio_write = cifs_file_aio_write,
+       .aio_write = cifs_strict_writev,
        .open = cifs_open,
        .release = cifs_close,
        .fsync = cifs_strict_fsync,

diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index f23206d..14789a9 100644 (file)
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -85,7 +85,9 @@ extern ssize_t cifs_user_read(struct file *file, char __user *read_data,
 extern ssize_t cifs_strict_readv(struct kiocb *iocb, const struct iovec *iov,
                                 unsigned long nr_segs, loff_t pos);
 extern ssize_t cifs_user_write(struct file *file, const char __user *write_data,
-                        size_t write_size, loff_t *poffset);
+                              size_t write_size, loff_t *poffset);
+extern ssize_t cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
+                                 unsigned long nr_segs, loff_t pos);
 extern int cifs_lock(struct file *, int, struct file_lock *);
 extern int cifs_fsync(struct file *, int);
 extern int cifs_strict_fsync(struct file *, int);

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 982895f..35c989f 100644 (file)
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -85,6 +85,8 @@ 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 d7d65a7..0de17c1 100644 (file)
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -848,7 +848,7 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *pfLock)
 }
 
 /* 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)
 {
@@ -1619,6 +1619,206 @@ int cifs_flush(struct file *file, fl_owner_t id)
        return rc;
 }
 
+static int
+cifs_write_allocate_pages(struct page **pages, unsigned long num_pages)
+{
+       int rc = 0;
+       unsigned long i;
+
+       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;
+               }
+       }
+
+       return rc;
+
+error:
+       for (i = 0; i < num_pages; i++)
+               put_page(pages[i]);
+       return rc;
+}
+
+static inline
+size_t get_numpages(const size_t wsize, const size_t len, size_t *cur_len)
+{
+       size_t num_pages;
+       size_t clen;
+
+       clen = min_t(const size_t, len, wsize);
+       num_pages = clen / PAGE_CACHE_SIZE;
+       if (clen % PAGE_CACHE_SIZE)
+               num_pages++;
+
+       if (cur_len)
+               *cur_len = clen;
+
+       return num_pages;
+}
+
+static ssize_t
+cifs_iovec_write(struct file *file, const struct iovec *iov,
+                unsigned long nr_segs, loff_t *poffset)
+{
+       size_t total_written = 0, written = 0;
+       unsigned long num_pages, npages;
+       size_t copied, len, cur_len, i;
+       struct kvec *to_send;
+       struct page **pages;
+       struct iov_iter it;
+       struct inode *inode;
+       struct cifsFileInfo *open_file;
+       struct cifsTconInfo *pTcon;
+       struct cifs_sb_info *cifs_sb;
+       int xid, rc;
+
+       len = iov_length(iov, nr_segs);
+       if (!len)
+               return 0;
+
+       rc = generic_write_checks(file, poffset, &len, 0);
+       if (rc)
+               return rc;
+
+       cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
+       num_pages = get_numpages(cifs_sb->wsize, len, &cur_len);
+
+       pages = kmalloc(sizeof(struct pages *)*num_pages, GFP_KERNEL);
+       if (!pages)
+               return -ENOMEM;
+
+       to_send = kmalloc(sizeof(struct kvec)*(num_pages + 1), GFP_KERNEL);
+       if (!to_send) {
+               kfree(pages);
+               return -ENOMEM;
+       }
+
+       rc = cifs_write_allocate_pages(pages, num_pages);
+       if (rc) {
+               kfree(pages);
+               kfree(to_send);
+               return rc;
+       }
+
+       xid = GetXid();
+       open_file = file->private_data;
+       pTcon = tlink_tcon(open_file->tlink);
+       inode = file->f_path.dentry->d_inode;
+
+       iov_iter_init(&it, iov, nr_segs, len, 0);
+       npages = num_pages;
+
+       do {
+               size_t save_len = cur_len;
+               for (i = 0; i < npages; i++) {
+                       copied = min_t(const size_t, cur_len, PAGE_CACHE_SIZE);
+                       copied = iov_iter_copy_from_user(pages[i], &it, 0,
+                                                        copied);
+                       cur_len -= copied;
+                       iov_iter_advance(&it, copied);
+                       to_send[i+1].iov_base = kmap(pages[i]);
+                       to_send[i+1].iov_len = copied;
+               }
+
+               cur_len = save_len - cur_len;
+
+               do {
+                       if (open_file->invalidHandle) {
+                               rc = cifs_reopen_file(open_file, false);
+                               if (rc != 0)
+                                       break;
+                       }
+                       rc = CIFSSMBWrite2(xid, pTcon, open_file->netfid,
+                                          cur_len, *poffset, &written,
+                                          to_send, npages, 0);
+               } while (rc == -EAGAIN);
+
+               for (i = 0; i < npages; i++)
+                       kunmap(pages[i]);
+
+               if (written) {
+                       len -= written;
+                       total_written += written;
+                       cifs_update_eof(CIFS_I(inode), *poffset, written);
+                       *poffset += written;
+               } else if (rc < 0) {
+                       if (!total_written)
+                               total_written = rc;
+                       break;
+               }
+
+               /* get length and number of kvecs of the next write */
+               npages = get_numpages(cifs_sb->wsize, len, &cur_len);
+       } while (len > 0);
+
+       if (total_written > 0) {
+               spin_lock(&inode->i_lock);
+               if (*poffset > inode->i_size)
+                       i_size_write(inode, *poffset);
+               spin_unlock(&inode->i_lock);
+       }
+
+       cifs_stats_bytes_written(pTcon, total_written);
+       mark_inode_dirty_sync(inode);
+
+       for (i = 0; i < num_pages; i++)
+               put_page(pages[i]);
+       kfree(to_send);
+       kfree(pages);
+       FreeXid(xid);
+       return total_written;
+}
+
+static ssize_t cifs_user_writev(struct kiocb *iocb, const struct iovec *iov,
+                               unsigned long nr_segs, loff_t pos)
+{
+       ssize_t written;
+       struct inode *inode;
+
+       inode = iocb->ki_filp->f_path.dentry->d_inode;
+
+       /*
+        * 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.
+        */
+
+       written = cifs_iovec_write(iocb->ki_filp, iov, nr_segs, &pos);
+       if (written > 0) {
+               CIFS_I(inode)->invalid_mapping = true;
+               iocb->ki_pos = pos;
+       }
+
+       return written;
+}
+
+ssize_t cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
+                          unsigned long nr_segs, loff_t pos)
+{
+       struct inode *inode;
+
+       inode = iocb->ki_filp->f_path.dentry->d_inode;
+
+       if (CIFS_I(inode)->clientCanCacheAll)
+               return generic_file_aio_write(iocb, iov, nr_segs, pos);
+
+       /*
+        * 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.
+        */
+
+       return cifs_user_writev(iocb, iov, nr_segs, pos);
+}
+
 static ssize_t
 cifs_iovec_read(struct file *file, const struct iovec *iov,
                 unsigned long nr_segs, loff_t *poffset)