1 files changed, 68 insertions, 62 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index cbefe1f1f9f..c4a8a060512 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -107,7 +107,7 @@ static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
 
 	/* want handles we can use to read with first
 	   in the list so we do not have to walk the
-	   list to search for one in prepare_write */
+	   list to search for one in write_begin */
 	if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
 		list_add_tail(&pCifsFile->flist,
 			      &pCifsInode->openFileList);
@@ -915,7 +915,7 @@ ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 }
 
 static ssize_t cifs_write(struct file *file, const char *write_data,
-	size_t write_size, loff_t *poffset)
+			  size_t write_size, loff_t *poffset)
 {
 	int rc = 0;
 	unsigned int bytes_written = 0;
@@ -1065,6 +1065,7 @@ struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode)
 struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
 {
 	struct cifsFileInfo *open_file;
+	bool any_available = false;
 	int rc;
 
 	/* Having a null inode here (because mapping->host was set to zero by
@@ -1080,8 +1081,10 @@ struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode)
 	read_lock(&GlobalSMBSeslock);
 refind_writable:
 	list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
-		if (open_file->closePend)
+		if (open_file->closePend ||
+		    (!any_available && open_file->pid != current->tgid))
 			continue;
+
 		if (open_file->pfile &&
 		    ((open_file->pfile->f_flags & O_RDWR) ||
 		     (open_file->pfile->f_flags & O_WRONLY))) {
@@ -1131,6 +1134,11 @@ refind_writable:
 			   of the loop here. */
 		}
 	}
+	/* couldn't find useable FH with same pid, try any available */
+	if (!any_available) {
+		any_available = true;
+		goto refind_writable;
+	}
 	read_unlock(&GlobalSMBSeslock);
 	return NULL;
 }
@@ -1447,49 +1455,52 @@ static int cifs_writepage(struct page *page, struct writeback_control *wbc)
 	return rc;
 }
 
-static int cifs_commit_write(struct file *file, struct page *page,
-	unsigned offset, unsigned to)
+static int cifs_write_end(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
 {
-	int xid;
-	int rc = 0;
-	struct inode *inode = page->mapping->host;
-	loff_t position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
-	char *page_data;
+	int rc;
+	struct inode *inode = mapping->host;
 
-	xid = GetXid();
-	cFYI(1, ("commit write for page %p up to position %lld for %d",
-		 page, position, to));
-	spin_lock(&inode->i_lock);
-	if (position > inode->i_size)
-		i_size_write(inode, position);
+	cFYI(1, ("write_end for page %p from pos %lld with %d bytes",
+		 page, pos, copied));
+
+	if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
+		SetPageUptodate(page);
 
-	spin_unlock(&inode->i_lock);
 	if (!PageUptodate(page)) {
-		position =  ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
-		/* can not rely on (or let) writepage write this data */
-		if (to < offset) {
-			cFYI(1, ("Illegal offsets, can not copy from %d to %d",
-				offset, to));
-			FreeXid(xid);
-			return rc;
-		}
+		char *page_data;
+		unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
+		int xid;
+
+		xid = GetXid();
 		/* this is probably better than directly calling
 		   partialpage_write since in this function the file handle is
 		   known which we might as well	leverage */
 		/* BB check if anything else missing out of ppw
 		   such as updating last write time */
 		page_data = kmap(page);
-		rc = cifs_write(file, page_data + offset, to-offset,
-				&position);
-		if (rc > 0)
-			rc = 0;
-		/* else if (rc < 0) should we set writebehind rc? */
+		rc = cifs_write(file, page_data + offset, copied, &pos);
+		/* if (rc < 0) should we set writebehind rc? */
 		kunmap(page);
+
+		FreeXid(xid);
 	} else {
+		rc = copied;
+		pos += copied;
 		set_page_dirty(page);
 	}
 
-	FreeXid(xid);
+	if (rc > 0) {
+		spin_lock(&inode->i_lock);
+		if (pos > inode->i_size)
+			i_size_write(inode, pos);
+		spin_unlock(&inode->i_lock);
+	}
+
+	unlock_page(page);
+	page_cache_release(page);
+
 	return rc;
 }
 
@@ -2035,49 +2046,44 @@ bool is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
 		return true;
 }
 
-static int cifs_prepare_write(struct file *file, struct page *page,
-	unsigned from, unsigned to)
+static int cifs_write_begin(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned flags,
+			struct page **pagep, void **fsdata)
 {
-	int rc = 0;
-	loff_t i_size;
-	loff_t offset;
+	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+	loff_t offset = pos & (PAGE_CACHE_SIZE - 1);
 
-	cFYI(1, ("prepare write for page %p from %d to %d", page, from, to));
-	if (PageUptodate(page))
+	cFYI(1, ("write_begin from %lld len %d", (long long)pos, len));
+
+	*pagep = __grab_cache_page(mapping, index);
+	if (!*pagep)
+		return -ENOMEM;
+
+	if (PageUptodate(*pagep))
 		return 0;
 
 	/* If we are writing a full page it will be up to date,
 	   no need to read from the server */
-	if ((to == PAGE_CACHE_SIZE) && (from == 0)) {
-		SetPageUptodate(page);
+	if (len == PAGE_CACHE_SIZE && flags & AOP_FLAG_UNINTERRUPTIBLE)
 		return 0;
-	}
 
-	offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
-	i_size = i_size_read(page->mapping->host);
+	if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
+		int rc;
 
-	if ((offset >= i_size) ||
-	    ((from == 0) && (offset + to) >= i_size)) {
-		/*
-		 * We don't need to read data beyond the end of the file.
-		 * zero it, and set the page uptodate
-		 */
-		simple_prepare_write(file, page, from, to);
-		SetPageUptodate(page);
-	} else if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
 		/* might as well read a page, it is fast enough */
-		rc = cifs_readpage_worker(file, page, &offset);
+		rc = cifs_readpage_worker(file, *pagep, &offset);
+
+		/* we do not need to pass errors back
+		   e.g. if we do not have read access to the file
+		   because cifs_write_end will attempt synchronous writes
+		   -- shaggy */
 	} else {
 		/* we could try using another file handle if there is one -
 		   but how would we lock it to prevent close of that handle
 		   racing with this read? In any case
-		   this will be written out by commit_write so is fine */
+		   this will be written out by write_end so is fine */
 	}
 
-	/* we do not need to pass errors back
-	   e.g. if we do not have read access to the file
-	   because cifs_commit_write will do the right thing.  -- shaggy */
-
 	return 0;
 }
 
@@ -2086,8 +2092,8 @@ const struct address_space_operations cifs_addr_ops = {
 	.readpages = cifs_readpages,
 	.writepage = cifs_writepage,
 	.writepages = cifs_writepages,
-	.prepare_write = cifs_prepare_write,
-	.commit_write = cifs_commit_write,
+	.write_begin = cifs_write_begin,
+	.write_end = cifs_write_end,
 	.set_page_dirty = __set_page_dirty_nobuffers,
 	/* .sync_page = cifs_sync_page, */
 	/* .direct_IO = */
@@ -2102,8 +2108,8 @@ const struct address_space_operations cifs_addr_ops_smallbuf = {
 	.readpage = cifs_readpage,
 	.writepage = cifs_writepage,
 	.writepages = cifs_writepages,
-	.prepare_write = cifs_prepare_write,
-	.commit_write = cifs_commit_write,
+	.write_begin = cifs_write_begin,
+	.write_end = cifs_write_end,
 	.set_page_dirty = __set_page_dirty_nobuffers,
 	/* .sync_page = cifs_sync_page, */
 	/* .direct_IO = */