[CIFS] fix regression in cifs_write_begin/cifs_write_end (a98ee8c1) · Commits · 戴 / test

fs/cifs/file.c

+56 −21

Original line number	Diff line number	Diff line
		@@ -1475,7 +1475,11 @@ static int cifs_write_end(struct file file, struct address_space mapping,
		cFYI(1, ("write_end for page %p from pos %lld with %d bytes",
		page, pos, copied));

		if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
		if (PageChecked(page)) {
		if (copied == len)
		SetPageUptodate(page);
		ClearPageChecked(page);
		} else if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE)
		SetPageUptodate(page);

		if (!PageUptodate(page)) {
		@@ -2062,39 +2066,70 @@ static int cifs_write_begin(struct file file, struct address_space mapping,
		{
		pgoff_t index = pos >> PAGE_CACHE_SHIFT;
		loff_t offset = pos & (PAGE_CACHE_SIZE - 1);
		loff_t page_start = pos & PAGE_MASK;
		loff_t i_size;
		struct page *page;
		int rc = 0;

		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;
		page = __grab_cache_page(mapping, index);
		if (!page) {
		rc = -ENOMEM;
		goto out;
		}

		/* If we are writing a full page it will be up to date,
		no need to read from the server */
		if (len == PAGE_CACHE_SIZE && flags & AOP_FLAG_UNINTERRUPTIBLE)
		return 0;
		if (PageUptodate(page))
		goto out;

		if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
		int rc;
		/*
		* If we write a full page it will be up to date, no need to read from
		* the server. If the write is short, we'll end up doing a sync write
		* instead.
		*/
		if (len == PAGE_CACHE_SIZE)
		goto out;

		/* might as well read a page, it is fast enough */
		rc = cifs_readpage_worker(file, *pagep, &offset);
		/*
		* optimize away the read when we have an oplock, and we're not
		* expecting to use any of the data we'd be reading in. That
		* is, when the page lies beyond the EOF, or straddles the EOF
		* and the write will cover all of the existing data.
		*/
		if (CIFS_I(mapping->host)->clientCanCacheRead) {
		i_size = i_size_read(mapping->host);
		if (page_start >= i_size \|\|
		(offset == 0 && (pos + len) >= i_size)) {
		zero_user_segments(page, 0, offset,
		offset + len,
		PAGE_CACHE_SIZE);
		/*
		* PageChecked means that the parts of the page
		* to which we're not writing are considered up
		* to date. Once the data is copied to the
		* page, it can be set uptodate.
		*/
		SetPageChecked(page);
		goto out;
		}
		}

		/* 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 */
		if ((file->f_flags & O_ACCMODE) != O_WRONLY) {
		/*
		* might as well read a page, it is fast enough. If we get
		* an error, we don't need to return it. cifs_write_end will
		* do a sync write instead since PG_uptodate isn't set.
		*/
		cifs_readpage_worker(file, page, &page_start);
		} 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 write_end so is fine */
		}

		return 0;
		out:
		*pagep = page;
		return rc;
		}

		const struct address_space_operations cifs_addr_ops = {

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