Commit 7e48ff82 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Separate page processing from writepages 



Signed-off-by: default avatarPavel Shilovsky <pshilovsky@samba.org>
Reviewed-by: default avatarJeff Layton <jlayton@samba.org>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent 038bc961

fs/cifs/file.c

+82 −70
Original line number Diff line number Diff line
@@ -1878,73 +1878,15 @@ static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to) 
	return rc;

}



static int cifs_writepages(struct address_space *mapping,

			   struct writeback_control *wbc)

static unsigned int

wdata_prepare_pages(struct cifs_writedata *wdata, unsigned int found_pages,

		    struct address_space *mapping,

		    struct writeback_control *wbc,

		    pgoff_t end, pgoff_t *index, pgoff_t *next, bool *done)

{

	struct cifs_sb_info *cifs_sb = CIFS_SB(mapping->host->i_sb);

	bool done = false, scanned = false, range_whole = false;

	pgoff_t end, index;

	struct cifs_writedata *wdata;

	struct TCP_Server_Info *server;

	unsigned int nr_pages = 0, i;

	struct page *page;

	int rc = 0;



	/*

	 * If wsize is smaller than the page cache size, default to writing

	 * one page at a time via cifs_writepage

	 */

	if (cifs_sb->wsize < PAGE_CACHE_SIZE)

		return generic_writepages(mapping, wbc);



	if (wbc->range_cyclic) {

		index = mapping->writeback_index; /* Start from prev offset */

		end = -1;

	} else {

		index = wbc->range_start >> PAGE_CACHE_SHIFT;

		end = wbc->range_end >> PAGE_CACHE_SHIFT;

		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)

			range_whole = true;

		scanned = true;

	}

retry:

	while (!done && index <= end) {

		unsigned int i, nr_pages, found_pages;

		pgoff_t next = 0, tofind;

		struct page **pages;



		tofind = min((cifs_sb->wsize / PAGE_CACHE_SIZE) - 1,

				end - index) + 1;



		wdata = cifs_writedata_alloc((unsigned int)tofind,

					     cifs_writev_complete);

		if (!wdata) {

			rc = -ENOMEM;

			break;

		}



		/*

		 * find_get_pages_tag seems to return a max of 256 on each

		 * iteration, so we must call it several times in order to

		 * fill the array or the wsize is effectively limited to

		 * 256 * PAGE_CACHE_SIZE.

		 */

		found_pages = 0;

		pages = wdata->pages;

		do {

			nr_pages = find_get_pages_tag(mapping, &index,

							PAGECACHE_TAG_DIRTY,

							tofind, pages);

			found_pages += nr_pages;

			tofind -= nr_pages;

			pages += nr_pages;

		} while (nr_pages && tofind && index <= end);



		if (found_pages == 0) {

			kref_put(&wdata->refcount, cifs_writedata_release);

			break;

		}



		nr_pages = 0;

	for (i = 0; i < found_pages; i++) {

		page = wdata->pages[i];

		/*
@@ -1966,12 +1908,12 @@ retry: 
		}



		if (!wbc->range_cyclic && page->index > end) {

				done = true;

			*done = true;

			unlock_page(page);

			break;

		}



			if (next && (page->index != next)) {

		if (*next && (page->index != *next)) {

			/* Not next consecutive page */

			unlock_page(page);

			break;
@@ -1991,22 +1933,21 @@ retry: 
		 * See cifs_writepage() for more commentary.

		 */

		set_page_writeback(page);



		if (page_offset(page) >= i_size_read(mapping->host)) {

				done = true;

			*done = true;

			unlock_page(page);

			end_page_writeback(page);

			break;

		}



		wdata->pages[i] = page;

			next = page->index + 1;

		*next = page->index + 1;

		++nr_pages;

	}



	/* reset index to refind any pages skipped */

	if (nr_pages == 0)

			index = wdata->pages[0]->index + 1;

		*index = wdata->pages[0]->index + 1;



	/* put any pages we aren't going to use */

	for (i = nr_pages; i < found_pages; i++) {
@@ -2014,6 +1955,77 @@ retry: 
		wdata->pages[i] = NULL;

	}



	return nr_pages;

}



static int cifs_writepages(struct address_space *mapping,

			   struct writeback_control *wbc)

{

	struct cifs_sb_info *cifs_sb = CIFS_SB(mapping->host->i_sb);

	bool done = false, scanned = false, range_whole = false;

	pgoff_t end, index;

	struct cifs_writedata *wdata;

	struct TCP_Server_Info *server;

	int rc = 0;



	/*

	 * If wsize is smaller than the page cache size, default to writing

	 * one page at a time via cifs_writepage

	 */

	if (cifs_sb->wsize < PAGE_CACHE_SIZE)

		return generic_writepages(mapping, wbc);



	if (wbc->range_cyclic) {

		index = mapping->writeback_index; /* Start from prev offset */

		end = -1;

	} else {

		index = wbc->range_start >> PAGE_CACHE_SHIFT;

		end = wbc->range_end >> PAGE_CACHE_SHIFT;

		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)

			range_whole = true;

		scanned = true;

	}

retry:

	while (!done && index <= end) {

		unsigned int i, nr_pages, found_pages;

		pgoff_t next = 0, tofind;

		struct page **pages;



		tofind = min((cifs_sb->wsize / PAGE_CACHE_SIZE) - 1,

				end - index) + 1;



		wdata = cifs_writedata_alloc((unsigned int)tofind,

					     cifs_writev_complete);

		if (!wdata) {

			rc = -ENOMEM;

			break;

		}



		/*

		 * find_get_pages_tag seems to return a max of 256 on each

		 * iteration, so we must call it several times in order to

		 * fill the array or the wsize is effectively limited to

		 * 256 * PAGE_CACHE_SIZE.

		 */

		found_pages = 0;

		pages = wdata->pages;

		do {

			nr_pages = find_get_pages_tag(mapping, &index,

							PAGECACHE_TAG_DIRTY,

							tofind, pages);

			found_pages += nr_pages;

			tofind -= nr_pages;

			pages += nr_pages;

		} while (nr_pages && tofind && index <= end);



		if (found_pages == 0) {

			kref_put(&wdata->refcount, cifs_writedata_release);

			break;

		}



		nr_pages = wdata_prepare_pages(wdata, found_pages, mapping, wbc,

					       end, &index, &next, &done);



		/* nothing to write? */

		if (nr_pages == 0) {

			kref_put(&wdata->refcount, cifs_writedata_release);

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