Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit bda97eab authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

tmpfs: copy truncate_inode_pages_range 



Bring truncate.c's code for truncate_inode_pages_range() inline into
shmem_truncate_range(), replacing its first call (there's a followup
call below, but leave that one, it will disappear next).

Don't play with it yet, apart from leaving out the cleancache flush, and
(importantly) the nrpages == 0 skip, and moving shmem_setattr()'s
partial page preparation into its partial page handling.

Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 41ffe5d5

mm/shmem.c

+79 −20
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ static struct vfsmount *shm_mnt; 
#include <linux/shmem_fs.h>

#include <linux/writeback.h>

#include <linux/blkdev.h>

#include <linux/pagevec.h>

#include <linux/percpu_counter.h>

#include <linux/splice.h>

#include <linux/security.h>
@@ -242,11 +243,88 @@ void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) 
	struct address_space *mapping = inode->i_mapping;

	struct shmem_inode_info *info = SHMEM_I(inode);

	pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;

	unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);

	pgoff_t end = (lend >> PAGE_CACHE_SHIFT);

	struct pagevec pvec;

	pgoff_t index;

	swp_entry_t swap;

	int i;



	truncate_inode_pages_range(mapping, lstart, lend);

	BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1));



	pagevec_init(&pvec, 0);

	index = start;

	while (index <= end && pagevec_lookup(&pvec, mapping, index,

			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {

		mem_cgroup_uncharge_start();

		for (i = 0; i < pagevec_count(&pvec); i++) {

			struct page *page = pvec.pages[i];



			/* We rely upon deletion not changing page->index */

			index = page->index;

			if (index > end)

				break;



			if (!trylock_page(page))

				continue;

			WARN_ON(page->index != index);

			if (PageWriteback(page)) {

				unlock_page(page);

				continue;

			}

			truncate_inode_page(mapping, page);

			unlock_page(page);

		}

		pagevec_release(&pvec);

		mem_cgroup_uncharge_end();

		cond_resched();

		index++;

	}



	if (partial) {

		struct page *page = NULL;

		shmem_getpage(inode, start - 1, &page, SGP_READ, NULL);

		if (page) {

			zero_user_segment(page, partial, PAGE_CACHE_SIZE);

			set_page_dirty(page);

			unlock_page(page);

			page_cache_release(page);

		}

	}



	index = start;

	for ( ; ; ) {

		cond_resched();

		if (!pagevec_lookup(&pvec, mapping, index,

			min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {

			if (index == start)

				break;

			index = start;

			continue;

		}

		if (index == start && pvec.pages[0]->index > end) {

			pagevec_release(&pvec);

			break;

		}

		mem_cgroup_uncharge_start();

		for (i = 0; i < pagevec_count(&pvec); i++) {

			struct page *page = pvec.pages[i];



			/* We rely upon deletion not changing page->index */

			index = page->index;

			if (index > end)

				break;



			lock_page(page);

			WARN_ON(page->index != index);

			wait_on_page_writeback(page);

			truncate_inode_page(mapping, page);

			unlock_page(page);

		}

		pagevec_release(&pvec);

		mem_cgroup_uncharge_end();

		index++;

	}



	if (end > SHMEM_NR_DIRECT)

		end = SHMEM_NR_DIRECT;
@@ -289,24 +367,7 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) 
	if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {

		loff_t oldsize = inode->i_size;

		loff_t newsize = attr->ia_size;

		struct page *page = NULL;



		if (newsize < oldsize) {

			/*

			 * If truncating down to a partial page, then

			 * if that page is already allocated, hold it

			 * in memory until the truncation is over, so

			 * truncate_partial_page cannot miss it were

			 * it assigned to swap.

			 */

			if (newsize & (PAGE_CACHE_SIZE-1)) {

				(void) shmem_getpage(inode,

					newsize >> PAGE_CACHE_SHIFT,

						&page, SGP_READ, NULL);

				if (page)

					unlock_page(page);

			}

		}

		if (newsize != oldsize) {

			i_size_write(inode, newsize);

			inode->i_ctime = inode->i_mtime = CURRENT_TIME;
@@ -318,8 +379,6 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr) 
			/* unmap again to remove racily COWed private pages */

			unmap_mapping_range(inode->i_mapping, holebegin, 0, 1);

		}

		if (page)

			page_cache_release(page);

	}



	setattr_copy(inode, attr);