Unverified Commit 84e0e03b authored by Phillip Lougher's avatar Phillip Lougher Committed by Christian Brauner
Browse files

Squashfs: Ensure all readahead pages have been used 

In the recent work to remove page->index, a sanity check
that ensured all the readhead pages were covered by the
Squashfs data block was removed [1].

To avoid any regression, this commit adds the sanity check
back in an equivalent way.  Namely the page actor will now
return error if any pages are unused after completion.

[1] https://lore.kernel.org/all/20240818235847.170468-3-phillip@squashfs.org.uk/



--

Signed-off-by: default avatarPhillip Lougher <phillip@squashfs.org.uk>
Link: https://lore.kernel.org/r/20240822233106.121522-1-phillip@squashfs.org.uk


V3: last_page should be actor->last_page
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent d937c813

fs/squashfs/file.c

+2 −2
Original line number Diff line number Diff line
@@ -535,7 +535,7 @@ static int squashfs_readahead_fragment(struct page **page, 


	last_page = squashfs_page_actor_free(actor);



	if (copied == expected) {

	if (copied == expected && !IS_ERR(last_page)) {

		/* Last page (if present) may have trailing bytes not filled */

		bytes = copied % PAGE_SIZE;

		if (bytes && last_page)
@@ -625,7 +625,7 @@ static void squashfs_readahead(struct readahead_control *ractl) 


		last_page = squashfs_page_actor_free(actor);



		if (res == expected) {

		if (res == expected && !IS_ERR(last_page)) {

			int bytes;



			/* Last page (if present) may have trailing bytes not filled */

fs/squashfs/file_direct.c

+1 −1
Original line number Diff line number Diff line
@@ -80,7 +80,7 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, 
	if (res < 0)

		goto mark_errored;



	if (res != expected) {

	if (res != expected || IS_ERR(last_page)) {

		res = -EIO;

		goto mark_errored;

	}

fs/squashfs/page_actor.h

+2 −1
Original line number Diff line number Diff line
@@ -33,10 +33,11 @@ extern struct squashfs_page_actor *squashfs_page_actor_init_special( 
				loff_t start_index);

static inline struct page *squashfs_page_actor_free(struct squashfs_page_actor *actor)

{

	struct page *last_page = actor->last_page;

	struct page *last_page = actor->next_page == actor->pages ? actor->last_page : ERR_PTR(-EIO);



	kfree(actor->tmp_buffer);

	kfree(actor);



	return last_page;

}

static inline void *squashfs_first_page(struct squashfs_page_actor *actor)