Unverified Commit 6f09ffb1 authored by Phillip Lougher's avatar Phillip Lougher Committed by Christian Brauner
Browse files

Squashfs: Update squashfs_readahead() to not use page->index 



This commit removes references to page->index in the pages returned
from __readahead_batch(), and instead uses the 'start' variable.

This does reveal a bug in the previous code in that 'start' was
not updated every time around the loop.  This is fixed in this
commit.

Signed-off-by: default avatarPhillip Lougher <phillip@squashfs.org.uk>
Link: https://lore.kernel.org/r/20240818235847.170468-3-phillip@squashfs.org.uk


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 2258e22f

fs/squashfs/file.c

+6 −10
Original line number Diff line number Diff line
@@ -551,7 +551,6 @@ static void squashfs_readahead(struct readahead_control *ractl) 
		return;



	for (;;) {

		pgoff_t index;

		int res, bsize;

		u64 block = 0;

		unsigned int expected;
@@ -570,13 +569,8 @@ static void squashfs_readahead(struct readahead_control *ractl) 
		if (readahead_pos(ractl) >= i_size_read(inode))

			goto skip_pages;



		index = pages[0]->index >> shift;



		if ((pages[nr_pages - 1]->index >> shift) != index)

			goto skip_pages;



		if (index == file_end && squashfs_i(inode)->fragment_block !=

						SQUASHFS_INVALID_BLK) {

		if (start >> msblk->block_log == file_end &&

				squashfs_i(inode)->fragment_block != SQUASHFS_INVALID_BLK) {

			res = squashfs_readahead_fragment(pages, nr_pages,

							  expected);

			if (res)
@@ -584,7 +578,7 @@ static void squashfs_readahead(struct readahead_control *ractl) 
			continue;

		}



		bsize = read_blocklist(inode, index, &block);

		bsize = read_blocklist(inode, start >> msblk->block_log, &block);

		if (bsize == 0)

			goto skip_pages;
@@ -602,7 +596,7 @@ static void squashfs_readahead(struct readahead_control *ractl) 


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

			bytes = res % PAGE_SIZE;

			if (index == file_end && bytes && last_page)

			if (start >> msblk->block_log == file_end && bytes && last_page)

				memzero_page(last_page, bytes,

					     PAGE_SIZE - bytes);
@@ -616,6 +610,8 @@ static void squashfs_readahead(struct readahead_control *ractl) 
			unlock_page(pages[i]);

			put_page(pages[i]);

		}



		start += readahead_batch_length(ractl);

	}



	kfree(pages);