Messages in this thread Patch in this message | | | From | Jintao Yin <> | Subject | Re: BISECT result: 6.0.0-RC kernels trigger Firefox snap bug with 6.0.0-rc3 through 6.0.0-rc7 | Date | Thu, 20 Oct 2022 14:59:42 +0800 |
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This diff is based on Phillip's latest two patches and fixes another wrong check of last page in file_direct.c. At the same time, improve the logic to update the status of pages only if page actor touches them.
Please help test and feedbacks are welcome.
Hi Phillip,
If check (bytes && used_pages > 0) is enough (since bytes is non-zero only when handling the last block) or should I caculate the real last page index from the file size and check the page index?
Thanks,
Jintao
diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c index e56510964b22..5efa2a9f9630 100644 --- a/fs/squashfs/file.c +++ b/fs/squashfs/file.c @@ -506,8 +506,9 @@ static int squashfs_readahead_fragment(struct page **page, squashfs_i(inode)->fragment_size); struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info; unsigned int n, mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1; + int res = buffer->error; - if (buffer->error) + if (res) goto out; expected += squashfs_i(inode)->fragment_offset; @@ -529,7 +530,7 @@ static int squashfs_readahead_fragment(struct page **page, out: squashfs_cache_put(buffer); - return buffer->error; + return res; } static void squashfs_readahead(struct readahead_control *ractl) @@ -557,6 +558,7 @@ static void squashfs_readahead(struct readahead_control *ractl) int res, bsize; u64 block = 0; unsigned int expected; + int nr_used_pages; nr_pages = __readahead_batch(ractl, pages, max_pages); if (!nr_pages) @@ -593,18 +595,18 @@ static void squashfs_readahead(struct readahead_control *ractl) res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor); - squashfs_page_actor_free(actor); + nr_used_pages = squashfs_page_actor_free(actor); if (res == expected) { int bytes; /* Last page (if present) may have trailing bytes not filled */ bytes = res % PAGE_SIZE; - if (pages[nr_pages - 1]->index == file_end && bytes) - memzero_page(pages[nr_pages - 1], bytes, + if (index == file_end && bytes && nr_used_pages > 0) + memzero_page(pages[nr_used_pages - 1], bytes, PAGE_SIZE - bytes); - for (i = 0; i < nr_pages; i++) { + for (i = 0; i < nr_used_pages; i++) { flush_dcache_page(pages[i]); SetPageUptodate(pages[i]); } diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c index f1ccad519e28..8d875d8c5709 100644 --- a/fs/squashfs/file_direct.c +++ b/fs/squashfs/file_direct.c @@ -30,7 +30,7 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1; int start_index = target_page->index & ~mask; int end_index = start_index | mask; - int i, n, pages, bytes, res = -ENOMEM; + int i, n, pages, used_pages, bytes, res = -ENOMEM; struct page **page; struct squashfs_page_actor *actor; void *pageaddr; @@ -74,7 +74,7 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, /* Decompress directly into the page cache buffers */ res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor); - squashfs_page_actor_free(actor); + used_pages = squashfs_page_actor_free(actor); if (res < 0) goto mark_errored; @@ -86,16 +86,18 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, /* Last page (if present) may have trailing bytes not filled */ bytes = res % PAGE_SIZE; - if (page[pages - 1]->index == end_index && bytes) { - pageaddr = kmap_local_page(page[pages - 1]); + if (bytes && used_pages > 0) { + pageaddr = kmap_local_page(page[used_pages - 1]); memset(pageaddr + bytes, 0, PAGE_SIZE - bytes); kunmap_local(pageaddr); } /* Mark pages as uptodate, unlock and release */ for (i = 0; i < pages; i++) { - flush_dcache_page(page[i]); - SetPageUptodate(page[i]); + if (i < used_pages) { + flush_dcache_page(page[i]); + SetPageUptodate(page[i]); + } unlock_page(page[i]); if (page[i] != target_page) put_page(page[i]); @@ -112,8 +114,10 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize, for (i = 0; i < pages; i++) { if (page[i] == NULL || page[i] == target_page) continue; - flush_dcache_page(page[i]); - SetPageError(page[i]); + if (i < used_pages) { + flush_dcache_page(page[i]); + SetPageError(page[i]); + } unlock_page(page[i]); put_page(page[i]); } diff --git a/fs/squashfs/page_actor.h b/fs/squashfs/page_actor.h index 95ffbb543d91..c2c5c3937ef9 100644 --- a/fs/squashfs/page_actor.h +++ b/fs/squashfs/page_actor.h @@ -29,10 +29,12 @@ extern struct squashfs_page_actor *squashfs_page_actor_init(void **buffer, extern struct squashfs_page_actor *squashfs_page_actor_init_special( struct squashfs_sb_info *msblk, struct page **page, int pages, int length); -static inline void squashfs_page_actor_free(struct squashfs_page_actor *actor) +static inline int squashfs_page_actor_free(struct squashfs_page_actor *actor) { + int res = actor->next_page; kfree(actor->tmp_buffer); kfree(actor); + return res; } static inline void *squashfs_first_page(struct squashfs_page_actor *actor) {
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