From: Matthew Wilcox (Oracle) Date: Fri, 22 May 2026 18:14:07 +0000 (+0100) Subject: Revert "btrfs: fix the file offset calculation inside btrfs_decompress_buf2page()" X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0279bed34c22dd5ebff12e5af8ef940de93c5523;p=thirdparty%2Flinux.git Revert "btrfs: fix the file offset calculation inside btrfs_decompress_buf2page()" It seems that af566bdaff54 was tested against a tree which did not contain commit 12851bd921d4 ("fs: Turn page_offset() into a wrapper around folio_pos()). Unfortunately it has a bug of its own; on 32-bit systems, shifting by PAGE_SHIFT will overflow on files larger than 4GiB. Since page_offset() is now fixed, just revert af566bdaff54. Fixes: af566bdaff54 (btrfs: fix the file offset calculation inside btrfs_decompress_buf2page()) Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Qu Wenruo Reviewed-by: Boris Burkov Tested-by: Boris Burkov Signed-off-by: David Sterba --- diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index cce85eebf2bee..ffb6b52863a78 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -1170,22 +1170,6 @@ void __cold btrfs_exit_compress(void) bioset_exit(&btrfs_compressed_bioset); } -/* - * The bvec is a single page bvec from a bio that contains folios from a filemap. - * - * Since the folio may be a large one, and if the bv_page is not a head page of - * a large folio, then page->index is unreliable. - * - * Thus we need this helper to grab the proper file offset. - */ -static u64 file_offset_from_bvec(const struct bio_vec *bvec) -{ - const struct page *page = bvec->bv_page; - const struct folio *folio = page_folio(page); - - return (page_pgoff(folio, page) << PAGE_SHIFT) + bvec->bv_offset; -} - /* * Copy decompressed data from working buffer to pages. * @@ -1238,7 +1222,7 @@ int btrfs_decompress_buf2page(const char *buf, u32 buf_len, * cb->start may underflow, but subtracting that value can still * give us correct offset inside the full decompressed extent. */ - bvec_offset = file_offset_from_bvec(&bvec) - cb->start; + bvec_offset = page_offset(bvec.bv_page) + bvec.bv_offset - cb->start; /* Haven't reached the bvec range, exit */ if (decompressed + buf_len <= bvec_offset)