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Message-ID: <20260122215457.GH5910@frogsfrogsfrogs>
Date: Thu, 22 Jan 2026 13:54:57 -0800
From: "Darrick J. Wong" <djwong@...nel.org>
To: Christoph Hellwig <hch@....de>
Cc: Eric Biggers <ebiggers@...nel.org>, Al Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
David Sterba <dsterba@...e.com>, Theodore Ts'o <tytso@....edu>,
Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <chao@...nel.org>,
Andrey Albershteyn <aalbersh@...hat.com>,
"Matthew Wilcox (Oracle)" <willy@...radead.org>,
linux-fsdevel@...r.kernel.org, linux-btrfs@...r.kernel.org,
linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
fsverity@...ts.linux.dev
Subject: Re: [PATCH 08/11] ext4: consolidate fsverity_info lookup
On Thu, Jan 22, 2026 at 09:22:04AM +0100, Christoph Hellwig wrote:
> Look up the fsverity_info once in ext4_mpage_readpages, and then use it
> for the readahead, local verification of holes and pass it along to the
> I/O completion workqueue in struct bio_post_read_ctx.
>
> This amortizes the lookup better once it becomes less efficient.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> fs/ext4/readpage.c | 33 ++++++++++++++-------------------
> 1 file changed, 14 insertions(+), 19 deletions(-)
>
> diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
> index 02f918cf1945..6092d6d59063 100644
> --- a/fs/ext4/readpage.c
> +++ b/fs/ext4/readpage.c
> @@ -61,6 +61,7 @@ enum bio_post_read_step {
>
> struct bio_post_read_ctx {
> struct bio *bio;
> + struct fsverity_info *vi;
> struct work_struct work;
> unsigned int cur_step;
> unsigned int enabled_steps;
> @@ -96,7 +97,7 @@ static void verity_work(struct work_struct *work)
> struct bio_post_read_ctx *ctx =
> container_of(work, struct bio_post_read_ctx, work);
> struct bio *bio = ctx->bio;
> - struct inode *inode = bio_first_folio_all(bio)->mapping->host;
> + struct fsverity_info *vi = ctx->vi;
>
> /*
> * fsverity_verify_bio() may call readahead() again, and although verity
> @@ -109,7 +110,7 @@ static void verity_work(struct work_struct *work)
> mempool_free(ctx, bio_post_read_ctx_pool);
> bio->bi_private = NULL;
>
> - fsverity_verify_bio(*fsverity_info_addr(inode), bio);
> + fsverity_verify_bio(vi, bio);
>
> __read_end_io(bio);
> }
> @@ -172,22 +173,16 @@ static void mpage_end_io(struct bio *bio)
> __read_end_io(bio);
> }
>
> -static inline bool ext4_need_verity(const struct inode *inode, pgoff_t idx)
> -{
> - return fsverity_active(inode) &&
> - idx < DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
> -}
> -
> static void ext4_set_bio_post_read_ctx(struct bio *bio,
> const struct inode *inode,
> - pgoff_t first_idx)
> + struct fsverity_info *vi)
> {
> unsigned int post_read_steps = 0;
>
> if (fscrypt_inode_uses_fs_layer_crypto(inode))
> post_read_steps |= 1 << STEP_DECRYPT;
>
> - if (ext4_need_verity(inode, first_idx))
> + if (vi)
> post_read_steps |= 1 << STEP_VERITY;
>
> if (post_read_steps) {
> @@ -196,6 +191,7 @@ static void ext4_set_bio_post_read_ctx(struct bio *bio,
> mempool_alloc(bio_post_read_ctx_pool, GFP_NOFS);
>
> ctx->bio = bio;
> + ctx->vi = vi;
> ctx->enabled_steps = post_read_steps;
> bio->bi_private = ctx;
> }
> @@ -223,6 +219,7 @@ int ext4_mpage_readpages(struct inode *inode,
> sector_t first_block;
> unsigned page_block;
> struct block_device *bdev = inode->i_sb->s_bdev;
> + struct fsverity_info *vi = NULL;
> int length;
> unsigned relative_block = 0;
> struct ext4_map_blocks map;
> @@ -244,9 +241,11 @@ int ext4_mpage_readpages(struct inode *inode,
> folio = readahead_folio(rac);
>
> if (first_folio) {
> - if (ext4_need_verity(inode, folio->index))
> - fsverity_readahead(*fsverity_info_addr(inode),
> - folio, nr_pages);
> + if (folio->index <
> + DIV_ROUND_UP(inode->i_size, PAGE_SIZE))
I keep seeing this predicate, maybe it should go into fsverity.h as a
helper function with the comment about mmap that I was muttering about
in the previous patch?
Or maybe a "get verity info for given folio index" helper?
/*
* Grab the fsverity context needed to verify the contents of the folio.
*
* <Big fat comment from before, about mmap and whatnot>
*/
static inline struct fsverity_info *vi
fsverity_folio_info(const struct folio *folio)
{
struct inode *inode = folio->mapping->host;
if (folio->index < DIV_ROUND_UP(inode->i_size, PAGE_SIZE))
return fsverity_get_info(inode);
return NULL;
}
then ext4 just does:
vi = fsverity_folio_info(folio);
if (vi)
fsverity_readahead(vi, folio, nr_pages);
Hrm?
--D
> + vi = fsverity_get_info(inode);
> + if (vi)
> + fsverity_readahead(vi, folio, nr_pages);
> first_folio = false;
> }
>
> @@ -337,11 +336,7 @@ int ext4_mpage_readpages(struct inode *inode,
> folio_zero_segment(folio, first_hole << blkbits,
> folio_size(folio));
> if (first_hole == 0) {
> - struct fsverity_info *vi =
> - *fsverity_info_addr(folio->mapping->host);
> -
> - if (ext4_need_verity(inode, folio->index) &&
> - !fsverity_verify_folio(vi, folio))
> + if (vi && !fsverity_verify_folio(vi, folio))
> goto set_error_page;
> folio_end_read(folio, true);
> continue;
> @@ -369,7 +364,7 @@ int ext4_mpage_readpages(struct inode *inode,
> REQ_OP_READ, GFP_KERNEL);
> fscrypt_set_bio_crypt_ctx(bio, inode, next_block,
> GFP_KERNEL);
> - ext4_set_bio_post_read_ctx(bio, inode, folio->index);
> + ext4_set_bio_post_read_ctx(bio, inode, vi);
> bio->bi_iter.bi_sector = first_block << (blkbits - 9);
> bio->bi_end_io = mpage_end_io;
> if (rac)
> --
> 2.47.3
>
>
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