On Tue, Mar 31, 2026 at 11:28:08PM +0200, Andrey Albershteyn wrote: > Obtain fsverity info for folios with file data and fsverity metadata. > Filesystem can pass vi down to ioend and then to fsverity for > verification. This is different from other filesystems ext4, f2fs, btrfs > supporting fsverity, these filesystems don't need fsverity_info for > reading fsverity metadata. While reading merkle tree iomap requires > fsverity info to synthesize hashes for zeroed data block. > > fsverity metadata has two kinds of holes - ones in merkle tree and one > after fsverity descriptor. > > Merkle tree holes are blocks full of hashes of zeroed data blocks. These > are not stored on the disk but synthesized on the fly. This saves a bit > of space for sparse files. Due to this iomap also need to lookup > fsverity_info for folios with fsverity metadata. ->vi has a hash of the > zeroed data block which will be used to fill the merkle tree block. > > The hole past descriptor is interpreted as end of metadata region. As we > don't have EOF here we use this hole as an indication that rest of the > folio is empty. This patch marks rest of the folio beyond fsverity > descriptor as uptodate. > > For file data, fsverity needs to verify consistency of the whole file > against the root hash, hashes of holes are included in the merkle tree. > Verify them too. > > Issue reading of fsverity merkle tree on the fsverity inodes. This way > metadata will be available at I/O completion time. > > Signed-off-by: Andrey Albershteyn <[email protected]>
Still looks fine, thanks for reducing the patch count :) Reviewed-by: "Darrick J. Wong" <[email protected]> --D > --- > fs/iomap/buffered-io.c | 41 +++++++++++++++++++++++++++++++++++++++-- > include/linux/iomap.h | 2 ++ > 2 files changed, 41 insertions(+), 2 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index a80fcb598cc8..7ac319618f8e 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -9,6 +9,7 @@ > #include <linux/swap.h> > #include <linux/migrate.h> > #include <linux/fserror.h> > +#include <linux/fsverity.h> > #include "internal.h" > #include "trace.h" > > @@ -561,9 +562,27 @@ static int iomap_read_folio_iter(struct iomap_iter *iter, > if (plen == 0) > return 0; > > - /* zero post-eof blocks as the page may be mapped */ > - if (iomap_block_needs_zeroing(iter, pos)) { > + /* > + * Handling of fsverity "holes". We hit this for two case: > + * 1. No need to go further, the hole after fsverity > + * descriptor is the end of the fsverity metadata. > + * > + * 2. This folio contains merkle tree blocks which need to be > + * synthesized. If we already have fsverity info (ctx->vi) > + * synthesize these blocks. > + */ > + if ((iomap->flags & IOMAP_F_FSVERITY) && > + iomap->type == IOMAP_HOLE) { > + if (ctx->vi) > + fsverity_fill_zerohash(folio, poff, plen, > + ctx->vi); > + iomap_set_range_uptodate(folio, poff, plen); > + } else if (iomap_block_needs_zeroing(iter, pos)) { > + /* zero post-eof blocks as the page may be mapped */ > folio_zero_range(folio, poff, plen); > + if (ctx->vi && > + !fsverity_verify_blocks(ctx->vi, folio, plen, poff)) > + return -EIO; > iomap_set_range_uptodate(folio, poff, plen); > } else { > if (!*bytes_submitted) > @@ -614,6 +633,15 @@ void iomap_read_folio(const struct iomap_ops *ops, > > trace_iomap_readpage(iter.inode, 1); > > + /* > + * Fetch fsverity_info for both data and fsverity metadata, as iomap > + * needs zeroed hash for merkle tree block synthesis > + */ > + ctx->vi = fsverity_get_info(iter.inode); > + if (ctx->vi && iter.pos < i_size_read(iter.inode)) > + fsverity_readahead(ctx->vi, folio->index, > + folio_nr_pages(folio)); > + > while ((ret = iomap_iter(&iter, ops)) > 0) > iter.status = iomap_read_folio_iter(&iter, ctx, > &bytes_submitted); > @@ -681,6 +709,15 @@ void iomap_readahead(const struct iomap_ops *ops, > > trace_iomap_readahead(rac->mapping->host, readahead_count(rac)); > > + /* > + * Fetch fsverity_info for both data and fsverity metadata, as iomap > + * needs zeroed hash for merkle tree block synthesis > + */ > + ctx->vi = fsverity_get_info(iter.inode); > + if (ctx->vi && iter.pos < i_size_read(iter.inode)) > + fsverity_readahead(ctx->vi, readahead_index(rac), > + readahead_count(rac)); > + > while (iomap_iter(&iter, ops) > 0) > iter.status = iomap_readahead_iter(&iter, ctx, > &cur_bytes_submitted); > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 4506a99d5285..4d9202cae29f 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -435,6 +435,7 @@ struct iomap_ioend { > loff_t io_offset; /* offset in the file */ > sector_t io_sector; /* start sector of ioend */ > void *io_private; /* file system private data */ > + struct fsverity_info *io_vi; /* fsverity info */ > struct bio io_bio; /* MUST BE LAST! */ > }; > > @@ -509,6 +510,7 @@ struct iomap_read_folio_ctx { > struct readahead_control *rac; > void *read_ctx; > loff_t read_ctx_file_offset; > + struct fsverity_info *vi; > }; > > struct iomap_read_ops { > -- > 2.51.2 > > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
