[PATCH v2 13/23] xfs: add iomap's readpage operations

Andrey Albershteyn
2023-04-04T14:57:01Z

The read IO path provides callout for configuring ioend. This allows
filesystem to add verification of completed BIOs. The
xfs_prepare_read_ioend() configures bio->bi_end_io which places
verification task in the workqueue. The task does fs-verity
verification and then call back to the iomap to finish IO.

This patch add callouts implementation to verify pages with
fs-verity. Also implements folio operation .verify_folio for direct
folio verification by fs-verity.

Signed-off-by: Andrey Albershteyn <aalbersh@redhat.com>
---
fs/xfs/xfs_aops.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_iomap.c | 11 +++++++++++
fs/xfs/xfs_linux.h | 1 +
3 files changed, 57 insertions(+)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index daa0dd4768fb..2a3ab5afd665 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -548,6 +548,49 @@ xfs_vm_bmap(
return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
}

+static void
+xfs_read_work_end_io(
+ struct work_struct *work)
+{
+ struct iomap_read_ioend *ioend =
+ container_of(work, struct iomap_read_ioend, work);
+ struct bio *bio = &ioend->read_inline_bio;
+
+ fsverity_verify_bio(bio);
+ iomap_read_end_io(bio);
+ /*
+ * The iomap_read_ioend has been freed by bio_put() in
+ * iomap_read_end_io()
+ */
+}
+
+static void
+xfs_read_end_io(
+ struct bio *bio)
+{
+ struct iomap_read_ioend *ioend =
+ container_of(bio, struct iomap_read_ioend, read_inline_bio);
+ struct xfs_inode *ip = XFS_I(ioend->io_inode);
+
+ WARN_ON_ONCE(!queue_work(ip->i_mount->m_postread_workqueue,
+ &ioend->work));
+}
+
+static void
+xfs_prepare_read_ioend(
+ struct iomap_read_ioend *ioend)
+{
+ if (!fsverity_active(ioend->io_inode))
+ return;
+
+ INIT_WORK(&ioend->work, &xfs_read_work_end_io);
+ ioend->read_inline_bio.bi_end_io = &xfs_read_end_io;
+}
+
+static const struct iomap_readpage_ops xfs_readpage_ops = {
+ .prepare_ioend = &xfs_prepare_read_ioend,
+};
+
STATIC int
xfs_vm_read_folio(
struct file *unused,
@@ -555,6 +598,7 @@ xfs_vm_read_folio(
{
struct iomap_readpage_ctx ctx = {
.cur_folio = folio,
+ .ops = &xfs_readpage_ops,
};

return iomap_read_folio(&ctx, &xfs_read_iomap_ops);
@@ -566,6 +610,7 @@ xfs_vm_readahead(
{
struct iomap_readpage_ctx ctx = {
.rac = rac,
+ .ops = &xfs_readpage_ops,
};

iomap_readahead(&ctx, &xfs_read_iomap_ops);
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 285885c308bd..e0f3c5d709f6 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -27,6 +27,7 @@
#include "xfs_dquot_item.h"
#include "xfs_dquot.h"
#include "xfs_reflink.h"
+#include "xfs_verity.h"

#define XFS_ALLOC_ALIGN(mp, off) \
(((off) >> mp->m_allocsize_log) << mp->m_allocsize_log)
@@ -83,8 +84,18 @@ xfs_iomap_valid(
return true;
}

+static bool
+xfs_verify_folio(
+ struct folio *folio,
+ loff_t pos,
+ unsigned int len)
+{
+ return fsverity_verify_folio(folio, len, pos);
+}
+
static const struct iomap_folio_ops xfs_iomap_folio_ops = {
.iomap_valid = xfs_iomap_valid,
+ .verify_folio = xfs_verify_folio,
};

int
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index e88f18f85e4b..c574fbf4b67d 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -63,6 +63,7 @@ typedef __u32 xfs_nlink_t;
#include <linux/rhashtable.h>
#include <linux/xattr.h>
#include <linux/mnt_idmapping.h>
+#include <linux/fsverity.h>

#include <asm/page.h>
#include <asm/div64.h>
--
2.38.4