[PATCH 15/29] xfs: create an icache tag for files with cached merkle tree blocks

Darrick J. Wong
2024-03-30T00:39:59Z

From: Darrick J. Wong <djwong@kernel.org>

Create a radix tree tag for the inode cache so that merkle tree block
shrinkers can find verity inodes quickly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_fsverity.c | 30 ++++++++++++++++++
fs/xfs/xfs_fsverity.h | 4 ++
fs/xfs/xfs_icache.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_icache.h | 8 +++++
fs/xfs/xfs_trace.h | 23 ++++++++++++++
5 files changed, 145 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_fsverity.c b/fs/xfs/xfs_fsverity.c
index 46640a495e705..37876ce612540 100644
--- a/fs/xfs/xfs_fsverity.c
+++ b/fs/xfs/xfs_fsverity.c
@@ -295,18 +295,46 @@ xfs_fsverity_shrinker_count(
return min_t(s64, ULONG_MAX, count);
}

+struct xfs_fsverity_scan {
+ struct xfs_icwalk icw;
+ struct shrink_control *sc;
+
+ unsigned long scanned;
+ unsigned long freed;
+};
+
+/* Scan an inode as part of a verity scan. */
+int
+xfs_fsverity_scan_inode(
+ struct xfs_inode *ip,
+ struct xfs_icwalk *icw)
+{
+ xfs_irele(ip);
+ return 0;
+}
+
/* Actually try to reclaim merkle tree blocks. */
static unsigned long
xfs_fsverity_shrinker_scan(
struct shrinker *shrink,
struct shrink_control *sc)
{
+ struct xfs_fsverity_scan vs = {
+ .sc = sc,
+ };
struct xfs_mount *mp = shrink->private_data;
+ int error;

if (!xfs_has_verity(mp))
return SHRINK_STOP;

- return 0;
+ error = xfs_icwalk_verity(mp, &vs.icw);
+ if (error)
+ xfs_alert(mp, "%s: verity scan failed, error %d", __func__,
+ error);
+
+ trace_xfs_fsverity_shrinker_scan(mp, vs.scanned, vs.freed, _RET_IP_);
+ return vs.freed;
}

/* Register a shrinker so we can release cached merkle tree blocks. */
diff --git a/fs/xfs/xfs_fsverity.h b/fs/xfs/xfs_fsverity.h
index 7148e0c4dde1f..21ba0d82f26d8 100644
--- a/fs/xfs/xfs_fsverity.h
+++ b/fs/xfs/xfs_fsverity.h
@@ -13,6 +13,9 @@ void xfs_fsverity_cache_destroy(struct xfs_inode *ip);
int xfs_fsverity_register_shrinker(struct xfs_mount *mp);
void xfs_fsverity_unregister_shrinker(struct xfs_mount *mp);

+struct xfs_icwalk;
+int xfs_fsverity_scan_inode(struct xfs_inode *ip, struct xfs_icwalk *icw);
+
extern const struct fsverity_operations xfs_fsverity_ops;
#else
# define xfs_fsverity_cache_init(ip) ((void)0)
@@ -20,6 +23,7 @@ extern const struct fsverity_operations xfs_fsverity_ops;
# define xfs_fsverity_cache_destroy(ip) ((void)0)
# define xfs_fsverity_register_shrinker(mp) (0)
# define xfs_fsverity_unregister_shrinker(mp) ((void)0)
+# define xfs_fsverity_scan_inode(ip, icw) (0)
#endif /* CONFIG_FS_VERITY */

#endif /* __XFS_FSVERITY_H__ */
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 0757062c318d0..424133f900739 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -38,6 +38,8 @@
#define XFS_ICI_RECLAIM_TAG 0
/* Inode has speculative preallocations (posteof or cow) to clean. */
#define XFS_ICI_BLOCKGC_TAG 1
+/* Inode has incore merkle tree blocks */
+#define XFS_ICI_VERITY_TAG 2

/*
* The goal for walking incore inodes. These can correspond with incore inode
@@ -47,6 +49,7 @@ enum xfs_icwalk_goal {
/* Goals directly associated with tagged inodes. */
XFS_ICWALK_BLOCKGC = XFS_ICI_BLOCKGC_TAG,
XFS_ICWALK_RECLAIM = XFS_ICI_RECLAIM_TAG,
+ XFS_ICWALK_VERITY = XFS_ICI_VERITY_TAG,
};

static int xfs_icwalk(struct xfs_mount *mp,
@@ -1649,6 +1652,7 @@ xfs_icwalk_igrab(
{
switch (goal) {
case XFS_ICWALK_BLOCKGC:
+ case XFS_ICWALK_VERITY:
return xfs_blockgc_igrab(ip);
case XFS_ICWALK_RECLAIM:
return xfs_reclaim_igrab(ip, icw);
@@ -1677,6 +1681,9 @@ xfs_icwalk_process_inode(
case XFS_ICWALK_RECLAIM:
xfs_reclaim_inode(ip, pag);
break;
+ case XFS_ICWALK_VERITY:
+ error = xfs_fsverity_scan_inode(ip, icw);
+ break;
}
return error;
}
@@ -1793,6 +1800,80 @@ xfs_icwalk_ag(
return last_error;
}

+#ifdef CONFIG_FS_VERITY
+/* Mark this inode as having cached merkle tree blocks */
+void
+xfs_inode_set_verity_tag(
+ struct xfs_inode *ip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_perag *pag;
+
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+ if (!pag)
+ return;
+
+ spin_lock(&pag->pag_ici_lock);
+ xfs_perag_set_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
+ XFS_ICI_VERITY_TAG);
+ spin_unlock(&pag->pag_ici_lock);
+ xfs_perag_put(pag);
+}
+
+/* Mark this inode as not having cached merkle tree blocks */
+void
+xfs_inode_clear_verity_tag(
+ struct xfs_inode *ip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_perag *pag;
+
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+ if (!pag)
+ return;
+
+ spin_lock(&pag->pag_ici_lock);
+ xfs_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
+ XFS_ICI_VERITY_TAG);
+ spin_unlock(&pag->pag_ici_lock);
+ xfs_perag_put(pag);
+}
+
+/* Walk all the verity inodes in the filesystem. */
+int
+xfs_icwalk_verity(
+ struct xfs_mount *mp,
+ struct xfs_icwalk *icw)
+{
+ struct xfs_perag *pag;
+ xfs_agnumber_t agno = 0;
+ int error = 0;
+
+ for_each_perag_tag(mp, agno, pag, XFS_ICWALK_VERITY) {
+ error = xfs_icwalk_ag(pag, XFS_ICWALK_VERITY, icw);
+ if (error)
+ break;
+
+ if ((icw->icw_flags & XFS_ICWALK_FLAG_SCAN_LIMIT) &&
+ icw->icw_scan_limit <= 0) {
+ xfs_perag_rele(pag);
+ break;
+ }
+ }
+
+ return error;
+}
+
+/* Stop a verity incore walk scan. */
+void
+xfs_icwalk_verity_stop(
+ struct xfs_icwalk *icw)
+{
+ icw->icw_flags |= XFS_ICWALK_FLAG_SCAN_LIMIT;
+ icw->icw_scan_limit = -1;
+}
+#endif /* CONFIG_FS_VERITY */
+
/* Walk all incore inodes to achieve a given goal. */
static int
xfs_icwalk(
diff --git a/fs/xfs/xfs_icache.h b/fs/xfs/xfs_icache.h
index 905944dafbe53..621ce0078e08b 100644
--- a/fs/xfs/xfs_icache.h
+++ b/fs/xfs/xfs_icache.h
@@ -81,4 +81,12 @@ void xfs_inodegc_stop(struct xfs_mount *mp);
void xfs_inodegc_start(struct xfs_mount *mp);
int xfs_inodegc_register_shrinker(struct xfs_mount *mp);

+#ifdef CONFIG_FS_VERITY
+int xfs_icwalk_verity(struct xfs_mount *mp, struct xfs_icwalk *icw);
+void xfs_icwalk_verity_stop(struct xfs_icwalk *icw);
+
+void xfs_inode_set_verity_tag(struct xfs_inode *ip);
+void xfs_inode_clear_verity_tag(struct xfs_inode *ip);
+#endif /* CONFIG_FS_VERITY */
+
#endif
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index e3edd43661bd9..a5b811c1731d7 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -5958,6 +5958,29 @@ TRACE_EVENT(xfs_fsverity_shrinker_count,
__entry->count,
__entry->caller_ip)
)
+
+TRACE_EVENT(xfs_fsverity_shrinker_scan,
+ TP_PROTO(struct xfs_mount *mp, unsigned long scanned,
+ unsigned long freed, unsigned long caller_ip),
+ TP_ARGS(mp, scanned, freed, caller_ip),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(unsigned long, scanned)
+ __field(unsigned long, freed)
+ __field(void *, caller_ip)
+ ),
+ TP_fast_assign(
+ __entry->dev = mp->m_super->s_dev;
+ __entry->scanned = scanned;
+ __entry->freed = freed;
+ __entry->caller_ip = (void *)caller_ip;
+ ),
+ TP_printk("dev %d:%d scanned %lu freed %lu caller %pS",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->scanned,
+ __entry->freed,
+ __entry->caller_ip)
+)
#endif /* CONFIG_XFS_VERITY */

#endif /* _TRACE_XFS_H */