From: "Darrick J. Wong" <djwong@kernel.org>
To: djwong@kernel.org
Cc: hch@infradead.org, linux-xfs@vger.kernel.org, hch@lst.de
Subject: [PATCH 2/2] xfs: only iget the file once when doing vectored scrub-by-handle
Date: Wed, 17 Apr 2024 16:14:07 -0700 [thread overview]
Message-ID: <171339555598.1999874.4695876291132839484.stgit@frogsfrogsfrogs> (raw)
In-Reply-To: <171339555559.1999874.4456227116424200314.stgit@frogsfrogsfrogs>
From: Darrick J. Wong <djwong@kernel.org>
If a program wants us to perform a scrub on a file handle and the fd
passed to ioctl() is not the file referenced in the handle, iget the
file once and pass it into the scrub code. This amortizes the untrusted
iget lookup over /all/ the scrubbers mentioned in the scrubv call.
When running fstests in "rebuild all metadata after each test" mode, I
observed a 10% reduction in runtime on account of avoiding repeated
inobt lookups.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/scrub/scrub.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 78b00ab85c9c9..43af5ce1f99f0 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -792,6 +792,37 @@ xfs_scrubv_check_barrier(
return 0;
}
+/*
+ * If the caller provided us with a nonzero inode number that isn't the ioctl
+ * file, try to grab a reference to it to eliminate all further untrusted inode
+ * lookups. If we can't get the inode, let each scrub function try again.
+ */
+STATIC struct xfs_inode *
+xchk_scrubv_open_by_handle(
+ struct xfs_mount *mp,
+ const struct xfs_scrub_vec_head *head)
+{
+ struct xfs_trans *tp;
+ struct xfs_inode *ip;
+ int error;
+
+ error = xfs_trans_alloc_empty(mp, &tp);
+ if (error)
+ return NULL;
+
+ error = xfs_iget(mp, tp, head->svh_ino, XCHK_IGET_FLAGS, 0, &ip);
+ xfs_trans_cancel(tp);
+ if (error)
+ return NULL;
+
+ if (VFS_I(ip)->i_generation != head->svh_gen) {
+ xfs_irele(ip);
+ return NULL;
+ }
+
+ return ip;
+}
+
/* Vectored scrub implementation to reduce ioctl calls. */
int
xfs_ioc_scrubv_metadata(
@@ -804,6 +835,7 @@ xfs_ioc_scrubv_metadata(
struct xfs_scrub_vec __user *uvectors;
struct xfs_inode *ip_in = XFS_I(file_inode(file));
struct xfs_mount *mp = ip_in->i_mount;
+ struct xfs_inode *handle_ip = NULL;
struct xfs_scrub_vec *v;
size_t vec_bytes;
unsigned int i;
@@ -848,6 +880,17 @@ xfs_ioc_scrubv_metadata(
trace_xchk_scrubv_item(mp, &head, i, v);
}
+ /*
+ * If the caller wants us to do a scrub-by-handle and the file used to
+ * call the ioctl is not the same file, load the incore inode and pin
+ * it across all the scrubv actions to avoid repeated UNTRUSTED
+ * lookups. The reference is not passed to deeper layers of scrub
+ * because each scrubber gets to decide its own strategy and return
+ * values for getting an inode.
+ */
+ if (head.svh_ino && head.svh_ino != ip_in->i_ino)
+ handle_ip = xchk_scrubv_open_by_handle(mp, &head);
+
/* Run all the scrubbers. */
for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
struct xfs_scrub_metadata sm = {
@@ -895,6 +938,8 @@ xfs_ioc_scrubv_metadata(
}
out_free:
+ if (handle_ip)
+ xfs_irele(handle_ip);
kfree(vectors);
return error;
}
next prev parent reply other threads:[~2024-04-17 23:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-17 23:10 [PATCHBOMB v13.3] xfs: tweaks and fixes to online repair, part 2 Darrick J. Wong
2024-04-17 23:13 ` [PATCHSET v13.3 1/2] xfs: reduce iget overhead in scrub Darrick J. Wong
2024-04-17 23:13 ` [PATCH 1/2] xfs: use dontcache for grabbing inodes during scrub Darrick J. Wong
2024-04-18 4:22 ` Christoph Hellwig
2024-04-17 23:14 ` Darrick J. Wong [this message]
2024-04-18 4:22 ` [PATCH 2/2] xfs: only iget the file once when doing vectored scrub-by-handle Christoph Hellwig
2024-04-17 23:13 ` [PATCHSET v13.3 2/2] xfs: minor fixes to online repair Darrick J. Wong
2024-04-17 23:14 ` [PATCH 1/4] xfs: drop the scrub file's iolock when transaction allocation fails Darrick J. Wong
2024-04-18 4:23 ` Christoph Hellwig
2024-04-17 23:14 ` [PATCH 2/4] xfs: fix iunlock calls in xrep_adoption_trans_alloc Darrick J. Wong
2024-04-18 4:23 ` Christoph Hellwig
2024-04-17 23:14 ` [PATCH 3/4] xfs: exchange-range for repairs is no longer dynamic Darrick J. Wong
2024-04-18 4:24 ` Christoph Hellwig
2024-04-17 23:15 ` [PATCH 4/4] xfs: invalidate dentries for a file before moving it to the orphanage Darrick J. Wong
2024-04-18 4:25 ` Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2024-04-24 3:07 [PATCHSET v13.4 8/9] xfs: reduce iget overhead in scrub Darrick J. Wong
2024-04-24 3:28 ` [PATCH 2/2] xfs: only iget the file once when doing vectored scrub-by-handle Darrick J. Wong
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