linux-kernel - [PATCH 06/10] afs: Improve dir check failure reports

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Date:   Fri, 15 Mar 2019 23:00:07 +0000
From:   David Howells <dhowells@...hat.com>
To:     linux-afs@...ts.infradead.org
Cc:     dhowells@...hat.com, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 06/10] afs: Improve dir check failure reports

Improve the content of directory check failure reports from:

	kAFS: afs_dir_check_page(6d57): bad magic 1/2 is 0000

to dump more information about the individual blocks in a directory page.

Signed-off-by: David Howells <dhowells@...hat.com>
---

 fs/afs/dir.c |   38 ++++++++++++++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 8a2562e3a316..378a96a1116e 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -159,6 +159,38 @@ static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
 	return false;
 }
 
+/*
+ * Check the contents of a directory that we've just read.
+ */
+static bool afs_dir_check_pages(struct afs_vnode *dvnode, struct afs_read *req)
+{
+	struct afs_xdr_dir_page *dbuf;
+	unsigned int i, j, qty = PAGE_SIZE / sizeof(union afs_xdr_dir_block);
+
+	for (i = 0; i < req->nr_pages; i++)
+		if (!afs_dir_check_page(dvnode, req->pages[i], req->actual_len))
+			goto bad;
+	return true;
+
+bad:
+	pr_warn("DIR %llx:%llx f=%llx l=%llx al=%llx r=%llx\n",
+		dvnode->fid.vid, dvnode->fid.vnode,
+		req->file_size, req->len, req->actual_len, req->remain);
+	pr_warn("DIR %llx %x %x %x\n",
+		req->pos, req->index, req->nr_pages, req->offset);
+
+	for (i = 0; i < req->nr_pages; i++) {
+		dbuf = kmap(req->pages[i]);
+		for (j = 0; j < qty; j++) {
+			union afs_xdr_dir_block *block = &dbuf->blocks[j];
+
+			pr_warn("[%02x] %32phN\n", i * qty + j, block);
+		}
+		kunmap(req->pages[i]);
+	}
+	return false;
+}
+
 /*
  * open an AFS directory file
  */
@@ -288,10 +320,8 @@ static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
 
 		/* Validate the data we just read. */
 		ret = -EIO;
-		for (i = 0; i < req->nr_pages; i++)
-			if (!afs_dir_check_page(dvnode, req->pages[i],
-						req->actual_len))
-				goto error_unlock;
+		if (!afs_dir_check_pages(dvnode, req))
+			goto error_unlock;
 
 		// TODO: Trim excess pages