libnbd/0003-Revert-copy-file-ops.c...

72 lines
2.5 KiB
Diff

From 4e456ff6363580177ceffdad79b8fc1e8c7f35eb Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Wed, 3 Mar 2021 10:12:31 +0000
Subject: [PATCH 3/5] Revert "copy: file-ops.c: Remove unneeded check"
This reverts commit 0f6e4f38bc440fc52c20a3a448ef031f806ec5e2.
This fails on ppc64le only with:
lt-nbdcopy: file-ops.c:136: page_was_cached: Assertion `page < rwf->cached_pages.size' failed.
Coincidentally this is the only architecture on Fedora that uses a 64K
page size, although I don't know if that is connected. I was not able
to make this fail on x86.
---
copy/file-ops.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/copy/file-ops.c b/copy/file-ops.c
index 47ec768..ea725a4 100644
--- a/copy/file-ops.c
+++ b/copy/file-ops.c
@@ -102,7 +102,7 @@ page_size_init (void)
/* Load the page cache map for a particular file into
* rwf->cached_pages. Only used when reading files. This doesn't
* fail: if a system call fails then rwf->cached_pages.size will be
- * zero which is handled in page_cache_evict.
+ * zero which is handled in page_was_cached.
*/
static inline void
page_cache_map (struct rw_file *rwf)
@@ -126,16 +126,19 @@ page_cache_map (struct rw_file *rwf)
munmap (ptr, rwf->rw.size);
}
-/* Test if a single page of the file was cached before nbdcopy ran.
- * Valid only if we mapped the cached pages.
- */
+/* Test if a single page of the file was cached before nbdcopy ran. */
static inline bool
page_was_cached (struct rw_file *rwf, uint64_t offset)
{
uint64_t page = offset / page_size;
- assert (page < rwf->cached_pages.size);
-
- return (rwf->cached_pages.ptr[page] & 1) != 0;
+ if (page < rwf->cached_pages.size)
+ return (rwf->cached_pages.ptr[page] & 1) != 0;
+ else
+ /* This path is taken if we didn't manage to map the input file
+ * for any reason. In this case assume that pages were mapped so
+ * we will not evict them: essentially fall back to doing nothing.
+ */
+ return true;
}
/* Evict file contents from the page cache if they were not present in
@@ -147,10 +150,6 @@ page_cache_evict (struct rw_file *rwf, uint64_t orig_offset, size_t orig_len)
uint64_t offset, n;
size_t len;
- /* If we didn't manage to map the input file for any reason, assume
- * that pages were mapped so we will not evict them: essentially fall
- * back to doing nothing.
- */
if (rwf->cached_pages.size == 0) return;
/* Only bother with whole pages. */
--
2.29.0.rc2