9d635982f2
resolves: RHEL-78830 Add extra system call checking and debugging to nbdkit-file-plugin resolves: RHEL-85515
83 lines
3.2 KiB
Diff
83 lines
3.2 KiB
Diff
From 93e3804d42b5e6f4afcd7524eb07d776b56c883d Mon Sep 17 00:00:00 2001
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From: "Richard W.M. Jones" <rjones@redhat.com>
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Date: Fri, 28 Mar 2025 20:35:54 +0000
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Subject: [PATCH] file: If sync_file_range fails to start, don't add window to
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list
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When starting the process of writing out the newest range, we
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previously didn't check if sync_file_range succeeded or failed. But
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if it failed there's no reason to add it to the list of windows. Also
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debug any failures.
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This shouldn't change any semantics as far as we're aware.
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Thanks: Eric Sandeen
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(cherry picked from commit d35f0636373e6a58c8f3fcfcf505af248e27c574)
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---
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plugins/file/file.c | 48 ++++++++++++++++++++++++++-------------------
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1 file changed, 28 insertions(+), 20 deletions(-)
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diff --git a/plugins/file/file.c b/plugins/file/file.c
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index 77de1cc8..0271a56b 100644
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--- a/plugins/file/file.c
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+++ b/plugins/file/file.c
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@@ -123,27 +123,35 @@ evict_writes (int fd, uint64_t offset, size_t len)
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{
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ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&window_lock);
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- /* Evict the oldest window from the page cache. */
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- if (window[0].len > 0) {
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- if (sync_file_range (window[0].fd, window[0].offset, window[0].len,
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- SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|
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- SYNC_FILE_RANGE_WAIT_AFTER) == -1)
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- nbdkit_debug ("sync_file_range: wait: (ignored): %m");
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- if (posix_fadvise (window[0].fd, window[0].offset, window[0].len,
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- POSIX_FADV_DONTNEED) == -1)
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- nbdkit_debug ("posix_fadvise: POSIX_FADV_DONTNEED: (ignored): %m");
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- }
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-
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- /* Move the Nth window to N-1. */
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- memmove (&window[0], &window[1], sizeof window[0] * (NR_WINDOWS-1));
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-
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- /* Set up the current window and tell Linux to start writing it out
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- * to disk (asynchronously).
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+ /* Tell Linux to start writing the current range out to disk
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+ * (asynchronously).
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*/
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- sync_file_range (fd, offset, len, SYNC_FILE_RANGE_WRITE);
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- window[NR_WINDOWS-1].fd = fd;
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- window[NR_WINDOWS-1].offset = offset;
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- window[NR_WINDOWS-1].len = len;
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+ if (sync_file_range (fd, offset, len, SYNC_FILE_RANGE_WRITE) == -1) {
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+ /* sync_file_range to start the write failed */
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+ nbdkit_debug ("sync_file_range: write: (ignored): %m");
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+ }
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+ else {
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+ /* sync_file_range to start the write succeeded, so
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+ * evict the oldest window from the page cache.
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+ */
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+ if (window[0].len > 0) {
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+ if (sync_file_range (window[0].fd, window[0].offset, window[0].len,
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+ SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|
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+ SYNC_FILE_RANGE_WAIT_AFTER) == -1)
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+ nbdkit_debug ("sync_file_range: wait: (ignored): %m");
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+ if (posix_fadvise (window[0].fd, window[0].offset, window[0].len,
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+ POSIX_FADV_DONTNEED) == -1)
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+ nbdkit_debug ("posix_fadvise: POSIX_FADV_DONTNEED: (ignored): %m");
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+ }
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+
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+ /* Move the Nth window to N-1. */
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+ memmove (&window[0], &window[1], sizeof window[0] * (NR_WINDOWS-1));
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+
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+ /* Add the range to the newest end of the list of windows. */
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+ window[NR_WINDOWS-1].fd = fd;
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+ window[NR_WINDOWS-1].offset = offset;
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+ window[NR_WINDOWS-1].len = len;
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+ }
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}
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/* When we close the handle we must remove any windows which are still
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--
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2.47.1
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