From 45f740e3b4a707e5d2db739b16fb33f4d7b466cf Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Wed, 4 Jun 2025 21:15:26 +0100
Subject: [PATCH] file: Add offset/count to error messages

Although the same information is available in debug logs, if verbose
messages (-v) are not used then the information is lost.  As it might
be useful occasionally, ensure it is captured in errors.

(cherry picked from commit 253574354252f4a77e2df0769b721e76f1777651)
---
 plugins/file/file.c | 35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/plugins/file/file.c b/plugins/file/file.c
index 9ba61187..ade6f5ff 100644
--- a/plugins/file/file.c
+++ b/plugins/file/file.c
@@ -839,7 +839,8 @@ file_pread (void *handle, void *buf, uint32_t count, uint64_t offset,
   while (count > 0) {
     ssize_t r = pread (h->fd, buf, count, offset);
     if (r == -1) {
-      nbdkit_error ("pread: %s: %m", h->name);
+      nbdkit_error ("pread: %s: offset=%" PRIu64 ", count=%" PRIu32 ": %m",
+                    h->name, offset, count);
       return -1;
     }
     if (r == 0) {
@@ -875,7 +876,8 @@ file_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset,
   while (count > 0) {
     ssize_t r = pwrite (h->fd, buf, count, offset);
     if (r == -1) {
-      nbdkit_error ("pwrite: %s: %m", h->name);
+      nbdkit_error ("pwrite: %s: offset=%" PRIu64 ", count=%" PRIu32 ": %m",
+                    h->name, offset, count);
       return -1;
     }
     buf += r;
@@ -957,7 +959,8 @@ file_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
     }
 
     if (!is_enotsup (errno)) {
-      nbdkit_error ("zero: %s: %m", h->name);
+      nbdkit_error ("zero: %s: offset=%" PRIu64 ", count=%" PRIu32 ": %m",
+                    h->name, offset, count);
       return -1;
     }
 
@@ -993,7 +996,8 @@ file_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
       }
 
       if (!is_enotsup (errno)) {
-        nbdkit_error ("zero: %s: %m", h->name);
+        nbdkit_error ("zero: %s: offset=%" PRIu64 ", count=%" PRIu32 ": %m",
+                      h->name, offset, count);
         return -1;
       }
 
@@ -1001,7 +1005,8 @@ file_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
     }
     else {
       if (!is_enotsup (errno)) {
-        nbdkit_error ("zero: %s: %m", h->name);
+        nbdkit_error ("zero: %s: offset=%" PRIu64 ", count=%" PRIu32 ": %m",
+                      h->name, offset, count);
         return -1;
       }
 
@@ -1023,7 +1028,8 @@ file_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
     }
 
     if (!is_enotsup (errno)) {
-      nbdkit_error ("zero: %s: %m", h->name);
+      nbdkit_error ("zero: %s: offset=%" PRIu64 ", count=%" PRIu32 ": %m",
+                    h->name, offset, count);
       return -1;
     }
 
@@ -1051,14 +1057,16 @@ file_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
       }
 
       if (!is_enotsup (errno)) {
-        nbdkit_error ("zero: %s: %m", h->name);
+        nbdkit_error ("zero: %s: offset=%" PRIu64 ", count=%" PRIu32 ": %m",
+                      h->name, offset, count);
         return -1;
       }
 
       h->can_fallocate = false;
     } else {
       if (!is_enotsup (errno)) {
-        nbdkit_error ("zero: %s: %m", h->name);
+        nbdkit_error ("zero: %s:  offset=%" PRIu64 ", count=%" PRIu32 ":%m",
+                      h->name, offset, count);
         return -1;
       }
 
@@ -1082,7 +1090,8 @@ file_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
     }
 
     if (errno != ENOTTY) {
-      nbdkit_error ("zero: %s: %m", h->name);
+      nbdkit_error ("zero: %s: offset=%" PRIu64 ", count=%" PRIu32 ": %m",
+                    h->name, offset, count);
       return -1;
     }
 
@@ -1120,7 +1129,9 @@ file_trim (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
       /* Trim is advisory; we don't care if it fails for anything other
        * than EIO or EPERM. */
       if (errno == EPERM || errno == EIO) {
-        nbdkit_error ("fallocate: %s: %m", h->name);
+        nbdkit_error ("fallocate: %s: offset=%" PRIu64 ", count=%" PRIu32 ":"
+                      " %m",
+                      h->name, offset, count);
         return -1;
       }
 
@@ -1241,7 +1252,9 @@ file_cache (void *handle, uint32_t count, uint64_t offset, uint32_t flags)
   r = posix_fadvise (h->fd, offset, count, POSIX_FADV_WILLNEED);
   if (r) {
     errno = r;
-    nbdkit_error ("posix_fadvise: %s: %m", h->name);
+    nbdkit_error ("posix_fadvise: %s: offset=%" PRIu64 ", count=%" PRIu32 ":"
+                  " %m",
+                  h->name, offset, count);
     return -1;
   }
   return 0;
-- 
2.47.1