As explained in detail in the PR, the problem happens when multiple
requests lead to a single RPM and one of the threads does prefetching.
In that case, the requested file is added to fdcache and thus skip
as interned.
---
debuginfod/debuginfod.cxx | 69 ++++++++++++++++++++++++---------------
1 file changed, 43 insertions(+), 26 deletions(-)
diff --git a/debuginfod/debuginfod.cxx b/debuginfod/debuginfod.cxx
index a089d0bd..e69a4bbc 100644
--- a/debuginfod/debuginfod.cxx
+++ b/debuginfod/debuginfod.cxx
@@ -1610,39 +1610,23 @@ string canonicalized_archive_entry_pathname(struct
archive_entry *e)
return string("/")+fn;
}
-
-
+// Try getting build_r match from fdcache.
static struct MHD_Response*
-handle_buildid_r_match (bool internal_req_p,
- int64_t b_mtime,
- const string& b_source0,
- const string& b_source1,
- int *result_fd)
+try_buildid_r_match_from_cache (const string& b_source0, const string&
b_source1, int *result_fd)
{
- struct stat fs;
- int rc = stat (b_source0.c_str(), &fs);
- if (rc != 0)
- throw libc_exception (errno, string("stat ") + b_source0);
-
- if ((int64_t) fs.st_mtime != b_mtime)
- {
- if (verbose)
- obatched(clog) << "mtime mismatch for " << b_source0 << endl;
- return 0;
- }
-
// check for a match in the fdcache first
+ struct stat fs;
int fd = fdcache.lookup(b_source0, b_source1);
- while (fd >= 0) // got one!; NB: this is really an if() with a possible
branch out to the end
+ if (fd >= 0) // got one!; NB: this is really an if() with a possible branch
out to the end
{
- rc = fstat(fd, &fs);
+ int rc = fstat(fd, &fs);
if (rc < 0) // disappeared?
{
if (verbose)
obatched(clog) << "cannot fstat fdcache " << b_source0 << endl;
close(fd);
fdcache.clear(b_source0, b_source1);
- break; // branch out of if "loop", to try new libarchive fetch
attempt
+ return 0;
}
struct MHD_Response* r = MHD_create_response_from_fd (fs.st_size, fd);
@@ -1651,7 +1635,7 @@ handle_buildid_r_match (bool internal_req_p,
if (verbose)
obatched(clog) << "cannot create fd-response for " << b_source0 <<
endl;
close(fd);
- break; // branch out of if "loop", to try new libarchive fetch
attempt
+ return 0;
}
inc_metric ("http_responses_total","result","archive fdcache");
@@ -1668,9 +1652,34 @@ handle_buildid_r_match (bool internal_req_p,
if (result_fd)
*result_fd = fd;
return r;
- // NB: see, we never go around the 'loop' more than once
}
+ return NULL;
+}
+
+static struct MHD_Response*
+handle_buildid_r_match (bool internal_req_p,
+ int64_t b_mtime,
+ const string& b_source0,
+ const string& b_source1,
+ int *result_fd)
+{
+ struct stat fs;
+ int rc = stat (b_source0.c_str(), &fs);
+ if (rc != 0)
+ throw libc_exception (errno, string("stat ") + b_source0);
+
+ if ((int64_t) fs.st_mtime != b_mtime)
+ {
+ if (verbose)
+ obatched(clog) << "mtime mismatch for " << b_source0 << endl;
+ return 0;
+ }
+
+ struct MHD_Response *r = try_buildid_r_match_from_cache (b_source0,
b_source1, result_fd);
+ if (r != 0)
+ return r;
+
// no match ... grumble, must process the archive
string archive_decoder = "/dev/null";
string archive_extension = "";
@@ -1721,7 +1730,7 @@ handle_buildid_r_match (bool internal_req_p,
// 2) extract the matching entry name (set r = result)
// 3) extract some number of prefetched entries (just into fdcache)
// 4) abort any further processing
- struct MHD_Response* r = 0; // will set in stage 2
+ r = 0; // will set in stage 2
unsigned prefetch_count =
internal_req_p ? 0 : fdcache_prefetch; // will decrement in stage 3
@@ -1743,7 +1752,15 @@ handle_buildid_r_match (bool internal_req_p,
continue;
if (fdcache.probe (b_source0, fn)) // skip if already interned
+ {
+ if (r == 0)
+ {
+ r = try_buildid_r_match_from_cache (b_source0, b_source1, result_fd);
+ if (r != NULL)
+ return r;
+ }
continue;
+ }
// extract this file to a temporary file
char* tmppath = NULL;
@@ -1751,7 +1768,7 @@ handle_buildid_r_match (bool internal_req_p,
if (rc < 0)
throw libc_exception (ENOMEM, "cannot allocate tmppath");
defer_dtor<void*,void> tmmpath_freer (tmppath, free);
- fd = mkstemp (tmppath);
+ int fd = mkstemp (tmppath);
if (fd < 0)
throw libc_exception (errno, "cannot create temporary file");
// NB: don't unlink (tmppath), as fdcache will take charge of it.
--
2.37.1
