[RFC v5 107/126] blklogwrites: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &fatal_err
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and than propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatel, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit (together with its neighbors) was generated by

for f in $(git grep -l errp \*.[ch]); do \
    spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
    --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
done;

then fix a bit of compilation problems: coccinelle for some reason
leaves several
f() {
    ...
    goto out;
    ...
    out:
}
patterns, with "out:" at function end.

then
./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"

(auto-msg was a file with this commit message)

Still, for backporting it may be more comfortable to use only the first
command and then do one huge commit.

Reported-by: Kevin Wolf <address@hidden>
Reported-by: Greg Kurz <address@hidden>
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 block/blklogwrites.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index 04d8b33607..841cfeef95 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -141,36 +141,33 @@ static uint64_t 
blk_log_writes_find_cur_log_sector(BdrvChild *log,
 static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags,
                                Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     BDRVBlkLogWritesState *s = bs->opaque;
     QemuOpts *opts;
-    Error *local_err = NULL;
     int ret;
     uint64_t log_sector_size;
     bool log_append;
 
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
-    qemu_opts_absorb_qdict(opts, options, &local_err);
-    if (local_err) {
+    qemu_opts_absorb_qdict(opts, options, errp);
+    if (*errp) {
         ret = -EINVAL;
-        error_propagate(errp, local_err);
         goto fail;
     }
 
     /* Open the file */
     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false,
-                               &local_err);
-    if (local_err) {
+                               errp);
+    if (*errp) {
         ret = -EINVAL;
-        error_propagate(errp, local_err);
         goto fail;
     }
 
     /* Open the log file */
     s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_file, false,
-                                  &local_err);
-    if (local_err) {
+                                  errp);
+    if (*errp) {
         ret = -EINVAL;
-        error_propagate(errp, local_err);
         goto fail;
     }
 
@@ -220,10 +217,9 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict 
*options, int flags,
         if (blk_log_writes_sector_size_valid(log_sector_size)) {
             s->cur_log_sector =
                 blk_log_writes_find_cur_log_sector(s->log_file, 
log_sector_size,
-                                    le64_to_cpu(log_sb.nr_entries), 
&local_err);
-            if (local_err) {
+                                    le64_to_cpu(log_sb.nr_entries), errp);
+            if (*errp) {
                 ret = -EINVAL;
-                error_propagate(errp, local_err);
                 goto fail_log;
             }
 
-- 
2.21.0