gvsafronov/futriix
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Redis exit for fsync error when the AOF fsync policy is 'always' (#8347)

Browse Source 
With AOF policy of fsync "always", redis should respect the contract with the user
that on acknowledged write data is already synced on disk.

Redis was already exiting for AOF write error,  but don't care about fsync failure.
So to guarantee data safe, redis should exit for fsync error too (when the AOF fsync
policy is 'always').
This commit is contained in:
Wang Yuan 2021-01-28 22:25:35 +08:00 committed by GitHub
parent 7104c334c0
commit ee97bf309f
1 changed files with 23 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
src/aof.c
View File

@ -451,10 +451,11 @@ void flushAppendOnlyFile(int force) {
/* Handle the AOF write error. */
if (server.aof_fsync == AOF_FSYNC_ALWAYS) {
/* We can't recover when the fsync policy is ALWAYS since the
* reply for the client is already in the output buffers, and we
* have the contract with the user that on acknowledged write data
* is synced on disk. */
/* We can't recover when the fsync policy is ALWAYS since the reply
* for the client is already in the output buffers (both writes and
* reads), and the changes to the db can't be rolled back. Since we
* have a contract with the user that on acknowledged or observed
* writes are is synced on disk, we must exit. */
serverLog(LL_WARNING,"Can't recover from AOF write error when the AOF fsync policy is 'always'. Exiting...");
exit(1);
} else {
@ -502,7 +503,14 @@ try_fsync:
/* redis_fsync is defined as fdatasync() for Linux in order to avoid
* flushing metadata. */
latencyStartMonitor(latency);
redis_fsync(server.aof_fd); /* Let's try to get this data on the disk */
/* Let's try to get this data on the disk. To guarantee data safe when
* the AOF fsync policy is 'always', we should exit if failed to fsync
* AOF (see comment next to the exit(1) after write error above). */
if (redis_fsync(server.aof_fd) == -1) {
serverLog(LL_WARNING,"Can't persist AOF for fsync error when the "
"AOF fsync policy is 'always': %s. Exiting...", strerror(errno));
exit(1);
}
latencyEndMonitor(latency);
latencyAddSampleIfNeeded("aof-fsync-always",latency);
server.aof_fsync_offset = server.aof_current_size;
@ -1847,6 +1855,16 @@ void backgroundRewriteDoneHandler(int exitcode, int bysignal) {
close(newfd);
goto cleanup;
}
if (server.aof_fsync == AOF_FSYNC_EVERYSEC) {
aof_background_fsync(newfd);
} else if (server.aof_fsync == AOF_FSYNC_ALWAYS) {
if (redis_fsync(newfd) == -1) {
serverLog(LL_WARNING,
"Error trying to fsync the parent diff to the rewritten AOF: %s", strerror(errno));
close(newfd);
goto cleanup;
}
}
latencyEndMonitor(latency);
latencyAddSampleIfNeeded("aof-rewrite-diff-write",latency);
@ -1916,10 +1934,6 @@ void backgroundRewriteDoneHandler(int exitcode, int bysignal) {
/* AOF enabled, replace the old fd with the new one. */
oldfd = server.aof_fd;
server.aof_fd = newfd;
if (server.aof_fsync == AOF_FSYNC_ALWAYS)
redis_fsync(newfd);
else if (server.aof_fsync == AOF_FSYNC_EVERYSEC)
aof_background_fsync(newfd);
server.aof_selected_db = -1; /* Make sure SELECT is re-issued */
aofUpdateCurrentSize();
server.aof_rewrite_base_size = server.aof_current_size;