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| author | Michael Paquier <michael@paquier.xyz> | 2018-06-25 11:19:05 +0900 |
|---|---|---|
| committer | Michael Paquier <michael@paquier.xyz> | 2018-06-25 11:19:05 +0900 |
| commit | 6cb3372411fd6ed8ba0f8d36ae578a2daa517c16 (patch) | |
| tree | d5edfa830767d98fb76b8d3561e2109ecff956cd /src/backend/access/transam/xlogutils.c | |
| parent | 370e68ae1c0a8504a10b211a9c1d9e0ffa101259 (diff) | |
| download | postgresql-6cb3372411fd6ed8ba0f8d36ae578a2daa517c16.tar.gz postgresql-6cb3372411fd6ed8ba0f8d36ae578a2daa517c16.zip | |
Address set of issues with errno handling
System calls mixed up in error code paths are causing two issues which
several code paths have not correctly handled:
1) For write() calls, sometimes the system may return less bytes than
what has been written without errno being set. Some paths were careful
enough to consider that case, and assumed that errno should be set to
ENOSPC, other calls missed that.
2) errno generated by a system call is overwritten by other system calls
which may succeed once an error code path is taken, causing what is
reported to the user to be incorrect.
This patch uses the brute-force approach of correcting all those code
paths. Some refactoring could happen in the future, but this is let as
future work, which is not targeted for back-branches anyway.
Author: Michael Paquier
Reviewed-by: Ashutosh Sharma
Discussion: https://postgr.es/m/20180622061535.GD5215@paquier.xyz
Diffstat (limited to 'src/backend/access/transam/xlogutils.c')
| -rw-r--r-- | src/backend/access/transam/xlogutils.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index 52fe55e2afb..4ecdc9220f0 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -718,9 +718,10 @@ XLogRead(char *buf, int segsize, TimeLineID tli, XLogRecPtr startptr, if (lseek(sendFile, (off_t) startoff, SEEK_SET) < 0) { char path[MAXPGPATH]; + int save_errno = errno; XLogFilePath(path, tli, sendSegNo, segsize); - + errno = save_errno; ereport(ERROR, (errcode_for_file_access(), errmsg("could not seek in log segment %s to offset %u: %m", @@ -741,9 +742,10 @@ XLogRead(char *buf, int segsize, TimeLineID tli, XLogRecPtr startptr, if (readbytes <= 0) { char path[MAXPGPATH]; + int save_errno = errno; XLogFilePath(path, tli, sendSegNo, segsize); - + errno = save_errno; ereport(ERROR, (errcode_for_file_access(), errmsg("could not read from log segment %s, offset %u, length %lu: %m", |