Also sneak entries for commits 97ff2a564 et al into the sections for the previous releases in the relevant branches. Those fixes did go out in the previous releases, but missed getting documented.
The fsync code from the backend essentially assumes that somebody's already validated PGDATA, at least to the extent of it being a readable directory. That's safe enough for initdb's normal code path too, but "initdb -S" doesn't have any other processing at all that touches the target directory. To have reasonable error-case behavior, add a pg_check_dir call. Per gripe from Peter E.
The argument that this is a sufficiently-expected case to be silently ignored seems pretty thin. Andres had brought it up back when we were still considering that most fsync failures should be hard errors, and it probably would be legit not to fail hard for ETXTBSY --- but the same is true for EROFS and other cases, which is why we gave up on hard failures. ETXTBSY is surely not a normal case, so logging the failure seems fine from here.
Make initdb's version of this logic look as much like the backend's as possible. This is much less critical than in the backend since not so many people use "initdb -S", but we want the same corner-case error handling in both cases. Back-patch to 9.3 where initdb -S option was introduced. Before that, initdb only had to deal with freshly-created data directories, wherein no failures should be expected. Abhijit Menon-Sen
Commit 2ce439f3379aed857517c8ce207485655000fc8e introduced a rather serious regression, namely that if its scan of the data directory came across any un-fsync-able files, it would fail and thereby prevent database startup. Worse yet, symlinks to such files also caused the problem, which meant that crash restart was guaranteed to fail on certain common installations such as older Debian. After discussion, we agreed that (1) failure to start is worse than any consequence of not fsync'ing is likely to be, therefore treat all errors in this code as nonfatal; (2) we should not chase symlinks other than those that are expected to exist, namely pg_xlog/ and tablespace links under pg_tblspc/. The latter restriction avoids possibly fsync'ing a much larger part of the filesystem than intended, if the user has left random symlinks hanging about in the data directory. This commit takes care of that and also does some code beautification, mainly moving the relevant code into fd.c, which seems a much better place for it than xlog.c, and making sure that the conditional compilation for the pre_sync_fname pass has something to do with whether pg_flush_data works. I also relocated the call site in xlog.c down a few lines; it seems a bit silly to be doing this before ValidateXLOGDirectoryStructure(). The similar logic in initdb.c ought to be made to match this, but that change is noncritical and will be dealt with separately. Back-patch to all active branches, like the prior commit. Abhijit Menon-Sen and Tom Lane
Seems to have been an oversight in the original leakproofness patch. Per report and patch from Jeevan Chalke. In passing, prettify some awkward leakproof-related code in AlterFunction.
specparse.y and specscanner.l used "string" as a token name. Now, bison likes to define each token name as a macro for the token code it assigns, which means those names are basically off-limits for any other use within the grammar file or included headers. So names as generic as "string" are dangerous. This is what was causing the recent failures on protosciurus: some versions of Solaris' sys/kstat.h use "string" as a field name. With late-model bison we don't see this problem because the token macros aren't defined till later (that is why castoroides didn't show the problem even though it's on the same machine). But protosciurus uses bison 1.875 which defines the token macros up front. This land mine has been there from day one; we'd have found it sooner except that protosciurus wasn't trying to run the isolation tests till recently. To fix, rename the token to "string_literal" which is hopefully less likely to collide with names used by system headers. Back-patch to all branches containing the isolation tests.
This reverts commit 54547bd87f49326d67051254c363e6597d16ffda. This appears to have been a thinko on my part. I will try to come up wioth a better solution.
According to recent tests, this case now works fine, so there's no reason to reject it anymore. (Even if there are still some OpenBSD platforms in the wild where it doesn't work, removing the check won't break any case that worked before.) We can actually remove the entire test that discovers whether libpython is threaded, since without the OpenBSD case there's no need to know that at all. Per report from Davin Potts. Back-patch to all active branches.