Add another transfer mode --clone to pg_upgrade (besides the existing
--link and the default copy), using special file cloning calls. This
makes the file transfer faster and more space efficient, achieving
speed similar to --link mode without the associated drawbacks.
On Linux, file cloning is supported on Btrfs and XFS (if formatted with
reflink support). On macOS, file cloning is supported on APFS.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
There's a project policy against using plain "char buf[BLCKSZ]" local
or static variables as page buffers; preferred style is to palloc or
malloc each buffer to ensure it is MAXALIGN'd. However, that policy's
been ignored in an increasing number of places. We've apparently got
away with it so far, probably because (a) relatively few people use
platforms on which misalignment causes core dumps and/or (b) the
variables chance to be sufficiently aligned anyway. But this is not
something to rely on. Moreover, even if we don't get a core dump,
we might be paying a lot of cycles for misaligned accesses.
To fix, invent new union types PGAlignedBlock and PGAlignedXLogBlock
that the compiler must allocate with sufficient alignment, and use
those in place of plain char arrays.
I used these types even for variables where there's no risk of a
misaligned access, since ensuring proper alignment should make
kernel data transfers faster. I also changed some places where
we had been palloc'ing short-lived buffers, for coding style
uniformity and to save palloc/pfree overhead.
Since this seems to be a live portability hazard (despite the lack
of field reports), back-patch to all supported versions.
Patch by me; thanks to Michael Paquier for review.
Discussion: https://postgr.es/m/1535618100.1286.3.camel@credativ.de
Consolidate directory and file create permissions for tools which work
with the PG data directory by adding a new module (common/file_perm.c)
that contains variables (pg_file_create_mode, pg_dir_create_mode) and
constants to initialize them (0600 for files and 0700 for directories).
Convert mkdir() calls in the backend to MakePGDirectory() if the
original call used default permissions (always the case for regular PG
directories).
Add tests to make sure permissions in PGDATA are set correctly by the
tools which modify the PG data directory.
Authors: David Steele <david@pgmasters.net>,
Adam Brightwell <adam.brightwell@crunchydata.com>
Reviewed-By: Michael Paquier, with discussion amongst many others.
Discussion: https://postgr.es/m/ad346fe6-b23e-59f1-ecb7-0e08390ad629%40pgmasters.net
pg_upgrade has always attempted to ensure that the transient dump files
it creates are inaccessible except to the owner. However, refactoring
in commit 76a7650c4 broke that for the file containing "pg_dumpall -g"
output; since then, that file was protected according to the process's
default umask. Since that file may contain role passwords (hopefully
encrypted, but passwords nonetheless), this is a particularly unfortunate
oversight. Prudent users of pg_upgrade on multiuser systems would
probably run it under a umask tight enough that the issue is moot, but
perhaps some users are depending only on pg_upgrade's umask changes to
protect their data.
To fix this in a future-proof way, let's just tighten the umask at
process start. There are no files pg_upgrade needs to write at a
weaker security level; and if there were, transiently relaxing the
umask around where they're created would be a safer approach.
Report and patch by Tom Lane; the idea for the fix is due to Noah Misch.
Back-patch to all supported branches.
Security: CVE-2018-1053
Change pg_bsd_indent to follow upstream rules for placement of comments
to the right of code, and remove pgindent hack that caused comments
following #endif to not obey the general rule.
Commit e3860ffa4d wasn't actually using
the published version of pg_bsd_indent, but a hacked-up version that
tried to minimize the amount of movement of comments to the right of
code. The situation of interest is where such a comment has to be
moved to the right of its default placement at column 33 because there's
code there. BSD indent has always moved right in units of tab stops
in such cases --- but in the previous incarnation, indent was working
in 8-space tab stops, while now it knows we use 4-space tabs. So the
net result is that in about half the cases, such comments are placed
one tab stop left of before. This is better all around: it leaves
more room on the line for comment text, and it means that in such
cases the comment uniformly starts at the next 4-space tab stop after
the code, rather than sometimes one and sometimes two tabs after.
Also, ensure that comments following #endif are indented the same
as comments following other preprocessor commands such as #else.
That inconsistency turns out to have been self-inflicted damage
from a poorly-thought-through post-indent "fixup" in pgindent.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
The previous design for this had copyFile(), linkFile(), and
rewriteVisibilityMap() returning strerror strings, with the caller
producing one-size-fits-all error messages based on that. This made it
impossible to produce messages that described the failures with any degree
of precision, especially not short-read problems since those don't set
errno at all.
Since pg_upgrade has no intention of continuing after any error in this
area, let's fix this by just letting these functions call pg_fatal() for
themselves, making it easy for each point of failure to have a suitable
error message. Taking this approach also allows dropping cleanup code
that was unnecessary and was often rather sloppy about preserving errno.
To not lose relevant info that was reported before, pass in the schema name
and table name of the current table so that they can be included in the
error reports.
An additional problem was the use of getErrorText(), which was flat out
wrong for all but a couple of call sites, because it unconditionally did
"_dosmaperr(GetLastError())" on Windows. That's only appropriate when
reporting an error from a Windows-native API, which only a couple of
the callers were actually doing. Thus, even the reported strerror string
would be unrelated to the actual failure in many cases on Windows.
To fix, get rid of getErrorText() altogether, and just have call sites
do strerror(errno) instead, since that's the way all the rest of our
frontend programs do it. Add back the _dosmaperr() calls in the two
places where that's actually appropriate.
In passing, make assorted messages hew more closely to project style
guidelines, notably by removing initial capitals in not-complete-sentence
primary error messages. (I didn't make any effort to clean up places
I didn't have another reason to touch, though.)
Per discussion of a report from Thomas Kellerer. Back-patch to 9.6,
but no further; given the relative infrequency of reports of problems
here, it's not clear it's worth adapting the patch to older branches.
Patch by me, but with credit to Alvaro Herrera for spotting the issue
with getErrorText's misuse of _dosmaperr().
Discussion: <nsjrbh$8li$1@blaine.gmane.org>
This is new code in 9.6, and evidently we missed out testing it as
thoroughly as it should have been. Bugs fixed here:
1. Use binary not text mode to open the files on Windows. Before, if
the visibility map chanced to contain two bytes that looked like \r\n,
Windows' read() would convert that to \n, which both corrupts the map
data and causes the file to look shorter than it should. Unless you
were *very* unlucky and had an exact multiple of 8K such occurrences
in each VM file, this would cause pg_upgrade to report a failure,
though with a rather obscure error message.
2. The code for copying rebuilt bytes into the output was simply wrong.
It chanced to work okay on little-endian machines but would emit the
bytes in the wrong order on big-endian, leading to silent corruption
of the visibility map data.
3. The code was careless about alignment of the working buffers. Given
all three of an alignment-picky architecture, a compiler that chooses
to put the new_vmbuf[] local variable at an odd starting address, and
a checksum-enabled database, pg_upgrade would dump core.
Point one was reported by Thomas Kellerer, the other two detected by
code-reading.
Point two is much the nastiest of these issues from an impact standpoint,
though fortunately it affects only a minority of users. The Windows issue
will definitely bite people, but it seems quite unlikely that there would
be undetected corruption from that.
In addition, I failed to resist the temptation to do some minor cosmetic
adjustments, mostly improving the comments.
It would be a good idea to try to improve the error reporting here, but
that seems like material for a separate patch.
Discussion: <nsjrbh$8li$1@blaine.gmane.org>
For historical reasons, copyFile and rewriteVisibilityMap took a force
argument which was always passed as true, meaning that any existing
file should be overwritten. However, it seems much safer to instead
fail if a file we need to write already exists.
While we're at it, remove the "force" argument altogether, since it was
never passed as anything other than true (and now we would never pass
it as anything other than false, if we kept it).
Noted by Andres Freund during post-commit review of the patch that added
rewriteVisibilityMap, commit 7087166a88,
but this also changes the behavior when copying files without rewriting
them.
Patch by Masahiko Sawada.
In the old logic, if read() were to return an error, we'd silently stop
rewriting the visibility map at that point in the file. That's safe,
but reporting the error is better, so do that instead.
Report by Andres Freund. Patch by Masahiko Sawada, with one correction
by me.
Commit a892234f83 added a second bit per
page to the visibility map, but pg_upgrade has been unaware of it up
until now. Therefore, a pg_upgrade from an earlier major release of
PostgreSQL to any commit preceding this one and following the one
mentioned above would result in invalid visibility map contents on the
new cluster, very possibly leading to data corruption. This plugs
that hole.
Masahiko Sawada, reviewed by Jeff Janes, Bruce Momjian, Simon Riggs,
Michael Paquier, Andres Freund, me, and others.
We've not found a use for this so far, and the current need, which
is to convert the visibility map to a new format, does not suit the
existing design anyway. So just rip it out.
Author: Masahiko Sawada, slightly revised by me.
Discussion: 20160215211313.GB31273@momjian.us
Also fix getErrorText() to return the right error string on failure.
This behavior now matches that of other operating systems.
Report by Noah Misch
Backpatch through 9.1
Amit Kapila