Regression fix.
* ab/fsck-unexpected-type:
object-file: free(*contents) only in read_loose_object() caller
object-file: fix SEGV on free() regression in v2.34.0-rc2
In the preceding commit a free() of uninitialized memory regression in
96e41f58fe (fsck: report invalid object type-path combinations,
2021-10-01) was fixed, but we'd still have an issue with leaking
memory from fsck_loose(). Let's fix that issue too.
That issue was introduced in my 31deb28f5e (fsck: don't hard die on
invalid object types, 2021-10-01). It can be reproduced under
SANITIZE=leak with the test I added in 093fffdfbe (fsck tests: add
test for fsck-ing an unknown type, 2021-10-01):
./t1450-fsck.sh --run=84 -vixd
In some sense it's not a problem, we lost the same amount of memory in
terms of things malloc'd and not free'd. It just moved from the "still
reachable" to "definitely lost" column in valgrind(1) nomenclature[1],
since we'd have die()'d before.
But now that we don't hard die() anymore in the library let's properly
free() it. Doing so makes this code much easier to follow, since we'll
now have one function owning the freeing of the "contents" variable,
not two.
For context on that memory management pattern the read_loose_object()
function was added in f6371f9210 (sha1_file: add read_loose_object()
function, 2017-01-13) and subsequently used in c68b489e56 (fsck:
parse loose object paths directly, 2017-01-13). The pattern of it
being the task of both sides to free() the memory has been there in
this form since its inception.
1. https://valgrind.org/docs/manual/mc-manual.html#mc-manual.leaks
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a regression introduced in my 96e41f58fe (fsck: report invalid
object type-path combinations, 2021-10-01). When fsck-ing blobs larger
than core.bigFileThreshold, we'd free() a pointer to uninitialized
memory.
This issue would have been caught by SANITIZE=address, but since it
involves core.bigFileThreshold, none of the existing tests in our test
suite covered it.
Running them with the "big_file_threshold" in "environment.c" changed
to say "6" would have shown this failure, but let's add a dedicated
test for this scenario based on Han Xin's report[1].
The bug was introduced between v9 and v10[2] of the fsck series merged
in 061a21d36d (Merge branch 'ab/fsck-unexpected-type', 2021-10-25).
1. https://lore.kernel.org/git/20211111030302.75694-1-hanxin.hx@alibaba-inc.com/
2. https://lore.kernel.org/git/cover-v10-00.17-00000000000-20211001T091051Z-avarab@gmail.com/
Reported-by: Han Xin <chiyutianyi@gmail.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git commit" gave duplicated error message when the object store
was unwritable, which has been corrected.
* ab/fix-commit-error-message-upon-unwritable-object-store:
commit: fix duplication regression in permission error output
unwritable tests: assert exact error output
Follow through the work to use the repo interface to access
submodule objects in-process, instead of abusing the alternate
object database interface.
* jt/no-abuse-alternate-odb-for-submodules:
submodule: trace adding submodule ODB as alternate
submodule: pass repo to check_has_commit()
object-file: only register submodule ODB if needed
merge-{ort,recursive}: remove add_submodule_odb()
refs: peeling non-the_repository iterators is BUG
refs: teach arbitrary repo support to iterators
refs: plumb repo into ref stores
"git fsck" has been taught to report mismatch between expected and
actual types of an object better.
* ab/fsck-unexpected-type:
fsck: report invalid object type-path combinations
fsck: don't hard die on invalid object types
object-file.c: stop dying in parse_loose_header()
object-file.c: return ULHR_TOO_LONG on "header too long"
object-file.c: use "enum" return type for unpack_loose_header()
object-file.c: simplify unpack_loose_short_header()
object-file.c: make parse_loose_header_extended() public
object-file.c: return -1, not "status" from unpack_loose_header()
object-file.c: don't set "typep" when returning non-zero
cat-file tests: test for current --allow-unknown-type behavior
cat-file tests: add corrupt loose object test
cat-file tests: test for missing/bogus object with -t, -s and -p
cat-file tests: move bogus_* variable declarations earlier
fsck tests: test for garbage appended to a loose object
fsck tests: test current hash/type mismatch behavior
fsck tests: refactor one test to use a sub-repo
fsck tests: add test for fsck-ing an unknown type
Fix a regression in the error output emitted when .git/objects can't
be written to. Before 9c4d6c0297 (cache-tree: Write updated
cache-tree after commit, 2014-07-13) we'd emit only one "insufficient
permission" error, now we'll do so again.
The cause is rather straightforward, we've got WRITE_TREE_SILENT for
the use-case of wanting to prepare an index silently, quieting any
permission etc. error output. Then when we attempt to update to
that (possibly broken) index we'll run into the same errors again.
But with 9c4d6c0297 the gap between the cache-tree API and the object
store wasn't closed in terms of asking write_object_file() to be
silent. I.e. post-9c4d6c0297b the first call is to prepare_index(),
and after that we'll call prepare_to_commit(). We only want verbose
error output from the latter.
So let's add and use that facility with a corresponding HASH_SILENT
flag, its only user is cache-tree.c's update_one(), which will set it
if its "WRITE_TREE_SILENT" flag is set.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a35e03dee0 ("submodule: lazily add submodule ODBs as alternates",
2021-09-08), Git was taught to add all known submodule ODBs as
alternates when attempting to read an object that doesn't exist, as a
fallback for when a submodule object is read as if it were in
the_repository. However, this behavior wasn't restricted to happen only
when reading from the_repository. Fix this.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Futz with the way 'errno' is relied on in the refs API to carry the
failure modes up the call chain.
* hn/refs-errno-cleanup:
refs: make errno output explicit for read_raw_ref_fn
refs/files-backend: stop setting errno from lock_ref_oid_basic
refs: remove EINVAL errno output from specification of read_raw_ref_fn
refs file backend: move raceproof_create_file() here
Improve the error that's emitted in cases where we find a loose object
we parse, but which isn't at the location we expect it to be.
Before this change we'd prefix the error with a not-a-OID derived from
the path at which the object was found, due to an emergent behavior in
how we'd end up with an "OID" in these codepaths.
Now we'll instead say what object we hashed, and what path it was
found at. Before this patch series e.g.:
$ git hash-object --stdin -w -t blob </dev/null
e69de29bb2
$ mv objects/e6/ objects/e7
Would emit ("[...]" used to abbreviate the OIDs):
git fsck
error: hash mismatch for ./objects/e7/9d[...] (expected e79d[...])
error: e79d[...]: object corrupt or missing: ./objects/e7/9d[...]
Now we'll instead emit:
error: e69d[...]: hash-path mismatch, found at: ./objects/e7/9d[...]
Furthermore, we'll do the right thing when the object type and its
location are bad. I.e. this case:
$ git hash-object --stdin -w -t garbage --literally </dev/null
8315a83d2acc4c174aed59430f9a9c4ed926440f
$ mv objects/83 objects/84
As noted in an earlier commits we'd simply die early in those cases,
until preceding commits fixed the hard die on invalid object type:
$ git fsck
fatal: invalid object type
Now we'll instead emit sensible error messages:
$ git fsck
error: 8315[...]: hash-path mismatch, found at: ./objects/84/15[...]
error: 8315[...]: object is of unknown type 'garbage': ./objects/84/15[...]
In both fsck.c and object-file.c we're using null_oid as a sentinel
value for checking whether we got far enough to be certain that the
issue was indeed this OID mismatch.
We need to add the "object corrupt or missing" special-case to deal
with cases where read_loose_object() will return an error before
completing check_object_signature(), e.g. if we have an error in
unpack_loose_rest() because we find garbage after the valid gzip
content:
$ git hash-object --stdin -w -t blob </dev/null
e69de29bb2
$ chmod 755 objects/e6/9de29bb2d1d6434b8b29ae775ad8c2e48c5391
$ echo garbage >>objects/e6/9de29bb2d1d6434b8b29ae775ad8c2e48c5391
$ git fsck
error: garbage at end of loose object 'e69d[...]'
error: unable to unpack contents of ./objects/e6/9d[...]
error: e69d[...]: object corrupt or missing: ./objects/e6/9d[...]
There is currently some weird messaging in the edge case when the two
are combined, i.e. because we're not explicitly passing along an error
state about this specific scenario from check_stream_oid() via
read_loose_object() we'll end up printing the null OID if an object is
of an unknown type *and* it can't be unpacked by zlib, e.g.:
$ git hash-object --stdin -w -t garbage --literally </dev/null
8315a83d2acc4c174aed59430f9a9c4ed926440f
$ chmod 755 objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
$ echo garbage >>objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
$ /usr/bin/git fsck
fatal: invalid object type
$ ~/g/git/git fsck
error: garbage at end of loose object '8315a83d2acc4c174aed59430f9a9c4ed926440f'
error: unable to unpack contents of ./objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
error: 8315a83d2acc4c174aed59430f9a9c4ed926440f: object corrupt or missing: ./objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
error: 0000000000000000000000000000000000000000: object is of unknown type 'garbage': ./objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
[...]
I think it's OK to leave that for future improvements, which would
involve enum-ifying more error state as we've done with "enum
unpack_loose_header_result" in preceding commits. In these
increasingly more obscure cases the worst that can happen is that
we'll get slightly nonsensical or inapplicable error messages.
There's other such potential edge cases, all of which might produce
some confusing messaging, but still be handled correctly as far as
passing along errors goes. E.g. if check_object_signature() returns
and oideq(real_oid, null_oid()) is true, which could happen if it
returns -1 due to the read_istream() call having failed.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the error fsck emits on invalid object types, such as:
$ git hash-object --stdin -w -t garbage --literally </dev/null
<OID>
From the very ungraceful error of:
$ git fsck
fatal: invalid object type
$
To:
$ git fsck
error: <OID>: object is of unknown type 'garbage': <OID_PATH>
[ other fsck output ]
We'll still exit with non-zero, but now we'll finish the rest of the
traversal. The tests that's being added here asserts that we'll still
complain about other fsck issues (e.g. an unrelated dangling blob).
To do this we need to pass down the "OBJECT_INFO_ALLOW_UNKNOWN_TYPE"
flag from read_loose_object() through to parse_loose_header(). Since
the read_loose_object() function is only used in builtin/fsck.c we can
simply change it to accept a "struct object_info" (which contains the
OBJECT_INFO_ALLOW_UNKNOWN_TYPE in its flags). See
f6371f9210 (sha1_file: add read_loose_object() function, 2017-01-13)
for the introduction of read_loose_object().
Since we'll need a "struct strbuf" to hold the "type_name" let's pass
it to the for_each_loose_file_in_objdir() callback to avoid allocating
a new one for each loose object in the iteration. It also makes the
memory management simpler than sticking it in fsck_loose() itself, as
we'll only need to strbuf_reset() it, with no need to do a
strbuf_release() before each "return".
Before this commit we'd never check the "type" if read_loose_object()
failed, but now we do. We therefore need to initialize it to OBJ_NONE
to be able to tell the difference between e.g. its
unpack_loose_header() having failed, and us getting past that and into
parse_loose_header().
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make parse_loose_header() return error codes and data instead of
invoking die() by itself.
For now we'll move the relevant die() call to loose_object_info() and
read_loose_object() to keep this change smaller. In a subsequent
commit we'll make read_loose_object() return an error code instead of
dying. We should also address the "allow_unknown" case (should be
moved to builtin/cat-file.c), but for now I'll be leaving it.
For making parse_loose_header() not die() change its prototype to
accept a "struct object_info *" instead of the "unsigned long *sizep"
it accepted before. Its callers can now check the populated populated
"oi->typep".
Because of this we don't need to pass in the "unsigned int flags"
which we used for OBJECT_INFO_ALLOW_UNKNOWN_TYPE, we can instead do
that check in loose_object_info().
This also refactors some confusing control flow around the "status"
variable. In some cases we set it to the return value of "error()",
i.e. -1, and later checked if "status < 0" was true.
Since 93cff9a978 (sha1_loose_object_info: return error for corrupted
objects, 2017-04-01) the return value of loose_object_info() (then
named sha1_loose_object_info()) had been a "status" variable that be
any negative value, as we were expecting to return the "enum
object_type".
The only negative type happens to be OBJ_BAD, but the code still
assumed that more might be added. This was then used later in
e.g. c84a1f3ed4 (sha1_file: refactor read_object, 2017-06-21). Now
that parse_loose_header() will return 0 on success instead of the
type (which it'll stick into the "struct object_info") we don't need
to conflate these two cases in its callers.
Since parse_loose_header() doesn't need to return an arbitrary
"status" we only need to treat its "ret < 0" specially, but can
idiomatically overwrite it with our own error() return. This along
with having made unpack_loose_header() return an "enum
unpack_loose_header_result" in an earlier commit means that we can
move the previously nested if/else cases mostly into the "ULHR_OK"
branch of the "switch" statement.
We should be less silent if we reach that "status = -1" branch, which
happens if we've got trailing garbage in loose objects, see
f6371f9210 (sha1_file: add read_loose_object() function, 2017-01-13)
for a better way to handle it. For now let's punt on it, a subsequent
commit will address that edge case.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Split up the return code for "header too long" from the generic
negative return value unpack_loose_header() returns, and report via
error() if we exceed MAX_HEADER_LEN.
As a test added earlier in this series in t1006-cat-file.sh shows
we'll correctly emit zlib errors from zlib.c already in this case, so
we have no need to carry those return codes further down the
stack. Let's instead just return ULHR_TOO_LONG saying we ran into the
MAX_HEADER_LEN limit, or other negative values for "unable to unpack
<OID> header".
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a preceding commit we changed and documented unpack_loose_header()
from its previous behavior of returning any negative value or zero, to
only -1 or 0.
Let's add an "enum unpack_loose_header_result" type and use it for
these return values, and have the compiler assert that we're
exhaustively covering all of them.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Combine the unpack_loose_short_header(),
unpack_loose_header_to_strbuf() and unpack_loose_header() functions
into one.
The unpack_loose_header_to_strbuf() function was added in
46f034483e (sha1_file: support reading from a loose object of unknown
type, 2015-05-03).
Its code was mostly copy/pasted between it and both of
unpack_loose_header() and unpack_loose_short_header(). We now have a
single unpack_loose_header() function which accepts an optional
"struct strbuf *" instead.
I think the remaining unpack_loose_header() function could be further
simplified, we're carrying some complexity just to be able to emit a
garbage type longer than MAX_HEADER_LEN, we could alternatively just
say "we found a garbage type <first 32 bytes>..." instead. But let's
leave the current behavior in place for now.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make the parse_loose_header_extended() function public and remove the
parse_loose_header() wrapper. The only direct user of it outside of
object-file.c itself was in streaming.c, that caller can simply pass
the required "struct object-info *" instead.
This change is being done in preparation for teaching
read_loose_object() to accept a flag to pass to
parse_loose_header(). It isn't strictly necessary for that change, we
could simply use parse_loose_header_extended() there, but will leave
the API in a better end state.
It would be a better end-state to have already moved the declaration
of these functions to object-store.h to avoid the forward declaration
of "struct object_info" in cache.h, but let's leave that cleanup for
some other time.
1. https://lore.kernel.org/git/patch-v6-09.22-5b9278e7bb4-20210907T104559Z-avarab@gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Return a -1 when git_inflate() fails instead of whatever Z_* status
we'd get from zlib.c. This makes no difference to any error we report,
but makes it more obvious that we don't care about the specific zlib
error codes here.
See d21f842690 (unpack_sha1_header(): detect malformed object header,
2016-09-25) for the commit that added the "return status" code. As far
as I can tell there was never a real reason (e.g. different reporting)
for carrying down the "status" as opposed to "-1".
At the time that d21f842690 was written there was a corresponding
"ret < Z_OK" check right after the unpack_sha1_header() call (the
"unpack_sha1_header()" function was later rename to our current
"unpack_loose_header()").
However, that check was removed in c84a1f3ed4 (sha1_file: refactor
read_object, 2017-06-21) without changing the corresponding return
code.
So let's do the minor cleanup of also changing this function to return
a -1.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the loose_object_info() function returns an error stop faking up
the "oi->typep" to OBJ_BAD. Let the return value of the function
itself suffice. This code cleanup simplifies subsequent changes.
That we set this at all is a relic from the past. Before
052fe5eaca (sha1_loose_object_info: make type lookup optional,
2013-07-12) we would always return the type_from_string(type) via the
parse_sha1_header() function, or -1 (i.e. OBJ_BAD) if we couldn't
parse it.
Then in a combination of 46f034483e (sha1_file: support reading from
a loose object of unknown type, 2015-05-03) and
b3ea7dd32d (sha1_loose_object_info: handle errors from
unpack_sha1_rest, 2017-10-05) our API drifted even further towards
conflating the two again.
Having read the code paths involved carefully I think this is OK. We
are just about to return -1, and we have only one caller:
do_oid_object_info_extended(). That function will in turn go on to
return -1 when we return -1 here.
This might be introducing a subtle bug where a caller of
oid_object_info_extended() would inspect its "typep" and expect a
meaningful value if the function returned -1.
Such a problem would not occur for its simpler oid_object_info()
sister function. That one always returns the "enum object_type", which
in the case of -1 would be the OBJ_BAD.
Having read the code for all the callers of these functions I don't
believe any such bug is being introduced here, and in any case we'd
likely already have such a bug for the "sizep" member (although
blindly checking "typep" first would be a more common case).
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Replace a handcrafted data structure used to keep track of bad
objects in the packfile API by an oidset.
* rs/packfile-bad-object-list-in-oidset:
packfile: use oidset for bad objects
packfile: convert has_packed_and_bad() to object_id
packfile: convert mark_bad_packed_object() to object_id
midx: inline nth_midxed_pack_entry()
oidset: make oidset_size() an inline function
The code to make "git grep" recurse into submodules has been
updated to migrate away from the "add submodule's object store as
an alternate object store" mechanism (which is suboptimal).
* jt/grep-wo-submodule-odb-as-alternate:
t7814: show lack of alternate ODB-adding
submodule-config: pass repo upon blob config read
grep: add repository to OID grep sources
grep: allocate subrepos on heap
grep: read submodule entry with explicit repo
grep: typesafe versions of grep_source_init
grep: use submodule-ODB-as-alternate lazy-addition
submodule: lazily add submodule ODBs as alternates
The single caller has a full object ID, so pass it on instead of just
its hash member.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All callers have full object IDs, so pass them on instead of just their
hash member.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach Git to add submodule ODBs as alternates to the object store of
the_repository only upon the first access of an object not in
the_repository, and not when add_submodule_odb() is called.
This provides a means of gradually migrating from accessing a
submodule's object through alternates to accessing a submodule's object
by explicitly passing its repository object. Any Git command can declare
that it might access submodule objects by calling add_submodule_odb()
(as they do now), but the submodule ODBs themselves will not be added
until needed, so individual commands and/or combinations of arguments
can be migrated one by one.
[The advantage of explicit repository-object passing is code clarity (it
is clear which repository an object read is from), performance (there is
no need to linearly search through all submodule ODBs whenever an object
is accessed from any repository, whether superproject or submodule), and
the possibility of future features like partial clone submodules (which
right now is not possible because if an object is missing, we do not
know which repository to lazy-fetch into).]
This commit also introduces an environment variable that a test may set
to make the actual registration of alternates fatal, in order to
demonstrate that its codepaths do not need this registration.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Reviewed-by: Emily Shaffer <emilyshaffer@google.com>
Reviewed-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Opening multiple instance of the same MIDX can lead to problems like two
separate packed_git structures which represent the same pack being added
to the repository's object store.
The above scenario can happen because prepare_midx_pack() checks if
`m->packs[pack_int_id]` is NULL in order to determine if a pack has been
opened and installed in the repository before. But a caller can
construct two copies of the same MIDX by calling get_multi_pack_index()
and load_multi_pack_index() since the former manipulates the
object store directly but the latter is a lower-level routine which
allocates a new MIDX for each call.
So if prepare_midx_pack() is called on multiple MIDXs with the same
pack_int_id, then that pack will be installed twice in the object
store's packed_git pointer.
This can lead to problems in, for e.g., the pack-bitmap code, which does
something like the following (in pack-bitmap.c:open_pack_bitmap()):
struct bitmap_index *bitmap_git = ...;
for (p = get_all_packs(r); p; p = p->next) {
if (open_pack_bitmap_1(bitmap_git, p) == 0)
ret = 0;
}
which is a problem if two copies of the same pack exist in the
packed_git list because pack-bitmap.c:open_pack_bitmap_1() contains a
conditional like the following:
if (bitmap_git->pack || bitmap_git->midx) {
/* ignore extra bitmap file; we can only handle one */
warning("ignoring extra bitmap file: %s", packfile->pack_name);
close(fd);
return -1;
}
Avoid this scenario by not letting write_midx_internal() open a MIDX
that isn't also pointed at by the object store. So long as this is the
case, other routines should prefer to open MIDXs with
get_multi_pack_index() or reprepare_packed_git() instead of creating
instances on their own. Because get_multi_pack_index() returns
`r->object_store->multi_pack_index` if it is non-NULL, we'll only have
one instance of a MIDX open at one time, avoiding these problems.
To encourage this, drop the `struct multi_pack_index *` parameter from
`write_midx_internal()`, and rely instead on the `object_dir` to find
(or initialize) the correct MIDX instance.
Likewise, replace the call to `close_midx()` with
`close_object_store()`, since we're about to replace the MIDX with a new
one and should invalidate the object store's memory of any MIDX that
might have existed beforehand.
Note that this now forbids passing object directories that don't belong
to alternate repositories over `--object-dir`, since before we would
have happily opened a MIDX in any directory, but now restrict ourselves
to only those reachable by `r->objects->multi_pack_index` (and alternate
MIDXs that we can see by walking the `next` pointer).
As far as I can tell, supporting arbitrary directories with
`--object-dir` was a historical accident, since even the documentation
says `<alt>` when referring to the value passed to this option.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the raceproof_create_file() API added to cache.h and
object-file.c in 177978f56a (raceproof_create_file(): new function,
2017-01-06) to its only user, refs/files-backend.c.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Build fix.
* cb/many-alternate-optim-fixup:
object-file: use unsigned arithmetic with bit mask
object-store: avoid extra ';' from KHASH_INIT
oidtree: avoid nested struct oidtree_node
33f379eee6 (make object_directory.loose_objects_subdir_seen a bitmap,
2021-07-07) replaced a wasteful 256-byte array with a 32-byte array
and bit operations. The mask calculation shifts a literal 1 of type
int left by anything between 0 and 31. UndefinedBehaviorSanitizer
doesn't like that and reports:
object-file.c:2477:18: runtime error: left shift of 1 by 31 places cannot be represented in type 'int'
Make sure to use an unsigned 1 instead to avoid the issue.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Optimization for repositories with many alternate object store.
* ew/many-alternate-optim:
oidtree: a crit-bit tree for odb_loose_cache
oidcpy_with_padding: constify `src' arg
make object_directory.loose_objects_subdir_seen a bitmap
avoid strlen via strbuf_addstr in link_alt_odb_entry
speed up alt_odb_usable() with many alternates
Prepare the internals for lazily fetching objects in submodules
from their promisor remotes.
* jt/partial-clone-submodule-1:
promisor-remote: teach lazy-fetch in any repo
run-command: refactor subprocess env preparation
submodule: refrain from filtering GIT_CONFIG_COUNT
promisor-remote: support per-repository config
repository: move global r_f_p_c to repo struct
This saves 8K per `struct object_directory', meaning it saves
around 800MB in my case involving 100K alternates (half or more
of those alternates are unlikely to hold loose objects).
This is implemented in two parts: a generic, allocation-free
`cbtree' and the `oidtree' wrapper on top of it. The latter
provides allocation using alloc_state as a memory pool to
improve locality and reduce free(3) overhead.
Unlike oid-array, the crit-bit tree does not require sorting.
Performance is bound by the key length, for oidtree that is
fixed at sizeof(struct object_id). There's no need to have
256 oidtrees to mitigate the O(n log n) overhead like we did
with oid-array.
Being a prefix trie, it is natively suited for expanding short
object IDs via prefix-limited iteration in
`find_short_object_filename'.
On my busy workstation, p4205 performance seems to be roughly
unchanged (+/-8%). Startup with 100K total alternates with no
loose objects seems around 10-20% faster on a hot cache.
(800MB in memory savings means more memory for the kernel FS
cache).
The generic cbtree implementation does impose some extra
overhead for oidtree in that it uses memcmp(3) on
"struct object_id" so it wastes cycles comparing 12 extra bytes
on SHA-1 repositories. I've not yet explored reducing this
overhead, but I expect there are many places in our code base
where we'd want to investigate this.
More information on crit-bit trees: https://cr.yp.to/critbit.html
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There's no point in using 8 bits per-directory when 1 bit
will do. This saves us 224 bytes per object directory, which
ends up being 22MB when dealing with 100K alternates.
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We can save a few milliseconds (across 100K odbs) by using
strbuf_addbuf() instead of strbuf_addstr() by passing `entry' as
a strbuf pointer rather than a "const char *".
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With many alternates, the duplicate check in alt_odb_usable()
wastes many cycles doing repeated fspathcmp() on every existing
alternate. Use a khash to speed up lookups by odb->path.
Since the kh_put_* API uses the supplied key without
duplicating it, we also take advantage of it to replace both
xstrdup() and strbuf_release() in link_alt_odb_entry() with
strbuf_detach() to avoid the allocation and copy.
In a test repository with 50K alternates and each of those 50K
alternates having one alternate each (for a total of 100K total
alternates); this speeds up lookup of a non-existent blob from
over 16 minutes to roughly 2.7 seconds on my busy workstation.
Note: all underlying git object directories were small and
unpacked with only loose objects and no packs. Having to load
packs increases times significantly.
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Linux users may benefit from additional information on how to
avoid ENOMEM from mmap despite the system having enough RAM to
accomodate them. We can't reliably unmap pack windows to work
around the issue since malloc and other library routines may
mmap without our knowledge.
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is one step towards supporting partial clone submodules.
Even after this patch, we will still lack partial clone submodules
support, primarily because a lot of Git code that accesses submodule
objects does so by adding their object stores as alternates, meaning
that any lazy fetches that would occur in the submodule would be done
based on the config of the superproject, not of the submodule. This also
prevents testing of the functionality in this patch by user-facing
commands. So for now, test this mechanism using a test helper.
Besides that, there is some code that uses the wrapper functions
like has_promisor_remote(). Those will need to be checked to see if they
could support the non-wrapper functions instead (and thus support any
repository, not just the_repository).
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git clean" and "git ls-files -i" had confusion around working on
or showing ignored paths inside an ignored directory, which has
been corrected.
* en/dir-traversal:
dir: introduce readdir_skip_dot_and_dotdot() helper
dir: update stale description of treat_directory()
dir: traverse into untracked directories if they may have ignored subfiles
dir: avoid unnecessary traversal into ignored directory
t3001, t7300: add testcase showcasing missed directory traversal
t7300: add testcase showing unnecessary traversal into ignored directory
ls-files: error out on -i unless -o or -c are specified
dir: report number of visited directories and paths with trace2
dir: convert trace calls to trace2 equivalents
Many places in the code were doing
while ((d = readdir(dir)) != NULL) {
if (is_dot_or_dotdot(d->d_name))
continue;
...process d...
}
Introduce a readdir_skip_dot_and_dotdot() helper to make that a one-liner:
while ((d = readdir_skip_dot_and_dotdot(dir)) != NULL) {
...process d...
}
This helper particularly simplifies checks for empty directories.
Also use this helper in read_cached_dir() so that our statistics are
consistent across platforms. (In other words, read_cached_dir() should
have been using is_dot_or_dotdot() and skipping such entries, but did
not and left it to treat_path() to detect and mark such entries as
path_none.)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Up until recently, object IDs did not have an algorithm member, only a
hash. Consequently, it was possible to share one null (all-zeros)
object ID among all hash algorithms. Now that we're going to be
handling objects from multiple hash algorithms, it's important to make
sure that all object IDs have a correct algorithm field.
Introduce a per-algorithm null OID, and add it to struct hash_algo.
Introduce a wrapper function as well, and use it everywhere we used to
use the null_oid constant.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that struct object_id has an algorithm field, we should populate it.
This will allow us to handle object IDs in any supported algorithm and
distinguish between them. Ensure that the field is written whenever we
write an object ID by storing it explicitly every time we write an
object. Set values for the empty blob and tree values as well.
In addition, use the algorithm field to compare object IDs. Note that
because we zero-initialize struct object_id in many places throughout
the codebase, we default to the default algorithm in cases where the
algorithm field is zero rather than explicitly initialize all of those
locations.
This leads to a branch on every comparison, but the alternative is to
compare the entire buffer each time and padding the buffer for SHA-1.
That alternative ranges up to 3.9% worse than this approach on the perf
t0001, t1450, and t1451.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we're hashing a value which is going to be an object ID, we want to
zero-pad that value if necessary. To do so, use the final_oid_fn
instead of the final_fn anytime we're going to create an object ID to
ensure we perform this operation.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To avoid the penalty of having to branch in hash comparison functions,
we'll want to always compare the full hash member in a struct object_id,
which will require that SHA-1 object IDs be zero-padded. To do so, add
a function which finalizes a hash context and writes it into an object
ID that performs this padding.
Move the definition of struct object_id and the constant definitions
higher up so we they are available for us to use.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add and apply a semantic patch for converting code that open-codes
CALLOC_ARRAY to use it instead. It shortens the code and infers the
element size automatically.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change all remnants of "sha1" in hash-lookup.c and .h and rename them to
reflect that we're not just able to handle SHA-1 these days.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Drop the last remnant of "sha1" in this file and rename it to reflect
that we're not just able to handle SHA-1 these days.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano
Ævar Arnfjörð Bjarmason
Jonathan Tan
René Scharfe
Taylor Blau
Eric Wong
Elijah Newren
brian m. carlson
Martin Ågren