In preceding commits the race of renaming .idx files in place before
.rev files and other auxiliary files was fixed in pack-write.c's
finish_tmp_packfile(), builtin/repack.c's "struct exts", and
builtin/index-pack.c's final(). As noted in the change to pack-write.c
we left in place the issue of writing *.bitmap files after the *.idx,
let's fix that issue.
See 7cc8f97108 (pack-objects: implement bitmap writing, 2013-12-21)
for commentary at the time when *.bitmap was implemented about how
those files are written out, nothing in that commit contradicts what's
being done here.
Note that this commit and preceding ones only close any race condition
with *.idx files being written before their auxiliary files if we're
optimistic about our lack of fsync()-ing in this are not tripping us
over. See the thread at [1] for a rabbit hole of various discussions
about filesystem races in the face of doing and not doing fsync() (and
if doing fsync(), not doing it properly).
We may want to fsync the containing directory once after renaming the
*.idx file into place, but that is outside the scope of this series.
1. https://lore.kernel.org/git/8735qgkvv1.fsf@evledraar.gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Split up the finish_tmp_packfile() function and use the split-up version
in pack-objects.c in preparation for moving the step of renaming the
*.idx file later as part of a function change.
Since the only other caller of finish_tmp_packfile() was in
bulk-checkin.c, and it won't be needing a change to its *.idx renaming,
provide a thin wrapper for the old function as a static function in that
file. If other callers end up needing the simpler version it could be
moved back to "pack-write.c" and "pack.h".
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a similar spirit as preceding patches to `git repack` and `git
pack-objects`, fix the identical problem in `git index-pack`.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor the renaming in final() into a helper function, this is
similar in spirit to a preceding refactoring of finish_tmp_packfile()
in pack-write.c.
Before e37d0b8730 (builtin/index-pack.c: write reverse indexes,
2021-01-25) it probably wasn't worth it to have this sort of helper,
due to the differing "else if" case for "pack" files v.s. "idx" files.
But since we've got "rev" as well now, let's do the renaming via a
helper, this is both a net decrease in lines, and improves the
readability, since we can easily see at a glance that the logic for
writing these three types of files is exactly the same, aside from the
obviously differing cases of "*final_name" being NULL, and
"make_read_only_if_same" being different.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a similar spirit as the previous patch, fix the identical problem
from `git repack` (which invokes `pack-objects` with a temporary
location for output, and then moves the files into their final locations
itself).
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We treat the presence of an `.idx` file as the indicator of whether or
not it's safe to use a packfile. But `finish_tmp_packfile()` (which is
responsible for writing the pack and moving the temporary versions of
all of its auxiliary files into place) is inconsistent about the write
order.
Specifically, it moves the `.rev` file into place after the `.idx`,
leaving open the possibility to open a pack which looks "ready" (because
the `.idx` file exists and is readable) but appears momentarily to not
have a `.rev` file. This causes Git to fall back to generating the
pack's reverse index in memory.
Though racy, this amounts to an unnecessary slow-down at worst, and
doesn't affect the correctness of the resulting reverse index.
Close this race by moving the .rev file into place before moving the
.idx file into place.
This still leaves the issue of `.idx` files being renamed into place
before the auxiliary `.bitmap` file is renamed when in pack-object.c's
write_pack_file() "write_bitmap_index" is true. That race will be
addressed in subsequent commits.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor the renaming in finish_tmp_packfile() into a helper function.
The callers are now expected to pass a "name_buffer" ending in
"pack-OID." instead of the previous "pack-", we then append "pack",
"idx" or "rev" to it.
By doing the strbuf_setlen() in rename_tmp_packfile() we reuse the
buffer and avoid the repeated allocations we'd get if that function had
its own temporary "struct strbuf".
This approach of reusing the buffer does make the last user in
pack-object.c's write_pack_file() slightly awkward, since we needlessly
do a strbuf_setlen() before calling strbuf_release() for consistency. In
subsequent changes we'll move that bitmap writing code around, so let's
not skip the strbuf_setlen() now.
The previous strbuf_reset() idiom originated with 5889271114
(finish_tmp_packfile():use strbuf for pathname construction,
2014-03-03), which in turn was a minimal adjustment of pre-strbuf code
added in 0e990530ae (finish_tmp_packfile(): a helper function,
2011-10-28).
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
finish_bulk_checkin() stores the checksum from finalize_hashfile() by
writing to the `hash` member of `struct object_id`, but that hash has
nothing to do with an object id (it's just a convenient location that
happens to be sized correctly).
Store the hash directly in an unsigned char array. This behaves the same
as writing to the `hash` member, but makes the intent clearer (and
avoids allocating an extra four bytes for the `algo` member of `struct
object_id`). It likewise prevents the possibility of a segfault when
reading `algo` (e.g., by calling `oid_to_hex()`) if it is uninitialized.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Line-wrap the definition of finish_tmp_packfile() to make subsequent
changes easier to read. See 0e990530ae (finish_tmp_packfile(): a
helper function, 2011-10-28) for the commit that introduced this
overly long line.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Codepath to access recently added oidtree data structure had
to make unaligned accesses to oids, which has been corrected.
* rs/oidtree-alignment-fix:
oidtree: avoid unaligned access to crit-bit tree
Also fixed some typos reported by "git-po-helper".
Signed-off-by: Peter Krefting <peter@softwolves.pp.se>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
The flexible array member "k" of struct cb_node is used to store the key
of the crit-bit tree node. It offers no alignment guarantees -- in fact
the current struct layout puts it one byte after a 4-byte aligned
address, i.e. guaranteed to be misaligned.
oidtree uses a struct object_id as cb_node key. Since cf0983213c (hash:
add an algo member to struct object_id, 2021-04-26) it requires 4-byte
alignment. The mismatch is reported by UndefinedBehaviorSanitizer at
runtime like this:
hash.h:277:2: runtime error: member access within misaligned address 0x00015000802d for type 'struct object_id', which requires 4 byte alignment
0x00015000802d: note: pointer points here
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior hash.h:277:2 in
We can fix that by:
1. eliminating the alignment requirement of struct object_id,
2. providing the alignment in struct cb_node, or
3. avoiding the issue by only using memcpy to access "k".
Currently we only store one of two values in "algo" in struct object_id.
We could use a uint8_t for that instead and widen it only once we add
support for our twohundredth algorithm or so. That would not only avoid
alignment issues, but also reduce the memory requirements for each
instance of struct object_id by ca. 9%.
Supporting keys with alignment requirements might be useful to spread
the use of crit-bit trees. It can be achieved by using a wider type for
"k" (e.g. uintmax_t), using different types for the members "byte" and
"otherbits" (e.g. uint16_t or uint32_t for each), or by avoiding the use
of flexible arrays like khash.h does.
This patch implements the third option, though, because it has the least
potential for causing side-effects and we're close to the next release.
If one of the other options is implemented later as well to get their
additional benefits we can get rid of the extra copies introduced here.
Reported-by: Andrzej Hunt <andrzej@ahunt.org>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Translate 48 new messages (5230t0f0u) for git 2.33.0, and also fixed
typos found by "git-po-helper".
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Fangyi Zhou <me@fangyi.io>
Format README.md using GFM (GitHub Flavored Markdown) syntax.
- In order to use more than 3 level headings, use ATX style headings
instead of setext style headings.
- In order to add highlights for code blocks, use fenced code blocks
instead of indented code blocks.
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Update translation for following component:
* builtin/submodule--helper.c
Translate following new component:
* builtin/revert.c
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
* 'master' of github.com:git/git: (51 commits)
Git 2.33-rc2
object-file: use unsigned arithmetic with bit mask
Revert 'diff-merges: let "-m" imply "-p"'
object-store: avoid extra ';' from KHASH_INIT
oidtree: avoid nested struct oidtree_node
Git 2.33-rc1
test: fix for COLUMNS and bash 5
The eighth batch
diff: --pickaxe-all typofix
mingw: align symlinks-related rmdir() behavior with Linux
t7508: avoid non POSIX BRE
use fspathhash() everywhere
t0001: fix broken not-quite getcwd(3) test in bed67874e2
Documentation: render special characters correctly
reset: clear_unpack_trees_porcelain to plug leak
builtin/rebase: fix options.strategy memory lifecycle
builtin/merge: free found_ref when done
builtin/mv: free or UNLEAK multiple pointers at end of cmd_mv
convert: release strbuf to avoid leak
read-cache: call diff_setup_done to avoid leak
...
Jiang Xin reported possible typos in po/id.po, all of them are mismatch
variable names. Fix them.
Reported-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
