There seems to be some internal stack overflow detection in MSVC's
`malloc()` machinery that seems to be independent of the `stack reserve`
and `heap reserve` sizes specified in the executable (editable via
`EDITBIN /STACK:<n> <exe>` and `EDITBIN /HEAP:<n> <exe>`).
In the newly test cases added by `jk/tree-name-and-depth-limit`, this
stack overflow detection is unfortunately triggered before Git can print
out the error message about too-deep trees and exit gracefully. Instead,
it exits with `STATUS_STACK_OVERFLOW`. This corresponds to the numeric
value -1073741571, something the MSYS2 runtime we sadly need to use to
run Git's test suite cannot handle and which it internally maps to the
exit code 127. Git's test suite, in turn, mistakes this to mean that the
command was not found, and fails both test cases.
Here is an example stack trace from an example run:
[0x0] ntdll!RtlpAllocateHeap+0x31 0x4212603f50 0x7ff9d6d4cd49
[0x1] ntdll!RtlpAllocateHeapInternal+0x6c9 0x42126041b0 0x7ff9d6e14512
[0x2] ntdll!RtlDebugAllocateHeap+0x102 0x42126042b0 0x7ff9d6dcd8b0
[0x3] ntdll!RtlpAllocateHeap+0x7ec70 0x4212604350 0x7ff9d6d4cd49
[0x4] ntdll!RtlpAllocateHeapInternal+0x6c9 0x42126045b0 0x7ff9596ed480
[0x5] ucrtbased!heap_alloc_dbg_internal+0x210 0x42126046b0 0x7ff9596ed20d
[0x6] ucrtbased!heap_alloc_dbg+0x4d 0x4212604750 0x7ff9596f037f
[0x7] ucrtbased!_malloc_dbg+0x2f 0x42126047a0 0x7ff9596f0dee
[0x8] ucrtbased!malloc+0x1e 0x42126047d0 0x7ff730fcc1ef
[0x9] git!do_xmalloc+0x2f 0x4212604800 0x7ff730fcc2b9
[0xa] git!do_xmallocz+0x59 0x4212604840 0x7ff730fca779
[0xb] git!xmallocz_gently+0x19 0x4212604880 0x7ff7311b0883
[0xc] git!unpack_compressed_entry+0x43 0x42126048b0 0x7ff7311ac9a4
[0xd] git!unpack_entry+0x554 0x42126049a0 0x7ff7311b0628
[0xe] git!cache_or_unpack_entry+0x58 0x4212605250 0x7ff7311ad3a8
[0xf] git!packed_object_info+0x98 0x42126052a0 0x7ff7310a92da
[0x10] git!do_oid_object_info_extended+0x3fa 0x42126053b0 0x7ff7310a44e7
[0x11] git!oid_object_info_extended+0x37 0x4212605460 0x7ff7310a38ba
[0x12] git!repo_read_object_file+0x9a 0x42126054a0 0x7ff7310a6147
[0x13] git!read_object_with_reference+0x97 0x4212605560 0x7ff7310b4656
[0x14] git!fill_tree_descriptor+0x66 0x4212605620 0x7ff7310dc0a5
[0x15] git!traverse_trees_recursive+0x3f5 0x4212605680 0x7ff7310dd831
[0x16] git!unpack_callback+0x441 0x4212605790 0x7ff7310b4c95
[0x17] git!traverse_trees+0x5d5 0x42126058a0 0x7ff7310dc0f2
[0x18] git!traverse_trees_recursive+0x442 0x4212605980 0x7ff7310dd831
[0x19] git!unpack_callback+0x441 0x4212605a90 0x7ff7310b4c95
[0x1a] git!traverse_trees+0x5d5 0x4212605ba0 0x7ff7310dc0f2
[0x1b] git!traverse_trees_recursive+0x442 0x4212605c80 0x7ff7310dd831
[0x1c] git!unpack_callback+0x441 0x4212605d90 0x7ff7310b4c95
[0x1d] git!traverse_trees+0x5d5 0x4212605ea0 0x7ff7310dc0f2
[0x1e] git!traverse_trees_recursive+0x442 0x4212605f80 0x7ff7310dd831
[0x1f] git!unpack_callback+0x441 0x4212606090 0x7ff7310b4c95
[0x20] git!traverse_trees+0x5d5 0x42126061a0 0x7ff7310dc0f2
[0x21] git!traverse_trees_recursive+0x442 0x4212606280 0x7ff7310dd831
[...]
[0xfad] git!cmd_main+0x2a2 0x42126ff740 0x7ff730fb6345
[0xfae] git!main+0xe5 0x42126ff7c0 0x7ff730fbff93
[0xfaf] git!wmain+0x2a3 0x42126ff830 0x7ff731318859
[0xfb0] git!invoke_main+0x39 0x42126ff8a0 0x7ff7313186fe
[0xfb1] git!__scrt_common_main_seh+0x12e 0x42126ff8f0 0x7ff7313185be
[0xfb2] git!__scrt_common_main+0xe 0x42126ff960 0x7ff7313188ee
[0xfb3] git!wmainCRTStartup+0xe 0x42126ff990 0x7ff9d5ed257d
[0xfb4] KERNEL32!BaseThreadInitThunk+0x1d 0x42126ff9c0 0x7ff9d6d6aa78
[0xfb5] ntdll!RtlUserThreadStart+0x28 0x42126ff9f0 0x0
I verified manually that `traverse_trees_cur_depth` was 562 when that
happened, which is far below the 2048 that were already accepted into
Git as a hard limit.
Despite many attempts to figure out which of the internals trigger this
`STATUS_STACK_OVERFLOW` and how to maybe increase certain sizes to avoid
running into this issue and let Git behave the same way as under Linux,
I failed to find any build-time/runtime knob we could turn to that
effect.
Note: even switching to using a different allocator (I used mimalloc
because that's what Git for Windows uses for its GCC builds) does not
help, as the zlib code used to unpack compressed pack entries _still_
uses the regular `malloc()`. And runs into the same issue.
Note also: switching to using a different allocator _also_ for zlib code
seems _also_ not to help. I tried that, and it still exited with
`STATUS_STACK_OVERFLOW` that seems to have been triggered by a
`mi_assert_internal()`, i.e. an internal assertion of mimalloc...
So the best bet to work around this for now seems to just lower the
maximum allowed tree depth _even further_ for MSVC builds.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On my Linux system, all of our recursive tree walking algorithms can run
up to the 4096 default limit without segfaulting. But not all platforms
will have stack sizes as generous (nor might even Linux if we kick off a
recursive walk within a thread).
In particular, several of the tests added in the previous few commits
fail in our Windows CI environment. Through some guess-and-check
pushing, I found that 3072 is still too much, but 2048 is OK.
These are obviously vague heuristics, and there is nothing to promise
that another system might not have trouble at even lower values. But it
seems unlikely anybody will be too angry about a 2048-depth limit (this
is close to the default max-pathname limit on Linux even for a
pathological path like "a/a/a/..."). So let's just lower it.
Some alternatives are:
- configure separate defaults for Windows versus other platforms.
- just skip the tests on Windows. This leaves Windows users with the
annoying case that they can be crashed by running out of stack
space, but there shouldn't be any security implications (they can't
go deep enough to hit integer overflow problems).
Since the original default was arbitrary, it seems less confusing to
just lower it, keeping behavior consistent across platforms.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most of our tree traversal algorithms use recursion to visit sub-trees.
For pathologically large trees, this can cause us to run out of stack
space and abort in an uncontrolled way. Let's put our own limit here so
that we can fail gracefully rather than segfaulting.
In similar cases where we recursed along the commit graph, we rewrote
the algorithms to avoid recursion and keep any stack data on the heap.
But the commit graph is meant to grow without bound, whereas it's not an
imposition to put a limit on the maximum size of tree we'll handle.
And this has a bonus side effect: coupled with a limit on individual
tree entry names, this limits the total size of a path we may encounter.
This gives us an extra protection against code handling long path names
which may suffer from integer overflows in the size (which could then be
exploited by malicious trees).
The default of 4096 is set to be much longer than anybody would care
about in the real world. Even with single-letter interior tree names
(like "a/b/c"), such a path is at least 8191 bytes. While most operating
systems will let you create such a path incrementally, trying to
reference the whole thing in a system call (as Git would do when
actually trying to access it) will result in ENAMETOOLONG. Coupled with
the recent fsck.largePathname warning, the maximum total pathname Git
will handle is (by default) 16MB.
This config option doesn't do anything yet; future patches will convert
various algorithms to respect the limit.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 99fb6e04cb (pack-objects: convert to use parse_options(),
2012-02-01) git pack-objects has accepted --no-keep-true-parents, but
this option does the same as --keep-true-parents. That's because it's
defined using OPT_SET_INT with a value of 0, which sets 0 when negated
as well.
Turn --no-keep-true-parents into the opposite of --keep-true-parents by
using OPT_BOOL and storing the option's status directly in a variable
named "grafts_keep_true_parents" instead of in negative form in
"grafts_replace_parents".
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Header files cleanup.
* en/header-split-cache-h-part-3: (28 commits)
fsmonitor-ll.h: split this header out of fsmonitor.h
hash-ll, hashmap: move oidhash() to hash-ll
object-store-ll.h: split this header out of object-store.h
khash: name the structs that khash declares
merge-ll: rename from ll-merge
git-compat-util.h: remove unneccessary include of wildmatch.h
builtin.h: remove unneccessary includes
list-objects-filter-options.h: remove unneccessary include
diff.h: remove unnecessary include of oidset.h
repository: remove unnecessary include of path.h
log-tree: replace include of revision.h with simple forward declaration
cache.h: remove this no-longer-used header
read-cache*.h: move declarations for read-cache.c functions from cache.h
repository.h: move declaration of the_index from cache.h
merge.h: move declarations for merge.c from cache.h
diff.h: move declaration for global in diff.c from cache.h
preload-index.h: move declarations for preload-index.c from elsewhere
sparse-index.h: move declarations for sparse-index.c from cache.h
name-hash.h: move declarations for name-hash.c from cache.h
run-command.h: move declarations for run-command.c from cache.h
...
Introduce a mechanism to disable replace refs globally and per
repository.
* ds/disable-replace-refs:
repository: create read_replace_refs setting
replace-objects: create wrapper around setting
repository: create disable_replace_refs()
The vast majority of files including object-store.h did not need dir.h
nor khash.h. Split the header into two files, and let most just depend
upon object-store-ll.h, while letting the two callers that need it
depend on the full object-store.h.
After this patch:
$ git grep -h include..object-store | sort | uniq -c
2 #include "object-store.h"
129 #include "object-store-ll.h"
Diff best viewed with `--color-moved`.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This also made it clear that several .c files that depended upon path.h
were missing a #include for it; add the missing includes while at it.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since this header showed up in some places besides just #include
statements, update/clean-up/remove those other places as well.
Note that compat/fsmonitor/fsm-path-utils-darwin.c previously got
away with violating the rule that all files must start with an include
of git-compat-util.h (or a short-list of alternate headers that happen
to include it first). This change exposed the violation and caused it
to stop building correctly; fix it by having it include
git-compat-util.h first, as per policy.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'read_replace_refs' global specifies whether or not we should
respect the references of the form 'refs/replace/<oid>' to replace which
object we look up when asking for '<oid>'. This global has caused issues
when it is not initialized properly, such as in b6551feadf (merge-tree:
load default git config, 2023-05-10).
To make this more robust, move its config-based initialization out of
git_default_config and into prepare_repo_settings(). This provides a
repository-scoped version of the 'read_replace_refs' global.
The global still has its purpose: it is disabled process-wide by the
GIT_NO_REPLACE_OBJECTS environment variable or by a call to
disable_replace_refs() in some specific Git commands.
Since we already encapsulated the use of the constant inside
replace_refs_enabled(), we can perform the initialization inside that
method, if necessary. This solves the problem of forgetting to check the
config, as we will check it before returning this value.
Due to this encapsulation, the global can move to be static within
replace-object.c.
There is an interesting behavior change possible here: we now have a
repository-scoped understanding of this config value. Thus, if there was
a command that recurses into submodules and might follow replace refs,
then it would now respect the core.useReplaceRefs config value in each
repository.
'git grep --recurse-submodules' is such a command that recurses into
submodules in-process. We can demonstrate the granularity of this config
value via a test in t7814.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Several builtins depend on being able to disable the replace references
so we actually operate on each object individually. These currently do
so by directly mutating the 'read_replace_refs' global.
A future change will move this global into a different place, so it will
be necessary to change all of these lines. However, we can simplify that
transition by abstracting the purpose of these global assignments with a
method call.
We will need to keep this read_replace_refs global forever, as we want
to make sure that we never use replace refs throughout the life of the
process if this method is called. Future changes may present a
repository-scoped version of the variable to represent that repository's
core.useReplaceRefs config value, but a zero-valued read_replace_refs
will always override such a setting.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move 'repository_format_worktree_config' out of the global scope and into
the 'repository' struct. This change is similar to how
'repository_format_partial_clone' was moved in ebaf3bcf1a (repository: move
global r_f_p_c to repo struct, 2021-06-17), adding it to the 'repository'
struct and updating 'setup.c' & 'repository.c' functions to assign the value
appropriately.
The primary goal of this change is to be able to load the worktree config of
a submodule depending on whether that submodule - not its superproject - has
'extensions.worktreeConfig' enabled. To ensure 'do_git_config_sequence()'
has access to the newly repo-scoped configuration, add a 'struct repository'
argument to 'do_git_config_sequence()' and pass it the 'repo' value from
'config_with_options()'.
Finally, add/update tests in 't3007-ls-files-recurse-submodules.sh' to
verify 'extensions.worktreeConfig' is read an used independently by
superprojects and submodules.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Dozens of files made use of trace and trace2 functions, without
explicitly including trace.h or trace2.h. This made it more difficult
to find which files could remove a dependence on cache.h. Make C files
explicitly include trace.h or trace2.h if they are using them.
Signed-off-by: Elijah Newren <newren@gmail.com>
Acked-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is another step towards letting us remove the include of cache.h in
strbuf.c. It does mean that we also need to add includes of abspath.h
in a number of C files.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Dozens of files made use of gettext functions, without explicitly
including gettext.h. This made it more difficult to find which files
could remove a dependence on cache.h. Make C files explicitly include
gettext.h if they are using it.
However, while compat/fsmonitor/fsm-ipc-darwin.c should also gain an
include of gettext.h, it was left out to avoid conflicting with an
in-flight topic.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Adjust several files to be more explicit about their dependency on
replace-objects to accommodate this change.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "--super-prefix" option to "git" was initially added in [1] for
use with "ls-files"[2], and shortly thereafter "submodule--helper"[3]
and "grep"[4]. It wasn't until [5] that "read-tree" made use of it.
At the time [5] made sense, but since then we've made "ls-files"
recurse in-process in [6], "grep" in [7], and finally
"submodule--helper" in the preceding commits.
Let's also remove it from "read-tree", which allows us to remove the
option to "git" itself.
We can do this because the only remaining user of it is the submodule
API, which will now invoke "read-tree" with its new "--super-prefix"
option. It will only do so when the "submodule_move_head()" function
is called.
That "submodule_move_head()" function was then only invoked by
"read-tree" itself, but now rather than setting an environment
variable to pass "--super-prefix" between cmd_read_tree() we:
- Set a new "super_prefix" in "struct unpack_trees_options". The
"super_prefixed()" function in "unpack-trees.c" added in [5] will now
use this, rather than get_super_prefix() looking up the environment
variable we set earlier in the same process.
- Add the same field to the "struct checkout", which is only needed to
ferry the "super_prefix" in the "struct unpack_trees_options" all the
way down to the "entry.c" callers of "submodule_move_head()".
Those calls which used the super prefix all originated in
"cmd_read_tree()". The only other caller is the "unlink_entry()"
caller in "builtin/checkout.c", which now passes a "NULL".
1. 74866d7579 (git: make super-prefix option, 2016-10-07)
2. e77aa336f1 (ls-files: optionally recurse into submodules, 2016-10-07)
3. 89c8626557 (submodule helper: support super prefix, 2016-12-08)
4. 0281e487fd (grep: optionally recurse into submodules, 2016-12-16)
5. 3d415425c7 (unpack-trees: support super-prefix option, 2017-01-17)
6. 188dce131f (ls-files: use repository object, 2017-06-22)
7. f9ee2fcdfa (grep: recurse in-process using 'struct repository', 2017-08-02)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Undoes 'jk/unused-annotation' topic and redoes it to work around
Coccinelle rules misfiring false positives in unrelated codepaths.
* ab/unused-annotation:
git-compat-util.h: use "deprecated" for UNUSED variables
git-compat-util.h: use "UNUSED", not "UNUSED(var)"
Annotate function parameters that are not used (but cannot be
removed for structural reasons), to prepare us to later compile
with -Wunused warning turned on.
* jk/unused-annotation:
is_path_owned_by_current_uid(): mark "report" parameter as unused
run-command: mark unused async callback parameters
mark unused read_tree_recursive() callback parameters
hashmap: mark unused callback parameters
config: mark unused callback parameters
streaming: mark unused virtual method parameters
transport: mark bundle transport_options as unused
refs: mark unused virtual method parameters
refs: mark unused reflog callback parameters
refs: mark unused each_ref_fn parameters
git-compat-util: add UNUSED macro
As reported in [1] the "UNUSED(var)" macro introduced in
2174b8c75d (Merge branch 'jk/unused-annotation' into next,
2022-08-24) breaks coccinelle's parsing of our sources in files where
it occurs.
Let's instead partially go with the approach suggested in [2] of
making this not take an argument. As noted in [1] "coccinelle" will
ignore such tokens in argument lists that it doesn't know about, and
it's less of a surprise to syntax highlighters.
This undoes the "help us notice when a parameter marked as unused is
actually use" part of 9b24034754 (git-compat-util: add UNUSED macro,
2022-08-19), a subsequent commit will further tweak the macro to
implement a replacement for that functionality.
1. https://lore.kernel.org/git/220825.86ilmg4mil.gmgdl@evledraar.gmail.com/
2. https://lore.kernel.org/git/220819.868rnk54ju.gmgdl@evledraar.gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Hashmap comparison functions must conform to a particular callback
interface, but many don't use all of their parameters. Especially the
void cmp_data pointer, but some do not use keydata either (because they
can easily form a full struct to pass when doing lookups). Let's mark
these to make -Wunused-parameter happy.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The git_replace_ref_base global is used to store the value of the
GIT_REPLACE_REF_BASE environment variable or the default of
"refs/replace/". This is initialized within setup_git_env().
The ref_namespaces array is a new centralized location for information
such as the ref namespace used for replace refs. Instead of having this
namespace stored in two places, use the ref_namespaces array instead.
For simplicity, create a local git_replace_ref_base variable wherever
the global was previously used.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git interprets different meanings to different refs based on their
names. Some meanings are cosmetic, like how refs in 'refs/remotes/*'
are colored differently from refs in 'refs/heads/*'. Others are more
critical, such as how replace refs are interpreted.
Before making behavior changes based on ref namespaces, collect all
known ref namespaces into a array of ref_namespace_info structs. This
array is indexed by the new ref_namespace enum for quick access.
As of this change, this array is purely documentation. Future changes
will add dependencies on this array.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The path taken by "git multi-pack-index" command from the end user
was compared with path internally prepared by the tool withut first
normalizing, which lead to duplicated paths not being noticed,
which has been corrected.
* ds/midx-normalize-pathname-before-comparison:
cache: use const char * for get_object_directory()
multi-pack-index: use --object-dir real path
midx: use real paths in lookup_multi_pack_index()
The get_object_directory() method returns the exact string stored at
the_repository->objects->odb->path. The return type of "char *" implies
that the caller must keep track of the buffer and free() it when
complete. This causes significant problems later when the ODB is
accessed.
Use "const char *" as the return type to avoid this confusion. There are
no current callers that care about the non-const definition.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Built-in fsmonitor (part 2).
* jh/builtin-fsmonitor-part2: (30 commits)
t7527: test status with untracked-cache and fsmonitor--daemon
fsmonitor: force update index after large responses
fsmonitor--daemon: use a cookie file to sync with file system
fsmonitor--daemon: periodically truncate list of modified files
t/perf/p7519: add fsmonitor--daemon test cases
t/perf/p7519: speed up test on Windows
t/perf/p7519: fix coding style
t/helper/test-chmtime: skip directories on Windows
t/perf: avoid copying builtin fsmonitor files into test repo
t7527: create test for fsmonitor--daemon
t/helper/fsmonitor-client: create IPC client to talk to FSMonitor Daemon
help: include fsmonitor--daemon feature flag in version info
fsmonitor--daemon: implement handle_client callback
compat/fsmonitor/fsm-listen-darwin: implement FSEvent listener on MacOS
compat/fsmonitor/fsm-listen-darwin: add MacOS header files for FSEvent
compat/fsmonitor/fsm-listen-win32: implement FSMonitor backend on Windows
fsmonitor--daemon: create token-based changed path cache
fsmonitor--daemon: define token-ids
fsmonitor--daemon: add pathname classification
fsmonitor--daemon: implement 'start' command
...
Replace core.fsyncObjectFiles with two new configuration variables,
core.fsync and core.fsyncMethod.
* ns/core-fsyncmethod:
core.fsync: documentation and user-friendly aggregate options
core.fsync: new option to harden the index
core.fsync: add configuration parsing
core.fsync: introduce granular fsync control infrastructure
core.fsyncmethod: add writeout-only mode
wrapper: make inclusion of Windows csprng header tightly scoped
Move fsmonitor config settings to a new and opaque
`struct fsmonitor_settings` structure. Add a lazily-loaded pointer
to this into `struct repo_settings`
Create an `enum fsmonitor_mode` type in `struct fsmonitor_settings` to
represent the state of fsmonitor. This lets us represent which, if
any, fsmonitor provider (hook or IPC) is enabled.
Create `fsm_settings__get_*()` getters to lazily look up fsmonitor-
related config settings.
Get rid of the `core_fsmonitor` global variable. Move the code to
lookup the existing `core.fsmonitor` config value into the fsmonitor
settings.
Create a hook pathname variable in `struct fsmonitor-settings` and
only set it when in hook mode.
Extend the definition of `core.fsmonitor` to be either a boolean
or a hook pathname. When true, the builtin FSMonitor is used.
When false or unset, no FSMonitor (neither builtin nor hook) is
used.
The existing `core_fsmonitor` global variable was used to store the
pathname to the fsmonitor hook *and* it was used as a boolean to see
if fsmonitor was enabled. This dual usage and global visibility leads
to confusion when we add the IPC-based provider. So lets hide the
details in fsmonitor-settings.c and let it decide which provider to
use in the case of multiple settings. This avoids cluttering up
repo-settings.c with these private details.
A future commit in builtin-fsmonitor series will add the ability to
disqualify worktrees for various reasons, such as being mounted from a
remote volume, where fsmonitor should not be started. Having the
config settings hidden in fsmonitor-settings.c allows such worktree
restrictions to override the config values used.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This change introduces code to parse the core.fsync setting and
configure the fsync_components variable.
core.fsync is configured as a comma-separated list of component names to
sync. Each time a core.fsync variable is encountered in the
configuration heirarchy, we start off with a clean state with the
platform default value. Passing 'none' resets the value to indicate
nothing will be synced. We gather all negative and positive entries from
the comma separated list and then compute the new value by removing all
the negative entries and adding all of the positive entries.
We issue a warning for components that are not recognized so that the
configuration code is compatible with configs from future versions of
Git with more repo components.
Complete documentation for the new setting is included in a later patch
in the series so that it can be reviewed once in final form.
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit introduces the infrastructure for the core.fsync
configuration knob. The repository components we want to sync
are identified by flags so that we can turn on or off syncing
for specific components.
If core.fsyncObjectFiles is set and the core.fsync configuration
also includes FSYNC_COMPONENT_LOOSE_OBJECT, we will fsync any
loose objects. This picks the strictest data integrity behavior
if core.fsync and core.fsyncObjectFiles are set to conflicting values.
This change introduces the currently unused fsync_component
helper, which will be used by a later patch that adds fsyncing to
the refs backend.
Actual configuration and documentation of the fsync components
list are in other patches in the series to separate review of
the underlying mechanism from the policy of how it's configured.
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit introduces the `core.fsyncMethod` configuration
knob, which can currently be set to `fsync` or `writeout-only`.
The new writeout-only mode attempts to tell the operating system to
flush its in-memory page cache to the storage hardware without issuing a
CACHE_FLUSH command to the storage controller.
Writeout-only fsync is significantly faster than a vanilla fsync on
common hardware, since data is written to a disk-side cache rather than
all the way to a durable medium. Later changes in this patch series will
take advantage of this primitive to implement batching of hardware
flushes.
When git_fsync is called with FSYNC_WRITEOUT_ONLY, it may fail and the
caller is expected to do an ordinary fsync as needed.
On Apple platforms, the fsync system call does not issue a CACHE_FLUSH
directive to the storage controller. This change updates fsync to do
fcntl(F_FULLFSYNC) to make fsync actually durable. We maintain parity
with existing behavior on Apple platforms by setting the default value
of the new core.fsyncMethod option.
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Typically with sparse checkouts, we expect files outside the sparsity
patterns to be marked as SKIP_WORKTREE and be missing from the working
tree. Sometimes this expectation would be violated however; including
in cases such as:
* users grabbing files from elsewhere and writing them to the worktree
(perhaps by editing a cached copy in an editor, copying/renaming, or
even untarring)
* various git commands having incomplete or no support for the
SKIP_WORKTREE bit[1,2]
* users attempting to "abort" a sparse-checkout operation with a
not-so-early Ctrl+C (updating $GIT_DIR/info/sparse-checkout and the
working tree is not atomic)[3].
When the SKIP_WORKTREE bit in the index did not reflect the presence of
the file in the working tree, it traditionally caused confusion and was
difficult to detect and recover from. So, in a sparse checkout, since
af6a51875a (repo_read_index: clear SKIP_WORKTREE bit from files present
in worktree, 2022-01-14), Git automatically clears the SKIP_WORKTREE
bit at index read time for entries corresponding to files that are
present in the working tree.
There is another workflow, however, where it is expected that paths
outside the sparsity patterns appear to exist in the working tree and
that they do not lose the SKIP_WORKTREE bit, at least until they get
modified. A Git-aware virtual file system[4] takes advantage of its
position as a file system driver to expose all files in the working
tree, fetch them on demand using partial clone on access, and tell Git
to pay attention to them on demand by updating the sparse checkout
pattern on writes. This means that commands like "git status" only have
to examine files that have potentially been modified, whereas commands
like "ls" are able to show the entire codebase without requiring manual
updates to the sparse checkout pattern.
Thus since af6a51875a, Git with such Git-aware virtual file systems
unsets the SKIP_WORKTREE bit for all files and commands like "git
status" have to fetch and examine them all.
Introduce a configuration setting sparse.expectFilesOutsideOfPatterns to
allow limiting the tracked set of files to a small set once again. A
Git-aware virtual file system or other application that wants to
maintain files outside of the sparse checkout can set this in a
repository to instruct Git not to check for the presence of
SKIP_WORKTREE files. The setting defaults to false, so most users of
sparse checkout will still get the benefit of an automatically updating
index to recover from the variety of difficult issues detailed in
af6a51875a for paths with SKIP_WORKTREE set despite the path being
present.
[1] https://lore.kernel.org/git/xmqqbmb1a7ga.fsf@gitster-ct.c.googlers.com/
[2] The three long paragraphs in the middle of
https://lore.kernel.org/git/CABPp-BH9tju7WVm=QZDOvaMDdZbpNXrVWQdN-jmfN8wC6YVhmw@mail.gmail.com/
[3] https://lore.kernel.org/git/CABPp-BFnFpzwGC11TLoLs8YK5yiisA5D5-fFjXnJsbESVDwZsA@mail.gmail.com/
[4] such as the vfsd described in
https://lore.kernel.org/git/20220207190320.2960362-1-jonathantanmy@google.com/
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
New interface into the tmp-objdir API to help in-core use of the
quarantine feature.
* ns/tmp-objdir:
tmp-objdir: disable ref updates when replacing the primary odb
tmp-objdir: new API for creating temporary writable databases
When creating a subprocess with a temporary ODB, we set the
GIT_QUARANTINE_ENVIRONMENT env var to tell child Git processes not
to update refs, since the tmp-objdir may go away.
Introduce a similar mechanism for in-process temporary ODBs when
we call tmp_objdir_replace_primary_odb. Now both mechanisms set
the disable_ref_updates flag on the odb, which is queried by
the ref_transaction_prepare function.
Peff's test case [1] was invoking ref updates via the cachetextconv
setting. That particular code silently does nothing when a ref
update is forbidden. See the call to notes_cache_put in
fill_textconv where errors are ignored.
[1] https://lore.kernel.org/git/YVOn3hDsb5pnxR53@coredump.intra.peff.net/
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The tmp_objdir API provides the ability to create temporary object
directories, but was designed with the goal of having subprocesses
access these object stores, followed by the main process migrating
objects from it to the main object store or just deleting it. The
subprocesses would view it as their primary datastore and write to it.
Here we add the tmp_objdir_replace_primary_odb function that replaces
the current process's writable "main" object directory with the
specified one. The previous main object directory is restored in either
tmp_objdir_migrate or tmp_objdir_destroy.
For the --remerge-diff usecase, add a new `will_destroy` flag in `struct
object_database` to mark ephemeral object databases that do not require
fsync durability.
Add 'git prune' support for removing temporary object databases, and
make sure that they have a name starting with tmp_ and containing an
operation-specific name.
Based-on-patch-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "GIT_TEST_FSYNC" environment variable now exists for
disabling fsync() even on packfiles and other "critical" data.
Running "make test -j8 NO_SVN_TESTS=1" on a noisy 8-core system
on an HDD, test runtime drops from ~4 minutes down to ~3 minutes.
Using "GIT_TEST_FSYNC=1" re-enables fsync() for comparison
purposes.
SVN interopability tests are minimally affected since SVN will
still use fsync in various places.
This will also be useful for 3rd-party tools which create
throwaway git repositories of temporary data, but remains
undocumented for end users.
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The ref iteration code used to optionally allow dangling refs to be
shown, which has been tightened up.
* jk/ref-paranoia:
refs: drop "broken" flag from for_each_fullref_in()
ref-filter: drop broken-ref code entirely
ref-filter: stop setting FILTER_REFS_INCLUDE_BROKEN
repack, prune: drop GIT_REF_PARANOIA settings
refs: turn on GIT_REF_PARANOIA by default
refs: omit dangling symrefs when using GIT_REF_PARANOIA
refs: add DO_FOR_EACH_OMIT_DANGLING_SYMREFS flag
refs-internal.h: reorganize DO_FOR_EACH_* flag documentation
refs-internal.h: move DO_FOR_EACH_* flags next to each other
t5312: be more assertive about command failure
t5312: test non-destructive repack
t5312: create bogus ref as necessary
t5312: drop "verbose" helper
t5600: provide detached HEAD for corruption failures
t5516: don't use HEAD ref for invalid ref-deletion tests
t7900: clean up some more broken refs
Code cleanup.
* ab/repo-settings-cleanup:
repository.h: don't use a mix of int and bitfields
repo-settings.c: simplify the setup
read-cache & fetch-negotiator: check "enum" values in switch()
environment.c: remove test-specific "ignore_untracked..." variable
wrapper.c: add x{un,}setenv(), and use xsetenv() in environment.c
Now that GIT_REF_PARANOIA is the default, we don't need to selectively
enable it for destructive operations. In fact, it's harmful to do so,
because it overrides any GIT_REF_PARANOIA=0 setting that the user may
have provided (because they're trying to work around some corruption).
With these uses gone, we can further clean up the ref_paranoia global,
and make it a static variable inside the refs code.
Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
