Граф коммитов

458 Коммитов

Автор SHA1 Сообщение Дата
Junio C Hamano 030faf2fa5 Merge branch 'kw/write-index-reduce-alloc'
We used to spend more than necessary cycles allocating and freeing
piece of memory while writing each index entry out.  This has been
optimized.

* kw/write-index-reduce-alloc:
  read-cache: avoid allocating every ondisk entry when writing
  read-cache: fix memory leak in do_write_index
  perf: add test for writing the index
2017-08-26 22:55:08 -07:00
Kevin Willford ce012deb98 read-cache: avoid allocating every ondisk entry when writing
When writing the index for each entry an ondisk struct will be
allocated and freed in ce_write_entry.  We can do better by
using a ondisk struct on the stack for each entry.

This is accomplished by using a stack ondisk_cache_entry_extended
outside looping through the entries in do_write_index.  Only the
fixed fields of this struct are used when writing and depending on
whether it is extended or not the flags2 field will be written.
The name field is not used and instead the cache_entry name field
is used directly when writing out the name.  Because ce_write is
using a buffer and memcpy to fill the buffer before flushing to disk,
we don't have to worry about doing multiple ce_write calls.

Running the p0007-write-cache.sh tests would save anywhere
between 3-7% when the index had over a million entries with no
performance degradation on small repos.

Signed-off-by: Kevin Willford <kewillf@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-21 16:02:59 -07:00
Kevin Willford b50386c7c0 read-cache: fix memory leak in do_write_index
The previous_name_buf was never getting released when there
was an error in ce_write_entry or allow was false and execution
was returned to the caller.

Signed-off-by: Kevin Willford <kewillf@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-21 15:57:02 -07:00
Patryk Obara e3506559d4 sha1_file: convert index_fd to struct object_id
Convert all remaining callers as well.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-20 21:52:08 -07:00
Patryk Obara 98e019b067 sha1_file: convert index_path to struct object_id
Convert all remaining callers as well.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-20 21:51:38 -07:00
Patryk Obara bebfecb94c read-cache: convert to struct object_id
Replace hashcmp with oidcmp.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-20 21:51:08 -07:00
René Scharfe f331ab9d4c use MOVE_ARRAY
Simplify the code for moving members inside of an array and make it more
robust by using the helper macro MOVE_ARRAY.  It calculates the size
based on the specified number of elements for us and supports NULL
pointers when that number is zero.  Raw memmove(3) calls with NULL can
cause the compiler to (over-eagerly) optimize out later NULL checks.

This patch was generated with contrib/coccinelle/array.cocci and spatch
(Coccinelle).

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-17 14:54:56 -07:00
Junio C Hamano 8e90578ffb Merge branch 'cc/shared-index-permfix'
The split index code did not honor core.sharedrepository setting
correctly.

* cc/shared-index-permfix:
  t1700: make sure split-index respects core.sharedrepository
  t1301: move modebits() to test-lib-functions.sh
  read-cache: use shared perms when writing shared index
2017-07-05 13:32:57 -07:00
Christian Couder df801f3f9f read-cache: use shared perms when writing shared index
Since f6ecc62dbf (write_shared_index(): use tempfile module, 2015-08-10)
write_shared_index() has been using mks_tempfile() to create the
temporary file that will become the shared index.

But even before that, it looks like the functions used to create this
file didn't call adjust_shared_perm(), which means that the shared
index file has always been created with 600 permissions regardless
of the shared permission settings.

Because of that, on repositories created with `git init --shared=all`
and using the split index feature, one gets an error like:

fatal: .git/sharedindex.a52f910b489bc462f187ab572ba0086f7b5157de: index file open failed: Permission denied

when another user performs any operation that reads the shared index.

Call adjust_shared_perm() on the temporary file created by
mks_tempfile() ourselves to adjust the permission bits.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-25 10:42:52 -07:00
Junio C Hamano 50f03c6676 Merge branch 'ab/free-and-null'
A common pattern to free a piece of memory and assign NULL to the
pointer that used to point at it has been replaced with a new
FREE_AND_NULL() macro.

* ab/free-and-null:
  *.[ch] refactoring: make use of the FREE_AND_NULL() macro
  coccinelle: make use of the "expression" FREE_AND_NULL() rule
  coccinelle: add a rule to make "expression" code use FREE_AND_NULL()
  coccinelle: make use of the "type" FREE_AND_NULL() rule
  coccinelle: add a rule to make "type" code use FREE_AND_NULL()
  git-compat-util: add a FREE_AND_NULL() wrapper around free(ptr); ptr = NULL
2017-06-24 14:28:41 -07:00
Junio C Hamano f31d23a399 Merge branch 'bw/config-h'
Fix configuration codepath to pay proper attention to commondir
that is used in multi-worktree situation, and isolate config API
into its own header file.

* bw/config-h:
  config: don't implicitly use gitdir or commondir
  config: respect commondir
  setup: teach discover_git_directory to respect the commondir
  config: don't include config.h by default
  config: remove git_config_iter
  config: create config.h
2017-06-24 14:28:41 -07:00
Junio C Hamano 6ba4d62ba8 Merge branch 'nd/split-index-unshare'
* nd/split-index-unshare:
  Revert "split-index: add and use unshare_split_index()"
2017-06-24 12:04:25 -07:00
Junio C Hamano 64719b115d Revert "split-index: add and use unshare_split_index()"
This reverts commit f9d7abec2ad2f9eb3d8873169cc28c34273df082;
see public-inbox.org/git/CAP8UFD0bOfzY-_hBDKddOcJdPUpP2KEVaX_SrCgvAMYAHtseiQ@mail.gmail.com
2017-06-24 12:02:39 -07:00
Ævar Arnfjörð Bjarmason 6a83d90207 coccinelle: make use of the "type" FREE_AND_NULL() rule
Apply the result of the just-added coccinelle rule. This manually
excludes a few occurrences, mostly things that resulted in many
FREE_AND_NULL() on one line, that'll be manually fixed in a subsequent
change.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-16 12:44:03 -07:00
Brandon Williams b2141fc1d2 config: don't include config.h by default
Stop including config.h by default in cache.h.  Instead only include
config.h in those files which require use of the config system.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-15 12:56:22 -07:00
Junio C Hamano f24e079cb6 Merge branch 'jh/close-index-before-stat' into maint
The timestamp of the index file is now taken after the file is
closed, to help Windows, on which a stale timestamp is reported by
fstat() on a file that is opened for writing and data was written
but not yet closed.

* jh/close-index-before-stat:
  read-cache: close index.lock in do_write_index
2017-06-13 13:27:02 -07:00
Junio C Hamano 70f8ba5524 Merge branch 'jh/close-index-before-stat'
The timestamp of the index file is now taken after the file is
closed, to help Windows, on which a stale timestamp is reported by
fstat() on a file that is opened for writing and data was written
but not yet closed.

* jh/close-index-before-stat:
  read-cache: close index.lock in do_write_index
2017-06-05 09:18:10 +09:00
Junio C Hamano fa0624f79f Merge branch 'dt/unpack-save-untracked-cache-extension'
When "git checkout", "git merge", etc. manipulates the in-core
index, various pieces of information in the index extensions are
discarded from the original state, as it is usually not the case
that they are kept up-to-date and in-sync with the operation on the
main index.  The untracked cache extension is copied across these
operations now, which would speed up "git status" (as long as the
cache is properly invalidated).

* dt/unpack-save-untracked-cache-extension:
  unpack-trees: preserve index extensions
2017-05-30 11:16:45 +09:00
Junio C Hamano f382b756a6 Merge branch 'nd/split-index-unshare'
Plug some leaks and updates internal API used to implement the
split index feature to make it easier to avoid such a leak in the
future.

* nd/split-index-unshare:
  p3400: add perf tests for rebasing many changes
  split-index: add and use unshare_split_index()
2017-05-29 12:34:43 +09:00
David Turner edf3b90553 unpack-trees: preserve index extensions
Make git checkout (and other unpack_tree operations) preserve the
untracked cache. This is valuable for two reasons:

1. Often, an unpack_tree operation will not touch large parts of the
working tree, and thus most of the untracked cache will continue to be
valid.

2. Even if the untracked cache were entirely invalidated by such an
operation, the user has signaled their intention to have such a cache,
and we don't want to throw it away.

[jes: backed out the watchman-specific parts]

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-20 18:26:45 +09:00
Junio C Hamano f767178a5a Merge branch 'jk/no-null-sha1-in-cache-tree'
Code to update the cache-tree has been tightened so that we won't
accidentally write out any 0{40} entry in the tree object.

* jk/no-null-sha1-in-cache-tree:
  cache-tree: reject entries with null sha1
2017-05-16 11:51:50 +09:00
Nguyễn Thái Ngọc Duy f9d7abec2a split-index: add and use unshare_split_index()
When split-index is being used, we have two cache_entry arrays in
index_state->cache[] and index_state->split_index->base->cache[].

index_state->cache[] may share the same entries with base->cache[] so
we can quickly determine what entries are shared. This makes memory
management tricky, we can't free base->cache[] until we know
index_state->cache[] does not point to any of those entries.

unshare_split_index() is added for this purpose, to find shared
entries and either duplicate them in index_state->cache[], or discard
them. Either way it should be safe to free base->cache[] after
unshare_split_index().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 10:50:20 +09:00
Peter Krefting 78bde923f1 i18n: read-cache: typofix
Signed-off-by: Peter Krefting <peter@softwolves.pp.se>
Signed-off-by: Jean-Noel Avila <jn.avila@free.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-01 11:08:02 +09:00
Jeff Hostetler 9f41c7a6b3 read-cache: close index.lock in do_write_index
Teach do_write_index() to close the index.lock file
before getting the mtime and updating the istate.timestamp
fields.

On Windows, a file's mtime is not updated until the file is
closed.  On Linux, the mtime is set after the last flush.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-28 12:40:24 +09:00
Junio C Hamano 3961c51699 Merge branch 'cc/split-index-config'
The split-index code configuration code used an unsafe git_path()
function without copying its result out.

* cc/split-index-config:
  read-cache: avoid using git_path() in freshen_shared_index()
2017-04-26 15:39:09 +09:00
Junio C Hamano 6cbc478d83 Merge branch 'jh/add-index-entry-optim'
"git checkout" that handles a lot of paths has been optimized by
reducing the number of unnecessary checks of paths in the
has_dir_name() function.

* jh/add-index-entry-optim:
  read-cache: speed up has_dir_name (part 2)
  read-cache: speed up has_dir_name (part 1)
  read-cache: speed up add_index_entry during checkout
  p0006-read-tree-checkout: perf test to time read-tree
  read-cache: add strcmp_offset function
2017-04-26 15:39:07 +09:00
Jeff King a96d3cc3f6 cache-tree: reject entries with null sha1
We generally disallow null sha1s from entering the index,
due to 4337b5856 (do not write null sha1s to on-disk index,
2012-07-28). However, we loosened that in 83bd7437c
(write_index: optionally allow broken null sha1s,
2013-08-27) so that tools like filter-branch could be used
to repair broken history.

However, we should make sure that these broken entries do
not get propagated into new trees. For most entries, we'd
catch them with the missing-object check (since presumably
the null sha1 does not exist in our object database). But
gitlink entries do not need reachability, so we may blindly
copy the entry into a bogus tree.

This patch rejects all null sha1s (with the same "invalid
entry" message that missing objects get) when building trees
from the index. It does so even for non-gitlinks, and even
when "write-tree" is given the --missing-ok flag. The null
sha1 is a special sentinel value that is already rejected in
trees by fsck; whether the object exists or not, it is an
error to put it in a tree.

Note that for this to work, we must also avoid reusing an
existing cache-tree that contains the null sha1. This patch
does so by just refusing to write out any cache tree when
the index contains a null sha1. This is blunter than we need
to be; we could just reject the subtree that contains the
offending entry. But it's not worth the complexity. The
behavior is unchanged unless you have a broken index entry,
and even then we'd refuse the whole index write unless the
emergency GIT_ALLOW_NULL_SHA1 is in use. And even then the
end result is only a performance drop (any write-tree will
have to generate the whole cache-tree from scratch).

The tests bear some explanation.

The existing test in t7009 doesn't catch this problem,
because our index-filter runs "git rm --cached", which will
try to rewrite the updated index and barf on the bogus
entry. So we never even make it to write-tree.  The new test
there adds a noop index-filter, which does show the problem.

The new tests in t1601 are slightly redundant with what
filter-branch is doing under the hood in t7009. But as
they're much more direct, they're easier to reason about.
And should filter-branch ever change or go away, we'd want
to make sure that these plumbing commands behave sanely.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-23 18:21:59 -07:00
Christian Couder ccef2bb5fa read-cache: avoid using git_path() in freshen_shared_index()
When performing an interactive rebase in split-index mode,
the commit message that one should rework when squashing commits
can contain some garbage instead of the usual concatenation of
both of the commit messages.

The code uses git_path() to compute the shared index filename, and
passes it to check_and_freshen_file() as its argument; there is no
guarantee that the rotating pathname buffer passed as argument will
stay valid during the life of this call.  Make our own copy before
calling the function and pass the copy as its argument to avoid this
risky pattern.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-20 20:57:26 -07:00
Jeff Hostetler b986df5c35 read-cache: speed up has_dir_name (part 2)
Teach has_dir_name() to see if the path of the new item
is greater than the last path in the index array before
attempting to search for it.

has_dir_name() is looking for file/directory collisions
in the index and has to consider each sub-directory
prefix in turn.  This can cause multiple binary searches
for each path.

During operations like checkout, merge_working_tree()
populates the new index in sorted order, so we expect
to be able to append in many cases.

This commit is part 2 of 2.  This commit handles the
additional possible short-cuts as we look at each
sub-directory prefix.

The net-net gains for add_index_entry_with_check() and
both had_dir_name() commits are best seen for very
large repos.

Here are results for an INFLATED version of linux.git
with 1M files.

$ GIT_PERF_REPO=/mnt/test/linux_inflated.git/ ./run upstream/base HEAD ./p0006-read-tree-checkout.sh
Test                                                            upstream/base      HEAD
0006.2: read-tree br_base br_ballast (1043893)                  3.79(3.63+0.15)    2.68(2.52+0.15) -29.3%
0006.3: switch between br_base br_ballast (1043893)             7.55(6.58+0.44)    6.03(4.60+0.43) -20.1%
0006.4: switch between br_ballast br_ballast_plus_1 (1043893)   10.84(9.26+0.59)   8.44(7.06+0.65) -22.1%
0006.5: switch between aliases (1043893)                        10.93(9.39+0.58)   10.24(7.04+0.63) -6.3%

Here are results for a synthetic repo with 4.2M files.

$ GIT_PERF_REPO=~/work/gfw/t/perf/repos/gen-many-files-10.4.3.git/ ./run HEAD~3 HEAD ./p0006-read-tree-checkout.sh
Test                                                            HEAD~3               HEAD
0006.2: read-tree br_base br_ballast (4194305)                  29.96(19.26+10.50)   23.76(13.42+10.12) -20.7%
0006.3: switch between br_base br_ballast (4194305)             56.95(36.08+16.83)   45.54(25.94+15.68) -20.0%
0006.4: switch between br_ballast br_ballast_plus_1 (4194305)   90.94(51.50+31.52)   78.22(39.39+30.70) -14.0%
0006.5: switch between aliases (4194305)                        93.72(51.63+34.09)   77.94(39.00+30.88) -16.8%

Results for medium repos (like linux.git) are mixed and have
more variance (probably do to disk IO unrelated to this test.

$ GIT_PERF_REPO=/mnt/test/linux.git/ ./run HEAD~3 HEAD ./p0006-read-tree-checkout.sh
Test                                                          HEAD~3             HEAD
0006.2: read-tree br_base br_ballast (57994)                  0.25(0.21+0.03)    0.20(0.17+0.02) -20.0%
0006.3: switch between br_base br_ballast (57994)             10.67(6.06+2.92)   10.51(5.94+2.91) -1.5%
0006.4: switch between br_ballast br_ballast_plus_1 (57994)   0.59(0.47+0.16)    0.52(0.40+0.13) -11.9%
0006.5: switch between aliases (57994)                        0.59(0.44+0.17)    0.51(0.38+0.14) -13.6%

$ GIT_PERF_REPO=/mnt/test/linux.git/ ./run HEAD~3 HEAD ./p0006-read-tree-checkout.sh
Test                                                          HEAD~3             HEAD
0006.2: read-tree br_base br_ballast (57994)                  0.24(0.21+0.02)    0.21(0.18+0.02) -12.5%
0006.3: switch between br_base br_ballast (57994)             10.42(5.98+2.91)   10.66(5.86+3.09) +2.3%
0006.4: switch between br_ballast br_ballast_plus_1 (57994)   0.59(0.49+0.13)    0.53(0.37+0.16) -10.2%
0006.5: switch between aliases (57994)                        0.59(0.43+0.17)    0.50(0.37+0.14) -15.3%

Results for smaller repos (like git.git) are not significant.
$ ./run HEAD~3 HEAD ./p0006-read-tree-checkout.sh
Test                                                         HEAD~3            HEAD
0006.2: read-tree br_base br_ballast (3043)                  0.01(0.00+0.00)   0.01(0.00+0.00) +0.0%
0006.3: switch between br_base br_ballast (3043)             0.31(0.17+0.11)   0.29(0.19+0.08) -6.5%
0006.4: switch between br_ballast br_ballast_plus_1 (3043)   0.03(0.02+0.00)   0.03(0.02+0.00) +0.0%
0006.5: switch between aliases (3043)                        0.03(0.02+0.00)   0.03(0.02+0.00) +0.0%

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-19 20:33:01 -07:00
Jeff Hostetler 06b6d81b79 read-cache: speed up has_dir_name (part 1)
Teach has_dir_name() to see if the path of the new item
is greater than the last path in the index array before
attempting to search for it.

has_dir_name() is looking for file/directory collisions
in the index and has to consider each sub-directory
prefix in turn.  This can cause multiple binary searches
for each path.

During operations like checkout, merge_working_tree()
populates the new index in sorted order, so we expect
to be able to append in many cases.

This commit is part 1 of 2.  This commit handles the top
of has_dir_name() and the trivial optimization.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-19 20:33:01 -07:00
Jeff Hostetler e5494631ed read-cache: speed up add_index_entry during checkout
Teach add_index_entry_with_check() to see if the path
of the new item is greater than the last path in the
index array before attempting to search for it.

During checkout, merge_working_tree() populates the new
index in sorted order, so this change will save a binary
lookups per file.  This preserves the original behavior
but simply checks the last element before starting the
search.

This helps performance on very large repositories.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-19 20:33:01 -07:00
Jeff Hostetler a6db3fbb6e read-cache: add strcmp_offset function
Add strcmp_offset() function to also return the offset of the
first change.

Add unit test and helper to verify.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-15 02:21:12 -07:00
Jeff Hostetler a33fc72fe9 read-cache: force_verify_index_checksum
Teach git to skip verification of the SHA1-1 checksum at the end of
the index file in verify_hdr() which is called from read_index()
unless the "force_verify_index_checksum" global variable is set.

Teach fsck to force this verification.

The checksum verification is for detecting disk corruption, and for
small projects, the time it takes to compute SHA-1 is not that
significant, but for gigantic repositories this calculation adds
significant time to every command.

These effect can be seen using t/perf/p0002-read-cache.sh:

Test                                          HEAD~1            HEAD
--------------------------------------------------------------------------------------
0002.1: read_cache/discard_cache 1000 times   0.66(0.44+0.20)   0.30(0.27+0.02) -54.5%

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-15 00:58:36 -07:00
Junio C Hamano 94c9b5af70 Merge branch 'cc/split-index-config'
The experimental "split index" feature has gained a few
configuration variables to make it easier to use.

* cc/split-index-config: (22 commits)
  Documentation/git-update-index: explain splitIndex.*
  Documentation/config: add splitIndex.sharedIndexExpire
  read-cache: use freshen_shared_index() in read_index_from()
  read-cache: refactor read_index_from()
  t1700: test shared index file expiration
  read-cache: unlink old sharedindex files
  config: add git_config_get_expiry() from gc.c
  read-cache: touch shared index files when used
  sha1_file: make check_and_freshen_file() non static
  Documentation/config: add splitIndex.maxPercentChange
  t1700: add tests for splitIndex.maxPercentChange
  read-cache: regenerate shared index if necessary
  config: add git_config_get_max_percent_split_change()
  Documentation/git-update-index: talk about core.splitIndex config var
  Documentation/config: add information for core.splitIndex
  t1700: add tests for core.splitIndex
  update-index: warn in case of split-index incoherency
  read-cache: add and then use tweak_split_index()
  split-index: add {add,remove}_split_index() functions
  config: add git_config_get_split_index()
  ...
2017-03-17 13:50:23 -07:00
Christian Couder c3a0082502 read-cache: use freshen_shared_index() in read_index_from()
This way a share index file will not be garbage collected if
we still read from an index it is based from.

As we need to read the current index before creating a new
one, the tests have to be adjusted, so that we don't expect
an old shared index file to be deleted right away when we
create a new one.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-06 12:09:28 -08:00
Christian Couder de6ae5f9e3 read-cache: refactor read_index_from()
It looks better and is simpler to review when we don't compute
the same things many times in the function.

It will also help make the following commit simpler.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-06 12:09:28 -08:00
Christian Couder b968372279 read-cache: unlink old sharedindex files
Everytime split index is turned on, it creates a "sharedindex.XXXX"
file in the git directory. This change makes sure that shared index
files that haven't been used for a long time are removed when a new
shared index file is created.

The new "splitIndex.sharedIndexExpire" config variable is created
to tell the delay after which an unused shared index file can be
deleted. It defaults to "2.weeks.ago".

A previous commit made sure that each time a split index file is
created the mtime of the shared index file it references is updated.
This makes sure that recently used shared index file will not be
deleted.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-06 12:09:28 -08:00
Christian Couder 0d59ffb47e read-cache: touch shared index files when used
When a split-index file is created, let's update the mtime of the
shared index file that the split-index file is referencing.

In a following commit we will make shared index file expire
depending on their mtime, so updating the mtime makes sure that
the shared index file will not be deleted soon.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-01 13:34:51 -08:00
Christian Couder e6a1dd77e1 read-cache: regenerate shared index if necessary
When writing a new split-index and there is a big number of cache
entries in the split-index compared to the shared index, it is a
good idea to regenerate the shared index.

By default when the ratio reaches 20%, we will push back all
the entries from the split-index into a new shared index file
instead of just creating a new split-index file.

The threshold can be configured using the
"splitIndex.maxPercentChange" config variable.

We need to adjust the existing tests in t1700 by setting
"splitIndex.maxPercentChange" to 100 at the beginning of t1700,
as the existing tests are assuming that the shared index is
regenerated only when `git update-index --split-index` is used.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-01 13:24:22 -08:00
Christian Couder 4392531211 read-cache: add and then use tweak_split_index()
This will make us use the split-index feature or not depending
on the value of the "core.splitIndex" config variable.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-01 13:24:21 -08:00
Junio C Hamano feaad0eec7 Merge branch 'sb/in-core-index-doc'
Documentation and in-code comments updates.

* sb/in-core-index-doc:
  documentation: retire unfinished documentation
  cache.h: document add_[file_]to_index
  cache.h: document remove_index_entry_at
  cache.h: document index_name_pos
2017-01-31 13:14:59 -08:00
Stefan Beller 3bd72adff1 cache.h: document remove_index_entry_at
Do this by moving the existing documentation from
read-cache.c to cache.h.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-19 12:17:57 -08:00
Brandon Williams 875425080d index: improve constness for reading blob data
Improve constness of the index_state parameter to the
'read_blob_data_from_index' function.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-11 13:35:13 -08:00
Junio C Hamano 02d0457eb4 Merge branch 'jc/git-open-cloexec'
The codeflow of setting NOATIME and CLOEXEC on file descriptors Git
opens has been simplified.
We may want to drop the tip one, but we'll see.

* jc/git-open-cloexec:
  sha1_file: stop opening files with O_NOATIME
  git_open_cloexec(): use fcntl(2) w/ FD_CLOEXEC fallback
  git_open(): untangle possible NOATIME and CLOEXEC interactions
2017-01-10 15:24:26 -08:00
Junio C Hamano b3e83cc752 hold_locked_index(): align error handling with hold_lockfile_for_update()
Callers of the hold_locked_index() function pass 0 when they want to
prepare to write a new version of the index file without wishing to
die or emit an error message when the request fails (e.g. somebody
else already held the lock), and pass 1 when they want the call to
die upon failure.

This option is called LOCK_DIE_ON_ERROR by the underlying lockfile
API, and the hold_locked_index() function translates the paramter to
LOCK_DIE_ON_ERROR when calling the hold_lock_file_for_update().

Replace these hardcoded '1' with LOCK_DIE_ON_ERROR and stop
translating.  Callers other than the ones that are replaced with
this change pass '0' to the function; no behaviour change is
intended with this patch.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

Among the callers of hold_locked_index() that passes 0:

 - diff.c::refresh_index_quietly() at the end of "git diff" is an
   opportunistic update; it leaks the lockfile structure but it is
   just before the program exits and nobody should care.

 - builtin/describe.c::cmd_describe(),
   builtin/commit.c::cmd_status(),
   sequencer.c::read_and_refresh_cache() are all opportunistic
   updates and they are OK.

 - builtin/update-index.c::cmd_update_index() takes a lock upfront
   but we may end up not needing to update the index (i.e. the
   entries may be fully up-to-date), in which case we do not need to
   issue an error upon failure to acquire the lock.  We do diagnose
   and die if we indeed need to update, so it is OK.

 - wt-status.c::require_clean_work_tree() IS BUGGY.  It asks
   silence, does not check the returned value.  Compare with
   callsites like cmd_describe() and cmd_status() to notice that it
   is wrong to call update_index_if_able() unconditionally.
2016-12-07 11:31:59 -08:00
Junio C Hamano 1b8ac5ead5 git_open(): untangle possible NOATIME and CLOEXEC interactions
The way we structured the fallback/retry mechanism for opening with
O_NOATIME and O_CLOEXEC meant that if we failed due to lack of
support to open the file with O_NOATIME option (i.e. EINVAL), we
would still try to drop O_CLOEXEC first and retry, and then drop
O_NOATIME.  A platform on which O_NOATIME is defined in the header
without support from the kernel wouldn't have a chance to open with
O_CLOEXEC option due to this code structure.

Arguably, O_CLOEXEC is more important than O_NOATIME, as the latter
is mostly about performance, while the former can affect correctness.

Instead use O_CLOEXEC to open the file, and then use fcntl(2) to set
O_NOATIME on the resulting file descriptor.  open(2) itself does not
cause atime to be updated according to Linus [*1*].

The helper to do the former can be usable in the codepath in
ce_compare_data() that was recently added to open a file descriptor
with O_CLOEXEC; use it while we are at it.

*1* <CA+55aFw83E+zOd+z5h-CA-3NhrLjVr-anL6pubrSWttYx3zu8g@mail.gmail.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-10-28 06:23:07 -07:00
Lars Schneider a0a6cb9662 read-cache: make sure file handles are not inherited by child processes
This fixes "convert: add filter.<driver>.process option" (edcc8581) on
Windows.

Consider the case of a file that requires filtering and is present in
branch A but not in branch B. If A is the current HEAD and we checkout B
then the following happens:

1. ce_compare_data() opens the file
2.   index_fd() detects that the file requires to run a clean filter and
     calls index_stream_convert_blob()
4.     index_stream_convert_blob() calls convert_to_git_filter_fd()
5.       convert_to_git_filter_fd() calls apply_filter() which creates a
         new long running filter process (in case it is the first file
         of this kind to be filtered)
6.       The new filter process inherits all file handles. This is the
         default on Linux/OSX and is explicitly defined in the
         `CreateProcessW` call in `mingw.c` on Windows.
7. ce_compare_data() closes the file
8. Git unlinks the file as it is not present in B

The unlink operation does not work on Windows because the filter process
has still an open handle to the file. On Linux/OSX the unlink operation
succeeds but the file descriptors still leak into the child process.

Fix this problem by opening files in read-cache with the O_CLOEXEC flag
to ensure that the file descriptor does not remain open in a newly
spawned process similar to 05d1ed6148 ("mingw: ensure temporary file
handles are not inherited by child processes", 2016-08-22).

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-10-25 11:10:18 -07:00
Junio C Hamano ebc63580a1 Merge branch 'tg/add-chmod+x-fix'
"git add --chmod=+x <pathspec>" added recently only toggled the
executable bit for paths that are either new or modified. This has
been corrected to flip the executable bit for all paths that match
the given pathspec.

* tg/add-chmod+x-fix:
  t3700-add: do not check working tree file mode without POSIXPERM
  t3700-add: create subdirectory gently
  add: modify already added files when --chmod is given
  read-cache: introduce chmod_index_entry
  update-index: add test for chmod flags
2016-09-26 16:09:20 -07:00
Thomas Gummerer 610d55af0f add: modify already added files when --chmod is given
When the chmod option was added to git add, it was hooked up to the diff
machinery, meaning that it only works when the version in the index
differs from the version on disk.

As the option was supposed to mirror the chmod option in update-index,
which always changes the mode in the index, regardless of the status of
the file, make sure the option behaves the same way in git add.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-15 12:13:54 -07:00
Thomas Gummerer d9d7096662 read-cache: introduce chmod_index_entry
As there are chmod options for both add and update-index, introduce a
new chmod_index_entry function to do the work.  Use it in update-index,
while it will be used in add in the next patch.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-15 12:13:54 -07:00