Commit e1afca4fd "write_index(): update index_state->timestamp after
flushing to disk" on 2009-02-23 used stat.ctime to record the
timestamp of the index-file. This is wrong, so fix this and use the
correct stat.mtime timestamp instead.
Commit 110c46a909 "Not all systems use st_[cm]tim field for ns
resolution file timestamp" on 2009-03-08, has a similar bug for the
builtin-fetch-pack.c file.
Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some codepaths do not still use the ST_[CM]TIME_NSEC() pair of macros
introduced by the previous commit but assumes all systems use st_mtim
and st_ctim fields in "struct stat" to record nanosecond resolution part
of the file timestamps.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Traditionally, the lack of USE_NSEC meant "do not record nor use the
nanosecond resolution part of the file timestamps". To avoid problems on
filesystems that lose the ns part when the metadata is flushed to the disk
and then later read back in, disabling USE_NSEC has been a good idea in
general.
If you are on a filesystem without such an issue, it does not hurt to read
and store them in the cached stat data in the index entries even if your
git is compiled without USE_NSEC. The index left with such a version of
git can be read by git compiled with USE_NSEC and it can make use of the
nanosecond part to optimize the check to see if the path on the filesystem
hsa been modified since we last looked at.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since this timestamp is used to check for racy-clean files, it is
important to keep it uptodate.
For the 'git checkout' command without the '-q' option, this make a
huge difference. Before, each and every file which was updated, was
racy-clean after the call to unpack_trees() and write_index() but
before the GIT process ended.
And because of the call to show_local_changes() in builtin-checkout.c,
we ended up reading those files back into memory, doing a SHA1 to
check if the files was really different from the index. And, of
course, no file was different.
With this fix, 'git checkout' without the '-q' option should now be
almost as fast as with the '-q' option, but not quite, as we still do
some few lstat(2) calls more without the '-q' option.
Below is some average numbers for 10 checkout's to v2.6.27 and 10 to
v2.6.25 of the Linux kernel, to show the difference:
before (git version 1.6.2.rc1.256.g58a87):
7.860 user 2.427 sys 19.465 real 52.8% CPU faults: 0 major 95331 minor
after:
6.184 user 2.160 sys 17.619 real 47.4% CPU faults: 0 major 38994 minor
Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since the filesystem ext4 is now defined as stable in Linux v2.6.28,
and ext4 supports nanonsecond resolution timestamps natively, it is
time to make USE_NSEC work as expected.
This will make racy git situations less likely to happen. For 'git
checkout' this means it will be less likely that we have to open, read
the contents of the file into RAM, and check if file is really
modified or not. The result sould be a litle less used CPU time, less
pagefaults and a litle faster program, at least for 'git checkout'.
Since the number of possible racy git situations would increase when
disks gets faster, this patch would be more and more helpfull as times
go by. For a fast Solid State Disk, this patch should be helpfull.
Note that, when file operations starts to take less than 1 nanosecond,
one would again start to get more racy git situations.
For more info on racy git, see Documentation/technical/racy-git.txt
For more info on ext4, see http://kernelnewbies.org/Ext4
Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Below is oprofile output from GIT command 'git chekcout -q my-v2.6.25'
(move from tag v2.6.27 to tag v2.6.25 of the Linux kernel):
CPU: Core 2, speed 1999.95 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit
mask of 0x00 (Unhalted core cycles) count 20000
Counted INST_RETIRED_ANY_P events (number of instructions retired) with a
unit mask of 0x00 (No unit mask) count 20000
CPU_CLK_UNHALT...|INST_RETIRED:2...|
samples| %| samples| %|
------------------------------------
409247 100.000 342878 100.000 git
CPU_CLK_UNHALT...|INST_RETIRED:2...|
samples| %| samples| %|
------------------------------------
260476 63.6476 257843 75.1996 libz.so.1.2.3
100876 24.6492 64378 18.7758 kernel-2.6.28.4_2.vmlinux
30850 7.5382 7874 2.2964 libc-2.9.so
14775 3.6103 8390 2.4469 git
2020 0.4936 4325 1.2614 libcrypto.so.0.9.8
191 0.0467 32 0.0093 libpthread-2.9.so
58 0.0142 36 0.0105 ld-2.9.so
1 2.4e-04 0 0 libldap-2.3.so.0.2.31
Detail list of the top 20 function entries (libz counted in one blob):
CPU_CLK_UNHALTED INST_RETIRED_ANY_P
samples % samples % image name symbol name
260476 63.6862 257843 75.2725 libz.so.1.2.3 /lib/libz.so.1.2.3
16587 4.0555 3636 1.0615 libc-2.9.so memcpy
7710 1.8851 277 0.0809 libc-2.9.so memmove
3679 0.8995 1108 0.3235 kernel-2.6.28.4_2.vmlinux d_validate
3546 0.8670 2607 0.7611 kernel-2.6.28.4_2.vmlinux __getblk
3174 0.7760 1813 0.5293 libc-2.9.so _int_malloc
2396 0.5858 3681 1.0746 kernel-2.6.28.4_2.vmlinux copy_to_user
2270 0.5550 2528 0.7380 kernel-2.6.28.4_2.vmlinux __link_path_walk
2205 0.5391 1797 0.5246 kernel-2.6.28.4_2.vmlinux ext4_mark_iloc_dirty
2103 0.5142 1203 0.3512 kernel-2.6.28.4_2.vmlinux find_first_zero_bit
2077 0.5078 997 0.2911 kernel-2.6.28.4_2.vmlinux do_get_write_access
2070 0.5061 514 0.1501 git cache_name_compare
2043 0.4995 1501 0.4382 kernel-2.6.28.4_2.vmlinux rcu_irq_exit
2022 0.4944 1732 0.5056 kernel-2.6.28.4_2.vmlinux __ext4_get_inode_loc
2020 0.4939 4325 1.2626 libcrypto.so.0.9.8 /usr/lib/libcrypto.so.0.9.8
1965 0.4804 1384 0.4040 git patch_delta
1708 0.4176 984 0.2873 kernel-2.6.28.4_2.vmlinux rcu_sched_grace_period
1682 0.4112 727 0.2122 kernel-2.6.28.4_2.vmlinux sysfs_slab_alias
1659 0.4056 290 0.0847 git find_pack_entry_one
1480 0.3619 1307 0.3816 kernel-2.6.28.4_2.vmlinux ext4_writepage_trans_blocks
Notice the memmove line, where the CPU did 7710 / 277 = 27.8 cycles
per instruction, and compared to the total cycles spent inside the
source code of GIT for this command, all the memmove() calls
translates to (7710 * 100) / 14775 = 52.2% of this.
Retesting with a GIT program compiled for gcov usage, I found out that
the memmove() calls came from remove_index_entry_at() in read-cache.c,
where we have:
memmove(istate->cache + pos,
istate->cache + pos + 1,
(istate->cache_nr - pos) * sizeof(struct cache_entry *));
remove_index_entry_at() is called 4902 times from check_updates() in
unpack-trees.c, and each time called we move each cache_entry pointers
(from the removed one) one step to the left.
Since we have 28828 entries in the cache this time, and if we on
average move half of them each time, we in total move approximately
4902 * 0.5 * 28828 * 4 = 282 629 712 bytes, or twice this amount if
each pointer is 8 bytes (64 bit).
OK, is seems that the function check_updates() is called 28 times, so
the estimated guess above had been more correct if check_updates() had
been called only once, but the point is: we get lots of bytes moved.
To fix this, and use an O(N) algorithm instead, where N is the number
of cache_entries, we delete/remove all entries in one loop through all
entries.
From a retest, the new remove_marked_cache_entries() from the patch
below, ended up with the following output line from oprofile:
46 0.0105 15 0.0041 git remove_marked_cache_entries
If we can trust the numbers from oprofile in this case, we saved
approximately ((7710 - 46) * 20000) / (2 * 1000 * 1000 * 1000) = 0.077
seconds CPU time with this fix for this particular test. And notice
that now the CPU did only 46 / 15 = 3.1 cycles/instruction.
Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
After you resolve a conflicted merge to remove the path, "git add -u"
failed to record the removal. Instead it errored out by saying that the
removed path is not found in the work tree, but that is what the user
already knows, and the wanted to record the removal as the resolution,
so the error does not make sense.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This simplifies the code, and also makes ce_compare_link now able to
handle filesystems with odd 'st_size' return values for symlinks.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Writing a tree out of an index with an "intent to add" entry is blocked.
This implies that you cannot "git commit" from such a state; however you
can still do "git commit -a" or "git commit $that_path".
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This uses the extended index flag mechanism introduced earlier to mark
the entries added to the index via "git add -N" with CE_INTENT_TO_ADD.
The logic to detect an "intent to add" entry for the purpose of allowing
"git rm --cached $path" is tightened to check not just for a staged empty
blob, but with the CE_INTENT_TO_ADD bit. This protects an empty blob that
was explicitly added and then modified in the work tree from being dropped
with this sequence:
$ >empty
$ git add empty
$ echo "non empty" >empty
$ git rm --cached empty
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Earlier commit 5521883 (checkout: do not lose staged removal, 2008-09-07)
tightened the rule to prevent switching branches from losing local
changes, so that staged removal of paths can be protected, while
attempting to keep a loophole to still allow a special case of switching
out of an un-checked-out state.
However, the loophole was made a bit too tight, and did not allow
switching from one branch (in an un-checked-out state) to check out
another branch.
The change to builtin-checkout.c in this commit loosens it to allow this,
by not insisting the original commit and the new commit to be the same.
It also introduces a new function, is_index_unborn (and an associated
macro, is_cache_unborn), to check if the repository is truly in an
un-checked-out state more reliably, by making sure that $GIT_INDEX_FILE
did not exist when populating the in-core index structure. A few places
the earlier commit 5521883 added the check for the initial checkout
condition are updated to use this function.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If a file is different between the working tree copy, the index, and the
HEAD, then we do not allow it to be deleted without --force.
However, this is overly tight in the face of "git add --intent-to-add":
$ git add --intent-to-add file
$ : oops, I don't actually want to stage that yet
$ git rm --cached file
error: 'empty' has staged content different from both the
file and the HEAD (use -f to force removal)
$ git rm -f --cached file
Unfortunately, there is currently no way to distinguish between an empty
file that has been added and an "intent to add" file. The ideal behavior
would be to disallow the former while allowing the latter.
This patch loosens the safety valve to allow the deletion only if we are
deleting the cached entry and the cached content is empty. This covers
the intent-to-add situation, and assumes there is little harm in not
protecting users who have legitimately added an empty file. In many
cases, the file will still be empty, in which case the safety valve does
not trigger anyway (since the content remains untouched in the working
tree). Otherwise, we do remove the fact that no content was staged, but
given that the content is by definition empty, it is not terribly
difficult for a user to recreate it.
However, we still document the desired behavior in the form of two
tests. One checks the correct removal of an intent-to-add file. The other
checks that we still disallow removal of empty files, but is marked as
expect_failure to indicate this compromise. If the intent-to-add feature
is ever extended to differentiate between normal empty files and
intent-to-add files, then the safety valve can be re-tightened.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When aborting a failed merge that has brought in a new path using "git
reset --hard" or "git read-tree --reset -u", we used to first forget about
the new path (via read_cache_unmerged) and then matched the working tree
to what is recorded in the index, thus ending up leaving the new path in
the work tree.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the "git status" display code was originally converted
to C, we copied the code from ls-files to discover whether a
pathname returned by read_directory was an "other", or
untracked, file.
Much later, 5698454e updated the code in ls-files to handle
some new cases caused by gitlinks. This left the code in
wt-status.c broken: it would display submodule directories
as untracked directories. Nobody noticed until now, however,
because unless status.showUntrackedFiles was set to "all",
submodule directories were not actually reported by
read_directory. So the bug was only triggered in the
presence of a submodule _and_ this config option.
This patch pulls the ls-files code into a new function,
cache_name_is_other, and uses it in both places. This should
leave the ls-files functionality the same and fix the bug
in status.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The on-disk format of index only saves 16 bit flags, nearly all have
been used. The last bit (CE_EXTENDED) is used to for future extension.
This patch extends index entry format to save more flags in future.
The new entry format will be used when CE_EXTENDED bit is 1.
Because older implementation may not understand CE_EXTENDED bit and
misread the new format, if there is any extended entry in index, index
header version will turn 3, which makes it incompatible for older git.
If there is none, header version will return to 2 again.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Many call sites use strbuf_init(&foo, 0) to initialize local
strbuf variable "foo" which has not been accessed since its
declaration. These can be replaced with a static initialization
using the STRBUF_INIT macro which is just as readable, saves a
function call, and takes up fewer lines.
Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
If verification of path failed, it is always better to print an
error message saying this than relying on the caller function to
print a meaningful error message (especially when the callee already
prints error message for another situation).
Because the callers of add_index_entry_with_check() did not print
any error message, it resulted that the user would not notice the
problem when checkout of an invalid path failed.
Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
On ARM I have the following compilation errors:
CC fast-import.o
In file included from cache.h:8,
from builtin.h:6,
from fast-import.c:142:
arm/sha1.h:14: error: conflicting types for 'SHA_CTX'
/usr/include/openssl/sha.h:105: error: previous declaration of 'SHA_CTX' was here
arm/sha1.h:16: error: conflicting types for 'SHA1_Init'
/usr/include/openssl/sha.h:115: error: previous declaration of 'SHA1_Init' was here
arm/sha1.h:17: error: conflicting types for 'SHA1_Update'
/usr/include/openssl/sha.h:116: error: previous declaration of 'SHA1_Update' was here
arm/sha1.h:18: error: conflicting types for 'SHA1_Final'
/usr/include/openssl/sha.h:117: error: previous declaration of 'SHA1_Final' was here
make: *** [fast-import.o] Error 1
This is because openssl header files are always included in
git-compat-util.h since commit 684ec6c63c whenever NO_OPENSSL is not
set, which somehow brings in <openssl/sha1.h> clashing with the custom
ARM version. Compilation of git is probably broken on PPC too for the
same reason.
Turns out that the only file requiring openssl/ssl.h and openssl/err.h
is imap-send.c. But only moving those problematic includes there
doesn't solve the issue as it also includes cache.h which brings in the
conflicting local SHA1 header file.
As suggested by Jeff King, the best solution is to rename our references
to SHA1 functions and structure to something git specific, and define those
according to the implementation used.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
This adds "--intent-to-add" option to "git add". This is to let the
system know that you will tell it the final contents to be staged later,
iow, just be aware of the presense of the path with the type of the blob
for now. It is implemented by staging an empty blob as the content.
With this sequence:
$ git reset --hard
$ edit newfile
$ git add -N newfile
$ edit newfile oldfile
$ git diff
the diff will show all changes relative to the current commit. Then you
can do:
$ git commit -a ;# commit everything
or
$ git commit oldfile ;# only oldfile, newfile not yet added
to pretend you are working with an index-free system like CVS.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
unpack_trees() rebuilds the in-core index from scratch by allocating a new
structure and finishing it off by copying the built one to the final
index.
The resulting in-core index is Ok for most use, but read_cache() does not
recognize it as such. The function is meant to be no-op if you already
have loaded the index, until you call discard_cache().
This change the way read_cache() detects an already initialized in-core
index, by introducing an extra bit, and marks the handcrafted in-core
index as initialized, to avoid this problem.
A better fix in the longer term would be to change the read_cache() API so
that it will always discard and re-read from the on-disk index to avoid
confusion. But there are higher level API that have relied on the current
semantics, and they and their users all need to get converted, which is
outside the scope of 'maint' track.
An example of such a higher level API is write_cache_as_tree(), which is
used by git-write-tree as well as later Porcelains like git-merge, revert
and cherry-pick. In the longer term, we should remove read_cache() from
there and add one to cmd_write_tree(); other callers expect that the
in-core index they prepared is what gets written as a tree so no other
change is necessary for this particular codepath.
The original version of this patch marked the index by pointing an
otherwise wasted malloc'ed memory with o->result.alloc, but this version
uses Linus's idea to use a new "initialized" bit, which is conceptually
much cleaner.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We do not have any more bits in the on-disk index flags word, but we would
need to have more in the future. Use the last remaining bits as a signal
to tell us that the index entry we are looking at is an extended one.
Since we do not understand the extended format yet, we will just error out
when we see it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The ie_modified() function is the workhorse for refresh_cache_entry(),
i.e. checking if an index entry that is stat-dirty actually has changes.
After running quicker check to compare cached stat information with
results from the latest lstat(2) to answer "has modification" early, the
code goes on to check if there really is a change by comparing the staged
data with what is on the filesystem by asking ce_modified_check_fs().
However, this function always said "no change" for any gitlinks that has a
directory at the corresponding path. This made ie_modified() to miss
actual changes in the subproject.
The patch fixes this first by modifying an existing short-circuit logic
before calling the ce_modified_check_fs() function. It knows that for any
filesystem entity to which ie_match_stat() says its data has changed, if
its cached size is nonzero then the contents cannot match, which is a
correct optimization only for blob objects. We teach gitlink objects to
this special case, as we already know that any gitlink that
ie_match_stat() says is modified is indeed modified at this point in the
codepath.
With the above change, we could leave ce_modified_check_fs() broken, but
it also futureproofs the code by teaching it to use ce_compare_gitlink(),
instead of assuming (incorrectly) that any directory is unchanged.
Originally noticed by Alex Riesen on Cygwin.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A new configuration variable 'core.trustctime' is introduced to
allow ignoring st_ctime information when checking if paths
in the working tree has changed, because there are situations where
it produces too much false positives. Like when file system crawlers
keep changing it when scanning and using the ctime for marking scanned
files.
The default is to notice ctime changes.
Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The rewrite of git-mv from a shell script to a builtin was perhaps
a little too straightforward: the git add and git rm queues were
emulated directly, which resulted in a rather complicated code and
caused an inconsistent behaviour when moving dirty index entries;
git mv would update the entry based on working tree state,
except in case of overwrites, where the new entry would still have
sha1 of the old file.
This patch introduces rename_index_entry_at() into the index toolkit,
which will rename an entry while removing any entries the new entry
might render duplicate. This is then used in git mv instead
of all the file queues, resulting in a major simplification
of the code and an inevitable change in git mv -n output format.
Also the code used to refuse renaming overwriting symlink with a regular
file and vice versa; there is no need for that.
A few new tests have been added to the testsuite to reflect this change.
Signed-off-by: Petr Baudis <pasky@suse.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A private function add_files_to_cache() in builtin-add.c was borrowed by
checkout and commit re-implementors without getting properly refactored to
more library-ish place. This does the refactoring.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git update-index --refresh", "git reset" and "git add --refresh" have
reported paths that have local modifications as "needs update" since the
beginning of git.
Although this is logically correct in that you need to update the index at
that path before you can commit that change, it is now becoming more and
more clear, especially with the continuous push for user friendliness
since 1.5.0 series, that the message is suboptimal. After all, the change
may be something the user might want to get rid of, and "updating" would
be absolutely a wrong thing to do if that is the case.
I prepared two alternatives to solve this. Both aim to reword the message
to more neutral "locally modified".
This patch is a more intrusive variant that changes the message for only
Porcelain commands ("add" and "reset") while keeping the plumbing
"update-index" intact.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin-read-tree has a read_cache_unmerged() which is useful for other
builtins, for example builtin-merge uses it as well. Move it to
read-cache.c to avoid code duplication.
Signed-off-by: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We use size=0 as the magic token to say the entry is known to be racily
clean, but a sequence that does:
- update the path with a non-empty blob and write the index;
- update an unrelated path and write the index -- this smudges
the above entry;
- truncate the path to size zero.
would make both the size field for the path in the index and the size on
the filesystem zero. We should not mistake it as a clean index entry.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a cache entry has been marked as CE_VALID, the user has
promised us that any change in the work tree does not matter.
Just mark the entry as up-to-date, and continue.
Signed-off-by: Marius Storm-Olsen <marius@trolltech.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Like with the diff machinery, update-index should sometimes just
ignore submodules (e.g. to determine a clean state before a rebase).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the programs which used the function (as add_file_to_cache).
Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The commit sequence used to do
if (file_exists(p->path))
add_file_to_cache(p->path, 0);
where both "file_exists()" and "add_file_to_cache()" needed to do a
lstat() on the path to do their work.
This cuts down 'lstat()' calls for the partial commit case by two
for each path we know about (because we do this twice per path).
Just move the lstat() to the caller instead (that's all that
"file_exists()" really does), and pass the stat information down to the
add_to_cache() function.
This essentially makes 'add_to_index()' the core function that adds a path
to the index, getting the index pointer, the pathname and the stat
information as arguments. There are then shorthand helper functions that
use this core function:
- 'add_to_cache()' is just 'add_to_index()' with the default index
- 'add_file_to_cache/index()' is the same, but does the lstat() call
itself, so you can pass just the pathname if you don't already have the
stat information available.
So old users of the 'add_file_to_xyzzy()' are essentially left unchanged,
and this just exposes the more generic helper function that can take
existing stat information into account.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Because we do not even check the timestamp to determie if a gitlink
is up to date or not, triggering the racy-timestamp check for gitlinks
does not make sense.
This fixes the recently added test in t7506.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When writing the index out, we need to check the work tree again to see if
an entry whose timestamp indicates that it could be "racily clean", in
order to smudge it if it is stat-clean but with modified contents.
However, we can skip this step for entries marked with CE_UPTODATE,
which are known to be the really clean (i.e. the one we already have
checked when we prepared the index). This will reduce lstat(2) calls
necessary in git-status.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This expands on the previous patch, and allows "git add" to sanely handle
a filename that has changed case, keeping the case in the index constant,
and avoiding aliases.
In particular, if you have an index entry called "File", but the
checked-out tree is case-corrupted and has an entry called "file"
instead, doing a
git add .
(or naming "file" explicitly) will automatically notice that we have an
alias, and will replace the name "file" with the existing index
capitalization (ie "File").
However, if we actually have *both* a file called "File" and one called
"file", and they don't have the same lstat() information (ie we're on a
case-sensitive filesystem but have the "core.ignorecase" flag set), we
will error out if we try to add them both.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This simplifies the matching case of "I already have this file and it is
up-to-date" and makes it do the right thing in the face of
case-insensitive aliases.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It's really totally separate functionality, and if we want to start
doing case-insensitive hash lookups, I'd rather do it when it's
separated out.
It also renames "remove_index_entry()" to "remove_name_hash()", because
that really describes the thing better. It doesn't actually remove the
index entry, that's done by "remove_index_entry_at()", which is something
very different, despite the similarity in names.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is in an effort to make the source index of 'unpack_trees()' as
being const, and thus making the compiler help us verify that we only
access it for reading.
The constification also extended to some of the hashing helpers that get
called indirectly.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new helper is identical to base_name_compare(), except it compares
conflicting directory/file entries as equal in order to help handling DF
conflicts (thus the name).
Note that while a directory name compares as equal to a regular file
with the new helper, they then individually compare _differently_ to a
filename that has a dot after the basename (because '\0' < '.' < '/').
So a directory called "foo/" will compare equal to a file "foo", even
though "foo.c" will compare after "foo" and before "foo/"
This will be used by routines that want to traverse the git namespace
but then handle conflicting entries together when possible.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This makes the name hash removal function (which really just sets the
bit that disables lookups of it) available to external routines, and
makes read_cache_unmerged() use it when it drops an unmerged entry from
the index.
It's renamed to remove_index_entry(), and we drop the (unused) 'istate'
argument.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We handled the case of removing and re-inserting cache entries badly,
which is something that merging commonly needs to do (removing the
different stages, and then re-inserting one of them as the merged
state).
We even had a rather ugly special case for this failure case, where
replace_index_entry() basically turned itself into a no-op if the new
and the old entries were the same, exactly because the hash routines
didn't handle it on their own.
So what this patch does is to not just have the UNHASHED bit, but a
HASHED bit too, and when you insert an entry into the name hash, that
involves:
- clear the UNHASHED bit, because now it's valid again for lookup
(which is really all that UNHASHED meant)
- if we're being lazy, we're done here (but we still want to clear the
UNHASHED bit regardless of lazy mode, since we can become unlazy
later, and so we need the UNHASHED bit to always be set correctly,
even if we never actually insert the entry into the hash list)
- if it was already hashed, we just leave it on the list
- otherwise mark it HASHED and insert it into the list
this all means that unhashing and rehashing a name all just works
automatically. Obviously, you cannot change the name of an entry (that
would be a serious bug), but nothing can validly do that anyway (you'd
have to allocate a new struct cache_entry anyway since the name length
could change), so that's not a new limitation.
The code actually gets simpler in many ways, although the lazy hashing
does mean that there are a few odd cases (ie something can be marked
unhashed even though it was never on the hash in the first place, and
isn't actually marked hashed!).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This creates a hash index of every single file added to the index.
Right now that hash index isn't actually used for much: I implemented a
"cache_name_exists()" function that uses it to efficiently look up a
filename in the index without having to do the O(logn) binary search,
but quite frankly, that's not why this patch is interesting.
No, the whole and only reason to create the hash of the filenames in the
index is that by modifying the hash function, you can fairly easily do
things like making it always hash equivalent names into the same bucket.
That, in turn, means that suddenly questions like "does this name exist
in the index under an _equivalent_ name?" becomes much much cheaper.
Guiding principles behind this patch:
- it shouldn't be too costly. In fact, my primary goal here was to
actually speed up "git commit" with a fully populated kernel tree, by
being faster at checking whether a file already existed in the index. I
did succeed, but only barely:
Best before:
[torvalds@woody linux]$ time git commit > /dev/null
real 0m0.255s
user 0m0.168s
sys 0m0.088s
Best after:
[torvalds@woody linux]$ time ~/git/git commit > /dev/null
real 0m0.233s
user 0m0.144s
sys 0m0.088s
so some things are actually faster (~8%).
Caveat: that's really the best case. Other things are invariably going
to be slightly slower, since we populate that index cache, and quite
frankly, few things really use it to look things up.
That said, the cost is really quite small. The worst case is probably
doing a "git ls-files", which will do very little except puopulate the
index, and never actually looks anything up in it, just lists it.
Before:
[torvalds@woody linux]$ time git ls-files > /dev/null
real 0m0.016s
user 0m0.016s
sys 0m0.000s
After:
[torvalds@woody linux]$ time ~/git/git ls-files > /dev/null
real 0m0.021s
user 0m0.012s
sys 0m0.008s
and while the thing has really gotten relatively much slower, we're
still talking about something almost unmeasurable (eg 5ms). And that
really should be pretty much the worst case.
So we lose 5ms on one "benchmark", but win 22ms on another. Pick your
poison - this patch has the advantage that it will _likely_ speed up
the cases that are complex and expensive more than it slows down the
cases that are already so fast that nobody cares. But if you look at
relative speedups/slowdowns, it doesn't look so good.
- It should be simple and clean
The code may be a bit subtle (the reasons I do hash removal the way I
do etc), but it re-uses the existing hash.c files, so it really is
fairly small and straightforward apart from a few odd details.
Now, this patch on its own doesn't really do much, but I think it's worth
looking at, if only because if done correctly, the name hashing really can
make an improvement to the whole issue of "do we have a filename that
looks like this in the index already". And at least it gets real testing
by being used even by default (ie there is a real use-case for it even
without any insane filesystems).
NOTE NOTE NOTE! The current hash is a joke. I'm ashamed of it, I'm just
not ashamed of it enough to really care. I took all the numbers out of my
nether regions - I'm sure it's good enough that it works in practice, but
the whole point was that you can make a really much fancier hash that
hashes characters not directly, but by their upper-case value or something
like that, and thus you get a case-insensitive hash, while still keeping
the name and the index itself totally case sensitive.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This moves a common boolean expression into a helper function,
and makes the comparison between filesystem timestamp and index
timestamp done in the function in line with the other places.
st.st_mtime should be casted to (unsigned int) when compared to
an index timestamp ce_mtime.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is a D/F conflict if you want to add "foo/bar" to the index
when "foo" already exists. Also it is a conflict if you want to
add a file "foo" when "foo/bar" exists.
An exception is when the existing entry is there only to mark "I
used to be here but I am being removed". This is needed for
operations such as "git read-tree -m -u" that update the index
and then reflect the result to the work tree --- we need to
remember what to remove somewhere, and we use the index for
that. In such a case, an existing file "foo" is being removed
and we can create "foo/" directory and hang "bar" underneath it
without any conflict.
We used to use (ce->ce_mode == 0) to mark an entry that is being
removed, but (CE_REMOVE & ce->ce_flags) is used for that purpose
these days. An earlier commit forgot to convert the logic in
the code that checks D/F conflict condition.
The old code knew that "to be removed" entries cannot be at
higher stage and actively checked that condition, but it was an
unnecessary check. This patch removes the extra check as well.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Kjetil Barvik