git-commit-vandalism/preload-index.c
Linus Torvalds f62ce3de9d Make index preloading check the whole path to the file
This uses the new thread-safe 'threaded_has_symlink_leading_path()'
function to efficiently verify that the whole path leading up to the
filename is a proper path, and does not contain symlinks.

This makes 'ce_uptodate()' a much stronger guarantee: it no longer just
guarantees that the 'lstat()' of the path would match, it also means
that we know that people haven't played games with moving directories
around and covered it up with symlinks.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-07-09 22:38:34 -07:00

105 lines
2.3 KiB
C

/*
* Copyright (C) 2008 Linus Torvalds
*/
#include "cache.h"
#ifdef NO_PTHREADS
static void preload_index(struct index_state *index, const char **pathspec)
{
; /* nothing */
}
#else
#include <pthread.h>
/*
* Mostly randomly chosen maximum thread counts: we
* cap the parallelism to 20 threads, and we want
* to have at least 500 lstat's per thread for it to
* be worth starting a thread.
*/
#define MAX_PARALLEL (20)
#define THREAD_COST (500)
struct thread_data {
pthread_t pthread;
struct index_state *index;
const char **pathspec;
int offset, nr;
};
static void *preload_thread(void *_data)
{
int nr;
struct thread_data *p = _data;
struct index_state *index = p->index;
struct cache_entry **cep = index->cache + p->offset;
struct cache_def cache;
memset(&cache, 0, sizeof(cache));
nr = p->nr;
if (nr + p->offset > index->cache_nr)
nr = index->cache_nr - p->offset;
do {
struct cache_entry *ce = *cep++;
struct stat st;
if (ce_stage(ce))
continue;
if (ce_uptodate(ce))
continue;
if (!ce_path_match(ce, p->pathspec))
continue;
if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
continue;
if (lstat(ce->name, &st))
continue;
if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY))
continue;
ce_mark_uptodate(ce);
} while (--nr > 0);
return NULL;
}
static void preload_index(struct index_state *index, const char **pathspec)
{
int threads, i, work, offset;
struct thread_data data[MAX_PARALLEL];
if (!core_preload_index)
return;
threads = index->cache_nr / THREAD_COST;
if (threads < 2)
return;
if (threads > MAX_PARALLEL)
threads = MAX_PARALLEL;
offset = 0;
work = (index->cache_nr + threads - 1) / threads;
for (i = 0; i < threads; i++) {
struct thread_data *p = data+i;
p->index = index;
p->pathspec = pathspec;
p->offset = offset;
p->nr = work;
offset += work;
if (pthread_create(&p->pthread, NULL, preload_thread, p))
die("unable to create threaded lstat");
}
for (i = 0; i < threads; i++) {
struct thread_data *p = data+i;
if (pthread_join(p->pthread, NULL))
die("unable to join threaded lstat");
}
}
#endif
int read_index_preload(struct index_state *index, const char **pathspec)
{
int retval = read_index(index);
preload_index(index, pathspec);
return retval;
}