undef/git-commit-vandalism
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Merge branch 'jc/racy-delay'

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This commit is contained in:
Junio C Hamano 2006-08-12 19:41:44 -07:00
commit c1e4572b7d
1 changed files with 71 additions and 4 deletions
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75
read-cache.c
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@ -5,6 +5,7 @@
*/
#include "cache.h"
#include "cache-tree.h"
#include <time.h>
/* Index extensions.
*
@ -840,6 +841,18 @@ unmap:
static unsigned char write_buffer[WRITE_BUFFER_SIZE];
static unsigned long write_buffer_len;
static int ce_write_flush(SHA_CTX *context, int fd)
{
unsigned int buffered = write_buffer_len;
if (buffered) {
SHA1_Update(context, write_buffer, buffered);
if (write(fd, write_buffer, buffered) != buffered)
return -1;
write_buffer_len = 0;
}
return 0;
}
static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
{
while (len) {
@ -850,8 +863,8 @@ static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
memcpy(write_buffer + buffered, data, partial);
buffered += partial;
if (buffered == WRITE_BUFFER_SIZE) {
SHA1_Update(context, write_buffer, WRITE_BUFFER_SIZE);
if (write(fd, write_buffer, WRITE_BUFFER_SIZE) != WRITE_BUFFER_SIZE)
write_buffer_len = buffered;
if (ce_write_flush(context, fd))
return -1;
buffered = 0;
}
@ -923,7 +936,7 @@ static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
* $ echo filfre >nitfol
* $ git-update-index --add nitfol
*
* but it does not. Whe the second update-index runs,
* but it does not. When the second update-index runs,
* it notices that the entry "frotz" has the same timestamp
* as index, and if we were to smudge it by resetting its
* size to zero here, then the object name recorded
@ -945,7 +958,9 @@ int write_cache(int newfd, struct cache_entry **cache, int entries)
{
SHA_CTX c;
struct cache_header hdr;
int i, removed;
int i, removed, recent;
struct stat st;
time_t now;
for (i = removed = 0; i < entries; i++)
if (!cache[i]->ce_mode)
@ -983,5 +998,57 @@ int write_cache(int newfd, struct cache_entry **cache, int entries)
return -1;
}
}
/*
* To prevent later ce_match_stat() from always falling into
* check_fs(), if we have too many entries that can trigger
* racily clean check, we are better off delaying the return.
* We arbitrarily say if more than 20 paths or 25% of total
* paths are very new, we delay the return until the index
* file gets a new timestamp.
*
* NOTE! NOTE! NOTE!
*
* This assumes that nobody is touching the working tree while
* we are updating the index.
*/
/* Make sure that the new index file has st_mtime
* that is current enough -- ce_write() batches the data
* so it might not have written anything yet.
*/
ce_write_flush(&c, newfd);
now = fstat(newfd, &st) ? 0 : st.st_mtime;
if (now) {
recent = 0;
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
time_t entry_time = (time_t) ntohl(ce->ce_mtime.sec);
if (!ce->ce_mode)
continue;
if (now && now <= entry_time)
recent++;
}
if (20 < recent && entries <= recent * 4) {
#if 0
fprintf(stderr, "entries %d\n", entries);
fprintf(stderr, "recent %d\n", recent);
fprintf(stderr, "now %lu\n", now);
#endif
while (!fstat(newfd, &st) && st.st_mtime <= now) {
struct timespec rq, rm;
off_t where = lseek(newfd, 0, SEEK_CUR);
rq.tv_sec = 0;
rq.tv_nsec = 250000000;
nanosleep(&rq, &rm);
if ((where == (off_t) -1) ||
(write(newfd, "", 1) != 1) ||
(lseek(newfd, -1, SEEK_CUR) != where) ||
ftruncate(newfd, where))
break;
}
}
}
return ce_flush(&c, newfd);
}