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authorJunio C Hamano <junkio@cox.net>2006-08-12 19:41:44 -0700
committerJunio C Hamano <junkio@cox.net>2006-08-12 19:41:44 -0700
commitc1e4572b7d3447949ed2da1ab290217a70cf3933 (patch)
tree0d1fdd615e6d442f89bde5791aef87ea39fc6205
parentf3c5b39567535a41a371aad8a6affbeea0d4c0b9 (diff)
parent6015c28b1d6163f124332769989326ee470afbb6 (diff)
downloadgit-c1e4572b7d3447949ed2da1ab290217a70cf3933.tar.gz
git-c1e4572b7d3447949ed2da1ab290217a70cf3933.tar.xz
Merge branch 'jc/racy-delay'
-rw-r--r--read-cache.c75
1 files changed, 71 insertions, 4 deletions
diff --git a/read-cache.c b/read-cache.c
index f92cdaace..c923a3270 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -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);
}