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Merge branch 'jc/racy-delay' into next

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* jc/racy-delay:
  Racy git: avoid having to be always too careful
This commit is contained in:
Junio C Hamano
2006-08-07 01:59:10 -07:00
parent 6eca01426d b7e58b17b5
commit 7c7e45d0cc
1 changed files with 40 additions and 4 deletions
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44
read-cache.c
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@@ -5,6 +5,7 @@
*/
#include "cache.h"
#include "cache-tree.h"
#include <time.h>
/* Index extensions.
*
@@ -940,7 +941,7 @@ 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
@@ -962,7 +963,9 @@ 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)
@@ -976,15 +979,19 @@ int write_cache(int newfd, struct cache_entry **cache, int entries)
if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
return -1;
now = fstat(newfd, &st) ? 0 : st.st_mtime;
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 (index_file_timestamp &&
index_file_timestamp <= ntohl(ce->ce_mtime.sec))
if (index_file_timestamp && index_file_timestamp <= entry_time)
ce_smudge_racily_clean_entry(ce);
if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
return -1;
if (now && now <= entry_time)
recent++;
}
/* Write extension data here */
@@ -1000,5 +1007,34 @@ 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.
*/
if (20 < recent || entries <= recent * 4) {
now = fstat(newfd, &st) ? 0 : st.st_mtime;
while (now && !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);
}