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Record ns-timestamps if possible, but do not use it without USE_NSEC 

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>
This commit is contained in:
Kjetil Barvik 2009-03-04 18:47:40 +01:00 committed by Junio C Hamano
parent e1afca4fd3
commit c06ff4908b
5 changed files with 22 additions and 30 deletions
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8
Makefile
View File

@ -126,6 +126,9 @@ all::
# randomly break unless your underlying filesystem supports those sub-second
# times (my ext3 doesn't).
#
# Define NO_NSEC if your "struct stat" does not have "st_ctim.tv_nsec"
# available. This automatically turns USE_NSEC off.
#
# Define USE_STDEV below if you want git to care about the underlying device
# change being considered an inode change from the update-index perspective.
#
@ -737,6 +740,7 @@ ifeq ($(uname_S),AIX)
NO_MEMMEM = YesPlease
NO_MKDTEMP = YesPlease
NO_STRLCPY = YesPlease
NO_NSEC = YesPlease
FREAD_READS_DIRECTORIES = UnfortunatelyYes
INTERNAL_QSORT = UnfortunatelyYes
NEEDS_LIBICONV=YesPlease
@ -802,6 +806,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
RUNTIME_PREFIX = YesPlease
NO_POSIX_ONLY_PROGRAMS = YesPlease
NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
NO_NSEC = YesPlease
COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/regex -Icompat/fnmatch
COMPAT_CFLAGS += -DSNPRINTF_SIZE_CORR=1
COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
@ -923,6 +928,9 @@ endif
ifdef NO_ST_BLOCKS_IN_STRUCT_STAT
BASIC_CFLAGS += -DNO_ST_BLOCKS_IN_STRUCT_STAT
endif
ifdef NO_NSEC
BASIC_CFLAGS += -DNO_NSEC
endif
ifdef NO_C99_FORMAT
BASIC_CFLAGS += -DNO_C99_FORMAT
endif

4
builtin-fetch-pack.c
View File

@ -801,9 +801,7 @@ struct ref *fetch_pack(struct fetch_pack_args *my_args,
int fd;
mtime.sec = st.st_mtime;
#ifdef USE_NSEC
mtime.nsec = st.st_mtim.tv_nsec;
#endif
mtime.nsec = ST_MTIME_NSEC(st);
if (stat(shallow, &st)) {
if (mtime.sec)
die("shallow file was removed during fetch");

9
git-compat-util.h
View File

@ -384,4 +384,13 @@ void git_qsort(void *base, size_t nmemb, size_t size,
# define FORCE_DIR_SET_GID 0
#endif
#ifdef NO_NSEC
#undef USE_NSEC
#define ST_CTIME_NSEC(st) 0
#define ST_MTIME_NSEC(st) 0
#else
#define ST_CTIME_NSEC(st) ((unsigned int)((st).st_ctim.tv_nsec))
#define ST_MTIME_NSEC(st) ((unsigned int)((st).st_mtim.tv_nsec))
#endif
#endif

29
read-cache.c
View File

@ -69,13 +69,8 @@ void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
{
ce->ce_ctime.sec = (unsigned int)st->st_ctime;
ce->ce_mtime.sec = (unsigned int)st->st_mtime;
#ifdef USE_NSEC
ce->ce_ctime.nsec = (unsigned int)st->st_ctim.tv_nsec;
ce->ce_mtime.nsec = (unsigned int)st->st_mtim.tv_nsec;
#else
ce->ce_ctime.nsec = 0;
ce->ce_mtime.nsec = 0;
#endif
ce->ce_ctime.nsec = ST_CTIME_NSEC(*st);
ce->ce_mtime.nsec = ST_MTIME_NSEC(*st);
ce->ce_dev = st->st_dev;
ce->ce_ino = st->st_ino;
ce->ce_uid = st->st_uid;
@ -1183,13 +1178,8 @@ static void convert_from_disk(struct ondisk_cache_entry *ondisk, struct cache_en
ce->ce_ctime.sec = ntohl(ondisk->ctime.sec);
ce->ce_mtime.sec = ntohl(ondisk->mtime.sec);
#ifdef USE_NSEC
ce->ce_ctime.nsec = ntohl(ondisk->ctime.nsec);
ce->ce_mtime.nsec = ntohl(ondisk->mtime.nsec);
#else
ce->ce_ctime.nsec = 0;
ce->ce_mtime.nsec = 0;
#endif
ce->ce_dev = ntohl(ondisk->dev);
ce->ce_ino = ntohl(ondisk->ino);
ce->ce_mode = ntohl(ondisk->mode);
@ -1309,11 +1299,7 @@ int read_index_from(struct index_state *istate, const char *path)
dst_offset += ce_size(ce);
}
istate->timestamp.sec = st.st_mtime;
#ifdef USE_NSEC
istate->timestamp.nsec = (unsigned int)st.st_mtim.tv_nsec;
#else
istate->timestamp.nsec = 0;
#endif
istate->timestamp.nsec = ST_MTIME_NSEC(st);
while (src_offset <= mmap_size - 20 - 8) {
/* After an array of active_nr index entries,
@ -1500,13 +1486,8 @@ static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
ondisk->ctime.sec = htonl(ce->ce_ctime.sec);
ondisk->mtime.sec = htonl(ce->ce_mtime.sec);
#ifdef USE_NSEC
ondisk->ctime.nsec = htonl(ce->ce_ctime.nsec);
ondisk->mtime.nsec = htonl(ce->ce_mtime.nsec);
#else
ondisk->ctime.nsec = 0;
ondisk->mtime.nsec = 0;
#endif
ondisk->dev = htonl(ce->ce_dev);
ondisk->ino = htonl(ce->ce_ino);
ondisk->mode = htonl(ce->ce_mode);
@ -1583,9 +1564,7 @@ int write_index(struct index_state *istate, int newfd)
if (ce_flush(&c, newfd) || fstat(newfd, &st))
return -1;
istate->timestamp.sec = (unsigned int)st.st_ctime;
#ifdef USE_NSEC
istate->timestamp.nsec = (unsigned int)st.st_ctim.tv_nsec;
#endif
istate->timestamp.nsec = ST_CTIME_NSEC(st);
return 0;
}

2
unpack-trees.c
View File

@ -362,9 +362,7 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
o->result.initialized = 1;
if (o->src_index) {
o->result.timestamp.sec = o->src_index->timestamp.sec;
#ifdef USE_NSEC
o->result.timestamp.nsec = o->src_index->timestamp.nsec;
#endif
}
o->merge_size = len;