undef/git-commit-vandalism
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Use O_NOATIME when opening the sha1 files.

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We really don't care about atime, and it sucks to dirty the
inode cache just for it.

This is more than a one-liner only because we need to be able to
clear the O_NOATIME flag in case some of the objects are owned
by others (in which case open will return EPERM), and because not
everybody has the O_NOATIME flag.
This commit is contained in:
Linus Torvalds 2005-04-23 11:09:32 -07:00
parent a6ef3518f9
commit 144bde78e9
1 changed files with 26 additions and 3 deletions
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29
sha1_file.c
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@ -11,6 +11,16 @@
const char *sha1_file_directory = NULL; const char *sha1_file_directory = NULL;
#ifndef O_NOATIME
#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
#define O_NOATIME 01000000
#else
#define O_NOATIME 0
#endif
#endif
static unsigned int sha1_file_open_flag = O_NOATIME;
static unsigned hexval(char c) static unsigned hexval(char c)
{ {
if (c >= '0' && c <= '9') if (c >= '0' && c <= '9')
@ -96,13 +106,26 @@ int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, con
void *map_sha1_file(const unsigned char *sha1, unsigned long *size) void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
{ {
char *filename = sha1_file_name(sha1); char *filename = sha1_file_name(sha1);
int fd = open(filename, O_RDONLY);
struct stat st; struct stat st;
void *map; void *map;
int fd;
fd = open(filename, O_RDONLY | sha1_file_open_flag);
if (fd < 0) { if (fd < 0) {
perror(filename); /* See if it works without O_NOATIME */
return NULL; switch (sha1_file_open_flag) {
default:
fd = open(filename, O_RDONLY);
if (fd >= 0)
break;
/* Fallthrough */
case 0:
perror(filename);
return NULL;
}
/* If it failed once, it will probably fail again. Stop using O_NOATIME */
sha1_file_open_flag = 0;
} }
if (fstat(fd, &st) < 0) { if (fstat(fd, &st) < 0) {
close(fd); close(fd);