From: Jeff King <peff@peff.net>
To: steve.norman@thomsonreuters.com
Cc: pclouds@gmail.com, git@vger.kernel.org,
Michael Haggerty <mhagger@alum.mit.edu>
Subject: [PATCH 1/3] stat_validity: handle non-regular files
Date: Fri, 22 May 2015 19:51:43 -0400 [thread overview]
Message-ID: <20150522235143.GA4818@peff.net> (raw)
In-Reply-To: <20150522235116.GA4300@peff.net>
The stat_validity code was originally written to avoid
re-reading the packed-refs file when it has not changed. It
makes sure that the file continues to match S_ISREG() when
we check it.
However, we can use the same concept on a directory to see
whether it has been modified. Even though we still have to
touch the filesystem to do the stat, this can provide a
speedup even over opendir/readdir/closedir, especially on
high-latency filesystems like NFS.
This patch adds a "mode" field to stat_validity, which lets
us check that the mode has stayed the same (rather than
explicitly checking that it is a regular file).
As a bonus cleanup, we can stop allocating the embedded
"stat_data" on the heap. Prior to this patch, we needed to
represent the case where the file did not exist, and we used
"sv->sd == NULL" for that. Now we can simply check that
"sv->mode" is 0.
Signed-off-by: Jeff King <peff@peff.net>
---
cache.h | 3 ++-
read-cache.c | 16 ++++++----------
2 files changed, 8 insertions(+), 11 deletions(-)
diff --git a/cache.h b/cache.h
index c97d807..2941e7e 100644
--- a/cache.h
+++ b/cache.h
@@ -1660,7 +1660,8 @@ int sane_execvp(const char *file, char *const argv[]);
* for the index.
*/
struct stat_validity {
- struct stat_data *sd;
+ struct stat_data sd;
+ unsigned mode;
};
void stat_validity_clear(struct stat_validity *sv);
diff --git a/read-cache.c b/read-cache.c
index 36ff89f..115b000 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -2279,8 +2279,7 @@ void *read_blob_data_from_index(struct index_state *istate, const char *path, un
void stat_validity_clear(struct stat_validity *sv)
{
- free(sv->sd);
- sv->sd = NULL;
+ memset(sv, 0, sizeof(*sv));
}
int stat_validity_check(struct stat_validity *sv, const char *path)
@@ -2288,21 +2287,18 @@ int stat_validity_check(struct stat_validity *sv, const char *path)
struct stat st;
if (stat(path, &st) < 0)
- return sv->sd == NULL;
- if (!sv->sd)
- return 0;
- return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st);
+ return sv->mode == 0;
+ return sv->mode == st.st_mode && !match_stat_data(&sv->sd, &st);
}
void stat_validity_update(struct stat_validity *sv, int fd)
{
struct stat st;
- if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode))
+ if (fstat(fd, &st) < 0)
stat_validity_clear(sv);
else {
- if (!sv->sd)
- sv->sd = xcalloc(1, sizeof(struct stat_data));
- fill_stat_data(sv->sd, &st);
+ sv->mode = st.st_mode;
+ fill_stat_data(&sv->sd, &st);
}
}
--
2.4.1.538.g69ac333
next prev parent reply other threads:[~2015-05-22 23:51 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-21 13:13 Troubleshoot clone issue to NFS steve.norman
2015-05-21 14:00 ` Christian Couder
2015-05-21 14:31 ` Duy Nguyen
2015-05-21 14:38 ` Duy Nguyen
2015-05-21 15:53 ` steve.norman
2015-05-22 0:16 ` Duy Nguyen
2015-05-22 7:12 ` Jeff King
2015-05-22 8:35 ` steve.norman
2015-05-22 10:05 ` Duy Nguyen
2015-05-22 14:37 ` Junio C Hamano
2015-05-22 15:02 ` steve.norman
2015-05-22 23:51 ` [PATCH/RFC 0/3] using stat() to avoid re-scanning pack dir Jeff King
2015-05-22 23:51 ` Jeff King [this message]
2015-05-23 11:00 ` [PATCH 1/3] stat_validity: handle non-regular files Michael Haggerty
2015-05-24 8:29 ` Jeff King
2015-05-22 23:52 ` [PATCH 2/3] cache.h: move stat_validity definition up Jeff King
2015-05-22 23:54 ` [PATCH 3/3] prepare_packed_git: use stat_validity to avoid re-reading packs Jeff King
2015-05-23 1:19 ` [PATCH/RFC 0/3] using stat() to avoid re-scanning pack dir Duy Nguyen
2015-05-23 1:21 ` Duy Nguyen
2015-05-24 8:20 ` Jeff King
2015-05-24 9:00 ` Troubleshoot clone issue to NFS Duy Nguyen
2015-06-05 12:01 ` steve.norman
2015-06-05 12:18 ` Jeff King
2015-06-05 12:29 ` [PATCH] index-pack: avoid excessive re-reading of pack directory Jeff King
2015-06-09 17:24 ` Jeff King
2015-06-09 17:41 ` Jeff King
2015-06-10 3:46 ` Shawn Pearce
2015-06-10 14:00 ` Jeff King
2015-06-10 14:36 ` Duy Nguyen
2015-06-10 21:34 ` Shawn Pearce
2015-06-05 14:20 ` Troubleshoot clone issue to NFS steve.norman
2015-06-16 20:50 ` Jeff King
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