[PATCH 4/4] Add config option to enable 'fsync()' of object files
- From
Linus Torvalds <torvalds@linux-foundation.org>
- Date
- Jun 18, 2008, 22:32 UTC
- Message-ID
- <alpine.LFD.1.10.0806181531370.2907@woody.linux-foundation.org>
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- <alpine.LFD.1.10.0806181531120.2907@woody.linux-foundation.org>
From: Linus Torvalds <torvalds@linux-foundation.org> Date: Wed, 18 Jun 2008 15:18:44 -0700 Subject: [PATCH 4/4] Add config option to enable 'fsync()' of object files
As explained in the documentation[*] this is totally useless on filesystems that do ordered/journalled data writes, but it can be a useful safety feature on filesystems like HFS+ that only journal the metadata, not the actual file contents.
It defaults to off, although we could presumably in theory some day auto-enable it on a per-filesystem basis.
[*] Yes, I updated the docs for the thing. Hell really _has_ frozen
over, and the four horsemen are probably just beyond the horizon.
EVERYBODY PANIC!Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> ---
Ok, this is the actual real and trivial patch.
Documentation/config.txt | 8 ++++++++ cache.h | 1 + config.c | 5 +++++ environment.c | 1 + sha1_file.c | 3 ++- 5 files changed, 17 insertions(+), 1 deletions(-)
diff --git a/Documentation/config.txt b/Documentation/config.txt index 5331b45..01689f1 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -372,6 +372,14 @@ core.whitespace:: does not trigger if the character before such a carriage-return is not a whitespace (not enabled by default). +core.fsyncobjectfiles:: + This boolean will enable 'fsync()' when writing object files. ++ +This is a total waste of time and effort on a filesystem that orders +data writes properly, but can be useful for filesystems that do not use +journalling (traditional UNIX filesystems) or that only journal metadata +and not file contents (OS X's HFS+, or Linux ext3 with "data=writeback"). + alias.*:: Command aliases for the linkgit:git[1] command wrapper - e.g. after defining "alias.last = cat-file commit HEAD", the invocation diff --git a/cache.h b/cache.h index 81b7e17..01c8502 100644 --- a/cache.h +++ b/cache.h @@ -435,6 +435,7 @@ extern size_t packed_git_window_size; extern size_t packed_git_limit; extern size_t delta_base_cache_limit; extern int auto_crlf; +extern int fsync_object_files; enum safe_crlf { SAFE_CRLF_FALSE = 0, diff --git a/config.c b/config.c index 9d14a74..b2d5b4e 100644 --- a/config.c +++ b/config.c @@ -460,6 +460,11 @@ static int git_default_core_config(const char *var, const char *value) return 0; } + if (!strcmp(var, "core.fsyncobjectfiles")) { + fsync_object_files = git_config_bool(var, value); + return 0; + } + /* Add other config variables here and to Documentation/config.txt. */ return 0; } diff --git a/environment.c b/environment.c index 73feb2d..d5c3e29 100644 --- a/environment.c +++ b/environment.c @@ -29,6 +29,7 @@ const char *apply_default_whitespace; int zlib_compression_level = Z_BEST_SPEED; int core_compression_level; int core_compression_seen; +int fsync_object_files; size_t packed_git_window_size = DEFAULT_PACKED_GIT_WINDOW_SIZE; size_t packed_git_limit = DEFAULT_PACKED_GIT_LIMIT; size_t delta_base_cache_limit = 16 * 1024 * 1024; diff --git a/sha1_file.c b/sha1_file.c index e2a65c5..c34ac6d 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -2083,7 +2083,8 @@ int hash_sha1_file(const void *buf, unsigned long len, const char *type, /* Finalize a file on disk, and close it. */ static void close_sha1_file(int fd) { - /* For safe-mode, we could fsync_or_die(fd, "sha1 file") here */ + if (fsync_object_files) + fsync_or_die(fd, "sha1 file"); fchmod(fd, 0444); if (close(fd) != 0) die("unable to write sha1 file");
-- 1.5.6.rc3.7.g336d0.dirty