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| author | Junio C Hamano <gitster@pobox.com> | 2015-07-13 14:00:26 -0700 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2015-07-13 14:00:26 -0700 |
| commit | 43f23b09bffed2ab8852725e26f746d1f762cc85 (patch) | |
| tree | 0de5057d26f8c47b326869f698856a4ac42adeeb | |
| parent | e01787f1a1de589b7adc6f6946b53996a5e74c34 (diff) | |
| parent | b1ffafa978b99ed65b3c040ae762bfdec2379cfc (diff) | |
| download | git-43f23b09bffed2ab8852725e26f746d1f762cc85.tar.gz git-43f23b09bffed2ab8852725e26f746d1f762cc85.tar.xz | |
Merge branch 'kb/use-nsec-doc'
Clarify in the Makefile a guideline to decide use of USE_NSEC.
* kb/use-nsec-doc:
Makefile / racy-git.txt: clarify USE_NSEC prerequisites
| -rw-r--r-- | Documentation/technical/racy-git.txt | 8 | ||||
| -rw-r--r-- | Makefile | 9 |
2 files changed, 11 insertions, 6 deletions
diff --git a/Documentation/technical/racy-git.txt b/Documentation/technical/racy-git.txt index 242a044db..4a8be4d14 100644 --- a/Documentation/technical/racy-git.txt +++ b/Documentation/technical/racy-git.txt @@ -41,13 +41,17 @@ With a `USE_STDEV` compile-time option, `st_dev` is also compared, but this is not enabled by default because this member is not stable on network filesystems. With `USE_NSEC` compile-time option, `st_mtim.tv_nsec` and `st_ctim.tv_nsec` -members are also compared, but this is not enabled by default +members are also compared. On Linux, this is not enabled by default because in-core timestamps can have finer granularity than on-disk timestamps, resulting in meaningless changes when an inode is evicted from the inode cache. See commit 8ce13b0 of git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git ([PATCH] Sync in core time granularity with filesystems, -2005-01-04). +2005-01-04). This patch is included in kernel 2.6.11 and newer, but +only fixes the issue for file systems with exactly 1 ns or 1 s +resolution. Other file systems are still broken in current Linux +kernels (e.g. CEPH, CIFS, NTFS, UDF), see +https://lkml.org/lkml/2015/6/9/714 Racy Git -------- @@ -217,10 +217,11 @@ all:: # as the compiler can crash (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49299) # # Define USE_NSEC below if you want git to care about sub-second file mtimes -# and ctimes. Note that you need recent glibc (at least 2.2.4) for this, and -# it will BREAK YOUR LOCAL DIFFS! show-diff and anything using it will likely -# randomly break unless your underlying filesystem supports those sub-second -# times (my ext3 doesn't). +# and ctimes. Note that you need recent glibc (at least 2.2.4) for this. On +# Linux, kernel 2.6.11 or newer is required for reliable sub-second file times +# on file systems with exactly 1 ns or 1 s resolution. If you intend to use Git +# on other file systems (e.g. CEPH, CIFS, NTFS, UDF), don't enable USE_NSEC. See +# Documentation/technical/racy-git.txt for details. # # Define USE_ST_TIMESPEC if your "struct stat" uses "st_ctimespec" instead of # "st_ctim" |