Johannes SchindelinIt seems that accessing NTFS partitions with ufsd (at least on my EeePC) has an unnerving bug: if you link() a file and unlink() it right away, the target of the link() will have the correct size, but consist of NULs.
It seems as if the calls are simply not serialized correctly, as single-stepping through the function move_temp_to_file() works flawlessly.
As ufsd is "Commertial software", I cannot fix it, and have to work around it in Git.
At the same time, it seems that this fixes msysGit issues 222 and 229 to assume that Windows cannot handle link() && unlink().
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> ---
I know this is pretty late in the -rc1 cycle, but this is something I need to apply for msysGit anyway.
And it does not really seem too unobvious a fix, does it?
Documentation/config.txt | 5 +++++ Makefile | 8 ++++++++ cache.h | 2 ++ config.c | 5 +++++ environment.c | 4 ++++ sha1_file.c | 4 +++- 6 files changed, 27 insertions(+), 1 deletions(-)
Show changes to 6 files +27 −1
Documentation/config.txt, Makefile, cache.h, config.c, environment.c, sha1_file.c
diff --git a/Documentation/config.txt b/Documentation/config.txt index 35056e1..62cd903 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -429,6 +429,11 @@ relatively high IO latencies. With this set to 'true', git will do the index comparison to the filesystem data in parallel, allowing overlapping IO's. +core.unreliableHardlinks:: + Some filesystem drivers cannot properly handle hardlinking a file + and deleting the source right away. In such a case, you need to + set this config variable to 'true'. + 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/Makefile b/Makefile index 49f36f5..e3979e0 100644 --- a/Makefile +++ b/Makefile @@ -171,6 +171,10 @@ all:: # Define UNRELIABLE_FSTAT if your system's fstat does not return the same # information on a not yet closed file that lstat would return for the same # file after it was closed. +# +# Define UNRELIABLE_HARDLINKS if your operating systems has problems when +# hardlinking a file to another name and unlinking the original file right +# away (some NTFS drivers seem to zero the contents in that scenario). GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE @$(SHELL_PATH) ./GIT-VERSION-GEN @@ -835,6 +839,7 @@ ifneq (,$(findstring MINGW,$(uname_S))) NO_NSEC = YesPlease USE_WIN32_MMAP = YesPlease UNRELIABLE_FSTAT = UnfortunatelyYes + UNRELIABLE_HARDLINKS = UnfortunatelySometimes COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/regex -Icompat/fnmatch COMPAT_CFLAGS += -DSNPRINTF_SIZE_CORR=1 COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\" @@ -1018,6 +1023,9 @@ else COMPAT_OBJS += compat/win32mmap.o endif endif +ifdef UNRELIABLE_HARDLINKS + COMPAT_CFLAGS += -DUNRELIABLE_HARDLINKS=1 +endif ifdef NO_PREAD COMPAT_CFLAGS += -DNO_PREAD COMPAT_OBJS += compat/pread.o diff --git a/cache.h b/cache.h index ab1294d..ff9e145 100644 --- a/cache.h +++ b/cache.h @@ -554,6 +554,8 @@ extern enum branch_track git_branch_track; extern enum rebase_setup_type autorebase; extern enum push_default_type push_default; +extern int unreliable_hardlinks; + #define GIT_REPO_VERSION 0 extern int repository_format_version; extern int check_repository_format(void); diff --git a/config.c b/config.c index 8c1ae59..1750cfb 100644 --- a/config.c +++ b/config.c @@ -495,6 +495,11 @@ static int git_default_core_config(const char *var, const char *value) return 0; } + if (!strcmp(var, "core.unreliablehardlinks")) { + unreliable_hardlinks = 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 4696885..10578d2 100644 --- a/environment.c +++ b/environment.c @@ -43,6 +43,10 @@ unsigned whitespace_rule_cfg = WS_DEFAULT_RULE; enum branch_track git_branch_track = BRANCH_TRACK_REMOTE; enum rebase_setup_type autorebase = AUTOREBASE_NEVER; enum push_default_type push_default = PUSH_DEFAULT_UNSPECIFIED; +#ifndef UNRELIABLE_HARDLINKS +#define UNRELIABLE_HARDLINKS 0 +#endif +int unreliable_hardlinks = UNRELIABLE_HARDLINKS; /* Parallel index stat data preload? */ int core_preload_index = 0; diff --git a/sha1_file.c b/sha1_file.c index 8fe135d..f5a7970 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -2225,7 +2225,9 @@ int move_temp_to_file(const char *tmpfile, const char *filename) { int ret = 0; - if (link(tmpfile, filename)) + if (unreliable_hardlinks) + ret = ~EEXIST; + else if (link(tmpfile, filename)) ret = errno; /*
-- 1.6.2.1.613.g25746
