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| author | Junio C Hamano <gitster@pobox.com> | 2023-10-23 13:56:37 -0700 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2023-10-23 13:56:37 -0700 |
| commit | 5edbcead426056b54286499149244ae4cbf8b5f7 (patch) | |
| tree | ea98f4a8da0ff289aa9a87ff2c28893b05d6f8c6 | |
| parent | 626f689f7903b51342cf31ad3792ba5e9e41586d (diff) | |
| parent | 5143ac07b17e2b025865378fce24cc11ac7bf8b1 (diff) | |
| download | git-5edbcead426056b54286499149244ae4cbf8b5f7.tar.gz | |
Merge branch 'bc/racy-4gb-files'
The index file has room only for lower 32-bit of the file size in
the cached stat information, which means cached stat information
will have 0 in its sd_size member for a file whose size is multiple
of 4GiB. This is mistaken for a racily clean path. Avoid it by
storing a bogus sd_size value instead for such files.
* bc/racy-4gb-files:
Prevent git from rehashing 4GiB files
t: add a test helper to truncate files
| -rw-r--r-- | Makefile | 1 | ||||
| -rw-r--r-- | statinfo.c | 20 | ||||
| -rw-r--r-- | t/helper/test-tool.c | 1 | ||||
| -rw-r--r-- | t/helper/test-tool.h | 1 | ||||
| -rw-r--r-- | t/helper/test-truncate.c | 25 | ||||
| -rwxr-xr-x | t/t7508-status.sh | 16 |
6 files changed, 62 insertions, 2 deletions
@@ -852,6 +852,7 @@ TEST_BUILTINS_OBJS += test-submodule-nested-repo-config.o TEST_BUILTINS_OBJS += test-submodule.o TEST_BUILTINS_OBJS += test-subprocess.o TEST_BUILTINS_OBJS += test-trace2.o +TEST_BUILTINS_OBJS += test-truncate.o TEST_BUILTINS_OBJS += test-urlmatch-normalization.o TEST_BUILTINS_OBJS += test-userdiff.o TEST_BUILTINS_OBJS += test-wildmatch.o diff --git a/statinfo.c b/statinfo.c index 17bb8966c3..9367ca099c 100644 --- a/statinfo.c +++ b/statinfo.c @@ -2,6 +2,22 @@ #include "environment.h" #include "statinfo.h" +/* + * Munge st_size into an unsigned int. + */ +static unsigned int munge_st_size(off_t st_size) { + unsigned int sd_size = st_size; + + /* + * If the file is an exact multiple of 4 GiB, modify the value so it + * doesn't get marked as racily clean (zero). + */ + if (!sd_size && st_size) + return 0x80000000; + else + return sd_size; +} + void fill_stat_data(struct stat_data *sd, struct stat *st) { sd->sd_ctime.sec = (unsigned int)st->st_ctime; @@ -12,7 +28,7 @@ void fill_stat_data(struct stat_data *sd, struct stat *st) sd->sd_ino = st->st_ino; sd->sd_uid = st->st_uid; sd->sd_gid = st->st_gid; - sd->sd_size = st->st_size; + sd->sd_size = munge_st_size(st->st_size); } int match_stat_data(const struct stat_data *sd, struct stat *st) @@ -51,7 +67,7 @@ int match_stat_data(const struct stat_data *sd, struct stat *st) changed |= INODE_CHANGED; #endif - if (sd->sd_size != (unsigned int) st->st_size) + if (sd->sd_size != munge_st_size(st->st_size)) changed |= DATA_CHANGED; return changed; diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c index 9010ac6de7..876cd2dc31 100644 --- a/t/helper/test-tool.c +++ b/t/helper/test-tool.c @@ -86,6 +86,7 @@ static struct test_cmd cmds[] = { { "submodule-nested-repo-config", cmd__submodule_nested_repo_config }, { "subprocess", cmd__subprocess }, { "trace2", cmd__trace2 }, + { "truncate", cmd__truncate }, { "userdiff", cmd__userdiff }, { "urlmatch-normalization", cmd__urlmatch_normalization }, { "xml-encode", cmd__xml_encode }, diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h index f134f96b97..70dd4eba11 100644 --- a/t/helper/test-tool.h +++ b/t/helper/test-tool.h @@ -79,6 +79,7 @@ int cmd__submodule_config(int argc, const char **argv); int cmd__submodule_nested_repo_config(int argc, const char **argv); int cmd__subprocess(int argc, const char **argv); int cmd__trace2(int argc, const char **argv); +int cmd__truncate(int argc, const char **argv); int cmd__userdiff(int argc, const char **argv); int cmd__urlmatch_normalization(int argc, const char **argv); int cmd__xml_encode(int argc, const char **argv); diff --git a/t/helper/test-truncate.c b/t/helper/test-truncate.c new file mode 100644 index 0000000000..3931deaec7 --- /dev/null +++ b/t/helper/test-truncate.c @@ -0,0 +1,25 @@ +#include "test-tool.h" +#include "git-compat-util.h" + +/* + * Truncate a file to the given size. + */ +int cmd__truncate(int argc, const char **argv) +{ + char *p = NULL; + uintmax_t sz = 0; + int fd = -1; + + if (argc != 3) + die("expected filename and size"); + + sz = strtoumax(argv[2], &p, 0); + if (*p) + die("invalid size"); + + fd = xopen(argv[1], O_WRONLY | O_CREAT, 0600); + + if (ftruncate(fd, (off_t) sz) < 0) + die_errno("failed to truncate file"); + return 0; +} diff --git a/t/t7508-status.sh b/t/t7508-status.sh index 6928fd89f5..6c46648e11 100755 --- a/t/t7508-status.sh +++ b/t/t7508-status.sh @@ -1745,4 +1745,20 @@ test_expect_success 'slow status advice when core.untrackedCache true, and fsmon ) ' +test_expect_success EXPENSIVE 'status does not re-read unchanged 4 or 8 GiB file' ' + ( + mkdir large-file && + cd large-file && + # Files are 2 GiB, 4 GiB, and 8 GiB sparse files. + test-tool truncate file-a 0x080000000 && + test-tool truncate file-b 0x100000000 && + test-tool truncate file-c 0x200000000 && + # This will be slow. + git add file-a file-b file-c && + git commit -m "add large files" && + git diff-index HEAD file-a file-b file-c >actual && + test_must_be_empty actual + ) +' + test_done |