From: Neeraj Singh <neerajsi@xxxxxxxxxxxxx>
This commit introduces the new ability for the user to harden
the index. In the event of a system crash, the index must be
durable for the user to actually find a file that has been added
to the repo and then deleted from the working tree.
We use the presence of the COMMIT_LOCK flag and absence of the
alternate_index_output as a proxy for determining whether we're
updating the persistent index of the repo or some temporary
index. We don't sync these temporary indexes.
Signed-off-by: Neeraj Singh <neerajsi@xxxxxxxxxxxxx>
---
Documentation/config/core.txt | 1 +
cache.h | 4 +++-
config.c | 1 +
read-cache.c | 19 +++++++++++++------
4 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt
index 4f1747ec871..8e5b7a795ab 100644
--- a/Documentation/config/core.txt
+++ b/Documentation/config/core.txt
@@ -561,6 +561,7 @@ core.fsync::
* `pack` hardens objects added to the repo in packfile form.
* `pack-metadata` hardens packfile bitmaps and indexes.
* `commit-graph` hardens the commit graph file.
+* `index` hardens the index when it is modified.
* `objects` is an aggregate option that includes `loose-objects`, `pack`,
`pack-metadata`, and `commit-graph`.
* `default` is an aggregate option that is equivalent to `objects,-loose-object`
diff --git a/cache.h b/cache.h
index d83fbaf2619..4dc26d7b2c9 100644
--- a/cache.h
+++ b/cache.h
@@ -996,6 +996,7 @@ enum fsync_component {
FSYNC_COMPONENT_PACK = 1 << 1,
FSYNC_COMPONENT_PACK_METADATA = 1 << 2,
FSYNC_COMPONENT_COMMIT_GRAPH = 1 << 3,
+ FSYNC_COMPONENT_INDEX = 1 << 4,
};
#define FSYNC_COMPONENTS_DEFAULT (FSYNC_COMPONENT_PACK | \
@@ -1010,7 +1011,8 @@ enum fsync_component {
#define FSYNC_COMPONENTS_ALL (FSYNC_COMPONENT_LOOSE_OBJECT | \
FSYNC_COMPONENT_PACK | \
FSYNC_COMPONENT_PACK_METADATA | \
- FSYNC_COMPONENT_COMMIT_GRAPH)
+ FSYNC_COMPONENT_COMMIT_GRAPH | \
+ FSYNC_COMPONENT_INDEX)
/*
diff --git a/config.c b/config.c
index 29c867aab03..17039fa9c10 100644
--- a/config.c
+++ b/config.c
@@ -1221,6 +1221,7 @@ static const struct fsync_component_entry {
{ "pack", FSYNC_COMPONENT_PACK },
{ "pack-metadata", FSYNC_COMPONENT_PACK_METADATA },
{ "commit-graph", FSYNC_COMPONENT_COMMIT_GRAPH },
+ { "index", FSYNC_COMPONENT_INDEX },
{ "objects", FSYNC_COMPONENTS_OBJECTS },
{ "default", FSYNC_COMPONENTS_DEFAULT },
{ "all", FSYNC_COMPONENTS_ALL },
diff --git a/read-cache.c b/read-cache.c
index f3539681f49..783cb3ea5db 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -2816,7 +2816,7 @@ static int record_ieot(void)
* rely on it.
*/
static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
- int strip_extensions)
+ int strip_extensions, unsigned flags)
{
uint64_t start = getnanotime();
struct hashfile *f;
@@ -2830,6 +2830,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
int drop_cache_tree = istate->drop_cache_tree;
off_t offset;
+ int csum_fsync_flag;
int ieot_entries = 1;
struct index_entry_offset_table *ieot = NULL;
int nr, nr_threads;
@@ -3060,7 +3061,13 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
return -1;
}
- finalize_hashfile(f, istate->oid.hash, FSYNC_COMPONENT_NONE, CSUM_HASH_IN_STREAM);
+ csum_fsync_flag = 0;
+ if (!alternate_index_output && (flags & COMMIT_LOCK))
+ csum_fsync_flag = CSUM_FSYNC;
+
+ finalize_hashfile(f, istate->oid.hash, FSYNC_COMPONENT_INDEX,
+ CSUM_HASH_IN_STREAM | csum_fsync_flag);
+
if (close_tempfile_gently(tempfile)) {
error(_("could not close '%s'"), get_tempfile_path(tempfile));
return -1;
@@ -3115,7 +3122,7 @@ static int do_write_locked_index(struct index_state *istate, struct lock_file *l
*/
trace2_region_enter_printf("index", "do_write_index", the_repository,
"%s", get_lock_file_path(lock));
- ret = do_write_index(istate, lock->tempfile, 0);
+ ret = do_write_index(istate, lock->tempfile, 0, flags);
trace2_region_leave_printf("index", "do_write_index", the_repository,
"%s", get_lock_file_path(lock));
@@ -3209,7 +3216,7 @@ static int clean_shared_index_files(const char *current_hex)
}
static int write_shared_index(struct index_state *istate,
- struct tempfile **temp)
+ struct tempfile **temp, unsigned flags)
{
struct split_index *si = istate->split_index;
int ret, was_full = !istate->sparse_index;
@@ -3219,7 +3226,7 @@ static int write_shared_index(struct index_state *istate,
trace2_region_enter_printf("index", "shared/do_write_index",
the_repository, "%s", get_tempfile_path(*temp));
- ret = do_write_index(si->base, *temp, 1);
+ ret = do_write_index(si->base, *temp, 1, flags);
trace2_region_leave_printf("index", "shared/do_write_index",
the_repository, "%s", get_tempfile_path(*temp));
@@ -3328,7 +3335,7 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
ret = do_write_locked_index(istate, lock, flags);
goto out;
}
- ret = write_shared_index(istate, &temp);
+ ret = write_shared_index(istate, &temp, flags);
saved_errno = errno;
if (is_tempfile_active(temp))
--
gitgitgadget
