Hi,
this is the third version of my patch series that implements support for
graceful concurrent writes with the reftable backend.
There is only a single change compared to v2, namely that we handle `0`
and `-1` for the lock timeout config. With `0` we fail immediately, with
`-1` we lock indefinitely. This matches semantics of loose and packed
ref locking.
Thanks!
Patrick
Patrick Steinhardt (3):
refs/reftable: introduce "reftable.lockTimeout"
reftable/stack: allow locking of outdated stacks
refs/reftable: reload locked stack when preparing transaction
Documentation/config/reftable.txt | 8 ++++
refs/reftable-backend.c | 13 +++++-
reftable/reftable-stack.h | 13 +++++-
reftable/reftable-writer.h | 11 +++++
reftable/stack.c | 38 ++++++++++++------
t/t0610-reftable-basics.sh | 58 ++++++++++++++++++++++++++
t/unit-tests/t-reftable-stack.c | 67 ++++++++++++++++++++++++++++++-
7 files changed, 189 insertions(+), 19 deletions(-)
Range-diff against v2:
1: 700a35df125 ! 1: 77cffd3b1eb refs/reftable: introduce "reftable.lockTimeout"
@@ Documentation/config/reftable.txt: reftable.geometricFactor::
+ Whenever the reftable backend appends a new table to the stack, it has
+ to lock the central "tables.list" file before updating it. This config
+ controls how long the process will wait to acquire the lock in case
-+ another process has already acquired it. Default is 100 (i.e., retry
-+ for 100ms).
++ another process has already acquired it. Value 0 means not to retry at
++ all; -1 means to try indefinitely. Default is 100 (i.e., retry for
++ 100ms).
## refs/reftable-backend.c ##
@@ refs/reftable-backend.c: static int reftable_be_config(const char *var, const char *value,
@@ refs/reftable-backend.c: static int reftable_be_config(const char *var, const ch
die("reftable geometric factor cannot exceed %u", (unsigned)UINT8_MAX);
opts->auto_compaction_factor = factor;
+ } else if (!strcmp(var, "reftable.locktimeout")) {
-+ unsigned long lock_timeout = git_config_ulong(var, value, ctx->kvi);
++ int64_t lock_timeout = git_config_int64(var, value, ctx->kvi);
++ if (lock_timeout > LONG_MAX)
++ die("reftable lock timeout cannot exceed %"PRIdMAX, (intmax_t)LONG_MAX);
++ if (lock_timeout < 0 && lock_timeout != -1)
++ die("reftable lock timeout does not support negative values other than -1");
+ opts->lock_timeout_ms = lock_timeout;
}
@@ reftable/reftable-writer.h: struct reftable_write_options {
+ * Note that this does not apply to locking individual tables, as these
+ * should only ever be locked when already holding the "tables.list"
+ * lock.
++ *
++ * Passing 0 will fail immediately when the file is locked, passing a
++ * negative value will cause us to block indefinitely.
+ */
-+ unsigned lock_timeout_ms;
++ long lock_timeout_ms;
};
/* reftable_block_stats holds statistics for a single block type */
2: f4be0966e17 = 2: 6130565498e reftable/stack: allow locking of outdated stacks
3: 111b497ef17 = 3: 25d4e513a36 refs/reftable: reload locked stack when preparing transaction
--
2.46.0.551.gc5ee8f2d1c.dirty
