From c2f08236ed786a48e50af33ecc5c0f951c14761b Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Mon, 18 Nov 2024 16:33:57 +0100 Subject: reftable/system: stop depending on "hash.h" We include "hash.h" in "reftable/system.h" such that we can use hash format IDs as well as the raw size of SHA1 and SHA256. As we are in the process of converting the reftable library to become standalone we of course cannot rely on those constants anymore. Introduce a new `enum reftable_hash` to replace internal uses of the hash format IDs and new constants that replace internal uses of the hash size. Adapt the reftable backend to set up the correct hash function. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- reftable/stack.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'reftable/stack.c') diff --git a/reftable/stack.c b/reftable/stack.c index c33979536e..9ae716ff37 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -73,7 +73,7 @@ int reftable_new_stack(struct reftable_stack **dest, const char *dir, if (_opts) opts = *_opts; if (opts.hash_id == 0) - opts.hash_id = GIT_SHA1_FORMAT_ID; + opts.hash_id = REFTABLE_HASH_SHA1; *dest = NULL; @@ -1603,7 +1603,7 @@ struct segment suggest_compaction_segment(uint64_t *sizes, size_t n, static uint64_t *stack_table_sizes_for_compaction(struct reftable_stack *st) { - int version = (st->opts.hash_id == GIT_SHA1_FORMAT_ID) ? 1 : 2; + int version = (st->opts.hash_id == REFTABLE_HASH_SHA1) ? 1 : 2; int overhead = header_size(version) - 1; uint64_t *sizes; -- cgit v1.3 From 86b770b0bbf1aba3c8e43401936258c58648703a Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Mon, 18 Nov 2024 16:34:00 +0100 Subject: reftable/stack: stop using `fsync_component()` directly We're executing `fsync_component()` directly in the reftable library so that we can fsync data to disk depending on "core.fsync". But as we're in the process of converting the reftable library to become standalone we cannot use that function in the library anymore. Refactor the code such that users of the library can inject a custom fsync function via the write options. This allows us to get rid of the dependency on "write-or-die.h". Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- refs/reftable-backend.c | 7 +++++++ reftable/reftable-writer.h | 6 ++++++ reftable/stack.c | 49 ++++++++++++++++++++++++++++++---------------- 3 files changed, 45 insertions(+), 17 deletions(-) (limited to 'reftable/stack.c') diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c index 7d86d92097..2e774176ed 100644 --- a/refs/reftable-backend.c +++ b/refs/reftable-backend.c @@ -24,6 +24,7 @@ #include "../setup.h" #include "../strmap.h" #include "../trace2.h" +#include "../write-or-die.h" #include "parse.h" #include "refs-internal.h" @@ -273,6 +274,11 @@ static int reftable_be_config(const char *var, const char *value, return 0; } +static int reftable_be_fsync(int fd) +{ + return fsync_component(FSYNC_COMPONENT_REFERENCE, fd); +} + static struct ref_store *reftable_be_init(struct repository *repo, const char *gitdir, unsigned int store_flags) @@ -304,6 +310,7 @@ static struct ref_store *reftable_be_init(struct repository *repo, refs->write_options.disable_auto_compact = !git_env_bool("GIT_TEST_REFTABLE_AUTOCOMPACTION", 1); refs->write_options.lock_timeout_ms = 100; + refs->write_options.fsync = reftable_be_fsync; git_config(reftable_be_config, &refs->write_options); diff --git a/reftable/reftable-writer.h b/reftable/reftable-writer.h index 211860d08a..c85ef5a5bd 100644 --- a/reftable/reftable-writer.h +++ b/reftable/reftable-writer.h @@ -62,6 +62,12 @@ struct reftable_write_options { * negative value will cause us to block indefinitely. */ long lock_timeout_ms; + + /* + * Optional callback used to fsync files to disk. Falls back to using + * fsync(3P) when unset. + */ + int (*fsync)(int fd); }; /* reftable_block_stats holds statistics for a single block type */ diff --git a/reftable/stack.c b/reftable/stack.c index 9ae716ff37..c67bdd952c 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -8,7 +8,6 @@ https://developers.google.com/open-source/licenses/bsd #include "stack.h" -#include "../write-or-die.h" #include "system.h" #include "constants.h" #include "merged.h" @@ -43,17 +42,28 @@ static int stack_filename(struct reftable_buf *dest, struct reftable_stack *st, return 0; } -static ssize_t reftable_fd_write(void *arg, const void *data, size_t sz) +static int stack_fsync(const struct reftable_write_options *opts, int fd) { - int *fdp = (int *)arg; - return write_in_full(*fdp, data, sz); + if (opts->fsync) + return opts->fsync(fd); + return fsync(fd); } -static int reftable_fd_flush(void *arg) +struct fd_writer { + const struct reftable_write_options *opts; + int fd; +}; + +static ssize_t fd_writer_write(void *arg, const void *data, size_t sz) { - int *fdp = (int *)arg; + struct fd_writer *writer = arg; + return write_in_full(writer->fd, data, sz); +} - return fsync_component(FSYNC_COMPONENT_REFERENCE, *fdp); +static int fd_writer_flush(void *arg) +{ + struct fd_writer *writer = arg; + return stack_fsync(writer->opts, writer->fd); } int reftable_new_stack(struct reftable_stack **dest, const char *dir, @@ -765,7 +775,7 @@ int reftable_addition_commit(struct reftable_addition *add) goto done; } - err = fsync_component(FSYNC_COMPONENT_REFERENCE, lock_file_fd); + err = stack_fsync(&add->stack->opts, lock_file_fd); if (err < 0) { err = REFTABLE_IO_ERROR; goto done; @@ -858,8 +868,10 @@ int reftable_addition_add(struct reftable_addition *add, struct reftable_buf next_name = REFTABLE_BUF_INIT; struct reftable_writer *wr = NULL; struct tempfile *tab_file = NULL; + struct fd_writer writer = { + .opts = &add->stack->opts, + }; int err = 0; - int tab_fd; reftable_buf_reset(&next_name); @@ -887,10 +899,10 @@ int reftable_addition_add(struct reftable_addition *add, goto done; } } - tab_fd = get_tempfile_fd(tab_file); - err = reftable_writer_new(&wr, reftable_fd_write, reftable_fd_flush, - &tab_fd, &add->stack->opts); + writer.fd = get_tempfile_fd(tab_file); + err = reftable_writer_new(&wr, fd_writer_write, fd_writer_flush, + &writer, &add->stack->opts); if (err < 0) goto done; @@ -973,8 +985,11 @@ static int stack_compact_locked(struct reftable_stack *st, struct reftable_buf next_name = REFTABLE_BUF_INIT; struct reftable_buf tab_file_path = REFTABLE_BUF_INIT; struct reftable_writer *wr = NULL; + struct fd_writer writer= { + .opts = &st->opts, + }; struct tempfile *tab_file; - int tab_fd, err = 0; + int err = 0; err = format_name(&next_name, reftable_reader_min_update_index(st->readers[first]), reftable_reader_max_update_index(st->readers[last])); @@ -994,7 +1009,6 @@ static int stack_compact_locked(struct reftable_stack *st, err = REFTABLE_IO_ERROR; goto done; } - tab_fd = get_tempfile_fd(tab_file); if (st->opts.default_permissions && chmod(get_tempfile_path(tab_file), st->opts.default_permissions) < 0) { @@ -1002,8 +1016,9 @@ static int stack_compact_locked(struct reftable_stack *st, goto done; } - err = reftable_writer_new(&wr, reftable_fd_write, reftable_fd_flush, - &tab_fd, &st->opts); + writer.fd = get_tempfile_fd(tab_file); + err = reftable_writer_new(&wr, fd_writer_write, fd_writer_flush, + &writer, &st->opts); if (err < 0) goto done; @@ -1460,7 +1475,7 @@ static int stack_compact_range(struct reftable_stack *st, goto done; } - err = fsync_component(FSYNC_COMPONENT_REFERENCE, get_lock_file_fd(&tables_list_lock)); + err = stack_fsync(&st->opts, get_lock_file_fd(&tables_list_lock)); if (err < 0) { err = REFTABLE_IO_ERROR; unlink(new_table_path.buf); -- cgit v1.3 From 01e49941d6560dfebfac39a2ffe49d3d24b35069 Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Mon, 18 Nov 2024 16:34:03 +0100 Subject: reftable/system: provide thin wrapper for tempfile subsystem We use the tempfile subsystem to write temporary tables, but given that we're in the process of converting the reftable library to become standalone we cannot use this subsystem directly anymore. While we could in theory convert the code to use mkstemp(3p) instead, we'd lose access to our infrastructure that automatically prunes tempfiles via atexit(3p) or signal handlers. Provide a thin wrapper for the tempfile subsystem instead. Like this, the compatibility shim is fully self-contained in "reftable/system.c". Downstream users of the reftable library would have to implement their own tempfile shims by replacing "system.c" with a custom version. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- Makefile | 1 + reftable/stack.c | 57 ++++++++++++++++++++++--------------------------------- reftable/system.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++ reftable/system.h | 42 +++++++++++++++++++++++++++++++++++++++- 4 files changed, 114 insertions(+), 35 deletions(-) create mode 100644 reftable/system.c (limited to 'reftable/stack.c') diff --git a/Makefile b/Makefile index feeed6f932..50a79ad83f 100644 --- a/Makefile +++ b/Makefile @@ -2722,6 +2722,7 @@ REFTABLE_OBJS += reftable/pq.o REFTABLE_OBJS += reftable/reader.o REFTABLE_OBJS += reftable/record.o REFTABLE_OBJS += reftable/stack.o +REFTABLE_OBJS += reftable/system.o REFTABLE_OBJS += reftable/tree.o REFTABLE_OBJS += reftable/writer.o diff --git a/reftable/stack.c b/reftable/stack.c index c67bdd952c..2ac6a37151 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -16,7 +16,6 @@ https://developers.google.com/open-source/licenses/bsd #include "reftable-record.h" #include "reftable-merged.h" #include "writer.h" -#include "tempfile.h" static int stack_try_add(struct reftable_stack *st, int (*write_table)(struct reftable_writer *wr, @@ -867,7 +866,7 @@ int reftable_addition_add(struct reftable_addition *add, struct reftable_buf tab_file_name = REFTABLE_BUF_INIT; struct reftable_buf next_name = REFTABLE_BUF_INIT; struct reftable_writer *wr = NULL; - struct tempfile *tab_file = NULL; + struct reftable_tmpfile tab_file = REFTABLE_TMPFILE_INIT; struct fd_writer writer = { .opts = &add->stack->opts, }; @@ -887,20 +886,18 @@ int reftable_addition_add(struct reftable_addition *add, if (err < 0) goto done; - tab_file = mks_tempfile(temp_tab_file_name.buf); - if (!tab_file) { - err = REFTABLE_IO_ERROR; + err = tmpfile_from_pattern(&tab_file, temp_tab_file_name.buf); + if (err < 0) goto done; - } if (add->stack->opts.default_permissions) { - if (chmod(get_tempfile_path(tab_file), + if (chmod(tab_file.path, add->stack->opts.default_permissions)) { err = REFTABLE_IO_ERROR; goto done; } } - writer.fd = get_tempfile_fd(tab_file); + writer.fd = tab_file.fd; err = reftable_writer_new(&wr, fd_writer_write, fd_writer_flush, &writer, &add->stack->opts); if (err < 0) @@ -918,11 +915,9 @@ int reftable_addition_add(struct reftable_addition *add, if (err < 0) goto done; - err = close_tempfile_gently(tab_file); - if (err < 0) { - err = REFTABLE_IO_ERROR; + err = tmpfile_close(&tab_file); + if (err < 0) goto done; - } if (wr->min_update_index < add->next_update_index) { err = REFTABLE_API_ERROR; @@ -945,11 +940,9 @@ int reftable_addition_add(struct reftable_addition *add, On windows, this relies on rand() picking a unique destination name. Maybe we should do retry loop as well? */ - err = rename_tempfile(&tab_file, tab_file_name.buf); - if (err < 0) { - err = REFTABLE_IO_ERROR; + err = tmpfile_rename(&tab_file, tab_file_name.buf); + if (err < 0) goto done; - } REFTABLE_ALLOC_GROW(add->new_tables, add->new_tables_len + 1, add->new_tables_cap); @@ -960,7 +953,7 @@ int reftable_addition_add(struct reftable_addition *add, add->new_tables[add->new_tables_len++] = reftable_buf_detach(&next_name); done: - delete_tempfile(&tab_file); + tmpfile_delete(&tab_file); reftable_buf_release(&temp_tab_file_name); reftable_buf_release(&tab_file_name); reftable_buf_release(&next_name); @@ -980,7 +973,7 @@ uint64_t reftable_stack_next_update_index(struct reftable_stack *st) static int stack_compact_locked(struct reftable_stack *st, size_t first, size_t last, struct reftable_log_expiry_config *config, - struct tempfile **tab_file_out) + struct reftable_tmpfile *tab_file_out) { struct reftable_buf next_name = REFTABLE_BUF_INIT; struct reftable_buf tab_file_path = REFTABLE_BUF_INIT; @@ -988,7 +981,7 @@ static int stack_compact_locked(struct reftable_stack *st, struct fd_writer writer= { .opts = &st->opts, }; - struct tempfile *tab_file; + struct reftable_tmpfile tab_file = REFTABLE_TMPFILE_INIT; int err = 0; err = format_name(&next_name, reftable_reader_min_update_index(st->readers[first]), @@ -1004,19 +997,17 @@ static int stack_compact_locked(struct reftable_stack *st, if (err < 0) goto done; - tab_file = mks_tempfile(tab_file_path.buf); - if (!tab_file) { - err = REFTABLE_IO_ERROR; + err = tmpfile_from_pattern(&tab_file, tab_file_path.buf); + if (err < 0) goto done; - } if (st->opts.default_permissions && - chmod(get_tempfile_path(tab_file), st->opts.default_permissions) < 0) { + chmod(tab_file.path, st->opts.default_permissions) < 0) { err = REFTABLE_IO_ERROR; goto done; } - writer.fd = get_tempfile_fd(tab_file); + writer.fd = tab_file.fd; err = reftable_writer_new(&wr, fd_writer_write, fd_writer_flush, &writer, &st->opts); if (err < 0) @@ -1030,15 +1021,15 @@ static int stack_compact_locked(struct reftable_stack *st, if (err < 0) goto done; - err = close_tempfile_gently(tab_file); + err = tmpfile_close(&tab_file); if (err < 0) goto done; *tab_file_out = tab_file; - tab_file = NULL; + tab_file = REFTABLE_TMPFILE_INIT; done: - delete_tempfile(&tab_file); + tmpfile_delete(&tab_file); reftable_writer_free(wr); reftable_buf_release(&next_name); reftable_buf_release(&tab_file_path); @@ -1171,7 +1162,7 @@ static int stack_compact_range(struct reftable_stack *st, struct reftable_buf table_name = REFTABLE_BUF_INIT; struct lock_file tables_list_lock = LOCK_INIT; struct lock_file *table_locks = NULL; - struct tempfile *new_table = NULL; + struct reftable_tmpfile new_table = REFTABLE_TMPFILE_INIT; int is_empty_table = 0, err = 0; size_t first_to_replace, last_to_replace; size_t i, nlocks = 0; @@ -1439,11 +1430,9 @@ static int stack_compact_range(struct reftable_stack *st, if (err < 0) goto done; - err = rename_tempfile(&new_table, new_table_path.buf); - if (err < 0) { - err = REFTABLE_IO_ERROR; + err = tmpfile_rename(&new_table, new_table_path.buf); + if (err < 0) goto done; - } } /* @@ -1515,7 +1504,7 @@ done: rollback_lock_file(&table_locks[i]); reftable_free(table_locks); - delete_tempfile(&new_table); + tmpfile_delete(&new_table); reftable_buf_release(&new_table_name); reftable_buf_release(&new_table_path); reftable_buf_release(&tables_list_buf); diff --git a/reftable/system.c b/reftable/system.c new file mode 100644 index 0000000000..01f96f03d8 --- /dev/null +++ b/reftable/system.c @@ -0,0 +1,49 @@ +#include "system.h" +#include "basics.h" +#include "reftable-error.h" +#include "../tempfile.h" + +int tmpfile_from_pattern(struct reftable_tmpfile *out, const char *pattern) +{ + struct tempfile *tempfile; + + tempfile = mks_tempfile(pattern); + if (!tempfile) + return REFTABLE_IO_ERROR; + + out->path = tempfile->filename.buf; + out->fd = tempfile->fd; + out->priv = tempfile; + + return 0; +} + +int tmpfile_close(struct reftable_tmpfile *t) +{ + struct tempfile *tempfile = t->priv; + int ret = close_tempfile_gently(tempfile); + t->fd = -1; + if (ret < 0) + return REFTABLE_IO_ERROR; + return 0; +} + +int tmpfile_delete(struct reftable_tmpfile *t) +{ + struct tempfile *tempfile = t->priv; + int ret = delete_tempfile(&tempfile); + *t = REFTABLE_TMPFILE_INIT; + if (ret < 0) + return REFTABLE_IO_ERROR; + return 0; +} + +int tmpfile_rename(struct reftable_tmpfile *t, const char *path) +{ + struct tempfile *tempfile = t->priv; + int ret = rename_tempfile(&tempfile, path); + *t = REFTABLE_TMPFILE_INIT; + if (ret < 0) + return REFTABLE_IO_ERROR; + return 0; +} diff --git a/reftable/system.h b/reftable/system.h index 38d3534620..858189fd55 100644 --- a/reftable/system.h +++ b/reftable/system.h @@ -13,6 +13,46 @@ https://developers.google.com/open-source/licenses/bsd #include "git-compat-util.h" #include "lockfile.h" -#include "tempfile.h" + +/* + * An implementation-specific temporary file. By making this specific to the + * implementation it becomes possible to tie temporary files into any kind of + * signal or atexit handlers for cleanup on abnormal situations. + */ +struct reftable_tmpfile { + const char *path; + int fd; + void *priv; +}; +#define REFTABLE_TMPFILE_INIT ((struct reftable_tmpfile) { .fd = -1, }) + +/* + * Create a temporary file from a pattern similar to how mkstemp(3p) would. + * The `pattern` shall not be modified. On success, the structure at `out` has + * been initialized such that it is ready for use. Returns 0 on success, a + * reftable error code on error. + */ +int tmpfile_from_pattern(struct reftable_tmpfile *out, const char *pattern); + +/* + * Close the temporary file's file descriptor without removing the file itself. + * This is a no-op in case the file has already been closed beforehand. Returns + * 0 on success, a reftable error code on error. + */ +int tmpfile_close(struct reftable_tmpfile *t); + +/* + * Close the temporary file and delete it. This is a no-op in case the file has + * already been deleted or renamed beforehand. Returns 0 on success, a reftable + * error code on error. + */ +int tmpfile_delete(struct reftable_tmpfile *t); + +/* + * Rename the temporary file to the provided path. The temporary file must be + * active. Return 0 on success, a reftable error code on error. Deactivates the + * temporary file. + */ +int tmpfile_rename(struct reftable_tmpfile *t, const char *path); #endif -- cgit v1.3 From 6361226b79d24eb93a14e0b7d25f584269f9d5e6 Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Mon, 18 Nov 2024 16:34:05 +0100 Subject: reftable/stack: drop only use of `get_locked_file_path()` We've got a single callsite where we call `get_locked_file_path()`. As we're about to convert our usage of the lockfile subsystem to instead be used via a compatibility shim we'd have to implement more logic for this single callsite. While that would be okay if Git was the only supposed user of the reftable library, it's a bit more awkward when considering that we have to reimplement this functionality for every user of the library eventually. Refactor the code such that we don't call `get_locked_file_path()` anymore. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- reftable/stack.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'reftable/stack.c') diff --git a/reftable/stack.c b/reftable/stack.c index 2ac6a37151..223d7c622d 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -1493,9 +1493,15 @@ static int stack_compact_range(struct reftable_stack *st, */ for (i = 0; i < nlocks; i++) { struct lock_file *table_lock = &table_locks[i]; - char *table_path = get_locked_file_path(table_lock); - unlink(table_path); - reftable_free(table_path); + const char *lock_path = get_lock_file_path(table_lock); + + reftable_buf_reset(&table_name); + err = reftable_buf_add(&table_name, lock_path, + strlen(lock_path) - strlen(".lock")); + if (err) + continue; + + unlink(table_name.buf); } done: -- cgit v1.3 From 988e7f5e952bbb7b6ae885f4da744f536f22693f Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Mon, 18 Nov 2024 16:34:08 +0100 Subject: reftable/system: provide thin wrapper for lockfile subsystem We use the lockfile subsystem to write lockfiles for "tables.list". As with the tempfile subsystem, the lockfile subsystem also hooks into our infrastructure to prune stale locks via atexit(3p) or signal handlers. Furthermore, the lockfile subsystem also handles locking timeouts, which do add quite a bit of logic. Having to reimplement that in the context of Git wouldn't make a whole lot of sense, and it is quite likely that downstream users of the reftable library may have a better idea for how exactly to implement timeouts. So again, provide a thin wrapper for the lockfile subsystem instead such that the compatibility shim is fully self-contained. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- reftable/stack.c | 63 +++++++++++++----------------- reftable/system.c | 77 +++++++++++++++++++++++++++++++++++++ reftable/system.h | 45 +++++++++++++++++++++- t/unit-tests/lib-reftable.c | 1 + t/unit-tests/t-reftable-block.c | 1 + t/unit-tests/t-reftable-pq.c | 1 + t/unit-tests/t-reftable-readwrite.c | 1 + t/unit-tests/t-reftable-stack.c | 2 + 8 files changed, 154 insertions(+), 37 deletions(-) (limited to 'reftable/stack.c') diff --git a/reftable/stack.c b/reftable/stack.c index 223d7c622d..10d45e89d0 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -657,7 +657,7 @@ static int format_name(struct reftable_buf *dest, uint64_t min, uint64_t max) } struct reftable_addition { - struct lock_file tables_list_lock; + struct reftable_flock tables_list_lock; struct reftable_stack *stack; char **new_tables; @@ -676,10 +676,8 @@ static int reftable_stack_init_addition(struct reftable_addition *add, add->stack = st; - err = hold_lock_file_for_update_timeout(&add->tables_list_lock, - st->list_file, - LOCK_NO_DEREF, - st->opts.lock_timeout_ms); + err = flock_acquire(&add->tables_list_lock, st->list_file, + st->opts.lock_timeout_ms); if (err < 0) { if (errno == EEXIST) { err = REFTABLE_LOCK_ERROR; @@ -689,7 +687,7 @@ static int reftable_stack_init_addition(struct reftable_addition *add, goto done; } if (st->opts.default_permissions) { - if (chmod(get_lock_file_path(&add->tables_list_lock), + if (chmod(add->tables_list_lock.path, st->opts.default_permissions) < 0) { err = REFTABLE_IO_ERROR; goto done; @@ -733,7 +731,7 @@ static void reftable_addition_close(struct reftable_addition *add) add->new_tables_len = 0; add->new_tables_cap = 0; - rollback_lock_file(&add->tables_list_lock); + flock_release(&add->tables_list_lock); reftable_buf_release(&nm); } @@ -749,7 +747,6 @@ void reftable_addition_destroy(struct reftable_addition *add) int reftable_addition_commit(struct reftable_addition *add) { struct reftable_buf table_list = REFTABLE_BUF_INIT; - int lock_file_fd = get_lock_file_fd(&add->tables_list_lock); int err = 0; size_t i; @@ -767,20 +764,20 @@ int reftable_addition_commit(struct reftable_addition *add) goto done; } - err = write_in_full(lock_file_fd, table_list.buf, table_list.len); + err = write_in_full(add->tables_list_lock.fd, table_list.buf, table_list.len); reftable_buf_release(&table_list); if (err < 0) { err = REFTABLE_IO_ERROR; goto done; } - err = stack_fsync(&add->stack->opts, lock_file_fd); + err = stack_fsync(&add->stack->opts, add->tables_list_lock.fd); if (err < 0) { err = REFTABLE_IO_ERROR; goto done; } - err = commit_lock_file(&add->tables_list_lock); + err = flock_commit(&add->tables_list_lock); if (err < 0) { err = REFTABLE_IO_ERROR; goto done; @@ -1160,8 +1157,8 @@ static int stack_compact_range(struct reftable_stack *st, struct reftable_buf new_table_name = REFTABLE_BUF_INIT; struct reftable_buf new_table_path = REFTABLE_BUF_INIT; struct reftable_buf table_name = REFTABLE_BUF_INIT; - struct lock_file tables_list_lock = LOCK_INIT; - struct lock_file *table_locks = NULL; + struct reftable_flock tables_list_lock = REFTABLE_FLOCK_INIT; + struct reftable_flock *table_locks = NULL; struct reftable_tmpfile new_table = REFTABLE_TMPFILE_INIT; int is_empty_table = 0, err = 0; size_t first_to_replace, last_to_replace; @@ -1179,10 +1176,7 @@ static int stack_compact_range(struct reftable_stack *st, * Hold the lock so that we can read "tables.list" and lock all tables * which are part of the user-specified range. */ - err = hold_lock_file_for_update_timeout(&tables_list_lock, - st->list_file, - LOCK_NO_DEREF, - st->opts.lock_timeout_ms); + err = flock_acquire(&tables_list_lock, st->list_file, st->opts.lock_timeout_ms); if (err < 0) { if (errno == EEXIST) err = REFTABLE_LOCK_ERROR; @@ -1205,19 +1199,20 @@ static int stack_compact_range(struct reftable_stack *st, * older process is still busy compacting tables which are preexisting * from the point of view of the newer process. */ - REFTABLE_CALLOC_ARRAY(table_locks, last - first + 1); + REFTABLE_ALLOC_ARRAY(table_locks, last - first + 1); if (!table_locks) { err = REFTABLE_OUT_OF_MEMORY_ERROR; goto done; } + for (i = 0; i < last - first + 1; i++) + table_locks[i] = REFTABLE_FLOCK_INIT; for (i = last + 1; i > first; i--) { err = stack_filename(&table_name, st, reader_name(st->readers[i - 1])); if (err < 0) goto done; - err = hold_lock_file_for_update(&table_locks[nlocks], - table_name.buf, LOCK_NO_DEREF); + err = flock_acquire(&table_locks[nlocks], table_name.buf, 0); if (err < 0) { /* * When the table is locked already we may do a @@ -1253,7 +1248,7 @@ static int stack_compact_range(struct reftable_stack *st, * run into file descriptor exhaustion when we compress a lot * of tables. */ - err = close_lock_file_gently(&table_locks[nlocks++]); + err = flock_close(&table_locks[nlocks++]); if (err < 0) { err = REFTABLE_IO_ERROR; goto done; @@ -1265,7 +1260,7 @@ static int stack_compact_range(struct reftable_stack *st, * "tables.list" lock while compacting the locked tables. This allows * concurrent updates to the stack to proceed. */ - err = rollback_lock_file(&tables_list_lock); + err = flock_release(&tables_list_lock); if (err < 0) { err = REFTABLE_IO_ERROR; goto done; @@ -1288,10 +1283,7 @@ static int stack_compact_range(struct reftable_stack *st, * "tables.list". We'll then replace the compacted range of tables with * the new table. */ - err = hold_lock_file_for_update_timeout(&tables_list_lock, - st->list_file, - LOCK_NO_DEREF, - st->opts.lock_timeout_ms); + err = flock_acquire(&tables_list_lock, st->list_file, st->opts.lock_timeout_ms); if (err < 0) { if (errno == EEXIST) err = REFTABLE_LOCK_ERROR; @@ -1301,7 +1293,7 @@ static int stack_compact_range(struct reftable_stack *st, } if (st->opts.default_permissions) { - if (chmod(get_lock_file_path(&tables_list_lock), + if (chmod(tables_list_lock.path, st->opts.default_permissions) < 0) { err = REFTABLE_IO_ERROR; goto done; @@ -1456,7 +1448,7 @@ static int stack_compact_range(struct reftable_stack *st, goto done; } - err = write_in_full(get_lock_file_fd(&tables_list_lock), + err = write_in_full(tables_list_lock.fd, tables_list_buf.buf, tables_list_buf.len); if (err < 0) { err = REFTABLE_IO_ERROR; @@ -1464,14 +1456,14 @@ static int stack_compact_range(struct reftable_stack *st, goto done; } - err = stack_fsync(&st->opts, get_lock_file_fd(&tables_list_lock)); + err = stack_fsync(&st->opts, tables_list_lock.fd); if (err < 0) { err = REFTABLE_IO_ERROR; unlink(new_table_path.buf); goto done; } - err = commit_lock_file(&tables_list_lock); + err = flock_commit(&tables_list_lock); if (err < 0) { err = REFTABLE_IO_ERROR; unlink(new_table_path.buf); @@ -1492,12 +1484,11 @@ static int stack_compact_range(struct reftable_stack *st, * readers, so it is expected that unlinking tables may fail. */ for (i = 0; i < nlocks; i++) { - struct lock_file *table_lock = &table_locks[i]; - const char *lock_path = get_lock_file_path(table_lock); + struct reftable_flock *table_lock = &table_locks[i]; reftable_buf_reset(&table_name); - err = reftable_buf_add(&table_name, lock_path, - strlen(lock_path) - strlen(".lock")); + err = reftable_buf_add(&table_name, table_lock->path, + strlen(table_lock->path) - strlen(".lock")); if (err) continue; @@ -1505,9 +1496,9 @@ static int stack_compact_range(struct reftable_stack *st, } done: - rollback_lock_file(&tables_list_lock); + flock_release(&tables_list_lock); for (i = 0; table_locks && i < nlocks; i++) - rollback_lock_file(&table_locks[i]); + flock_release(&table_locks[i]); reftable_free(table_locks); tmpfile_delete(&new_table); diff --git a/reftable/system.c b/reftable/system.c index 01f96f03d8..adf8e4d30b 100644 --- a/reftable/system.c +++ b/reftable/system.c @@ -1,6 +1,7 @@ #include "system.h" #include "basics.h" #include "reftable-error.h" +#include "../lockfile.h" #include "../tempfile.h" int tmpfile_from_pattern(struct reftable_tmpfile *out, const char *pattern) @@ -47,3 +48,79 @@ int tmpfile_rename(struct reftable_tmpfile *t, const char *path) return REFTABLE_IO_ERROR; return 0; } + +int flock_acquire(struct reftable_flock *l, const char *target_path, + long timeout_ms) +{ + struct lock_file *lockfile; + int err; + + lockfile = reftable_malloc(sizeof(*lockfile)); + if (!lockfile) + return REFTABLE_OUT_OF_MEMORY_ERROR; + + err = hold_lock_file_for_update_timeout(lockfile, target_path, LOCK_NO_DEREF, + timeout_ms); + if (err < 0) { + reftable_free(lockfile); + if (errno == EEXIST) + return REFTABLE_LOCK_ERROR; + return -1; + } + + l->fd = get_lock_file_fd(lockfile); + l->path = get_lock_file_path(lockfile); + l->priv = lockfile; + + return 0; +} + +int flock_close(struct reftable_flock *l) +{ + struct lock_file *lockfile = l->priv; + int ret; + + if (!lockfile) + return REFTABLE_API_ERROR; + + ret = close_lock_file_gently(lockfile); + l->fd = -1; + if (ret < 0) + return REFTABLE_IO_ERROR; + + return 0; +} + +int flock_release(struct reftable_flock *l) +{ + struct lock_file *lockfile = l->priv; + int ret; + + if (!lockfile) + return 0; + + ret = rollback_lock_file(lockfile); + reftable_free(lockfile); + *l = REFTABLE_FLOCK_INIT; + if (ret < 0) + return REFTABLE_IO_ERROR; + + return 0; +} + +int flock_commit(struct reftable_flock *l) +{ + struct lock_file *lockfile = l->priv; + int ret; + + if (!lockfile) + return REFTABLE_API_ERROR; + + ret = commit_lock_file(lockfile); + reftable_free(lockfile); + *l = REFTABLE_FLOCK_INIT; + if (ret < 0) + return REFTABLE_IO_ERROR; + + return 0; +} diff --git a/reftable/system.h b/reftable/system.h index 858189fd55..7d5f803eeb 100644 --- a/reftable/system.h +++ b/reftable/system.h @@ -12,7 +12,6 @@ https://developers.google.com/open-source/licenses/bsd /* This header glues the reftable library to the rest of Git */ #include "git-compat-util.h" -#include "lockfile.h" /* * An implementation-specific temporary file. By making this specific to the @@ -55,4 +54,48 @@ int tmpfile_delete(struct reftable_tmpfile *t); */ int tmpfile_rename(struct reftable_tmpfile *t, const char *path); +/* + * An implementation-specific file lock. Same as with `reftable_tmpfile`, + * making this specific to the implementation makes it possible to tie this + * into signal or atexit handlers such that we know to clean up stale locks on + * abnormal exits. + */ +struct reftable_flock { + const char *path; + int fd; + void *priv; +}; +#define REFTABLE_FLOCK_INIT ((struct reftable_flock){ .fd = -1, }) + +/* + * Acquire the lock for the given target path by exclusively creating a file + * with ".lock" appended to it. If that lock exists, we wait up to `timeout_ms` + * to acquire the lock. If `timeout_ms` is 0 we don't wait, if it is negative + * we block indefinitely. + * + * Retrun 0 on success, a reftable error code on error. + */ +int flock_acquire(struct reftable_flock *l, const char *target_path, + long timeout_ms); + +/* + * Close the lockfile's file descriptor without removing the lock itself. This + * is a no-op in case the lockfile has already been closed beforehand. Returns + * 0 on success, a reftable error code on error. + */ +int flock_close(struct reftable_flock *l); + +/* + * Release the lock by unlinking the lockfile. This is a no-op in case the + * lockfile has already been released or committed beforehand. Returns 0 on + * success, a reftable error code on error. + */ +int flock_release(struct reftable_flock *l); + +/* + * Commit the lock by renaming the lockfile into place. Returns 0 on success, a + * reftable error code on error. + */ +int flock_commit(struct reftable_flock *l); + #endif diff --git a/t/unit-tests/lib-reftable.c b/t/unit-tests/lib-reftable.c index c1631f4527..d795dfb7c9 100644 --- a/t/unit-tests/lib-reftable.c +++ b/t/unit-tests/lib-reftable.c @@ -2,6 +2,7 @@ #include "test-lib.h" #include "reftable/constants.h" #include "reftable/writer.h" +#include "strbuf.h" void t_reftable_set_hash(uint8_t *p, int i, enum reftable_hash id) { diff --git a/t/unit-tests/t-reftable-block.c b/t/unit-tests/t-reftable-block.c index 13e10807da..22040aeefa 100644 --- a/t/unit-tests/t-reftable-block.c +++ b/t/unit-tests/t-reftable-block.c @@ -11,6 +11,7 @@ https://developers.google.com/open-source/licenses/bsd #include "reftable/blocksource.h" #include "reftable/constants.h" #include "reftable/reftable-error.h" +#include "strbuf.h" static void t_ref_block_read_write(void) { diff --git a/t/unit-tests/t-reftable-pq.c b/t/unit-tests/t-reftable-pq.c index 272da05bea..f3f8a0cdf3 100644 --- a/t/unit-tests/t-reftable-pq.c +++ b/t/unit-tests/t-reftable-pq.c @@ -9,6 +9,7 @@ https://developers.google.com/open-source/licenses/bsd #include "test-lib.h" #include "reftable/constants.h" #include "reftable/pq.h" +#include "strbuf.h" static void merged_iter_pqueue_check(const struct merged_iter_pqueue *pq) { diff --git a/t/unit-tests/t-reftable-readwrite.c b/t/unit-tests/t-reftable-readwrite.c index 57896922eb..91c881aedf 100644 --- a/t/unit-tests/t-reftable-readwrite.c +++ b/t/unit-tests/t-reftable-readwrite.c @@ -13,6 +13,7 @@ https://developers.google.com/open-source/licenses/bsd #include "reftable/reader.h" #include "reftable/reftable-error.h" #include "reftable/reftable-writer.h" +#include "strbuf.h" static const int update_index = 5; diff --git a/t/unit-tests/t-reftable-stack.c b/t/unit-tests/t-reftable-stack.c index 13fd8d8f94..b2f6c1c37e 100644 --- a/t/unit-tests/t-reftable-stack.c +++ b/t/unit-tests/t-reftable-stack.c @@ -13,6 +13,8 @@ https://developers.google.com/open-source/licenses/bsd #include "reftable/reader.h" #include "reftable/reftable-error.h" #include "reftable/stack.h" +#include "strbuf.h" +#include "tempfile.h" #include static void clear_dir(const char *dirname) -- cgit v1.3