diff options
| -rw-r--r-- | builtin/clone.c | 5 | ||||
| -rw-r--r-- | refs.c | 88 | ||||
| -rw-r--r-- | refs.h | 26 |
3 files changed, 98 insertions, 21 deletions
diff --git a/builtin/clone.c b/builtin/clone.c index 66bff5700f..14b1323568 100644 --- a/builtin/clone.c +++ b/builtin/clone.c @@ -493,13 +493,16 @@ static void write_remote_refs(const struct ref *local_refs) { const struct ref *r; + lock_packed_refs(LOCK_DIE_ON_ERROR); + for (r = local_refs; r; r = r->next) { if (!r->peer_ref) continue; add_packed_ref(r->peer_ref->name, r->old_sha1); } - pack_refs(PACK_REFS_ALL); + if (commit_packed_refs()) + die_errno("unable to overwrite old ref-pack file"); } static void write_followtags(const struct ref *refs, const char *msg) @@ -808,6 +808,13 @@ static int is_refname_available(const char *refname, const char *oldrefname, struct packed_ref_cache { struct ref_entry *root; + + /* + * Iff the packed-refs file associated with this instance is + * currently locked for writing, this points at the associated + * lock (which is owned by somebody else). + */ + struct lock_file *lock; }; /* @@ -826,9 +833,14 @@ static struct ref_cache { char name[1]; } ref_cache, *submodule_ref_caches; +/* Lock used for the main packed-refs file: */ +static struct lock_file packlock; + static void clear_packed_ref_cache(struct ref_cache *refs) { if (refs->packed) { + if (refs->packed->lock) + die("internal error: packed-ref cache cleared while locked"); free_ref_entry(refs->packed->root); free(refs->packed); refs->packed = NULL; @@ -1038,7 +1050,12 @@ static struct ref_dir *get_packed_refs(struct ref_cache *refs) void add_packed_ref(const char *refname, const unsigned char *sha1) { - add_ref(get_packed_refs(&ref_cache), + struct packed_ref_cache *packed_ref_cache = + get_packed_ref_cache(&ref_cache); + + if (!packed_ref_cache->lock) + die("internal error: packed refs not locked"); + add_ref(get_packed_ref_dir(packed_ref_cache), create_ref_entry(refname, sha1, REF_ISPACKED, 1)); } @@ -2035,6 +2052,52 @@ static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data) return 0; } +int lock_packed_refs(int flags) +{ + struct packed_ref_cache *packed_ref_cache; + + /* Discard the old cache because it might be invalid: */ + clear_packed_ref_cache(&ref_cache); + if (hold_lock_file_for_update(&packlock, git_path("packed-refs"), flags) < 0) + return -1; + /* Read the current packed-refs while holding the lock: */ + packed_ref_cache = get_packed_ref_cache(&ref_cache); + packed_ref_cache->lock = &packlock; + return 0; +} + +int commit_packed_refs(void) +{ + struct packed_ref_cache *packed_ref_cache = + get_packed_ref_cache(&ref_cache); + int error = 0; + + if (!packed_ref_cache->lock) + die("internal error: packed-refs not locked"); + write_or_die(packed_ref_cache->lock->fd, + PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER)); + + do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache), + 0, write_packed_entry_fn, + &packed_ref_cache->lock->fd); + if (commit_lock_file(packed_ref_cache->lock)) + error = -1; + packed_ref_cache->lock = NULL; + return error; +} + +void rollback_packed_refs(void) +{ + struct packed_ref_cache *packed_ref_cache = + get_packed_ref_cache(&ref_cache); + + if (!packed_ref_cache->lock) + die("internal error: packed-refs not locked"); + rollback_lock_file(packed_ref_cache->lock); + packed_ref_cache->lock = NULL; + clear_packed_ref_cache(&ref_cache); +} + struct ref_to_prune { struct ref_to_prune *next; unsigned char sha1[20]; @@ -2148,28 +2211,22 @@ static void prune_refs(struct ref_to_prune *r) } } -static struct lock_file packlock; - int pack_refs(unsigned int flags) { struct pack_refs_cb_data cbdata; - int fd; memset(&cbdata, 0, sizeof(cbdata)); cbdata.flags = flags; - fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), - LOCK_DIE_ON_ERROR); + lock_packed_refs(LOCK_DIE_ON_ERROR); cbdata.packed_refs = get_packed_refs(&ref_cache); do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0, pack_if_possible_fn, &cbdata); - write_or_die(fd, PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER)); - do_for_each_entry_in_dir(cbdata.packed_refs, 0, write_packed_entry_fn, &fd); - - if (commit_lock_file(&packlock) < 0) + if (commit_packed_refs()) die_errno("unable to overwrite old ref-pack file"); + prune_refs(cbdata.ref_to_prune); return 0; } @@ -2233,7 +2290,6 @@ static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data) static int repack_without_ref(const char *refname) { - int fd; struct ref_dir *packed; struct string_list refs_to_delete = STRING_LIST_INIT_DUP; struct string_list_item *ref_to_delete; @@ -2241,12 +2297,10 @@ static int repack_without_ref(const char *refname) if (!get_packed_ref(refname)) return 0; /* refname does not exist in packed refs */ - fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0); - if (fd < 0) { + if (lock_packed_refs(0)) { unable_to_lock_error(git_path("packed-refs"), errno); return error("cannot delete '%s' from packed refs", refname); } - clear_packed_ref_cache(&ref_cache); packed = get_packed_refs(&ref_cache); /* Remove refname from the cache: */ @@ -2255,7 +2309,7 @@ static int repack_without_ref(const char *refname) * The packed entry disappeared while we were * acquiring the lock. */ - rollback_lock_file(&packlock); + rollback_packed_refs(); return 0; } @@ -2267,9 +2321,7 @@ static int repack_without_ref(const char *refname) } /* Write what remains: */ - write_or_die(fd, PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER)); - do_for_each_entry_in_dir(packed, 0, write_packed_entry_fn, &fd); - return commit_lock_file(&packlock); + return commit_packed_refs(); } int delete_ref(const char *refname, const unsigned char *sha1, int delopt) @@ -77,12 +77,34 @@ extern int for_each_rawref(each_ref_fn, void *); extern void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname); /* - * Add a reference to the in-memory packed reference cache. To actually - * write the reference to the packed-refs file, call pack_refs(). + * Lock the packed-refs file for writing. Flags is passed to + * hold_lock_file_for_update(). Return 0 on success. + */ +extern int lock_packed_refs(int flags); + +/* + * Add a reference to the in-memory packed reference cache. This may + * only be called while the packed-refs file is locked (see + * lock_packed_refs()). To actually write the packed-refs file, call + * commit_packed_refs(). */ extern void add_packed_ref(const char *refname, const unsigned char *sha1); /* + * Write the current version of the packed refs cache from memory to + * disk. The packed-refs file must already be locked for writing (see + * lock_packed_refs()). Return zero on success. + */ +extern int commit_packed_refs(void); + +/* + * Rollback the lockfile for the packed-refs file, and discard the + * in-memory packed reference cache. (The packed-refs file will be + * read anew if it is needed again after this function is called.) + */ +extern void rollback_packed_refs(void); + +/* * Flags for controlling behaviour of pack_refs() * PACK_REFS_PRUNE: Prune loose refs after packing * PACK_REFS_ALL: Pack _all_ refs, not just tags and already packed refs |