diff options
| -rw-r--r-- | builtin/clone.c | 5 | ||||
| -rw-r--r-- | builtin/ls-files.c | 12 | ||||
| -rw-r--r-- | cache.h | 60 | ||||
| -rw-r--r-- | read-cache.c | 181 | ||||
| -rw-r--r-- | refs.c | 316 | ||||
| -rw-r--r-- | refs.h | 26 |
6 files changed, 466 insertions, 134 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) diff --git a/builtin/ls-files.c b/builtin/ls-files.c index 87f3b331ca..3a410c35d9 100644 --- a/builtin/ls-files.c +++ b/builtin/ls-files.c @@ -165,11 +165,13 @@ static void show_ce_entry(const char *tag, struct cache_entry *ce) } write_name(ce->name, ce_namelen(ce)); if (debug_mode) { - printf(" ctime: %d:%d\n", ce->ce_ctime.sec, ce->ce_ctime.nsec); - printf(" mtime: %d:%d\n", ce->ce_mtime.sec, ce->ce_mtime.nsec); - printf(" dev: %d\tino: %d\n", ce->ce_dev, ce->ce_ino); - printf(" uid: %d\tgid: %d\n", ce->ce_uid, ce->ce_gid); - printf(" size: %d\tflags: %x\n", ce->ce_size, ce->ce_flags); + struct stat_data *sd = &ce->ce_stat_data; + + printf(" ctime: %d:%d\n", sd->sd_ctime.sec, sd->sd_ctime.nsec); + printf(" mtime: %d:%d\n", sd->sd_mtime.sec, sd->sd_mtime.nsec); + printf(" dev: %d\tino: %d\n", sd->sd_dev, sd->sd_ino); + printf(" uid: %d\tgid: %d\n", sd->sd_uid, sd->sd_gid); + printf(" size: %d\tflags: %x\n", sd->sd_size, ce->ce_flags); } } @@ -119,15 +119,19 @@ struct cache_time { unsigned int nsec; }; +struct stat_data { + struct cache_time sd_ctime; + struct cache_time sd_mtime; + unsigned int sd_dev; + unsigned int sd_ino; + unsigned int sd_uid; + unsigned int sd_gid; + unsigned int sd_size; +}; + struct cache_entry { - struct cache_time ce_ctime; - struct cache_time ce_mtime; - unsigned int ce_dev; - unsigned int ce_ino; + struct stat_data ce_stat_data; unsigned int ce_mode; - unsigned int ce_uid; - unsigned int ce_gid; - unsigned int ce_size; unsigned int ce_flags; unsigned int ce_namelen; unsigned char sha1[20]; @@ -511,6 +515,21 @@ extern int limit_pathspec_to_literal(void); #define HASH_FORMAT_CHECK 2 extern int index_fd(unsigned char *sha1, int fd, struct stat *st, enum object_type type, const char *path, unsigned flags); extern int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags); + +/* + * Record to sd the data from st that we use to check whether a file + * might have changed. + */ +extern void fill_stat_data(struct stat_data *sd, struct stat *st); + +/* + * Return 0 if st is consistent with a file not having been changed + * since sd was filled. If there are differences, return a + * combination of MTIME_CHANGED, CTIME_CHANGED, OWNER_CHANGED, + * INODE_CHANGED, and DATA_CHANGED. + */ +extern int match_stat_data(const struct stat_data *sd, struct stat *st); + extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st); #define REFRESH_REALLY 0x0001 /* ignore_valid */ @@ -1338,4 +1357,31 @@ int checkout_fast_forward(const unsigned char *from, int sane_execvp(const char *file, char *const argv[]); +/* + * A struct to encapsulate the concept of whether a file has changed + * since we last checked it. This uses criteria similar to those used + * for the index. + */ +struct stat_validity { + struct stat_data *sd; +}; + +void stat_validity_clear(struct stat_validity *sv); + +/* + * Returns 1 if the path is a regular file (or a symlink to a regular + * file) and matches the saved stat_validity, 0 otherwise. A missing + * or inaccessible file is considered a match if the struct was just + * initialized, or if the previous update found an inaccessible file. + */ +int stat_validity_check(struct stat_validity *sv, const char *path); + +/* + * Update the stat_validity from a file opened at descriptor fd. If + * the file is missing, inaccessible, or not a regular file, then + * future calls to stat_validity_check will match iff one of those + * conditions continues to be true. + */ +void stat_validity_update(struct stat_validity *sv, int fd); + #endif /* CACHE_H */ diff --git a/read-cache.c b/read-cache.c index b297addb57..d5201f9b06 100644 --- a/read-cache.c +++ b/read-cache.c @@ -67,6 +67,61 @@ void rename_index_entry_at(struct index_state *istate, int nr, const char *new_n add_index_entry(istate, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE); } +void fill_stat_data(struct stat_data *sd, struct stat *st) +{ + sd->sd_ctime.sec = (unsigned int)st->st_ctime; + sd->sd_mtime.sec = (unsigned int)st->st_mtime; + sd->sd_ctime.nsec = ST_CTIME_NSEC(*st); + sd->sd_mtime.nsec = ST_MTIME_NSEC(*st); + sd->sd_dev = st->st_dev; + sd->sd_ino = st->st_ino; + sd->sd_uid = st->st_uid; + sd->sd_gid = st->st_gid; + sd->sd_size = st->st_size; +} + +int match_stat_data(const struct stat_data *sd, struct stat *st) +{ + int changed = 0; + + if (sd->sd_mtime.sec != (unsigned int)st->st_mtime) + changed |= MTIME_CHANGED; + if (trust_ctime && check_stat && + sd->sd_ctime.sec != (unsigned int)st->st_ctime) + changed |= CTIME_CHANGED; + +#ifdef USE_NSEC + if (check_stat && sd->sd_mtime.nsec != ST_MTIME_NSEC(*st)) + changed |= MTIME_CHANGED; + if (trust_ctime && check_stat && + sd->sd_ctime.nsec != ST_CTIME_NSEC(*st)) + changed |= CTIME_CHANGED; +#endif + + if (check_stat) { + if (sd->sd_uid != (unsigned int) st->st_uid || + sd->sd_gid != (unsigned int) st->st_gid) + changed |= OWNER_CHANGED; + if (sd->sd_ino != (unsigned int) st->st_ino) + changed |= INODE_CHANGED; + } + +#ifdef USE_STDEV + /* + * st_dev breaks on network filesystems where different + * clients will have different views of what "device" + * the filesystem is on + */ + if (check_stat && sd->sd_dev != (unsigned int) st->st_dev) + changed |= INODE_CHANGED; +#endif + + if (sd->sd_size != (unsigned int) st->st_size) + changed |= DATA_CHANGED; + + return changed; +} + /* * This only updates the "non-critical" parts of the directory * cache, ie the parts that aren't tracked by GIT, and only used @@ -74,15 +129,7 @@ void rename_index_entry_at(struct index_state *istate, int nr, const char *new_n */ void fill_stat_cache_info(struct cache_entry *ce, struct stat *st) { - ce->ce_ctime.sec = (unsigned int)st->st_ctime; - ce->ce_mtime.sec = (unsigned int)st->st_mtime; - ce->ce_ctime.nsec = ST_CTIME_NSEC(*st); - ce->ce_mtime.nsec = ST_MTIME_NSEC(*st); - ce->ce_dev = st->st_dev; - ce->ce_ino = st->st_ino; - ce->ce_uid = st->st_uid; - ce->ce_gid = st->st_gid; - ce->ce_size = st->st_size; + fill_stat_data(&ce->ce_stat_data, st); if (assume_unchanged) ce->ce_flags |= CE_VALID; @@ -195,43 +242,11 @@ static int ce_match_stat_basic(const struct cache_entry *ce, struct stat *st) default: die("internal error: ce_mode is %o", ce->ce_mode); } - if (ce->ce_mtime.sec != (unsigned int)st->st_mtime) - changed |= MTIME_CHANGED; - if (trust_ctime && check_stat && - ce->ce_ctime.sec != (unsigned int)st->st_ctime) - changed |= CTIME_CHANGED; - -#ifdef USE_NSEC - if (check_stat && ce->ce_mtime.nsec != ST_MTIME_NSEC(*st)) - changed |= MTIME_CHANGED; - if (trust_ctime && check_stat && - ce->ce_ctime.nsec != ST_CTIME_NSEC(*st)) - changed |= CTIME_CHANGED; -#endif - - if (check_stat) { - if (ce->ce_uid != (unsigned int) st->st_uid || - ce->ce_gid != (unsigned int) st->st_gid) - changed |= OWNER_CHANGED; - if (ce->ce_ino != (unsigned int) st->st_ino) - changed |= INODE_CHANGED; - } -#ifdef USE_STDEV - /* - * st_dev breaks on network filesystems where different - * clients will have different views of what "device" - * the filesystem is on - */ - if (check_stat && ce->ce_dev != (unsigned int) st->st_dev) - changed |= INODE_CHANGED; -#endif - - if (ce->ce_size != (unsigned int) st->st_size) - changed |= DATA_CHANGED; + changed |= match_stat_data(&ce->ce_stat_data, st); /* Racily smudged entry? */ - if (!ce->ce_size) { + if (!ce->ce_stat_data.sd_size) { if (!is_empty_blob_sha1(ce->sha1)) changed |= DATA_CHANGED; } @@ -246,11 +261,11 @@ static int is_racy_timestamp(const struct index_state *istate, istate->timestamp.sec && #ifdef USE_NSEC /* nanosecond timestamped files can also be racy! */ - (istate->timestamp.sec < ce->ce_mtime.sec || - (istate->timestamp.sec == ce->ce_mtime.sec && - istate->timestamp.nsec <= ce->ce_mtime.nsec)) + (istate->timestamp.sec < ce->ce_stat_data.sd_mtime.sec || + (istate->timestamp.sec == ce->ce_stat_data.sd_mtime.sec && + istate->timestamp.nsec <= ce->ce_stat_data.sd_mtime.nsec)) #else - istate->timestamp.sec <= ce->ce_mtime.sec + istate->timestamp.sec <= ce->ce_stat_data.sd_mtime.sec #endif ); } @@ -342,7 +357,7 @@ int ie_modified(const struct index_state *istate, * then we know it is. */ if ((changed & DATA_CHANGED) && - (S_ISGITLINK(ce->ce_mode) || ce->ce_size != 0)) + (S_ISGITLINK(ce->ce_mode) || ce->ce_stat_data.sd_size != 0)) return changed; changed_fs = ce_modified_check_fs(ce, st); @@ -1324,16 +1339,16 @@ static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *on { struct cache_entry *ce = xmalloc(cache_entry_size(len)); - ce->ce_ctime.sec = ntoh_l(ondisk->ctime.sec); - ce->ce_mtime.sec = ntoh_l(ondisk->mtime.sec); - ce->ce_ctime.nsec = ntoh_l(ondisk->ctime.nsec); - ce->ce_mtime.nsec = ntoh_l(ondisk->mtime.nsec); - ce->ce_dev = ntoh_l(ondisk->dev); - ce->ce_ino = ntoh_l(ondisk->ino); + ce->ce_stat_data.sd_ctime.sec = ntoh_l(ondisk->ctime.sec); + ce->ce_stat_data.sd_mtime.sec = ntoh_l(ondisk->mtime.sec); + ce->ce_stat_data.sd_ctime.nsec = ntoh_l(ondisk->ctime.nsec); + ce->ce_stat_data.sd_mtime.nsec = ntoh_l(ondisk->mtime.nsec); + ce->ce_stat_data.sd_dev = ntoh_l(ondisk->dev); + ce->ce_stat_data.sd_ino = ntoh_l(ondisk->ino); ce->ce_mode = ntoh_l(ondisk->mode); - ce->ce_uid = ntoh_l(ondisk->uid); - ce->ce_gid = ntoh_l(ondisk->gid); - ce->ce_size = ntoh_l(ondisk->size); + ce->ce_stat_data.sd_uid = ntoh_l(ondisk->uid); + ce->ce_stat_data.sd_gid = ntoh_l(ondisk->gid); + ce->ce_stat_data.sd_size = ntoh_l(ondisk->size); ce->ce_flags = flags & ~CE_NAMEMASK; ce->ce_namelen = len; hashcpy(ce->sha1, ondisk->sha1); @@ -1611,7 +1626,7 @@ static void ce_smudge_racily_clean_entry(struct cache_entry *ce) * The only thing we care about in this function is to smudge the * falsely clean entry due to touch-update-touch race, so we leave * everything else as they are. We are called for entries whose - * ce_mtime match the index file mtime. + * ce_stat_data.sd_mtime match the index file mtime. * * Note that this actually does not do much for gitlinks, for * which ce_match_stat_basic() always goes to the actual @@ -1650,7 +1665,7 @@ static void ce_smudge_racily_clean_entry(struct cache_entry *ce) * file, and never calls us, so the cached size information * for "frotz" stays 6 which does not match the filesystem. */ - ce->ce_size = 0; + ce->ce_stat_data.sd_size = 0; } } @@ -1660,16 +1675,16 @@ static char *copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk, { short flags; - ondisk->ctime.sec = htonl(ce->ce_ctime.sec); - ondisk->mtime.sec = htonl(ce->ce_mtime.sec); - ondisk->ctime.nsec = htonl(ce->ce_ctime.nsec); - ondisk->mtime.nsec = htonl(ce->ce_mtime.nsec); - ondisk->dev = htonl(ce->ce_dev); - ondisk->ino = htonl(ce->ce_ino); + ondisk->ctime.sec = htonl(ce->ce_stat_data.sd_ctime.sec); + ondisk->mtime.sec = htonl(ce->ce_stat_data.sd_mtime.sec); + ondisk->ctime.nsec = htonl(ce->ce_stat_data.sd_ctime.nsec); + ondisk->mtime.nsec = htonl(ce->ce_stat_data.sd_mtime.nsec); + ondisk->dev = htonl(ce->ce_stat_data.sd_dev); + ondisk->ino = htonl(ce->ce_stat_data.sd_ino); ondisk->mode = htonl(ce->ce_mode); - ondisk->uid = htonl(ce->ce_uid); - ondisk->gid = htonl(ce->ce_gid); - ondisk->size = htonl(ce->ce_size); + ondisk->uid = htonl(ce->ce_stat_data.sd_uid); + ondisk->gid = htonl(ce->ce_stat_data.sd_gid); + ondisk->size = htonl(ce->ce_stat_data.sd_size); hashcpy(ondisk->sha1, ce->sha1); flags = ce->ce_flags; @@ -1936,3 +1951,33 @@ void *read_blob_data_from_index(struct index_state *istate, const char *path, un *size = sz; return data; } + +void stat_validity_clear(struct stat_validity *sv) +{ + free(sv->sd); + sv->sd = NULL; +} + +int stat_validity_check(struct stat_validity *sv, const char *path) +{ + struct stat st; + + if (stat(path, &st) < 0) + return sv->sd == NULL; + if (!sv->sd) + return 0; + return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st); +} + +void stat_validity_update(struct stat_validity *sv, int fd) +{ + struct stat st; + + if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode)) + stat_validity_clear(sv); + else { + if (!sv->sd) + sv->sd = xcalloc(1, sizeof(struct stat_data)); + fill_stat_data(sv->sd, &st); + } +} @@ -750,6 +750,21 @@ static int do_for_each_entry_in_dirs(struct ref_dir *dir1, } /* + * Load all of the refs from the dir into our in-memory cache. The hard work + * of loading loose refs is done by get_ref_dir(), so we just need to recurse + * through all of the sub-directories. We do not even need to care about + * sorting, as traversal order does not matter to us. + */ +static void prime_ref_dir(struct ref_dir *dir) +{ + int i; + for (i = 0; i < dir->nr; i++) { + struct ref_entry *entry = dir->entries[i]; + if (entry->flag & REF_DIR) + prime_ref_dir(get_ref_dir(entry)); + } +} +/* * Return true iff refname1 and refname2 conflict with each other. * Two reference names conflict if one of them exactly matches the * leading components of the other; e.g., "foo/bar" conflicts with @@ -806,6 +821,30 @@ static int is_refname_available(const char *refname, const char *oldrefname, return 1; } +struct packed_ref_cache { + struct ref_entry *root; + + /* + * Count of references to the data structure in this instance, + * including the pointer from ref_cache::packed if any. The + * data will not be freed as long as the reference count is + * nonzero. + */ + unsigned int referrers; + + /* + * 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). The referrer count + * is also incremented when the file is locked and decremented + * when it is unlocked. + */ + struct lock_file *lock; + + /* The metadata from when this packed-refs cache was read */ + struct stat_validity validity; +}; + /* * Future: need to be in "struct repository" * when doing a full libification. @@ -813,7 +852,7 @@ static int is_refname_available(const char *refname, const char *oldrefname, static struct ref_cache { struct ref_cache *next; struct ref_entry *loose; - struct ref_entry *packed; + struct packed_ref_cache *packed; /* * The submodule name, or "" for the main repo. We allocate * length 1 rather than FLEX_ARRAY so that the main ref_cache @@ -822,11 +861,42 @@ 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; + +/* + * Increment the reference count of *packed_refs. + */ +static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs) +{ + packed_refs->referrers++; +} + +/* + * Decrease the reference count of *packed_refs. If it goes to zero, + * free *packed_refs and return true; otherwise return false. + */ +static int release_packed_ref_cache(struct packed_ref_cache *packed_refs) +{ + if (!--packed_refs->referrers) { + free_ref_entry(packed_refs->root); + stat_validity_clear(&packed_refs->validity); + free(packed_refs); + return 1; + } else { + return 0; + } +} + static void clear_packed_ref_cache(struct ref_cache *refs) { if (refs->packed) { - free_ref_entry(refs->packed); + struct packed_ref_cache *packed_refs = refs->packed; + + if (packed_refs->lock) + die("internal error: packed-ref cache cleared while locked"); refs->packed = NULL; + release_packed_ref_cache(packed_refs); } } @@ -996,29 +1066,57 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir) } } -static struct ref_dir *get_packed_refs(struct ref_cache *refs) +/* + * Get the packed_ref_cache for the specified ref_cache, creating it + * if necessary. + */ +static struct packed_ref_cache *get_packed_ref_cache(struct ref_cache *refs) { + const char *packed_refs_file; + + if (*refs->name) + packed_refs_file = git_path_submodule(refs->name, "packed-refs"); + else + packed_refs_file = git_path("packed-refs"); + + if (refs->packed && + !stat_validity_check(&refs->packed->validity, packed_refs_file)) + clear_packed_ref_cache(refs); + if (!refs->packed) { - const char *packed_refs_file; FILE *f; - refs->packed = create_dir_entry(refs, "", 0, 0); - if (*refs->name) - packed_refs_file = git_path_submodule(refs->name, "packed-refs"); - else - packed_refs_file = git_path("packed-refs"); + refs->packed = xcalloc(1, sizeof(*refs->packed)); + acquire_packed_ref_cache(refs->packed); + refs->packed->root = create_dir_entry(refs, "", 0, 0); f = fopen(packed_refs_file, "r"); if (f) { - read_packed_refs(f, get_ref_dir(refs->packed)); + stat_validity_update(&refs->packed->validity, fileno(f)); + read_packed_refs(f, get_ref_dir(refs->packed->root)); fclose(f); } } - return get_ref_dir(refs->packed); + return refs->packed; +} + +static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache) +{ + return get_ref_dir(packed_ref_cache->root); +} + +static struct ref_dir *get_packed_refs(struct ref_cache *refs) +{ + return get_packed_ref_dir(get_packed_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)); } @@ -1558,14 +1656,32 @@ void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname) static int do_for_each_entry(struct ref_cache *refs, const char *base, each_ref_entry_fn fn, void *cb_data) { - struct ref_dir *packed_dir = get_packed_refs(refs); - struct ref_dir *loose_dir = get_loose_refs(refs); + struct packed_ref_cache *packed_ref_cache; + struct ref_dir *loose_dir; + struct ref_dir *packed_dir; int retval = 0; + /* + * We must make sure that all loose refs are read before accessing the + * packed-refs file; this avoids a race condition in which loose refs + * are migrated to the packed-refs file by a simultaneous process, but + * our in-memory view is from before the migration. get_packed_ref_cache() + * takes care of making sure our view is up to date with what is on + * disk. + */ + loose_dir = get_loose_refs(refs); if (base && *base) { - packed_dir = find_containing_dir(packed_dir, base, 0); loose_dir = find_containing_dir(loose_dir, base, 0); } + if (loose_dir) + prime_ref_dir(loose_dir); + + packed_ref_cache = get_packed_ref_cache(refs); + acquire_packed_ref_cache(packed_ref_cache); + packed_dir = get_packed_ref_dir(packed_ref_cache); + if (base && *base) { + packed_dir = find_containing_dir(packed_dir, base, 0); + } if (packed_dir && loose_dir) { sort_ref_dir(packed_dir); @@ -1582,6 +1698,7 @@ static int do_for_each_entry(struct ref_cache *refs, const char *base, loose_dir, 0, fn, cb_data); } + release_packed_ref_cache(packed_ref_cache); return retval; } @@ -2036,6 +2153,73 @@ static void write_packed_entry(int fd, char *refname, unsigned char *sha1, } } +/* + * An each_ref_entry_fn that writes the entry to a packed-refs file. + */ +static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data) +{ + int *fd = cb_data; + enum peel_status peel_status = peel_entry(entry, 0); + + if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG) + error("internal error: %s is not a valid packed reference!", + entry->name); + write_packed_entry(*fd, entry->name, entry->u.value.sha1, + peel_status == PEEL_PEELED ? + entry->u.value.peeled : NULL); + 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; + /* Increment the reference count to prevent it from being freed: */ + acquire_packed_ref_cache(packed_ref_cache); + 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; + release_packed_ref_cache(packed_ref_cache); + 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; + release_packed_ref_cache(packed_ref_cache); + clear_packed_ref_cache(&ref_cache); +} + struct ref_to_prune { struct ref_to_prune *next; unsigned char sha1[20]; @@ -2044,35 +2228,50 @@ struct ref_to_prune { struct pack_refs_cb_data { unsigned int flags; + struct ref_dir *packed_refs; struct ref_to_prune *ref_to_prune; - int fd; }; -static int pack_one_ref(struct ref_entry *entry, void *cb_data) +/* + * An each_ref_entry_fn that is run over loose references only. If + * the loose reference can be packed, add an entry in the packed ref + * cache. If the reference should be pruned, also add it to + * ref_to_prune in the pack_refs_cb_data. + */ +static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data) { struct pack_refs_cb_data *cb = cb_data; enum peel_status peel_status; + struct ref_entry *packed_entry; int is_tag_ref = !prefixcmp(entry->name, "refs/tags/"); - /* ALWAYS pack refs that were already packed or are tags */ - if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref && - !(entry->flag & REF_ISPACKED)) + /* ALWAYS pack tags */ + if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref) return 0; /* Do not pack symbolic or broken refs: */ if ((entry->flag & REF_ISSYMREF) || !ref_resolves_to_object(entry)) return 0; + /* Add a packed ref cache entry equivalent to the loose entry. */ peel_status = peel_entry(entry, 1); if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG) die("internal error peeling reference %s (%s)", entry->name, sha1_to_hex(entry->u.value.sha1)); - write_packed_entry(cb->fd, entry->name, entry->u.value.sha1, - peel_status == PEEL_PEELED ? - entry->u.value.peeled : NULL); + packed_entry = find_ref(cb->packed_refs, entry->name); + if (packed_entry) { + /* Overwrite existing packed entry with info from loose entry */ + packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED; + hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1); + } else { + packed_entry = create_ref_entry(entry->name, entry->u.value.sha1, + REF_ISPACKED | REF_KNOWS_PEELED, 0); + add_ref(cb->packed_refs, packed_entry); + } + hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled); - /* If the ref was already packed, there is no need to prune it. */ - if ((cb->flags & PACK_REFS_PRUNE) && !(entry->flag & REF_ISPACKED)) { + /* Schedule the loose reference for pruning if requested. */ + if ((cb->flags & PACK_REFS_PRUNE)) { int namelen = strlen(entry->name) + 1; struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen); hashcpy(n->sha1, entry->u.value.sha1); @@ -2134,8 +2333,6 @@ 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; @@ -2143,26 +2340,38 @@ int pack_refs(unsigned int flags) memset(&cbdata, 0, sizeof(cbdata)); cbdata.flags = flags; - cbdata.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); - write_or_die(cbdata.fd, PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER)); + do_for_each_entry_in_dir(get_loose_refs(&ref_cache), 0, + pack_if_possible_fn, &cbdata); - do_for_each_entry(&ref_cache, "", pack_one_ref, &cbdata); - 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; } -static int repack_ref_fn(struct ref_entry *entry, void *cb_data) +/* + * If entry is no longer needed in packed-refs, add it to the string + * list pointed to by cb_data. Reasons for deleting entries: + * + * - Entry is broken. + * - Entry is overridden by a loose ref. + * - Entry does not point at a valid object. + * + * In the first and third cases, also emit an error message because these + * are indications of repository corruption. + */ +static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data) { - int *fd = cb_data; - enum peel_status peel_status; + struct string_list *refs_to_delete = cb_data; if (entry->flag & REF_ISBROKEN) { /* This shouldn't happen to packed refs. */ error("%s is broken!", entry->name); + string_list_append(refs_to_delete, entry->name); return 0; } if (!has_sha1_file(entry->u.value.sha1)) { @@ -2172,7 +2381,7 @@ static int repack_ref_fn(struct ref_entry *entry, void *cb_data) if (read_ref_full(entry->name, sha1, 0, &flags)) /* We should at least have found the packed ref. */ die("Internal error"); - if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) + if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) { /* * This packed reference is overridden by a * loose reference, so it is OK that its value @@ -2181,9 +2390,11 @@ static int repack_ref_fn(struct ref_entry *entry, void *cb_data) * collected. For this purpose we don't even * care whether the loose reference itself is * invalid, broken, symbolic, etc. Silently - * omit the packed reference from the output. + * remove the packed reference. */ + string_list_append(refs_to_delete, entry->name); return 0; + } /* * There is no overriding loose reference, so the fact * that this reference doesn't refer to a valid object @@ -2192,44 +2403,47 @@ static int repack_ref_fn(struct ref_entry *entry, void *cb_data) * the output. */ error("%s does not point to a valid object!", entry->name); + string_list_append(refs_to_delete, entry->name); return 0; } - peel_status = peel_entry(entry, 0); - write_packed_entry(*fd, entry->name, entry->u.value.sha1, - peel_status == PEEL_PEELED ? - entry->u.value.peeled : NULL); - return 0; } 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; 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. */ + + /* Remove refname from the cache: */ if (remove_entry(packed, refname) == -1) { /* * The packed entry disappeared while we were * acquiring the lock. */ - rollback_lock_file(&packlock); + rollback_packed_refs(); return 0; } - write_or_die(fd, PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER)); - do_for_each_entry_in_dir(packed, 0, repack_ref_fn, &fd); - return commit_lock_file(&packlock); + + /* Remove any other accumulated cruft: */ + do_for_each_entry_in_dir(packed, 0, curate_packed_ref_fn, &refs_to_delete); + for_each_string_list_item(ref_to_delete, &refs_to_delete) { + if (remove_entry(packed, ref_to_delete->string) == -1) + die("internal error"); + } + + /* Write what remains: */ + 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 |