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authorTavian Barnes <tavianator@tavianator.com>2024-02-05 14:02:55 -0500
committerTavian Barnes <tavianator@tavianator.com>2024-02-06 15:22:39 -0500
commit89ecb2a08467cd8aa6ba70f8519df494652cac96 (patch)
tree1095e93eb4e68bfc025a4aaa350f81bfd70544ba
parent10b6da04521cf3f65f3c47bece8e2e5e6e664d6d (diff)
downloadbfs-89ecb2a08467cd8aa6ba70f8519df494652cac96.tar.xz
bftw: stat() files asynchronously
-rw-r--r--src/bftw.c677
-rw-r--r--src/bftw.h20
-rw-r--r--src/eval.c20
-rw-r--r--tests/bfs/execdir_plus.sh2
4 files changed, 507 insertions, 212 deletions
diff --git a/src/bftw.c b/src/bftw.c
index d392aed..664651c 100644
--- a/src/bftw.c
+++ b/src/bftw.c
@@ -36,58 +36,130 @@
#include <string.h>
#include <sys/stat.h>
+/** Initialize a bftw_stat cache. */
+static void bftw_stat_init(struct bftw_stat *bufs, struct bfs_stat *stat_buf, struct bfs_stat *lstat_buf) {
+ bufs->stat_buf = stat_buf;
+ bufs->lstat_buf = lstat_buf;
+ bufs->stat_err = -1;
+ bufs->lstat_err = -1;
+}
+
+/** Fill a bftw_stat cache from another one. */
+static void bftw_stat_fill(struct bftw_stat *dest, const struct bftw_stat *src) {
+ if (dest->stat_err < 0 && src->stat_err >= 0) {
+ dest->stat_buf = src->stat_buf;
+ dest->stat_err = src->stat_err;
+ }
+
+ if (dest->lstat_err < 0 && src->lstat_err >= 0) {
+ dest->lstat_buf = src->lstat_buf;
+ dest->lstat_err = src->lstat_err;
+ }
+}
+
+/** Cache a bfs_stat() result. */
+static void bftw_stat_cache(struct bftw_stat *bufs, enum bfs_stat_flags flags, const struct bfs_stat *buf, int err) {
+ if (flags & BFS_STAT_NOFOLLOW) {
+ bufs->lstat_buf = buf;
+ bufs->lstat_err = err;
+ if (err || !S_ISLNK(buf->mode)) {
+ // Non-link, so share stat info
+ bufs->stat_buf = buf;
+ bufs->stat_err = err;
+ }
+ } else if (flags & BFS_STAT_TRYFOLLOW) {
+ if (err) {
+ bufs->stat_err = err;
+ } else if (S_ISLNK(buf->mode)) {
+ bufs->lstat_buf = buf;
+ bufs->lstat_err = err;
+ bufs->stat_err = ENOENT;
+ } else {
+ bufs->stat_buf = buf;
+ bufs->stat_err = err;
+ }
+ } else {
+ bufs->stat_buf = buf;
+ bufs->stat_err = err;
+ }
+}
+
/** Caching bfs_stat(). */
-static const struct bfs_stat *bftw_stat_impl(struct BFTW *ftwbuf, struct bftw_stat *cache, enum bfs_stat_flags flags) {
- if (!cache->buf) {
- if (cache->error) {
- errno = cache->error;
- } else if (bfs_stat(ftwbuf->at_fd, ftwbuf->at_path, flags, &cache->storage) == 0) {
- cache->buf = &cache->storage;
+static const struct bfs_stat *bftw_stat_impl(struct BFTW *ftwbuf, enum bfs_stat_flags flags) {
+ struct bftw_stat *bufs = &ftwbuf->stat_bufs;
+ struct bfs_stat *buf;
+
+ if (flags & BFS_STAT_NOFOLLOW) {
+ buf = (struct bfs_stat *)bufs->lstat_buf;
+ if (bufs->lstat_err == 0) {
+ return buf;
+ } else if (bufs->lstat_err > 0) {
+ errno = bufs->lstat_err;
+ return NULL;
+ }
+ } else {
+ buf = (struct bfs_stat *)bufs->stat_buf;
+ if (bufs->stat_err == 0) {
+ return buf;
+ } else if (bufs->stat_err > 0) {
+ errno = bufs->stat_err;
+ return NULL;
+ }
+ }
+
+ struct bfs_stat *ret;
+ int err;
+ if (bfs_stat(ftwbuf->at_fd, ftwbuf->at_path, flags, buf) == 0) {
+ ret = buf;
+ err = 0;
#ifdef S_IFWHT
- } else if (errno == ENOENT && ftwbuf->type == BFS_WHT) {
- // This matches the behavior of FTS_WHITEOUT on BSD
- memset(&cache->storage, 0, sizeof(cache->storage));
- cache->storage.mode = S_IFWHT;
- cache->buf = &cache->storage;
+ } else if (errno == ENOENT && ftwbuf->type == BFS_WHT) {
+ // This matches the behavior of FTS_WHITEOUT on BSD
+ ret = memset(buf, 0, sizeof(*buf));
+ ret->mode = S_IFWHT;
+ err = 0;
#endif
- } else {
- cache->error = errno;
- }
+ } else {
+ ret = NULL;
+ err = errno;
}
- return cache->buf;
+ bftw_stat_cache(bufs, flags, ret, err);
+ return ret;
}
const struct bfs_stat *bftw_stat(const struct BFTW *ftwbuf, enum bfs_stat_flags flags) {
struct BFTW *mutbuf = (struct BFTW *)ftwbuf;
const struct bfs_stat *ret;
- if (flags & BFS_STAT_NOFOLLOW) {
- ret = bftw_stat_impl(mutbuf, &mutbuf->lstat_cache, BFS_STAT_NOFOLLOW);
- if (ret && !S_ISLNK(ret->mode) && !mutbuf->stat_cache.buf) {
- // Non-link, so share stat info
- mutbuf->stat_cache.buf = ret;
+ if (flags & BFS_STAT_TRYFOLLOW) {
+ ret = bftw_stat_impl(mutbuf, BFS_STAT_FOLLOW);
+ if (!ret && errno_is_like(ENOENT)) {
+ ret = bftw_stat_impl(mutbuf, BFS_STAT_NOFOLLOW);
}
} else {
- ret = bftw_stat_impl(mutbuf, &mutbuf->stat_cache, BFS_STAT_FOLLOW);
- if (!ret && (flags & BFS_STAT_TRYFOLLOW) && errno_is_like(ENOENT)) {
- ret = bftw_stat_impl(mutbuf, &mutbuf->lstat_cache, BFS_STAT_NOFOLLOW);
- }
+ ret = bftw_stat_impl(mutbuf, flags);
}
return ret;
}
const struct bfs_stat *bftw_cached_stat(const struct BFTW *ftwbuf, enum bfs_stat_flags flags) {
+ const struct bftw_stat *bufs = &ftwbuf->stat_bufs;
+
if (flags & BFS_STAT_NOFOLLOW) {
- return ftwbuf->lstat_cache.buf;
- } else if (ftwbuf->stat_cache.buf) {
- return ftwbuf->stat_cache.buf;
- } else if ((flags & BFS_STAT_TRYFOLLOW) && error_is_like(ftwbuf->stat_cache.error, ENOENT)) {
- return ftwbuf->lstat_cache.buf;
- } else {
- return NULL;
+ if (bufs->lstat_err == 0) {
+ return bufs->lstat_buf;
+ }
+ } else if (bufs->stat_err == 0) {
+ return bufs->stat_buf;
+ } else if ((flags & BFS_STAT_TRYFOLLOW) && error_is_like(bufs->stat_err, ENOENT)) {
+ if (bufs->lstat_err == 0) {
+ return bufs->lstat_buf;
+ }
}
+
+ return NULL;
}
enum bfs_type bftw_type(const struct BFTW *ftwbuf, enum bfs_stat_flags flags) {
@@ -156,6 +228,9 @@ struct bftw_file {
/** The inode number, for cycle detection. */
ino_t ino;
+ /** Cached bfs_stat() info. */
+ struct bftw_stat stat_bufs;
+
/** The offset of this file in the full path. */
size_t nameoff;
/** The length of the file's name. */
@@ -276,6 +351,10 @@ struct bftw_queue {
struct bftw_list waiting;
/** A list of already-serviced files. */
struct bftw_list ready;
+ /** The current size of the queue. */
+ size_t size;
+ /** The number of files currently in-service. */
+ size_t ioqueued;
/** Tracks the imbalance between synchronous and async service. */
unsigned long imbalance;
};
@@ -286,6 +365,8 @@ static void bftw_queue_init(struct bftw_queue *queue, enum bftw_qflags flags) {
SLIST_INIT(&queue->buffer);
SLIST_INIT(&queue->waiting);
SLIST_INIT(&queue->ready);
+ queue->size = 0;
+ queue->ioqueued = 0;
queue->imbalance = 0;
}
@@ -304,6 +385,8 @@ static void bftw_queue_push(struct bftw_queue *queue, struct bftw_file *file) {
SLIST_APPEND(&queue->ready, file, ready);
}
}
+
+ ++queue->size;
}
/** Add any buffered files to the queue. */
@@ -339,8 +422,19 @@ static bool bftw_queue_balanced(const struct bftw_queue *queue) {
}
}
-/** Detatch the next waiting file to service it asynchronously. */
-static void bftw_queue_detach(struct bftw_queue *queue, struct bftw_file *file) {
+/** Update the queue balance for (a)sync service. */
+static void bftw_queue_rebalance(struct bftw_queue *queue, bool async) {
+ if (async) {
+ --queue->imbalance;
+ } else {
+ ++queue->imbalance;
+ }
+}
+
+/** Detatch the next waiting file. */
+static void bftw_queue_detach(struct bftw_queue *queue, struct bftw_file *file, bool async) {
+ bfs_assert(!file->ioqueued);
+
if (file == SLIST_HEAD(&queue->buffer)) {
// To maintain order, we can't detach any files until they're
// added to the waiting/ready lists
@@ -352,19 +446,34 @@ static void bftw_queue_detach(struct bftw_queue *queue, struct bftw_file *file)
bfs_bug("Detached file was not buffered or waiting");
}
- file->ioqueued = true;
- --queue->imbalance;
+ if (async) {
+ file->ioqueued = true;
+ ++queue->ioqueued;
+ bftw_queue_rebalance(queue, true);
+ }
}
/** Reattach a serviced file to the queue. */
-static void bftw_queue_attach(struct bftw_queue *queue, struct bftw_file *file) {
- file->ioqueued = false;
+static void bftw_queue_attach(struct bftw_queue *queue, struct bftw_file *file, bool async) {
+ if (async) {
+ bfs_assert(file->ioqueued);
+ file->ioqueued = false;
+ --queue->ioqueued;
+ } else {
+ bfs_assert(!file->ioqueued);
+ }
if (!(queue->flags & BFTW_QORDER)) {
SLIST_APPEND(&queue->ready, file, ready);
}
}
+/** Make a file ready immediately. */
+static void bftw_queue_skip(struct bftw_queue *queue, struct bftw_file *file) {
+ bftw_queue_detach(queue, file, false);
+ bftw_queue_attach(queue, file, false);
+}
+
/** Get the next waiting file. */
static struct bftw_file *bftw_queue_waiting(const struct bftw_queue *queue) {
if (!(queue->flags & BFTW_QBUFFER)) {
@@ -395,13 +504,6 @@ static struct bftw_file *bftw_queue_ready(const struct bftw_queue *queue) {
return SLIST_HEAD(&queue->ready);
}
-/** Check if a queue is empty. */
-static bool bftw_queue_empty(const struct bftw_queue *queue) {
- return SLIST_EMPTY(&queue->buffer)
- && SLIST_EMPTY(&queue->waiting)
- && SLIST_EMPTY(&queue->ready);
-}
-
/** Pop a file from the queue. */
static struct bftw_file *bftw_queue_pop(struct bftw_queue *queue) {
// Don't pop until we've had a chance to sort the buffer
@@ -413,10 +515,10 @@ static struct bftw_file *bftw_queue_pop(struct bftw_queue *queue) {
// If no files are ready, try the waiting list. Or, if
// BFTW_QORDER is set, we may need to pop from both lists.
file = SLIST_POP(&queue->waiting);
- if (file) {
- // This file will be serviced synchronously
- ++queue->imbalance;
- }
+ }
+
+ if (file) {
+ --queue->size;
}
return file;
@@ -444,6 +546,9 @@ struct bftw_cache {
size_t dir_limit;
/** Excess force-allocated bfs_dirs. */
size_t dir_excess;
+
+ /** bfs_stat arena. */
+ struct arena stat_bufs;
};
/** Initialize a cache. */
@@ -462,6 +567,8 @@ static void bftw_cache_init(struct bftw_cache *cache, size_t capacity) {
}
cache->dir_excess = 0;
+
+ ARENA_INIT(&cache->stat_bufs, struct bfs_stat);
}
/** Allocate a directory. */
@@ -603,8 +710,9 @@ static void bftw_cache_destroy(struct bftw_cache *cache) {
bfs_assert(LIST_EMPTY(cache));
bfs_assert(!cache->target);
- varena_destroy(&cache->files);
+ arena_destroy(&cache->stat_bufs);
arena_destroy(&cache->dirs);
+ varena_destroy(&cache->files);
}
/** Create a new bftw_file. */
@@ -642,6 +750,8 @@ static struct bftw_file *bftw_file_new(struct bftw_cache *cache, struct bftw_fil
file->dev = -1;
file->ino = -1;
+ bftw_stat_init(&file->stat_bufs, NULL, NULL);
+
file->namelen = namelen;
memcpy(file->name, name, namelen + 1);
@@ -661,6 +771,21 @@ static void bftw_file_set_dir(struct bftw_cache *cache, struct bftw_file *file,
}
}
+/** Free a file's cached stat() buffers. */
+static void bftw_stat_recycle(struct bftw_cache *cache, struct bftw_file *file) {
+ struct bftw_stat *bufs = &file->stat_bufs;
+
+ struct bfs_stat *stat_buf = (struct bfs_stat *)bufs->stat_buf;
+ struct bfs_stat *lstat_buf = (struct bfs_stat *)bufs->lstat_buf;
+ if (stat_buf) {
+ arena_free(&cache->stat_bufs, stat_buf);
+ } else if (lstat_buf) {
+ arena_free(&cache->stat_bufs, lstat_buf);
+ }
+
+ bftw_stat_init(bufs, NULL, NULL);
+}
+
/** Free a bftw_file. */
static void bftw_file_free(struct bftw_cache *cache, struct bftw_file *file) {
bfs_assert(file->refcount == 0);
@@ -669,6 +794,8 @@ static void bftw_file_free(struct bftw_cache *cache, struct bftw_file *file) {
bftw_file_close(cache, file);
}
+ bftw_stat_recycle(cache, file);
+
varena_free(&cache->files, file, file->namelen + 1);
}
@@ -729,6 +856,10 @@ struct bftw_state {
/** Extra data about the current file. */
struct BFTW ftwbuf;
+ /** stat() buffer storage. */
+ struct bfs_stat stat_buf;
+ /** lstat() buffer storage. */
+ struct bfs_stat lstat_buf;
};
/** Check if we have to buffer files before visiting them. */
@@ -755,6 +886,11 @@ static bool bftw_must_buffer(const struct bftw_state *state) {
return true;
}
+ if ((state->flags & BFTW_STAT) && state->nthreads > 1) {
+ // We will be buffering every file anyway for ioq_stat()
+ return true;
+ }
+
return false;
}
@@ -841,19 +977,32 @@ static int bftw_state_init(struct bftw_state *state, const struct bftw_args *arg
return 0;
}
-/** Unpin a directory, and possibly queue it for unwrapping. */
-static void bftw_unpin_dir(struct bftw_state *state, struct bftw_file *file, bool force) {
- bftw_cache_unpin(&state->cache, file);
+/** Queue a directory for unwrapping. */
+static void bftw_delayed_unwrap(struct bftw_state *state, struct bftw_file *file) {
+ bfs_assert(file->dir);
- if (file->dir && (force || file->pincount == 0)) {
- if (!SLIST_ATTACHED(&state->to_close, file)) {
- SLIST_APPEND(&state->to_close, file);
- }
+ if (!SLIST_ATTACHED(&state->to_close, file, ready)) {
+ SLIST_APPEND(&state->to_close, file, ready);
+ }
+}
+
+/** Unpin a file's parent. */
+static void bftw_unpin_parent(struct bftw_state *state, struct bftw_file *file, bool unwrap) {
+ struct bftw_file *parent = file->parent;
+ if (!parent) {
+ return;
+ }
+
+ bftw_cache_unpin(&state->cache, parent);
+
+ if (unwrap && parent->dir && parent->pincount == 0) {
+ bftw_delayed_unwrap(state, parent);
}
}
/** Pop a response from the I/O queue. */
static int bftw_ioq_pop(struct bftw_state *state, bool block) {
+ struct bftw_cache *cache = &state->cache;
struct ioq *ioq = state->ioq;
if (!ioq) {
return -1;
@@ -864,10 +1013,10 @@ static int bftw_ioq_pop(struct bftw_state *state, bool block) {
return -1;
}
- struct bftw_cache *cache = &state->cache;
- struct bftw_file *file;
- struct bftw_file *parent;
- struct bfs_dir *dir;
+ struct bftw_file *file = ent->ptr;
+ if (file) {
+ bftw_unpin_parent(state, file, true);
+ }
enum ioq_op op = ent->op;
switch (op) {
@@ -877,30 +1026,30 @@ static int bftw_ioq_pop(struct bftw_state *state, bool block) {
case IOQ_CLOSEDIR:
++cache->capacity;
- dir = ent->closedir.dir;
- bftw_freedir(cache, dir);
+ bftw_freedir(cache, ent->closedir.dir);
break;
case IOQ_OPENDIR:
- file = ent->ptr;
-
++cache->capacity;
- parent = file->parent;
- if (parent) {
- bftw_unpin_dir(state, parent, false);
- }
- dir = ent->opendir.dir;
if (ent->result >= 0) {
- bftw_file_set_dir(cache, file, dir);
+ bftw_file_set_dir(cache, file, ent->opendir.dir);
} else {
- bftw_freedir(cache, dir);
+ bftw_freedir(cache, ent->opendir.dir);
}
- bftw_queue_attach(&state->dirq, file);
+ bftw_queue_attach(&state->dirq, file, true);
break;
case IOQ_STAT:
+ if (ent->result >= 0) {
+ bftw_stat_cache(&file->stat_bufs, ent->stat.flags, ent->stat.buf, 0);
+ } else {
+ arena_free(&cache->stat_bufs, ent->stat.buf);
+ bftw_stat_cache(&file->stat_bufs, ent->stat.flags, NULL, -ent->result);
+ }
+
+ bftw_queue_attach(&state->fileq, file, true);
break;
}
@@ -1125,21 +1274,34 @@ static int bftw_unwrapdir(struct bftw_state *state, struct bftw_file *file) {
return bftw_ioq_closedir(state, dir);
}
+/** Try to pin a file's parent. */
+static int bftw_pin_parent(struct bftw_state *state, struct bftw_file *file) {
+ struct bftw_file *parent = file->parent;
+ if (!parent) {
+ return AT_FDCWD;
+ }
+
+ int fd = parent->fd;
+ if (fd < 0) {
+ bfs_static_assert(AT_FDCWD != -1);
+ return -1;
+ }
+
+ bftw_cache_pin(&state->cache, parent);
+ return fd;
+}
+
/** Open a directory asynchronously. */
static int bftw_ioq_opendir(struct bftw_state *state, struct bftw_file *file) {
+ struct bftw_cache *cache = &state->cache;
+
if (bftw_ioq_reserve(state) != 0) {
goto fail;
}
- int dfd = AT_FDCWD;
- struct bftw_cache *cache = &state->cache;
- struct bftw_file *parent = file->parent;
- if (parent) {
- dfd = parent->fd;
- if (dfd < 0) {
- goto fail;
- }
- bftw_cache_pin(cache, parent);
+ int dfd = bftw_pin_parent(state, file);
+ if (dfd < 0 && dfd != AT_FDCWD) {
+ goto fail;
}
if (bftw_cache_reserve(state) != 0) {
@@ -1161,9 +1323,7 @@ static int bftw_ioq_opendir(struct bftw_state *state, struct bftw_file *file) {
free:
bftw_freedir(cache, dir);
unpin:
- if (parent) {
- bftw_cache_unpin(cache, parent);
- }
+ bftw_unpin_parent(state, file, false);
fail:
return -1;
}
@@ -1177,7 +1337,7 @@ static void bftw_ioq_opendirs(struct bftw_state *state) {
}
if (bftw_ioq_opendir(state, dir) == 0) {
- bftw_queue_detach(&state->dirq, dir);
+ bftw_queue_detach(&state->dirq, dir, true);
} else {
break;
}
@@ -1191,24 +1351,36 @@ static void bftw_push_dir(struct bftw_state *state, struct bftw_file *file) {
bftw_ioq_opendirs(state);
}
-/** Check if we should block on the ioq when popping a directory. */
-static bool bftw_block_for_dir(const struct bftw_state *state) {
- // Always block with more than one background thread
- if (state->nthreads > 1) {
- return true;
+/** Pop a file from a queue, then activate it. */
+static bool bftw_pop(struct bftw_state *state, struct bftw_queue *queue) {
+ if (queue->size == 0) {
+ return false;
}
- // Block if the cache is full
- if (state->cache.capacity == 0) {
- return true;
+ while (!bftw_queue_ready(queue) && queue->ioqueued > 0) {
+ bool block = true;
+ if (bftw_queue_waiting(queue) && state->nthreads == 1) {
+ // With only one background thread, balance the work
+ // between it and the main thread
+ block = false;
+ }
+
+ if (bftw_ioq_pop(state, block) < 0) {
+ break;
+ }
}
- // Block if we have no other files/dirs to visit
- if (!bftw_queue_waiting(&state->dirq) && bftw_queue_empty(&state->fileq)) {
- return true;
+ struct bftw_file *file = bftw_queue_pop(queue);
+ if (!file) {
+ return false;
}
- return false;
+ while (file->ioqueued) {
+ bftw_ioq_pop(state, true);
+ }
+
+ state->file = file;
+ return true;
}
/** Pop a directory to read from the queue. */
@@ -1220,32 +1392,143 @@ static bool bftw_pop_dir(struct bftw_state *state) {
if (state->strategy == BFTW_BFS && bftw_queue_ready(&state->fileq)) {
return false;
}
+ } else if (!bftw_queue_ready(&state->dirq)) {
+ // Don't block if we have files ready to visit
+ if (bftw_queue_ready(&state->fileq)) {
+ return false;
+ }
+ }
+
+ return bftw_pop(state, &state->dirq);
+}
+
+/** Figure out bfs_stat() flags. */
+static enum bfs_stat_flags bftw_stat_flags(const struct bftw_state *state, size_t depth) {
+ enum bftw_flags mask = BFTW_FOLLOW_ALL;
+ if (depth == 0) {
+ mask |= BFTW_FOLLOW_ROOTS;
+ }
+
+ if (state->flags & mask) {
+ return BFS_STAT_TRYFOLLOW;
} else {
- while (!bftw_queue_ready(&state->dirq)) {
- if (bftw_ioq_pop(state, bftw_block_for_dir(state)) < 0) {
- break;
- }
+ return BFS_STAT_NOFOLLOW;
+ }
+}
+
+/** Check if a stat() call is necessary. */
+static bool bftw_must_stat(const struct bftw_state *state, size_t depth, enum bfs_type type, const char *name) {
+ if (state->flags & BFTW_STAT) {
+ return true;
+ }
+
+ switch (type) {
+ case BFS_UNKNOWN:
+ return true;
+
+ case BFS_DIR:
+ return state->flags & (BFTW_DETECT_CYCLES | BFTW_SKIP_MOUNTS | BFTW_PRUNE_MOUNTS);
+
+ case BFS_LNK:
+ if (!(bftw_stat_flags(state, depth) & BFS_STAT_NOFOLLOW)) {
+ return true;
+ }
+ fallthru;
+
+ default:
+#if __linux__
+ if (state->mtab && bfs_might_be_mount(state->mtab, name)) {
+ return true;
}
+#endif
+ return false;
}
+}
- struct bftw_file *file = bftw_queue_pop(&state->dirq);
- if (!file) {
+/** stat() a file asynchronously. */
+static int bftw_ioq_stat(struct bftw_state *state, struct bftw_file *file) {
+ if (bftw_ioq_reserve(state) != 0) {
+ goto fail;
+ }
+
+ int dfd = bftw_pin_parent(state, file);
+ if (dfd < 0 && dfd != AT_FDCWD) {
+ goto fail;
+ }
+
+ struct bftw_cache *cache = &state->cache;
+ struct bfs_stat *buf = arena_alloc(&cache->stat_bufs);
+ if (!buf) {
+ goto unpin;
+ }
+
+ enum bfs_stat_flags flags = bftw_stat_flags(state, file->depth);
+ if (ioq_stat(state->ioq, dfd, file->name, flags, buf, file) != 0) {
+ goto free;
+ }
+
+ return 0;
+
+free:
+ arena_free(&cache->stat_bufs, buf);
+unpin:
+ bftw_unpin_parent(state, file, false);
+fail:
+ return -1;
+}
+
+/** Check if we should stat() a file asynchronously. */
+static bool bftw_should_ioq_stat(struct bftw_state *state, struct bftw_file *file) {
+ // To avoid surprising users too much, process the roots in order
+ if (file->depth == 0) {
return false;
}
- while (file->ioqueued) {
- bftw_ioq_pop(state, true);
+#ifdef S_IFWHT
+ // ioq_stat() does not do whiteout emulation like bftw_stat_impl()
+ if (file->type == BFS_WHT) {
+ return false;
}
+#endif
- state->file = file;
- return true;
+ return bftw_must_stat(state, file->depth, file->type, file->name);
+}
+
+/** Call stat() on files that need it. */
+static void bftw_stat_files(struct bftw_state *state) {
+ while (true) {
+ struct bftw_file *file = bftw_queue_waiting(&state->fileq);
+ if (!file) {
+ break;
+ }
+
+ if (!bftw_should_ioq_stat(state, file)) {
+ bftw_queue_skip(&state->fileq, file);
+ continue;
+ }
+
+ if (!bftw_queue_balanced(&state->fileq)) {
+ break;
+ }
+
+ if (bftw_ioq_stat(state, file) == 0) {
+ bftw_queue_detach(&state->fileq, file, true);
+ } else {
+ break;
+ }
+ }
+}
+
+/** Push a file onto the queue. */
+static void bftw_push_file(struct bftw_state *state, struct bftw_file *file) {
+ bftw_queue_push(&state->fileq, file);
+ bftw_stat_files(state);
}
/** Pop a file to visit from the queue. */
static bool bftw_pop_file(struct bftw_state *state) {
bfs_assert(!state->file);
- state->file = bftw_queue_pop(&state->fileq);
- return state->file;
+ return bftw_pop(state, &state->fileq);
}
/** Build the path to the current file. */
@@ -1334,6 +1617,8 @@ static int bftw_opendir(struct bftw_state *state) {
return -1;
}
+ bftw_queue_rebalance(&state->dirq, false);
+
state->dir = bftw_file_opendir(state, file, state->path);
if (!state->dir) {
state->direrror = errno;
@@ -1364,47 +1649,6 @@ static int bftw_readdir(struct bftw_state *state) {
return ret;
}
-/** Check if a stat() call is needed for this visit. */
-static bool bftw_need_stat(const struct bftw_state *state) {
- if (state->flags & BFTW_STAT) {
- return true;
- }
-
- const struct BFTW *ftwbuf = &state->ftwbuf;
- if (ftwbuf->type == BFS_UNKNOWN) {
- return true;
- }
-
- if (ftwbuf->type == BFS_LNK && !(ftwbuf->stat_flags & BFS_STAT_NOFOLLOW)) {
- return true;
- }
-
- if (ftwbuf->type == BFS_DIR) {
- if (state->flags & (BFTW_DETECT_CYCLES | BFTW_SKIP_MOUNTS | BFTW_PRUNE_MOUNTS)) {
- return true;
- }
-#if __linux__
- } else if (state->mtab) {
- // Linux fills in d_type from the underlying inode, even when
- // the directory entry is a bind mount point. In that case, we
- // need to stat() to get the correct type. We don't need to
- // check for directories because they can only be mounted over
- // by other directories.
- if (bfs_might_be_mount(state->mtab, ftwbuf->path + ftwbuf->nameoff)) {
- return true;
- }
-#endif
- }
-
- return false;
-}
-
-/** Initialize bftw_stat cache. */
-static void bftw_stat_init(struct bftw_stat *cache) {
- cache->buf = NULL;
- cache->error = 0;
-}
-
/** Open a file if necessary. */
static int bftw_ensure_open(struct bftw_state *state, struct bftw_file *file, const char *path) {
int ret = file->fd;
@@ -1436,9 +1680,7 @@ static void bftw_init_ftwbuf(struct bftw_state *state, enum bftw_visit visit) {
ftwbuf->error = state->direrror;
ftwbuf->at_fd = AT_FDCWD;
ftwbuf->at_path = ftwbuf->path;
- ftwbuf->stat_flags = BFS_STAT_NOFOLLOW;
- bftw_stat_init(&ftwbuf->lstat_cache);
- bftw_stat_init(&ftwbuf->stat_cache);
+ bftw_stat_init(&ftwbuf->stat_bufs, &state->stat_buf, &state->lstat_buf);
struct bftw_file *parent = NULL;
if (de) {
@@ -1451,6 +1693,7 @@ static void bftw_init_ftwbuf(struct bftw_state *state, enum bftw_visit visit) {
ftwbuf->depth = file->depth;
ftwbuf->type = file->type;
ftwbuf->nameoff = file->nameoff;
+ bftw_stat_fill(&ftwbuf->stat_bufs, &file->stat_bufs);
}
if (parent) {
@@ -1468,22 +1711,15 @@ static void bftw_init_ftwbuf(struct bftw_state *state, enum bftw_visit visit) {
ftwbuf->nameoff = xbaseoff(ftwbuf->path);
}
+ ftwbuf->stat_flags = bftw_stat_flags(state, ftwbuf->depth);
+
if (ftwbuf->error != 0) {
ftwbuf->type = BFS_ERROR;
return;
}
- int follow_flags = BFTW_FOLLOW_ALL;
- if (ftwbuf->depth == 0) {
- follow_flags |= BFTW_FOLLOW_ROOTS;
- }
- bool follow = state->flags & follow_flags;
- if (follow) {
- ftwbuf->stat_flags = BFS_STAT_TRYFOLLOW;
- }
-
const struct bfs_stat *statbuf = NULL;
- if (bftw_need_stat(state)) {
+ if (bftw_must_stat(state, ftwbuf->depth, ftwbuf->type, ftwbuf->path + ftwbuf->nameoff)) {
statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
if (statbuf) {
ftwbuf->type = bfs_mode_to_type(statbuf->mode);
@@ -1522,6 +1758,11 @@ static bool bftw_is_mount(struct bftw_state *state, const char *name) {
return statbuf && statbuf->dev != parent->dev;
}
+/** Check if bfs_stat() was called from the main thread. */
+static bool bftw_stat_was_sync(const struct bftw_state *state, const struct bfs_stat *buf) {
+ return buf == &state->stat_buf || buf == &state->lstat_buf;
+}
+
/** Invoke the callback. */
static enum bftw_action bftw_call_back(struct bftw_state *state, const char *name, enum bftw_visit visit) {
if (visit == BFTW_POST && !(state->flags & BFTW_POST_ORDER)) {
@@ -1541,31 +1782,43 @@ static enum bftw_action bftw_call_back(struct bftw_state *state, const char *nam
return BFTW_STOP;
}
+ enum bftw_action ret = BFTW_PRUNE;
if ((state->flags & BFTW_SKIP_MOUNTS) && bftw_is_mount(state, name)) {
- return BFTW_PRUNE;
+ goto done;
}
- enum bftw_action ret = state->callback(ftwbuf, state->ptr);
+ ret = state->callback(ftwbuf, state->ptr);
switch (ret) {
case BFTW_CONTINUE:
- if (visit != BFTW_PRE) {
- return BFTW_PRUNE;
- }
- if (ftwbuf->type != BFS_DIR) {
- return BFTW_PRUNE;
- }
- if ((state->flags & BFTW_PRUNE_MOUNTS) && bftw_is_mount(state, name)) {
- return BFTW_PRUNE;
+ if (visit != BFTW_PRE || ftwbuf->type != BFS_DIR) {
+ ret = BFTW_PRUNE;
+ } else if (state->flags & BFTW_PRUNE_MOUNTS) {
+ if (bftw_is_mount(state, name)) {
+ ret = BFTW_PRUNE;
+ }
}
- fallthru;
+ break;
+
case BFTW_PRUNE:
case BFTW_STOP:
- return ret;
+ break;
default:
state->error = EINVAL;
return BFTW_STOP;
}
+
+done:
+ if (state->fileq.flags & BFTW_QBALANCE) {
+ // Detect any main-thread stat() calls to rebalance the queue
+ const struct bfs_stat *buf = bftw_cached_stat(ftwbuf, BFS_STAT_FOLLOW);
+ const struct bfs_stat *lbuf = bftw_cached_stat(ftwbuf, BFS_STAT_NOFOLLOW);
+ if (bftw_stat_was_sync(state, buf) || bftw_stat_was_sync(state, lbuf)) {
+ bftw_queue_rebalance(&state->fileq, false);
+ }
+ }
+
+ return ret;
}
/**
@@ -1589,8 +1842,13 @@ static int bftw_gc(struct bftw_state *state, enum bftw_gc_flags flags) {
int ret = 0;
struct bftw_file *file = state->file;
- if (file && state->dir) {
- bftw_unpin_dir(state, file, true);
+ if (file) {
+ if (state->dir) {
+ bftw_cache_unpin(&state->cache, file);
+ }
+ if (file->dir) {
+ bftw_delayed_unwrap(state, file);
+ }
}
state->dir = NULL;
state->de = NULL;
@@ -1607,7 +1865,7 @@ static int bftw_gc(struct bftw_state *state, enum bftw_gc_flags flags) {
}
state->direrror = 0;
- while ((file = SLIST_POP(&state->to_close))) {
+ while ((file = SLIST_POP(&state->to_close, ready))) {
bftw_unwrapdir(state, file);
}
@@ -1685,6 +1943,7 @@ static void bftw_flush(struct bftw_state *state) {
bftw_list_sort(&state->fileq.buffer);
}
bftw_queue_flush(&state->fileq);
+ bftw_stat_files(state);
bftw_queue_flush(&state->dirq);
bftw_ioq_opendirs(state);
@@ -1704,22 +1963,46 @@ static int bftw_closedir(struct bftw_state *state) {
static void bftw_save_ftwbuf(struct bftw_file *file, const struct BFTW *ftwbuf) {
file->type = ftwbuf->type;
- const struct bfs_stat *statbuf = ftwbuf->stat_cache.buf;
- if (!statbuf || (ftwbuf->stat_flags & BFS_STAT_NOFOLLOW)) {
- statbuf = ftwbuf->lstat_cache.buf;
- }
+ const struct bfs_stat *statbuf = bftw_cached_stat(ftwbuf, ftwbuf->stat_flags);
if (statbuf) {
file->dev = statbuf->dev;
file->ino = statbuf->ino;
}
}
+/** Check if we should buffer a file instead of visiting it. */
+static bool bftw_buffer_file(const struct bftw_state *state, const struct bftw_file *file, const char *name) {
+ if (!name) {
+ // Already buffered
+ return false;
+ }
+
+ if (state->flags & BFTW_BUFFER) {
+ return true;
+ }
+
+ // If we need to call stat(), and can do it async, buffer this file
+ if (!state->ioq) {
+ return false;
+ }
+
+ if (!bftw_queue_balanced(&state->fileq)) {
+ // stat() would run synchronously anyway
+ return false;
+ }
+
+ size_t depth = file ? file->depth + 1 : 1;
+ enum bfs_type type = state->de ? state->de->type : BFS_UNKNOWN;
+ return bftw_must_stat(state, depth, type, name);
+}
+
/** Visit and/or enqueue the current file. */
static int bftw_visit(struct bftw_state *state, const char *name) {
+ struct bftw_cache *cache = &state->cache;
struct bftw_file *file = state->file;
- if (name && (state->flags & BFTW_BUFFER)) {
- file = bftw_file_new(&state->cache, file, name);
+ if (bftw_buffer_file(state, file, name)) {
+ file = bftw_file_new(cache, file, name);
if (!file) {
state->error = errno;
return -1;
@@ -1729,14 +2012,14 @@ static int bftw_visit(struct bftw_state *state, const char *name) {
file->type = state->de->type;
}
- bftw_queue_push(&state->fileq, file);
+ bftw_push_file(state, file);
return 0;
}
switch (bftw_call_back(state, name, BFTW_PRE)) {
case BFTW_CONTINUE:
if (name) {
- file = bftw_file_new(&state->cache, state->file, name);
+ file = bftw_file_new(cache, state->file, name);
} else {
state->file = NULL;
}
@@ -1746,6 +2029,7 @@ static int bftw_visit(struct bftw_state *state, const char *name) {
}
bftw_save_ftwbuf(file, &state->ftwbuf);
+ bftw_stat_recycle(cache, file);
bftw_push_dir(state, file);
return 0;
@@ -1757,10 +2041,22 @@ static int bftw_visit(struct bftw_state *state, const char *name) {
}
default:
+ if (file && !name) {
+ bftw_gc(state, BFTW_VISIT_NONE);
+ }
return -1;
}
}
+/** Drain a bftw_queue. */
+static void bftw_drain(struct bftw_state *state, struct bftw_queue *queue) {
+ bftw_queue_flush(queue);
+
+ while (bftw_pop(state, queue)) {
+ bftw_gc(state, BFTW_VISIT_NONE);
+ }
+}
+
/**
* Dispose of the bftw() state.
*
@@ -1777,11 +2073,9 @@ static int bftw_state_destroy(struct bftw_state *state) {
state->ioq = NULL;
}
- bftw_queue_flush(&state->dirq);
- bftw_queue_flush(&state->fileq);
- do {
- bftw_gc(state, BFTW_VISIT_NONE);
- } while (bftw_pop_dir(state) || bftw_pop_file(state));
+ bftw_gc(state, BFTW_VISIT_NONE);
+ bftw_drain(state, &state->dirq);
+ bftw_drain(state, &state->fileq);
ioq_destroy(ioq);
@@ -1823,6 +2117,7 @@ static int bftw_impl(struct bftw_state *state) {
if (bftw_visit(state, NULL) != 0) {
return -1;
}
+ bftw_flush(state);
}
return 0;
diff --git a/src/bftw.h b/src/bftw.h
index e325d14..2805361 100644
--- a/src/bftw.h
+++ b/src/bftw.h
@@ -26,12 +26,14 @@ enum bftw_visit {
* Cached bfs_stat() info for a file.
*/
struct bftw_stat {
- /** A pointer to the bfs_stat() buffer, if available. */
- const struct bfs_stat *buf;
- /** Storage for the bfs_stat() buffer, if needed. */
- struct bfs_stat storage;
- /** The cached error code, if any. */
- int error;
+ /** The bfs_stat(BFS_STAT_FOLLOW) buffer. */
+ const struct bfs_stat *stat_buf;
+ /** The bfs_stat(BFS_STAT_NOFOLLOW) buffer. */
+ const struct bfs_stat *lstat_buf;
+ /** The cached bfs_stat(BFS_STAT_FOLLOW) error. */
+ int stat_err;
+ /** The cached bfs_stat(BFS_STAT_NOFOLLOW) error. */
+ int lstat_err;
};
/**
@@ -62,10 +64,8 @@ struct BFTW {
/** Flags for bfs_stat(). */
enum bfs_stat_flags stat_flags;
- /** Cached bfs_stat() info for BFS_STAT_NOFOLLOW. */
- struct bftw_stat lstat_cache;
- /** Cached bfs_stat() info for BFS_STAT_FOLLOW. */
- struct bftw_stat stat_cache;
+ /** Cached bfs_stat() info. */
+ struct bftw_stat stat_bufs;
};
/**
diff --git a/src/eval.c b/src/eval.c
index 6dc73d8..dfeaa1e 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1234,7 +1234,7 @@ static bool eval_file_unique(struct bfs_eval *state, struct trie *seen) {
/**
* Log a stat() call.
*/
-static void debug_stat(const struct bfs_ctx *ctx, const struct BFTW *ftwbuf, const struct bftw_stat *cache, enum bfs_stat_flags flags) {
+static void debug_stat(const struct bfs_ctx *ctx, const struct BFTW *ftwbuf, enum bfs_stat_flags flags, int err) {
bfs_debug_prefix(ctx, DEBUG_STAT);
fprintf(stderr, "bfs_stat(");
@@ -1254,10 +1254,10 @@ static void debug_stat(const struct bfs_ctx *ctx, const struct BFTW *ftwbuf, con
DEBUG_FLAG(flags, BFS_STAT_TRYFOLLOW);
DEBUG_FLAG(flags, BFS_STAT_NOSYNC);
- fprintf(stderr, ") == %d", cache->buf ? 0 : -1);
+ fprintf(stderr, ") == %d", err ? 0 : -1);
- if (cache->error) {
- fprintf(stderr, " [%d]", cache->error);
+ if (err) {
+ fprintf(stderr, " [%d]", err);
}
fprintf(stderr, "\n");
@@ -1271,14 +1271,14 @@ static void debug_stats(const struct bfs_ctx *ctx, const struct BFTW *ftwbuf) {
return;
}
- const struct bfs_stat *statbuf = ftwbuf->stat_cache.buf;
- if (statbuf || ftwbuf->stat_cache.error) {
- debug_stat(ctx, ftwbuf, &ftwbuf->stat_cache, BFS_STAT_FOLLOW);
+ const struct bftw_stat *bufs = &ftwbuf->stat_bufs;
+
+ if (bufs->stat_err >= 0) {
+ debug_stat(ctx, ftwbuf, BFS_STAT_FOLLOW, bufs->stat_err);
}
- const struct bfs_stat *lstatbuf = ftwbuf->lstat_cache.buf;
- if ((lstatbuf && lstatbuf != statbuf) || ftwbuf->lstat_cache.error) {
- debug_stat(ctx, ftwbuf, &ftwbuf->lstat_cache, BFS_STAT_NOFOLLOW);
+ if (bufs->lstat_err >= 0) {
+ debug_stat(ctx, ftwbuf, BFS_STAT_NOFOLLOW, bufs->lstat_err);
}
}
diff --git a/tests/bfs/execdir_plus.sh b/tests/bfs/execdir_plus.sh
index f66b898..6f24bdc 100644
--- a/tests/bfs/execdir_plus.sh
+++ b/tests/bfs/execdir_plus.sh
@@ -1,4 +1,4 @@
tree=$(invoke_bfs -D tree 2>&1 -quit)
[[ "$tree" == *"-S dfs"* ]] && skip
-bfs_diff basic -execdir "$TESTS/sort-args.sh" {} +
+bfs_diff -j1 basic -execdir "$TESTS/sort-args.sh" {} +