1 /* Blue Sky: File Systems in the Cloud
3 * Copyright (C) 2009 The Regents of the University of California
4 * Written by Michael Vrable <mvrable@cs.ucsd.edu>
15 #include "bluesky-private.h"
17 /* Miscellaneous useful functions that don't really fit anywhere else. */
19 bluesky_time_hires bluesky_now_hires()
23 if (clock_gettime(CLOCK_REALTIME, &time) != 0) {
24 perror("clock_gettime");
28 return (int64_t)(time.tv_sec) * 1000000000 + time.tv_nsec;
31 /* Convert a UTF-8 string to lowercase. This can be used to implement
32 * case-insensitive lookups and comparisons, by normalizing all values to
33 * lowercase first. Returns a newly-allocated string as a result. */
34 gchar *bluesky_lowercase(const gchar *s)
36 /* TODO: Unicode handling; for now just do ASCII. */
37 return g_ascii_strdown(s, -1);
40 gboolean bluesky_inode_is_ready(BlueSkyInode *inode)
45 g_mutex_lock(inode->lock);
46 gboolean valid = (inode->type != BLUESKY_PENDING
47 && inode->type != BLUESKY_INVALID);
49 g_mutex_unlock(inode->lock);
54 /**** Reference-counted strings. ****/
56 /* Create and return a new reference-counted string. The reference count is
57 * initially one. The newly-returned string takes ownership of the memory
58 * pointed at by data, and will call g_free on it when the reference count
60 BlueSkyRCStr *bluesky_string_new(gpointer data, gsize len)
62 BlueSkyRCStr *string = g_new(BlueSkyRCStr, 1);
66 g_atomic_int_set(&string->refcount, 1);
70 /* Create a new BlueSkyRCStr from a GString. The GString is destroyed. */
71 BlueSkyRCStr *bluesky_string_new_from_gstring(GString *s)
74 return bluesky_string_new(g_string_free(s, FALSE), len);
77 /* Create a new BlueSkyRCStr from a memory-mapped buffer. */
78 BlueSkyRCStr *bluesky_string_new_from_mmap(BlueSkyCacheFile *mmap,
79 int offset, gsize len)
81 g_assert(offset + len <= mmap->len);
83 BlueSkyRCStr *string = g_new(BlueSkyRCStr, 1);
85 g_atomic_int_inc(&mmap->mapcount);
86 string->data = (char *)mmap->addr + offset;
88 g_atomic_int_set(&string->refcount, 1);
92 void bluesky_string_ref(BlueSkyRCStr *string)
97 g_atomic_int_inc(&string->refcount);
100 void bluesky_string_unref(BlueSkyRCStr *string)
105 if (g_atomic_int_dec_and_test(&string->refcount)) {
106 if (string->mmap == NULL) {
107 g_free(string->data);
109 bluesky_mmap_unref(string->mmap);
115 /* Duplicate and return a new reference-counted string, containing a copy of
116 * the original data, with a reference count of 1. As an optimization, if the
117 * passed-in string already has a reference count of 1, the original is
118 * returned. Can be used to make a mutable copy of a shared string. For this
119 * to truly be safe, it is probably needed that there be some type of lock
120 * protecting access to the string. */
121 BlueSkyRCStr *bluesky_string_dup(BlueSkyRCStr *string)
126 if (string->mmap != NULL) {
128 s = bluesky_string_new(g_memdup(string->data, string->len),
130 bluesky_string_unref(string);
134 if (g_atomic_int_dec_and_test(&string->refcount)) {
135 /* There are no other shared copies, so return this one. */
136 g_atomic_int_inc(&string->refcount);
139 return bluesky_string_new(g_memdup(string->data, string->len),
144 /* Resize the data block used by a BlueSkyRCStr. The data pointer might change
145 * after making this call, so it should not be cached across calls to this
146 * function. To avoid confusing any other users, the caller probably ought to
147 * hold the only reference to the string (by calling bluesky_string_dup first
149 void bluesky_string_resize(BlueSkyRCStr *string, gsize len)
151 g_assert(string->mmap == NULL);
153 if (string->len == len)
156 g_warn_if_fail(string->refcount == 1);
158 string->data = g_realloc(string->data, len);
162 /* Cache LRU list management functions. These manage the doubly-linked list of
163 * inodes sorted by accessed/modified time. The FS lock should be held while
166 * _remove will unlink an inode from the linked list.
168 * _prepend and _append insert an inode at the head or tail of the linked list,
169 * and return a pointer to the linked list element (which should be stored in
170 * the inode); the inode should not already be in the list.
172 * _head and _tail simply return the first or last item inode in the list. */
173 void bluesky_list_unlink(GList *head, GList *item)
178 if (head->prev == item)
179 head->prev = item->prev;
180 head->next = g_list_delete_link(head->next, item);
183 GList *bluesky_list_prepend(GList *head, BlueSkyInode *inode)
185 head->next = g_list_prepend(head->next, inode);
186 if (head->prev == NULL)
187 head->prev = g_list_last(head->next);
191 GList *bluesky_list_append(GList *head, BlueSkyInode *inode)
193 if (head->next == NULL)
194 return bluesky_list_prepend(head, inode);
196 g_assert(head->prev != NULL && head->prev->next == NULL);
198 GList *link = g_list_alloc();
201 link->prev = head->prev;
202 head->prev->next = link;
207 BlueSkyInode *bluesky_list_head(GList *head)
209 if (head->next == NULL)
212 return (BlueSkyInode *)head->next->data;
215 BlueSkyInode *bluesky_list_tail(GList *head)
217 if (head->prev == NULL)
220 return (BlueSkyInode *)head->prev->data;
223 /**** Range sets. ****/
225 /* These are a data structure which can track a set of discontiguous integer
226 * ranges--such as the partitioning of the inode number space or the bytes in a
227 * log file into objects. This current prototype implementation just tracks
228 * the starting offset with a hash table and doesn't track the length, but
229 * should be extended later to track properly. */
231 struct BlueSkyRangeset {
235 static gint compare64(gconstpointer a, gconstpointer b, gpointer user_data)
237 uint64_t x = *(uint64_t *)a;
238 uint64_t y = *(uint64_t *)b;
248 BlueSkyRangeset *bluesky_rangeset_new()
250 BlueSkyRangeset *rangeset = g_new(BlueSkyRangeset, 1);
251 rangeset->seq = g_sequence_new(g_free);
255 void bluesky_rangeset_free(BlueSkyRangeset *rangeset)
257 g_sequence_free(rangeset->seq);
261 gboolean bluesky_rangeset_insert(BlueSkyRangeset *rangeset,
262 uint64_t start, uint64_t length,
266 i = g_sequence_search(rangeset->seq, &start, compare64, NULL);
267 i = g_sequence_iter_prev(i);
269 /* TODO: Checks that no other item overlaps. */
271 BlueSkyRangesetItem *item = g_new(BlueSkyRangesetItem, 1);
273 item->length = length;
275 g_sequence_insert_sorted(rangeset->seq, item, compare64, NULL);
280 const BlueSkyRangesetItem *bluesky_rangeset_lookup(BlueSkyRangeset *rangeset,
284 i = g_sequence_search(rangeset->seq, &offset, compare64, NULL);
285 i = g_sequence_iter_prev(i);
286 if (g_sequence_iter_is_end(i))
289 BlueSkyRangesetItem *item = (BlueSkyRangesetItem *)g_sequence_get(i);
290 if (offset >= item->start && offset < item->start + item->length)
296 /* Look up the first rangeset item starting at or following the given address.
297 * Can be used to iterate through a rangeset. */
298 const BlueSkyRangesetItem *bluesky_rangeset_lookup_next(BlueSkyRangeset *rangeset, uint64_t offset)
301 i = g_sequence_search(rangeset->seq, &offset, compare64, NULL);
302 i = g_sequence_iter_prev(i);
303 if (g_sequence_iter_is_end(i))
305 BlueSkyRangesetItem *item = (BlueSkyRangesetItem *)g_sequence_get(i);
306 if (item->start < offset) {
307 i = g_sequence_iter_next(i);
308 if (g_sequence_iter_is_end(i))
311 item = (BlueSkyRangesetItem *)g_sequence_get(i);
316 /* Determine the full extent of a rangeset--the smallest offset covered and the
317 * length needed to extend to the end of the last item. */
318 void bluesky_rangeset_get_extents(BlueSkyRangeset *rangeset,
319 uint64_t *start, uint64_t *length)
322 BlueSkyRangesetItem *item;
324 i = g_sequence_get_begin_iter(rangeset->seq);
325 if (g_sequence_iter_is_end(i)) {
331 item = (BlueSkyRangesetItem *)g_sequence_get(i);
332 *start = item->start;
334 i = g_sequence_get_end_iter(rangeset->seq);
335 i = g_sequence_iter_prev(i);
336 item = (BlueSkyRangesetItem *)g_sequence_get(i);
337 *length = (item->start + item->length) - *start;
340 /**** Request response-time tracking. ****/
343 bluesky_time_hires timestamp;
347 BlueSkyProfile *bluesky_profile_new()
349 return g_new0(BlueSkyProfile, 1);
352 void bluesky_profile_free(BlueSkyProfile *profile)
354 while (profile->events != NULL) {
355 RTEvent *event = (RTEvent *)profile->events->data;
356 g_free(event->message);
358 profile->events = g_list_delete_link(profile->events, profile->events);
360 g_free(profile->description);
364 void bluesky_profile_add_event(BlueSkyProfile *profile, char *message)
366 g_return_if_fail(profile != NULL);
368 RTEvent *event = g_new(RTEvent, 1);
369 event->timestamp = bluesky_now_hires();
370 event->message = message;
371 profile->events = g_list_prepend(profile->events, event);
374 void bluesky_profile_print(BlueSkyProfile *profile)
376 g_return_if_fail(profile != NULL);
378 g_print("Event Timeline: %s\n", profile->description);
379 GList *link = g_list_last(profile->events);
380 bluesky_time_hires last_time = 0;
381 while (link != NULL) {
382 RTEvent *event = (RTEvent *)link->data;
383 g_print(" [%"PRIi64" ns]: %s\n",
384 event->timestamp - last_time, event->message);
385 last_time = event->timestamp;
390 static GStaticPrivate per_thread_profile = G_STATIC_PRIVATE_INIT;
392 BlueSkyProfile *bluesky_profile_get()
394 return (BlueSkyProfile *)g_static_private_get(&per_thread_profile);
397 void bluesky_profile_set(BlueSkyProfile *profile)
399 g_static_private_set(&per_thread_profile, profile, NULL);