123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462 |
- #include <linux/fs.h>
- #include <linux/vfs.h>
- #include <linux/slab.h>
- #include <linux/vmalloc.h>
- #include <linux/sched.h>
- #include <linux/spinlock.h>
- #include <linux/wait.h>
- #include <linux/pagemap.h>
- #include "squashfs_fs.h"
- #include "squashfs_fs_sb.h"
- #include "squashfs.h"
- #include "page_actor.h"
- struct squashfs_cache_entry *squashfs_cache_get(struct super_block *sb,
- struct squashfs_cache *cache, u64 block, int length)
- {
- int i, n;
- struct squashfs_cache_entry *entry;
- spin_lock(&cache->lock);
- while (1) {
- for (i = cache->curr_blk, n = 0; n < cache->entries; n++) {
- if (cache->entry[i].block == block) {
- cache->curr_blk = i;
- break;
- }
- i = (i + 1) % cache->entries;
- }
- if (n == cache->entries) {
-
- if (cache->unused == 0) {
- cache->num_waiters++;
- spin_unlock(&cache->lock);
- wait_event(cache->wait_queue, cache->unused);
- spin_lock(&cache->lock);
- cache->num_waiters--;
- continue;
- }
-
- i = cache->next_blk;
- for (n = 0; n < cache->entries; n++) {
- if (cache->entry[i].refcount == 0)
- break;
- i = (i + 1) % cache->entries;
- }
- cache->next_blk = (i + 1) % cache->entries;
- entry = &cache->entry[i];
-
- cache->unused--;
- entry->block = block;
- entry->refcount = 1;
- entry->pending = 1;
- entry->num_waiters = 0;
- entry->error = 0;
- spin_unlock(&cache->lock);
- entry->length = squashfs_read_data(sb, block, length,
- &entry->next_index, entry->actor);
- spin_lock(&cache->lock);
- if (entry->length < 0)
- entry->error = entry->length;
- entry->pending = 0;
-
- if (entry->num_waiters) {
- spin_unlock(&cache->lock);
- wake_up_all(&entry->wait_queue);
- } else
- spin_unlock(&cache->lock);
- goto out;
- }
-
- entry = &cache->entry[i];
- if (entry->refcount == 0)
- cache->unused--;
- entry->refcount++;
-
- if (entry->pending) {
- entry->num_waiters++;
- spin_unlock(&cache->lock);
- wait_event(entry->wait_queue, !entry->pending);
- } else
- spin_unlock(&cache->lock);
- goto out;
- }
- out:
- TRACE("Got %s %d, start block %lld, refcount %d, error %d\n",
- cache->name, i, entry->block, entry->refcount, entry->error);
- if (entry->error)
- ERROR("Unable to read %s cache entry [%llx]\n", cache->name,
- block);
- return entry;
- }
- void squashfs_cache_put(struct squashfs_cache_entry *entry)
- {
- struct squashfs_cache *cache = entry->cache;
- spin_lock(&cache->lock);
- entry->refcount--;
- if (entry->refcount == 0) {
- cache->unused++;
-
- if (cache->num_waiters) {
- spin_unlock(&cache->lock);
- wake_up(&cache->wait_queue);
- return;
- }
- }
- spin_unlock(&cache->lock);
- }
- void squashfs_cache_delete(struct squashfs_cache *cache)
- {
- int i, j;
- if (cache == NULL)
- return;
- for (i = 0; i < cache->entries; i++) {
- if (cache->entry[i].data) {
- for (j = 0; j < cache->pages; j++)
- kfree(cache->entry[i].data[j]);
- kfree(cache->entry[i].data);
- }
- kfree(cache->entry[i].actor);
- }
- kfree(cache->entry);
- kfree(cache);
- }
- struct squashfs_cache *squashfs_cache_init(char *name, int entries,
- int block_size)
- {
- int i, j;
- struct squashfs_cache *cache = kzalloc(sizeof(*cache), GFP_KERNEL);
- if (cache == NULL) {
- ERROR("Failed to allocate %s cache\n", name);
- return NULL;
- }
- cache->entry = kcalloc(entries, sizeof(*(cache->entry)), GFP_KERNEL);
- if (cache->entry == NULL) {
- ERROR("Failed to allocate %s cache\n", name);
- goto cleanup;
- }
- cache->curr_blk = 0;
- cache->next_blk = 0;
- cache->unused = entries;
- cache->entries = entries;
- cache->block_size = block_size;
- cache->pages = block_size >> PAGE_SHIFT;
- cache->pages = cache->pages ? cache->pages : 1;
- cache->name = name;
- cache->num_waiters = 0;
- spin_lock_init(&cache->lock);
- init_waitqueue_head(&cache->wait_queue);
- for (i = 0; i < entries; i++) {
- struct squashfs_cache_entry *entry = &cache->entry[i];
- init_waitqueue_head(&cache->entry[i].wait_queue);
- entry->cache = cache;
- entry->block = SQUASHFS_INVALID_BLK;
- entry->data = kcalloc(cache->pages, sizeof(void *), GFP_KERNEL);
- if (entry->data == NULL) {
- ERROR("Failed to allocate %s cache entry\n", name);
- goto cleanup;
- }
- for (j = 0; j < cache->pages; j++) {
- entry->data[j] = kmalloc(PAGE_SIZE, GFP_KERNEL);
- if (entry->data[j] == NULL) {
- ERROR("Failed to allocate %s buffer\n", name);
- goto cleanup;
- }
- }
- entry->actor = squashfs_page_actor_init(entry->data,
- cache->pages, 0);
- if (entry->actor == NULL) {
- ERROR("Failed to allocate %s cache entry\n", name);
- goto cleanup;
- }
- }
- return cache;
- cleanup:
- squashfs_cache_delete(cache);
- return NULL;
- }
- int squashfs_copy_data(void *buffer, struct squashfs_cache_entry *entry,
- int offset, int length)
- {
- int remaining = length;
- if (length == 0)
- return 0;
- else if (buffer == NULL)
- return min(length, entry->length - offset);
- while (offset < entry->length) {
- void *buff = entry->data[offset / PAGE_SIZE]
- + (offset % PAGE_SIZE);
- int bytes = min_t(int, entry->length - offset,
- PAGE_SIZE - (offset % PAGE_SIZE));
- if (bytes >= remaining) {
- memcpy(buffer, buff, remaining);
- remaining = 0;
- break;
- }
- memcpy(buffer, buff, bytes);
- buffer += bytes;
- remaining -= bytes;
- offset += bytes;
- }
- return length - remaining;
- }
- int squashfs_read_metadata(struct super_block *sb, void *buffer,
- u64 *block, int *offset, int length)
- {
- struct squashfs_sb_info *msblk = sb->s_fs_info;
- int bytes, res = length;
- struct squashfs_cache_entry *entry;
- TRACE("Entered squashfs_read_metadata [%llx:%x]\n", *block, *offset);
- if (unlikely(length < 0))
- return -EIO;
- while (length) {
- entry = squashfs_cache_get(sb, msblk->block_cache, *block, 0);
- if (entry->error) {
- res = entry->error;
- goto error;
- } else if (*offset >= entry->length) {
- res = -EIO;
- goto error;
- }
- bytes = squashfs_copy_data(buffer, entry, *offset, length);
- if (buffer)
- buffer += bytes;
- length -= bytes;
- *offset += bytes;
- if (*offset == entry->length) {
- *block = entry->next_index;
- *offset = 0;
- }
- squashfs_cache_put(entry);
- }
- return res;
- error:
- squashfs_cache_put(entry);
- return res;
- }
- struct squashfs_cache_entry *squashfs_get_fragment(struct super_block *sb,
- u64 start_block, int length)
- {
- struct squashfs_sb_info *msblk = sb->s_fs_info;
- return squashfs_cache_get(sb, msblk->fragment_cache, start_block,
- length);
- }
- struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *sb,
- u64 start_block, int length)
- {
- struct squashfs_sb_info *msblk = sb->s_fs_info;
- return squashfs_cache_get(sb, msblk->read_page, start_block, length);
- }
- void *squashfs_read_table(struct super_block *sb, u64 block, int length)
- {
- int pages = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
- int i, res;
- void *table, *buffer, **data;
- struct squashfs_page_actor *actor;
- table = buffer = kmalloc(length, GFP_KERNEL);
- if (table == NULL)
- return ERR_PTR(-ENOMEM);
- data = kcalloc(pages, sizeof(void *), GFP_KERNEL);
- if (data == NULL) {
- res = -ENOMEM;
- goto failed;
- }
- actor = squashfs_page_actor_init(data, pages, length);
- if (actor == NULL) {
- res = -ENOMEM;
- goto failed2;
- }
- for (i = 0; i < pages; i++, buffer += PAGE_SIZE)
- data[i] = buffer;
- res = squashfs_read_data(sb, block, length |
- SQUASHFS_COMPRESSED_BIT_BLOCK, NULL, actor);
- kfree(data);
- kfree(actor);
- if (res < 0)
- goto failed;
- return table;
- failed2:
- kfree(data);
- failed:
- kfree(table);
- return ERR_PTR(res);
- }
|