* Client Extent Lock.
*
* Author: Nikita Danilov <nikita.danilov@sun.com>
+ * Author: Jinshan Xiong <jinshan.xiong@intel.com>
*/
#define DEBUG_SUBSYSTEM S_CLASS
EXPORT_SYMBOL(cl_lock_at_pgoff);
/**
- * Calculate the page offset at the layer of @lock.
- * At the time of this writing, @page is top page and @lock is sub lock.
- */
-static pgoff_t pgoff_at_lock(struct cl_page *page, struct cl_lock *lock)
-{
- struct lu_device_type *dtype;
- const struct cl_page_slice *slice;
-
- dtype = lock->cll_descr.cld_obj->co_lu.lo_dev->ld_type;
- slice = cl_page_at(page, dtype);
- LASSERT(slice != NULL);
- return slice->cpl_page->cp_index;
-}
-
-/**
- * Check if page @page is covered by an extra lock or discard it.
- */
-static int check_and_discard_cb(const struct lu_env *env, struct cl_io *io,
- struct cl_page *page, void *cbdata)
-{
- struct cl_thread_info *info = cl_env_info(env);
- struct cl_lock *lock = cbdata;
- pgoff_t index = pgoff_at_lock(page, lock);
-
- if (index >= info->clt_fn_index) {
- struct cl_lock *tmp;
-
- /* refresh non-overlapped index */
- tmp = cl_lock_at_pgoff(env, lock->cll_descr.cld_obj, index,
- lock, 1, 0);
- if (tmp != NULL) {
- /* Cache the first-non-overlapped index so as to skip
- * all pages within [index, clt_fn_index). This
- * is safe because if tmp lock is canceled, it will
- * discard these pages. */
- info->clt_fn_index = tmp->cll_descr.cld_end + 1;
- if (tmp->cll_descr.cld_end == CL_PAGE_EOF)
- info->clt_fn_index = CL_PAGE_EOF;
- cl_lock_put(env, tmp);
- } else if (cl_page_own(env, io, page) == 0) {
- /* discard the page */
- cl_page_unmap(env, io, page);
- cl_page_discard(env, io, page);
- cl_page_disown(env, io, page);
- } else {
- LASSERT(page->cp_state == CPS_FREEING);
- }
- }
-
- info->clt_next_index = index + 1;
- return CLP_GANG_OKAY;
-}
-
-static int discard_cb(const struct lu_env *env, struct cl_io *io,
- struct cl_page *page, void *cbdata)
-{
- struct cl_thread_info *info = cl_env_info(env);
- struct cl_lock *lock = cbdata;
-
- LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE);
- KLASSERT(ergo(page->cp_type == CPT_CACHEABLE,
- !PageWriteback(cl_page_vmpage(env, page))));
- KLASSERT(ergo(page->cp_type == CPT_CACHEABLE,
- !PageDirty(cl_page_vmpage(env, page))));
-
- info->clt_next_index = pgoff_at_lock(page, lock) + 1;
- if (cl_page_own(env, io, page) == 0) {
- /* discard the page */
- cl_page_unmap(env, io, page);
- cl_page_discard(env, io, page);
- cl_page_disown(env, io, page);
- } else {
- LASSERT(page->cp_state == CPS_FREEING);
- }
-
- return CLP_GANG_OKAY;
-}
-
-/**
- * Discard pages protected by the given lock. This function traverses radix
- * tree to find all covering pages and discard them. If a page is being covered
- * by other locks, it should remain in cache.
- *
- * If error happens on any step, the process continues anyway (the reasoning
- * behind this being that lock cancellation cannot be delayed indefinitely).
- */
-int cl_lock_discard_pages(const struct lu_env *env, struct cl_lock *lock)
-{
- struct cl_thread_info *info = cl_env_info(env);
- struct cl_io *io = &info->clt_io;
- struct cl_lock_descr *descr = &lock->cll_descr;
- cl_page_gang_cb_t cb;
- int res;
- int result;
-
- LINVRNT(cl_lock_invariant(env, lock));
- ENTRY;
-
- io->ci_obj = cl_object_top(descr->cld_obj);
- io->ci_ignore_layout = 1;
- result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
- if (result != 0)
- GOTO(out, result);
-
- cb = descr->cld_mode == CLM_READ ? check_and_discard_cb : discard_cb;
- info->clt_fn_index = info->clt_next_index = descr->cld_start;
- do {
- res = cl_page_gang_lookup(env, descr->cld_obj, io,
- info->clt_next_index, descr->cld_end,
- cb, (void *)lock);
- if (info->clt_next_index > descr->cld_end)
- break;
-
- if (res == CLP_GANG_RESCHED)
- cond_resched();
- } while (res != CLP_GANG_OKAY);
-out:
- cl_io_fini(env, io);
- RETURN(result);
-}
-EXPORT_SYMBOL(cl_lock_discard_pages);
-
-/**
* Eliminate all locks for a given object.
*
* Caller has to guarantee that no lock is in active use.
ENTRY;
head = cl_object_header(obj);
- /*
- * If locks are destroyed without cancellation, all pages must be
- * already destroyed (as otherwise they will be left unprotected).
- */
- LASSERT(ergo(!cancel,
- head->coh_tree.rnode == NULL && head->coh_pages == 0));
spin_lock(&head->coh_lock_guard);
while (!cfs_list_empty(&head->coh_locks)) {
git://git.whamcloud.com / fs / lustre-release.git / blobdiff