diff options
Diffstat (limited to 'cpukit/libcsupport/src/sup_fs_location.c')
| -rw-r--r-- | cpukit/libcsupport/src/sup_fs_location.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/cpukit/libcsupport/src/sup_fs_location.c b/cpukit/libcsupport/src/sup_fs_location.c new file mode 100644 index 0000000000..5234c01ddc --- /dev/null +++ b/cpukit/libcsupport/src/sup_fs_location.c @@ -0,0 +1,218 @@ +/* + * Copyright (c) 2012 embedded brains GmbH. All rights reserved. + * + * embedded brains GmbH + * Obere Lagerstr. 30 + * 82178 Puchheim + * Germany + * <rtems@embedded-brains.de> + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.com/license/LICENSE. + */ + +#if HAVE_CONFIG_H + #include "config.h" +#endif + +#define __RTEMS_VIOLATE_KERNEL_VISIBILITY__ + +#include <stdlib.h> + +#include <rtems/libio_.h> +#include <rtems/score/thread.h> + +static rtems_filesystem_global_location_t *deferred_released_global_locations; + +rtems_filesystem_location_info_t *rtems_filesystem_location_copy( + rtems_filesystem_location_info_t *dst, + const rtems_filesystem_location_info_t *src +) +{ + dst->node_access = src->node_access; + dst->node_access_2 = src->node_access_2; + dst->handlers = src->handlers; + dst->ops = src->ops; + dst->mt_entry = src->mt_entry; + rtems_filesystem_location_add_to_mt_entry(dst); + + return dst; +} + +void rtems_filesystem_location_detach( + rtems_filesystem_location_info_t *detach +) +{ + rtems_filesystem_location_free(detach); + rtems_filesystem_location_initialize_to_null(detach); +} + +void rtems_filesystem_location_copy_and_detach( + rtems_filesystem_location_info_t *copy, + rtems_filesystem_location_info_t *detach +) +{ + rtems_filesystem_location_copy(copy, detach); + rtems_filesystem_location_remove_from_mt_entry(detach); + rtems_filesystem_location_initialize_to_null(detach); +} + +rtems_filesystem_global_location_t *rtems_filesystem_location_transform_to_global( + rtems_filesystem_location_info_t *loc +) +{ + rtems_filesystem_global_location_t *global_loc = malloc(sizeof(*global_loc)); + + if (global_loc != NULL) { + global_loc->reference_count = 1; + global_loc->deferred_released_next = NULL; + global_loc->deferred_released_count = 0; + rtems_filesystem_location_copy(&global_loc->location, loc); + rtems_filesystem_location_remove_from_mt_entry(loc); + } else { + rtems_filesystem_location_free(loc); + global_loc = rtems_filesystem_global_location_obtain_null(); + errno = ENOMEM; + } + + return global_loc; +} + +void rtems_filesystem_global_location_assign( + rtems_filesystem_global_location_t **lhs_global_loc_ptr, + rtems_filesystem_global_location_t *rhs_global_loc +) +{ + rtems_filesystem_mt_entry_declare_lock_context(lock_context); + rtems_filesystem_global_location_t *lhs_global_loc; + + rtems_filesystem_mt_entry_lock(lock_context); + lhs_global_loc = *lhs_global_loc_ptr; + *lhs_global_loc_ptr = rhs_global_loc; + rtems_filesystem_mt_entry_unlock(lock_context); + + rtems_filesystem_global_location_release(lhs_global_loc); +} + +static void release_with_count( + rtems_filesystem_global_location_t *global_loc, + int count +) +{ + rtems_filesystem_mount_table_entry_t *mt_entry = + global_loc->location.mt_entry; + rtems_filesystem_mt_entry_declare_lock_context(lock_context); + bool do_free; + bool do_unmount; + + rtems_filesystem_mt_entry_lock(lock_context); + global_loc->reference_count -= count; + do_free = global_loc->reference_count == 0; + do_unmount = rtems_filesystem_is_ready_for_unmount(mt_entry); + rtems_filesystem_mt_entry_unlock(lock_context); + + if (do_free) { + rtems_filesystem_location_free(&global_loc->location); + free(global_loc); + } + + if (do_unmount) { + rtems_filesystem_do_unmount(mt_entry); + } +} + +static void deferred_release(void) +{ + rtems_filesystem_global_location_t *current = NULL; + + do { + int count = 0; + + _Thread_Disable_dispatch(); + current = deferred_released_global_locations; + if (current != NULL) { + deferred_released_global_locations = current->deferred_released_next; + count = current->deferred_released_count; + current->deferred_released_next = NULL; + current->deferred_released_count = 0; + } + _Thread_Enable_dispatch(); + + if (current != NULL) { + release_with_count(current, count); + } + } while (current != NULL); +} + +rtems_filesystem_global_location_t *rtems_filesystem_global_location_obtain( + rtems_filesystem_global_location_t *const *global_loc_ptr +) +{ + rtems_filesystem_mt_entry_declare_lock_context(lock_context); + rtems_filesystem_global_location_t *global_loc; + + if (deferred_released_global_locations != NULL) { + deferred_release(); + } + + rtems_filesystem_mt_entry_lock(lock_context); + global_loc = *global_loc_ptr; + if (global_loc == NULL || !global_loc->location.mt_entry->mounted) { + global_loc = &rtems_filesystem_global_location_null; + errno = ENXIO; + } + ++global_loc->reference_count; + rtems_filesystem_mt_entry_unlock(lock_context); + + return global_loc; +} + +void rtems_filesystem_global_location_release( + rtems_filesystem_global_location_t *global_loc +) +{ + if (!_Thread_Dispatch_in_critical_section()) { + release_with_count(global_loc, 1); + } else { + if (global_loc->deferred_released_count == 0) { + rtems_filesystem_global_location_t *head = + deferred_released_global_locations; + + global_loc->deferred_released_count = 1; + global_loc->deferred_released_next = head; + deferred_released_global_locations = global_loc; + } else { + ++global_loc->deferred_released_count; + } + } +} + +void rtems_filesystem_location_remove_from_mt_entry( + rtems_filesystem_location_info_t *loc +) +{ + rtems_filesystem_mt_entry_declare_lock_context(lock_context); + bool do_unmount; + + rtems_filesystem_mt_entry_lock(lock_context); + rtems_chain_extract_unprotected(&loc->mt_entry_node); + do_unmount = rtems_filesystem_is_ready_for_unmount(loc->mt_entry); + rtems_filesystem_mt_entry_unlock(lock_context); + + if (do_unmount) { + rtems_filesystem_do_unmount(loc->mt_entry); + } +} + +void rtems_filesystem_do_unmount( + rtems_filesystem_mount_table_entry_t *mt_entry +) +{ + rtems_filesystem_mt_lock(); + rtems_chain_extract_unprotected(&mt_entry->mt_node); + rtems_filesystem_mt_unlock(); + rtems_filesystem_global_location_release(mt_entry->mt_point_node); + (*mt_entry->mt_fs_root->location.ops->fsunmount_me_h)(mt_entry); + free(mt_entry); +} |