/* * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; see the file COPYING. If not, write to * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/fs.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/spinlock.h> #include <linux/atomic.h> #include <linux/fsnotify_backend.h> #include "fsnotify.h" #include "../internal.h" /* * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types * any notifier is interested in hearing for this inode. */ void fsnotify_recalc_inode_mask(struct inode *inode) { spin_lock(&inode->i_lock); inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks); spin_unlock(&inode->i_lock); __fsnotify_update_child_dentry_flags(inode); } void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) { struct inode *inode = mark->inode; BUG_ON(!mutex_is_locked(&mark->group->mark_mutex)); assert_spin_locked(&mark->lock); spin_lock(&inode->i_lock); hlist_del_init_rcu(&mark->obj_list); mark->inode = NULL; /* * this mark is now off the inode->i_fsnotify_marks list and we * hold the inode->i_lock, so this is the perfect time to update the * inode->i_fsnotify_mask */ inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks); spin_unlock(&inode->i_lock); } /* * Given a group clear all of the inode marks associated with that group. */ void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) { fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE); } /* * given a group and inode, find the mark associated with that combination. * if found take a reference to that mark and return it, else return NULL */ struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode) { struct fsnotify_mark *mark; spin_lock(&inode->i_lock); mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group); spin_unlock(&inode->i_lock); return mark; } /* * If we are setting a mark mask on an inode mark we should pin the inode * in memory. */ void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask) { struct inode *inode; assert_spin_locked(&mark->lock); if (mask && mark->inode && !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; inode = igrab(mark->inode); /* * we shouldn't be able to get here if the inode wasn't * already safely held in memory. But bug in case it * ever is wrong. */ BUG_ON(!inode); } } /* * Attach an initialized mark to a given inode. * These marks may be used for the fsnotify backend to determine which * event types should be delivered to which group and for which inodes. These * marks are ordered according to priority, highest number first, and then by * the group's location in memory. */ int fsnotify_add_inode_mark(struct fsnotify_mark *mark, struct fsnotify_group *group, struct inode *inode, int allow_dups) { int ret; mark->flags |= FSNOTIFY_MARK_FLAG_INODE; BUG_ON(!mutex_is_locked(&group->mark_mutex)); assert_spin_locked(&mark->lock); spin_lock(&inode->i_lock); mark->inode = inode; ret = fsnotify_add_mark_list(&inode->i_fsnotify_marks, mark, allow_dups); inode->i_fsnotify_mask = fsnotify_recalc_mask(&inode->i_fsnotify_marks); spin_unlock(&inode->i_lock); return ret; } /** * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. * @sb: superblock being unmounted. * * Called during unmount with no locks held, so needs to be safe against * concurrent modifiers. We temporarily drop sb->s_inode_list_lock and CAN block. */ void fsnotify_unmount_inodes(struct super_block *sb) { struct inode *inode, *next_i, *need_iput = NULL; spin_lock(&sb->s_inode_list_lock); list_for_each_entry_safe(inode, next_i, &sb->s_inodes, i_sb_list) { struct inode *need_iput_tmp; /* * We cannot __iget() an inode in state I_FREEING, * I_WILL_FREE, or I_NEW which is fine because by that point * the inode cannot have any associated watches. */ spin_lock(&inode->i_lock); if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { spin_unlock(&inode->i_lock); continue; } /* * If i_count is zero, the inode cannot have any watches and * doing an __iget/iput with MS_ACTIVE clear would actually * evict all inodes with zero i_count from icache which is * unnecessarily violent and may in fact be illegal to do. */ if (!atomic_read(&inode->i_count)) { spin_unlock(&inode->i_lock); continue; } need_iput_tmp = need_iput; need_iput = NULL; /* In case fsnotify_inode_delete() drops a reference. */ if (inode != need_iput_tmp) __iget(inode); else need_iput_tmp = NULL; spin_unlock(&inode->i_lock); /* In case the dropping of a reference would nuke next_i. */ while (&next_i->i_sb_list != &sb->s_inodes) { spin_lock(&next_i->i_lock); if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) && atomic_read(&next_i->i_count)) { __iget(next_i); need_iput = next_i; spin_unlock(&next_i->i_lock); break; } spin_unlock(&next_i->i_lock); next_i = list_next_entry(next_i, i_sb_list); } /* * We can safely drop s_inode_list_lock here because either * we actually hold references on both inode and next_i or * end of list. Also no new inodes will be added since the * umount has begun. */ spin_unlock(&sb->s_inode_list_lock); if (need_iput_tmp) iput(need_iput_tmp); /* for each watch, send FS_UNMOUNT and then remove it */ fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); fsnotify_inode_delete(inode); iput(inode); spin_lock(&sb->s_inode_list_lock); } spin_unlock(&sb->s_inode_list_lock); }