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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
  */
 
 #include <linux/dcache.h>
 #include <linux/fs.h>
 #include <linux/gfp.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mount.h>
 #include <linux/srcu.h>
 
 #include <linux/fsnotify_backend.h>
 #include "fsnotify.h"
 
 /*
  * Clear all of the marks on an inode when it is being evicted from core
  */
 void __fsnotify_inode_delete(struct inode *inode)
 {
     fsnotify_clear_marks_by_inode(inode);
 }
 EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
 
 void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
 {
     fsnotify_clear_marks_by_mount(mnt);
 }
 
 /**
  * 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.
  */
 static void fsnotify_unmount_inodes(struct super_block *sb)
 {
     struct inode *inode, *iput_inode = NULL;
 
     spin_lock(&sb->s_inode_list_lock);
     list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
         /*
          * 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 SB_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.
          * However, we should have been called /after/ evict_inodes
          * removed all zero refcount inodes, in any case.  Test to
          * be sure.
          */
         if (!atomic_read(&inode->i_count)) {
             spin_unlock(&inode->i_lock);
             continue;
         }
 
         __iget(inode);
         spin_unlock(&inode->i_lock);
         spin_unlock(&sb->s_inode_list_lock);
 
         iput(iput_inode);
 
         /* for each watch, send FS_UNMOUNT and then remove it */
         fsnotify_inode(inode, FS_UNMOUNT);
 
         fsnotify_inode_delete(inode);
 
         iput_inode = inode;
 
         cond_resched();
         spin_lock(&sb->s_inode_list_lock);
     }
     spin_unlock(&sb->s_inode_list_lock);
 
     iput(iput_inode);
 }
 
 void fsnotify_sb_delete(struct super_block *sb)
 {
     fsnotify_unmount_inodes(sb);
     fsnotify_clear_marks_by_sb(sb);
     /* Wait for outstanding object references from connectors */
     wait_var_event(&sb->s_fsnotify_connectors,
                !atomic_long_read(&sb->s_fsnotify_connectors));
 }
 
 /*
  * Given an inode, first check if we care what happens to our children.  Inotify
  * and dnotify both tell their parents about events.  If we care about any event
  * on a child we run all of our children and set a dentry flag saying that the
  * parent cares.  Thus when an event happens on a child it can quickly tell
  * if there is a need to find a parent and send the event to the parent.
  */
 void __fsnotify_update_child_dentry_flags(struct inode *inode)
 {
     struct dentry *alias;
     int watched;
 
     if (!S_ISDIR(inode->i_mode))
         return;
 
     /* determine if the children should tell inode about their events */
     watched = fsnotify_inode_watches_children(inode);
 
     spin_lock(&inode->i_lock);
     /* run all of the dentries associated with this inode.  Since this is a
      * directory, there damn well better only be one item on this list */
     hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
         struct dentry *child;
 
         /* run all of the children of the original inode and fix their
          * d_flags to indicate parental interest (their parent is the
          * original inode) */
         spin_lock(&alias->d_lock);
         list_for_each_entry(child, &alias->d_subdirs, d_child) {
             if (!child->d_inode)
                 continue;
 
             spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
             if (watched)
                 child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
             else
                 child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
             spin_unlock(&child->d_lock);
         }
         spin_unlock(&alias->d_lock);
     }
     spin_unlock(&inode->i_lock);
 }
 
 /* Are inode/sb/mount interested in parent and name info with this event? */
 static bool fsnotify_event_needs_parent(struct inode *inode, struct mount *mnt,
                     __u32 mask)
 {
     __u32 marks_mask = 0;
 
     /* We only send parent/name to inode/sb/mount for events on non-dir */
     if (mask & FS_ISDIR)
         return false;
 
     /*
      * All events that are possible on child can also may be reported with
      * parent/name info to inode/sb/mount.  Otherwise, a watching parent
      * could result in events reported with unexpected name info to sb/mount.
      */
     BUILD_BUG_ON(FS_EVENTS_POSS_ON_CHILD & ~FS_EVENTS_POSS_TO_PARENT);
 
     /* Did either inode/sb/mount subscribe for events with parent/name? */
     marks_mask |= fsnotify_parent_needed_mask(inode->i_fsnotify_mask);
     marks_mask |= fsnotify_parent_needed_mask(inode->i_sb->s_fsnotify_mask);
     if (mnt)
         marks_mask |= fsnotify_parent_needed_mask(mnt->mnt_fsnotify_mask);
 
     /* Did they subscribe for this event with parent/name info? */
     return mask & marks_mask;
 }
 
 /*
  * Notify this dentry's parent about a child's events with child name info
  * if parent is watching or if inode/sb/mount are interested in events with
  * parent and name info.
  *
  * Notify only the child without name info if parent is not watching and
  * inode/sb/mount are not interested in events with parent and name info.
  */
 int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
               int data_type)
 {
     const struct path *path = fsnotify_data_path(data, data_type);
     struct mount *mnt = path ? real_mount(path->mnt) : NULL;
     struct inode *inode = d_inode(dentry);
     struct dentry *parent;
     bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED;
     bool parent_needed, parent_interested;
     __u32 p_mask;
     struct inode *p_inode = NULL;
     struct name_snapshot name;
     struct qstr *file_name = NULL;
     int ret = 0;
 
     /*
      * Do inode/sb/mount care about parent and name info on non-dir?
      * Do they care about any event at all?
      */
     if (!inode->i_fsnotify_marks && !inode->i_sb->s_fsnotify_marks &&
         (!mnt || !mnt->mnt_fsnotify_marks) && !parent_watched)
         return 0;
 
     parent = NULL;
     parent_needed = fsnotify_event_needs_parent(inode, mnt, mask);
     if (!parent_watched && !parent_needed)
         goto notify;
 
     /* Does parent inode care about events on children? */
     parent = dget_parent(dentry);
     p_inode = parent->d_inode;
     p_mask = fsnotify_inode_watches_children(p_inode);
     if (unlikely(parent_watched && !p_mask))
         __fsnotify_update_child_dentry_flags(p_inode);
 
     /*
      * Include parent/name in notification either if some notification
      * groups require parent info or the parent is interested in this event.
      */
     parent_interested = mask & p_mask & ALL_FSNOTIFY_EVENTS;
     if (parent_needed || parent_interested) {
         /* When notifying parent, child should be passed as data */
         WARN_ON_ONCE(inode != fsnotify_data_inode(data, data_type));
 
         /* Notify both parent and child with child name info */
         take_dentry_name_snapshot(&name, dentry);
         file_name = &name.name;
         if (parent_interested)
             mask |= FS_EVENT_ON_CHILD;
     }
 
 notify:
     ret = fsnotify(mask, data, data_type, p_inode, file_name, inode, 0);
 
     if (file_name)
         release_dentry_name_snapshot(&name);
     dput(parent);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(__fsnotify_parent);
 
 static int fsnotify_handle_inode_event(struct fsnotify_group *group,
                        struct fsnotify_mark *inode_mark,
                        u32 mask, const void *data, int data_type,
                        struct inode *dir, const struct qstr *name,
                        u32 cookie)
 {
     const struct path *path = fsnotify_data_path(data, data_type);
     struct inode *inode = fsnotify_data_inode(data, data_type);
     const struct fsnotify_ops *ops = group->ops;
 
     if (WARN_ON_ONCE(!ops->handle_inode_event))
         return 0;
 
     if (WARN_ON_ONCE(!inode && !dir))
         return 0;
 
     if ((inode_mark->flags & FSNOTIFY_MARK_FLAG_EXCL_UNLINK) &&
         path && d_unlinked(path->dentry))
         return 0;
 
     /* Check interest of this mark in case event was sent with two marks */
     if (!(mask & inode_mark->mask & ALL_FSNOTIFY_EVENTS))
         return 0;
 
     return ops->handle_inode_event(inode_mark, mask, inode, dir, name, cookie);
 }
 
 static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
                  const void *data, int data_type,
                  struct inode *dir, const struct qstr *name,
                  u32 cookie, struct fsnotify_iter_info *iter_info)
 {
     struct fsnotify_mark *inode_mark = fsnotify_iter_inode_mark(iter_info);
     struct fsnotify_mark *parent_mark = fsnotify_iter_parent_mark(iter_info);
     int ret;
 
     if (WARN_ON_ONCE(fsnotify_iter_sb_mark(iter_info)) ||
         WARN_ON_ONCE(fsnotify_iter_vfsmount_mark(iter_info)))
         return 0;
 
     /*
      * For FS_RENAME, 'dir' is old dir and 'data' is new dentry.
      * The only ->handle_inode_event() backend that supports FS_RENAME is
      * dnotify, where it means file was renamed within same parent.
      */
     if (mask & FS_RENAME) {
         struct dentry *moved = fsnotify_data_dentry(data, data_type);
 
         if (dir != moved->d_parent->d_inode)
             return 0;
     }
 
     if (parent_mark) {
         ret = fsnotify_handle_inode_event(group, parent_mark, mask,
                           data, data_type, dir, name, 0);
         if (ret)
             return ret;
     }
 
     if (!inode_mark)
         return 0;
 
     if (mask & FS_EVENT_ON_CHILD) {
         /*
          * Some events can be sent on both parent dir and child marks
          * (e.g. FS_ATTRIB).  If both parent dir and child are
          * watching, report the event once to parent dir with name (if
          * interested) and once to child without name (if interested).
          * The child watcher is expecting an event without a file name
          * and without the FS_EVENT_ON_CHILD flag.
          */
         mask &= ~FS_EVENT_ON_CHILD;
         dir = NULL;
         name = NULL;
     }
 
     return fsnotify_handle_inode_event(group, inode_mark, mask, data, data_type,
                        dir, name, cookie);
 }
 
 static int send_to_group(__u32 mask, const void *data, int data_type,
              struct inode *dir, const struct qstr *file_name,
              u32 cookie, struct fsnotify_iter_info *iter_info)
 {
     struct fsnotify_group *group = NULL;
     __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
     __u32 marks_mask = 0;
     __u32 marks_ignore_mask = 0;
     bool is_dir = mask & FS_ISDIR;
     struct fsnotify_mark *mark;
     int type;
 
     if (!iter_info->report_mask)
         return 0;
 
     /* clear ignored on inode modification */
     if (mask & FS_MODIFY) {
         fsnotify_foreach_iter_mark_type(iter_info, mark, type) {
             if (!(mark->flags &
                   FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
                 mark->ignore_mask = 0;
         }
     }
 
     /* Are any of the group marks interested in this event? */
     fsnotify_foreach_iter_mark_type(iter_info, mark, type) {
         group = mark->group;
         marks_mask |= mark->mask;
         marks_ignore_mask |=
             fsnotify_effective_ignore_mask(mark, is_dir, type);
     }
 
     pr_debug("%s: group=%p mask=%x marks_mask=%x marks_ignore_mask=%x data=%p data_type=%d dir=%p cookie=%d\n",
          __func__, group, mask, marks_mask, marks_ignore_mask,
          data, data_type, dir, cookie);
 
     if (!(test_mask & marks_mask & ~marks_ignore_mask))
         return 0;
 
     if (group->ops->handle_event) {
         return group->ops->handle_event(group, mask, data, data_type, dir,
                         file_name, cookie, iter_info);
     }
 
     return fsnotify_handle_event(group, mask, data, data_type, dir,
                      file_name, cookie, iter_info);
 }
 
 static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp)
 {
     struct fsnotify_mark_connector *conn;
     struct hlist_node *node = NULL;
 
     conn = srcu_dereference(*connp, &fsnotify_mark_srcu);
     if (conn)
         node = srcu_dereference(conn->list.first, &fsnotify_mark_srcu);
 
     return hlist_entry_safe(node, struct fsnotify_mark, obj_list);
 }
 
 static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark)
 {
     struct hlist_node *node = NULL;
 
     if (mark)
         node = srcu_dereference(mark->obj_list.next,
                     &fsnotify_mark_srcu);
 
     return hlist_entry_safe(node, struct fsnotify_mark, obj_list);
 }
 
 /*
  * iter_info is a multi head priority queue of marks.
  * Pick a subset of marks from queue heads, all with the same group
  * and set the report_mask to a subset of the selected marks.
  * Returns false if there are no more groups to iterate.
  */
 static bool fsnotify_iter_select_report_types(
         struct fsnotify_iter_info *iter_info)
 {
     struct fsnotify_group *max_prio_group = NULL;
     struct fsnotify_mark *mark;
     int type;
 
     /* Choose max prio group among groups of all queue heads */
     fsnotify_foreach_iter_type(type) {
         mark = iter_info->marks[type];
         if (mark &&
             fsnotify_compare_groups(max_prio_group, mark->group) > 0)
             max_prio_group = mark->group;
     }
 
     if (!max_prio_group)
         return false;
 
     /* Set the report mask for marks from same group as max prio group */
     iter_info->current_group = max_prio_group;
     iter_info->report_mask = 0;
     fsnotify_foreach_iter_type(type) {
         mark = iter_info->marks[type];
         if (mark && mark->group == iter_info->current_group) {
             /*
              * FSNOTIFY_ITER_TYPE_PARENT indicates that this inode
              * is watching children and interested in this event,
              * which is an event possible on child.
              * But is *this mark* watching children?
              */
             if (type == FSNOTIFY_ITER_TYPE_PARENT &&
                 !(mark->mask & FS_EVENT_ON_CHILD) &&
                 !(fsnotify_ignore_mask(mark) & FS_EVENT_ON_CHILD))
                 continue;
 
             fsnotify_iter_set_report_type(iter_info, type);
         }
     }
 
     return true;
 }
 
 /*
  * Pop from iter_info multi head queue, the marks that belong to the group of
  * current iteration step.
  */
 static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info)
 {
     struct fsnotify_mark *mark;
     int type;
 
     /*
      * We cannot use fsnotify_foreach_iter_mark_type() here because we
      * may need to advance a mark of type X that belongs to current_group
      * but was not selected for reporting.
      */
     fsnotify_foreach_iter_type(type) {
         mark = iter_info->marks[type];
         if (mark && mark->group == iter_info->current_group)
             iter_info->marks[type] =
                 fsnotify_next_mark(iter_info->marks[type]);
     }
 }
 
 /*
  * fsnotify - This is the main call to fsnotify.
  *
  * The VFS calls into hook specific functions in linux/fsnotify.h.
  * Those functions then in turn call here.  Here will call out to all of the
  * registered fsnotify_group.  Those groups can then use the notification event
  * in whatever means they feel necessary.
  *
  * @mask:   event type and flags
  * @data:   object that event happened on
  * @data_type:  type of object for fanotify_data_XXX() accessors
  * @dir:    optional directory associated with event -
  *      if @file_name is not NULL, this is the directory that
  *      @file_name is relative to
  * @file_name:  optional file name associated with event
  * @inode:  optional inode associated with event -
  *      If @dir and @inode are both non-NULL, event may be
  *      reported to both.
  * @cookie: inotify rename cookie
  */
 int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
          const struct qstr *file_name, struct inode *inode, u32 cookie)
 {
     const struct path *path = fsnotify_data_path(data, data_type);
     struct super_block *sb = fsnotify_data_sb(data, data_type);
     struct fsnotify_iter_info iter_info = {};
     struct mount *mnt = NULL;
     struct inode *inode2 = NULL;
     struct dentry *moved;
     int inode2_type;
     int ret = 0;
     __u32 test_mask, marks_mask;
 
     if (path)
         mnt = real_mount(path->mnt);
 
     if (!inode) {
         /* Dirent event - report on TYPE_INODE to dir */
         inode = dir;
         /* For FS_RENAME, inode is old_dir and inode2 is new_dir */
         if (mask & FS_RENAME) {
             moved = fsnotify_data_dentry(data, data_type);
             inode2 = moved->d_parent->d_inode;
             inode2_type = FSNOTIFY_ITER_TYPE_INODE2;
         }
     } else if (mask & FS_EVENT_ON_CHILD) {
         /*
          * Event on child - report on TYPE_PARENT to dir if it is
          * watching children and on TYPE_INODE to child.
          */
         inode2 = dir;
         inode2_type = FSNOTIFY_ITER_TYPE_PARENT;
     }
 
     /*
      * Optimization: srcu_read_lock() has a memory barrier which can
      * be expensive.  It protects walking the *_fsnotify_marks lists.
      * However, if we do not walk the lists, we do not have to do
      * SRCU because we have no references to any objects and do not
      * need SRCU to keep them "alive".
      */
     if (!sb->s_fsnotify_marks &&
         (!mnt || !mnt->mnt_fsnotify_marks) &&
         (!inode || !inode->i_fsnotify_marks) &&
         (!inode2 || !inode2->i_fsnotify_marks))
         return 0;
 
     marks_mask = sb->s_fsnotify_mask;
     if (mnt)
         marks_mask |= mnt->mnt_fsnotify_mask;
     if (inode)
         marks_mask |= inode->i_fsnotify_mask;
     if (inode2)
         marks_mask |= inode2->i_fsnotify_mask;
 
 
     /*
      * If this is a modify event we may need to clear some ignore masks.
      * In that case, the object with ignore masks will have the FS_MODIFY
      * event in its mask.
      * Otherwise, return if none of the marks care about this type of event.
      */
     test_mask = (mask & ALL_FSNOTIFY_EVENTS);
     if (!(test_mask & marks_mask))
         return 0;
 
     iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
 
     iter_info.marks[FSNOTIFY_ITER_TYPE_SB] =
         fsnotify_first_mark(&sb->s_fsnotify_marks);
     if (mnt) {
         iter_info.marks[FSNOTIFY_ITER_TYPE_VFSMOUNT] =
             fsnotify_first_mark(&mnt->mnt_fsnotify_marks);
     }
     if (inode) {
         iter_info.marks[FSNOTIFY_ITER_TYPE_INODE] =
             fsnotify_first_mark(&inode->i_fsnotify_marks);
     }
     if (inode2) {
         iter_info.marks[inode2_type] =
             fsnotify_first_mark(&inode2->i_fsnotify_marks);
     }
 
     /*
      * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark
      * ignore masks are properly reflected for mount/sb mark notifications.
      * That's why this traversal is so complicated...
      */
     while (fsnotify_iter_select_report_types(&iter_info)) {
         ret = send_to_group(mask, data, data_type, dir, file_name,
                     cookie, &iter_info);
 
         if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
             goto out;
 
         fsnotify_iter_next(&iter_info);
     }
     ret = 0;
 out:
     srcu_read_unlock(&fsnotify_mark_srcu, iter_info.srcu_idx);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(fsnotify);
 
 static __init int fsnotify_init(void)
 {
     int ret;
 
     BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 23);
 
     ret = init_srcu_struct(&fsnotify_mark_srcu);
     if (ret)
         panic("initializing fsnotify_mark_srcu");
 
     fsnotify_mark_connector_cachep = KMEM_CACHE(fsnotify_mark_connector,
                             SLAB_PANIC);
 
     return 0;
 }
 core_initcall(fsnotify_init);

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