596207b5c5
Inotify does not currently know when a filesystem is acting as a wrapper
around another fs. This means that inotify watchers will miss any
modifications to the base file, as well as any made in a separate stacked
fs that points to the same file.
d_canonical_path solves this problem by allowing the fs to map a dentry to
a path in the lower fs. Inotify can use it to find the appropriate place to
watch to be informed of all changes to a file.
Change-Id: Icc7ff8f4798bf907d5c9ce32065a0471db751a26
Test: FileObserverTest and FileObserverTestLegacyPath on Cuttlefish
Bug: 171780975
Signed-off-by: Daniel Rosenberg <drosen@google.com>
[astrachan: Folded 34df4102216e ("ANDROID: fsnotify: Notify lower fs of
astrachan: open") into this patch]
Signed-off-by: Alistair Strachan <astrachan@google.com>
Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
Signed-off-by: Alessio Balsini <balsini@google.com>
Git-commit: f37e05049bf8197901ec042818a64110e59fac41
Git-repo: https://android.googlesource.com/kernel/common/
Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
302 lines
7.6 KiB
C
302 lines
7.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FS_NOTIFY_H
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#define _LINUX_FS_NOTIFY_H
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/*
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* include/linux/fsnotify.h - generic hooks for filesystem notification, to
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* reduce in-source duplication from both dnotify and inotify.
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*
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* We don't compile any of this away in some complicated menagerie of ifdefs.
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* Instead, we rely on the code inside to optimize away as needed.
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*
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* (C) Copyright 2005 Robert Love
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*/
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#include <linux/fsnotify_backend.h>
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#include <linux/audit.h>
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#include <linux/slab.h>
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#include <linux/bug.h>
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/* Notify this dentry's parent about a child's events. */
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static inline int fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask)
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{
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if (!dentry)
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dentry = path->dentry;
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return __fsnotify_parent(path, dentry, mask);
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}
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/* simple call site for access decisions */
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static inline int fsnotify_perm(struct file *file, int mask)
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{
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const struct path *path = &file->f_path;
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struct inode *inode = file_inode(file);
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__u32 fsnotify_mask = 0;
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int ret;
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if (file->f_mode & FMODE_NONOTIFY)
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return 0;
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if (!(mask & (MAY_READ | MAY_OPEN)))
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return 0;
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if (mask & MAY_OPEN)
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fsnotify_mask = FS_OPEN_PERM;
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else if (mask & MAY_READ)
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fsnotify_mask = FS_ACCESS_PERM;
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else
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BUG();
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ret = fsnotify_parent(path, NULL, fsnotify_mask);
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if (ret)
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return ret;
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return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
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}
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/*
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* fsnotify_link_count - inode's link count changed
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*/
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static inline void fsnotify_link_count(struct inode *inode)
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{
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fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
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}
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/*
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* fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
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*/
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static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
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const unsigned char *old_name,
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int isdir, struct inode *target, struct dentry *moved)
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{
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struct inode *source = moved->d_inode;
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u32 fs_cookie = fsnotify_get_cookie();
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__u32 old_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_FROM);
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__u32 new_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_TO);
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const unsigned char *new_name = moved->d_name.name;
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if (old_dir == new_dir)
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old_dir_mask |= FS_DN_RENAME;
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if (isdir) {
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old_dir_mask |= FS_ISDIR;
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new_dir_mask |= FS_ISDIR;
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}
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fsnotify(old_dir, old_dir_mask, source, FSNOTIFY_EVENT_INODE, old_name,
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fs_cookie);
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fsnotify(new_dir, new_dir_mask, source, FSNOTIFY_EVENT_INODE, new_name,
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fs_cookie);
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if (target)
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fsnotify_link_count(target);
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if (source)
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fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
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audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
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}
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/*
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* fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
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*/
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static inline void fsnotify_inode_delete(struct inode *inode)
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{
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__fsnotify_inode_delete(inode);
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}
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/*
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* fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
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*/
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static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
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{
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__fsnotify_vfsmount_delete(mnt);
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}
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/*
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* fsnotify_nameremove - a filename was removed from a directory
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*/
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static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
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{
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__u32 mask = FS_DELETE;
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if (isdir)
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mask |= FS_ISDIR;
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fsnotify_parent(NULL, dentry, mask);
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}
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/*
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* fsnotify_inoderemove - an inode is going away
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*/
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static inline void fsnotify_inoderemove(struct inode *inode)
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{
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fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
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__fsnotify_inode_delete(inode);
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}
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/*
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* fsnotify_create - 'name' was linked in
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*/
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static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
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{
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audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
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fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
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}
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/*
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* fsnotify_link - new hardlink in 'inode' directory
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* Note: We have to pass also the linked inode ptr as some filesystems leave
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* new_dentry->d_inode NULL and instantiate inode pointer later
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*/
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static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
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{
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fsnotify_link_count(inode);
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audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
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fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name, 0);
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}
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/*
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* fsnotify_mkdir - directory 'name' was created
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*/
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static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
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{
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__u32 mask = (FS_CREATE | FS_ISDIR);
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struct inode *d_inode = dentry->d_inode;
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audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
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fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
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}
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/*
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* fsnotify_access - file was read
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*/
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static inline void fsnotify_access(struct file *file)
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{
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const struct path *path = &file->f_path;
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struct inode *inode = file_inode(file);
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__u32 mask = FS_ACCESS;
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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if (!(file->f_mode & FMODE_NONOTIFY)) {
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fsnotify_parent(path, NULL, mask);
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fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
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}
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}
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/*
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* fsnotify_modify - file was modified
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*/
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static inline void fsnotify_modify(struct file *file)
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{
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const struct path *path = &file->f_path;
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struct inode *inode = file_inode(file);
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__u32 mask = FS_MODIFY;
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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if (!(file->f_mode & FMODE_NONOTIFY)) {
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fsnotify_parent(path, NULL, mask);
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fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
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}
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}
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/*
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* fsnotify_open - file was opened
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*/
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static inline void fsnotify_open(struct file *file)
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{
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const struct path *path = &file->f_path;
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struct inode *inode = file_inode(file);
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struct path lower_path;
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__u32 mask = FS_OPEN;
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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if (path->dentry->d_op && path->dentry->d_op->d_canonical_path) {
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path->dentry->d_op->d_canonical_path(path, &lower_path);
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fsnotify_parent(&lower_path, NULL, mask);
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fsnotify(lower_path.dentry->d_inode, mask, &lower_path,
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FSNOTIFY_EVENT_PATH, NULL, 0);
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path_put(&lower_path);
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}
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fsnotify_parent(path, NULL, mask);
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fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
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}
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/*
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* fsnotify_close - file was closed
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*/
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static inline void fsnotify_close(struct file *file)
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{
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const struct path *path = &file->f_path;
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struct inode *inode = file_inode(file);
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fmode_t mode = file->f_mode;
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__u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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if (!(file->f_mode & FMODE_NONOTIFY)) {
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fsnotify_parent(path, NULL, mask);
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fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
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}
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}
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/*
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* fsnotify_xattr - extended attributes were changed
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*/
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static inline void fsnotify_xattr(struct dentry *dentry)
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{
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struct inode *inode = dentry->d_inode;
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__u32 mask = FS_ATTRIB;
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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fsnotify_parent(NULL, dentry, mask);
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fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
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}
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/*
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* fsnotify_change - notify_change event. file was modified and/or metadata
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* was changed.
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*/
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static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
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{
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struct inode *inode = dentry->d_inode;
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__u32 mask = 0;
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if (ia_valid & ATTR_UID)
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mask |= FS_ATTRIB;
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if (ia_valid & ATTR_GID)
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mask |= FS_ATTRIB;
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if (ia_valid & ATTR_SIZE)
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mask |= FS_MODIFY;
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/* both times implies a utime(s) call */
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if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
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mask |= FS_ATTRIB;
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else if (ia_valid & ATTR_ATIME)
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mask |= FS_ACCESS;
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else if (ia_valid & ATTR_MTIME)
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mask |= FS_MODIFY;
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if (ia_valid & ATTR_MODE)
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mask |= FS_ATTRIB;
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if (mask) {
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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fsnotify_parent(NULL, dentry, mask);
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fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
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}
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}
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#endif /* _LINUX_FS_NOTIFY_H */
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