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b7f0468bb9
commit 49d31c2f389acfe83417083e1208422b4091cd9e upstream. take_dentry_name_snapshot() takes a safe snapshot of dentry name; if the name is a short one, it gets copied into caller-supplied structure, otherwise an extra reference to external name is grabbed (those are never modified). In either case the pointer to stable string is stored into the same structure. dentry must be held by the caller of take_dentry_name_snapshot(), but may be freely dropped afterwards - the snapshot will stay until destroyed by release_dentry_name_snapshot(). Intended use: struct name_snapshot s; take_dentry_name_snapshot(&s, dentry); ... access s.name ... release_dentry_name_snapshot(&s); Replaces fsnotify_oldname_...(), gets used in fsnotify to obtain the name to pass down with event. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> [carnil: backport 4.9: adjust context] [bwh: Backported to 3.16: - External names are not ref-counted, so copy them - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> [ghackmann@google.com: backported to 3.10: adjust context] Signed-off-by: Greg Hackmann <ghackmann@google.com> Change-Id: I612e687cbffa1a03107331a6b3f00911ffbebd8e Bug: 63689921
313 lines
7.6 KiB
C
313 lines
7.6 KiB
C
#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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/*
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* fsnotify_d_instantiate - instantiate a dentry for inode
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*/
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static inline void fsnotify_d_instantiate(struct dentry *dentry,
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struct inode *inode)
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{
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__fsnotify_d_instantiate(dentry, inode);
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}
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/* Notify this dentry's parent about a child's events. */
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static inline int fsnotify_parent(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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struct path *path = &file->f_path;
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struct inode *inode = path->dentry->d_inode;
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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_d_move - dentry has been moved
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*/
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static inline void fsnotify_d_move(struct dentry *dentry)
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{
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/*
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* On move we need to update dentry->d_flags to indicate if the new parent
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* cares about events from this dentry.
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*/
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__fsnotify_update_dcache_flags(dentry);
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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(moved, new_dir);
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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(dentry, inode);
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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(new_dentry, dir);
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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(dentry, inode);
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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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struct path *path = &file->f_path;
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struct inode *inode = path->dentry->d_inode;
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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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struct path *path = &file->f_path;
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struct inode *inode = path->dentry->d_inode;
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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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struct path *path = &file->f_path;
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struct inode *inode = path->dentry->d_inode;
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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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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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struct path *path = &file->f_path;
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struct inode *inode = file->f_path.dentry->d_inode;
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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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