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![Amir Goldstein](/assets/img/avatar_default.png)
Define a new data type to pass for event - FSNOTIFY_EVENT_DENTRY. Use it to pass the dentry instead of it's ->d_inode where available. This is needed in preparation to the refactor to retrieve the super block from the data field. In some cases (i.e. mkdir in kernfs), the data inode comes from a negative dentry, such that no super block information would be available. By receiving the dentry itself, instead of the inode, fsnotify can derive the super block even on these cases. Link: https://lore.kernel.org/r/20211025192746.66445-3-krisman@collabora.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> [Expand explanation in commit message] Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Jan Kara <jack@suse.cz>
332 lines
8.1 KiB
C
332 lines
8.1 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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/*
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* Notify this @dir inode about a change in a child directory entry.
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* The directory entry may have turned positive or negative or its inode may
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* have changed (i.e. renamed over).
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*
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* Unlike fsnotify_parent(), the event will be reported regardless of the
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* FS_EVENT_ON_CHILD mask on the parent inode and will not be reported if only
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* the child is interested and not the parent.
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*/
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static inline int fsnotify_name(__u32 mask, const void *data, int data_type,
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struct inode *dir, const struct qstr *name,
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u32 cookie)
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{
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if (atomic_long_read(&dir->i_sb->s_fsnotify_connectors) == 0)
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return 0;
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return fsnotify(mask, data, data_type, dir, name, NULL, cookie);
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}
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static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,
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__u32 mask)
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{
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fsnotify_name(mask, dentry, FSNOTIFY_EVENT_DENTRY, dir, &dentry->d_name, 0);
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}
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static inline void fsnotify_inode(struct inode *inode, __u32 mask)
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{
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if (atomic_long_read(&inode->i_sb->s_fsnotify_connectors) == 0)
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return;
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if (S_ISDIR(inode->i_mode))
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mask |= FS_ISDIR;
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fsnotify(mask, inode, FSNOTIFY_EVENT_INODE, NULL, NULL, inode, 0);
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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 dentry *dentry, __u32 mask,
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const void *data, int data_type)
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{
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struct inode *inode = d_inode(dentry);
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if (atomic_long_read(&inode->i_sb->s_fsnotify_connectors) == 0)
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return 0;
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if (S_ISDIR(inode->i_mode)) {
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mask |= FS_ISDIR;
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/* sb/mount marks are not interested in name of directory */
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if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
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goto notify_child;
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}
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/* disconnected dentry cannot notify parent */
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if (IS_ROOT(dentry))
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goto notify_child;
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return __fsnotify_parent(dentry, mask, data, data_type);
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notify_child:
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return fsnotify(mask, data, data_type, NULL, NULL, inode, 0);
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}
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/*
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* Simple wrappers to consolidate calls to fsnotify_parent() when an event
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* is on a file/dentry.
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*/
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static inline void fsnotify_dentry(struct dentry *dentry, __u32 mask)
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{
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fsnotify_parent(dentry, mask, dentry, FSNOTIFY_EVENT_DENTRY);
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}
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static inline int fsnotify_file(struct file *file, __u32 mask)
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{
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const struct path *path = &file->f_path;
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if (file->f_mode & FMODE_NONOTIFY)
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return 0;
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return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
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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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int ret;
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__u32 fsnotify_mask = 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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if (file->f_flags & __FMODE_EXEC) {
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ret = fsnotify_file(file, FS_OPEN_EXEC_PERM);
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if (ret)
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return ret;
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}
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} else if (mask & MAY_READ) {
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fsnotify_mask = FS_ACCESS_PERM;
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}
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return fsnotify_file(file, fsnotify_mask);
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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(inode, FS_ATTRIB);
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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 struct qstr *old_name,
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int isdir, struct inode *target,
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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_MOVED_FROM;
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__u32 new_dir_mask = FS_MOVED_TO;
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const struct qstr *new_name = &moved->d_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_name(old_dir_mask, source, FSNOTIFY_EVENT_INODE,
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old_dir, old_name, fs_cookie);
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fsnotify_name(new_dir_mask, source, FSNOTIFY_EVENT_INODE,
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new_dir, new_name, fs_cookie);
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if (target)
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fsnotify_link_count(target);
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fsnotify_inode(source, FS_MOVE_SELF);
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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_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(inode, FS_DELETE_SELF);
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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_dirent(inode, dentry, FS_CREATE);
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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,
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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_name(FS_CREATE, inode, FSNOTIFY_EVENT_INODE,
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dir, &new_dentry->d_name, 0);
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}
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/*
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* fsnotify_unlink - 'name' was unlinked
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*
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* Caller must make sure that dentry->d_name is stable.
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*/
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static inline void fsnotify_unlink(struct inode *dir, struct dentry *dentry)
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{
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/* Expected to be called before d_delete() */
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WARN_ON_ONCE(d_is_negative(dentry));
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fsnotify_dirent(dir, dentry, FS_DELETE);
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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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audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
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fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
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}
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/*
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* fsnotify_rmdir - directory 'name' was removed
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*
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* Caller must make sure that dentry->d_name is stable.
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*/
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static inline void fsnotify_rmdir(struct inode *dir, struct dentry *dentry)
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{
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/* Expected to be called before d_delete() */
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WARN_ON_ONCE(d_is_negative(dentry));
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fsnotify_dirent(dir, dentry, FS_DELETE | FS_ISDIR);
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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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fsnotify_file(file, FS_ACCESS);
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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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fsnotify_file(file, FS_MODIFY);
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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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__u32 mask = FS_OPEN;
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if (file->f_flags & __FMODE_EXEC)
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mask |= FS_OPEN_EXEC;
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fsnotify_file(file, mask);
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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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__u32 mask = (file->f_mode & FMODE_WRITE) ? FS_CLOSE_WRITE :
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FS_CLOSE_NOWRITE;
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fsnotify_file(file, mask);
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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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fsnotify_dentry(dentry, FS_ATTRIB);
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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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__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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fsnotify_dentry(dentry, mask);
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}
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#endif /* _LINUX_FS_NOTIFY_H */
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