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fsnotify: store struct file not struct path 

Al explains that calling dentry_open() with a mnt/dentry pair is only
garunteed to be safe if they are already used in an open struct file.  To
make sure this is the case don't store and use a struct path in fsnotify,
always use a struct file.

Signed-off-by: Eric Paris <eparis@redhat.com>
This commit is contained in:
Eric Paris 2010-07-28 10:18:37 -04:00
parent f70ab54cc6
commit 3bcf3860a4
8 changed files with 56 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
fs/notify/fanotify/fanotify.c
View File

@ -17,9 +17,9 @@ static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new)
old->data_type == new->data_type &&
old->tgid == new->tgid) {
switch (old->data_type) {
case (FSNOTIFY_EVENT_PATH):
if ((old->path.mnt == new->path.mnt) &&
(old->path.dentry == new->path.dentry))
case (FSNOTIFY_EVENT_FILE):
if ((old->file->f_path.mnt == new->file->f_path.mnt) &&
(old->file->f_path.dentry == new->file->f_path.dentry))
return true;
case (FSNOTIFY_EVENT_NONE):
return true;
@ -226,7 +226,7 @@ static bool fanotify_should_send_event(struct fsnotify_group *group, struct inod
return false;
/* if we don't have enough info to send an event to userspace say no */
if (data_type != FSNOTIFY_EVENT_PATH)
if (data_type != FSNOTIFY_EVENT_FILE)
return false;
if (mnt)

6
fs/notify/fanotify/fanotify_user.c
View File

@ -65,7 +65,7 @@ static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
if (client_fd < 0)
return client_fd;
if (event->data_type != FSNOTIFY_EVENT_PATH) {
if (event->data_type != FSNOTIFY_EVENT_FILE) {
WARN_ON(1);
put_unused_fd(client_fd);
return -EINVAL;
@ -75,8 +75,8 @@ static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
* we need a new file handle for the userspace program so it can read even if it was
* originally opened O_WRONLY.
*/
dentry = dget(event->path.dentry);
mnt = mntget(event->path.mnt);
dentry = dget(event->file->f_path.dentry);
mnt = mntget(event->file->f_path.mnt);
/* it's possible this event was an overflow event. in that case dentry and mnt
* are NULL; That's fine, just don't call dentry open */
if (dentry && mnt)

16
fs/notify/fsnotify.c
View File

@ -84,7 +84,7 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode)
}
/* Notify this dentry's parent about a child's events. */
void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
{
struct dentry *parent;
struct inode *p_inode;
@ -92,7 +92,7 @@ void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
bool should_update_children = false;
if (!dentry)
dentry = path->dentry;
dentry = file->f_path.dentry;
if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
return;
@ -124,8 +124,8 @@ void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
* specifies these are events which came from a child. */
mask |= FS_EVENT_ON_CHILD;
if (path)
fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
if (file)
fsnotify(p_inode, mask, file, FSNOTIFY_EVENT_FILE,
dentry->d_name.name, 0);
else
fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
@ -154,10 +154,10 @@ void __fsnotify_flush_ignored_mask(struct inode *inode, void *data, int data_is)
spin_unlock(&inode->i_lock);
}
if (data_is == FSNOTIFY_EVENT_PATH) {
if (data_is == FSNOTIFY_EVENT_FILE) {
struct vfsmount *mnt;
mnt = ((struct path *)data)->mnt;
mnt = ((struct file *)data)->f_path.mnt;
if (mnt && !hlist_empty(&mnt->mnt_fsnotify_marks)) {
spin_lock(&mnt->mnt_root->d_lock);
hlist_for_each_entry(mark, node, &mnt->mnt_fsnotify_marks, m.m_list) {
@ -228,8 +228,8 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
!(test_mask & fsnotify_vfsmount_mask))
return 0;
if (data_is == FSNOTIFY_EVENT_PATH)
mnt = ((struct path *)data)->mnt;
if (data_is == FSNOTIFY_EVENT_FILE)
mnt = ((struct file *)data)->f_path.mnt;
/* if this inode's directed listeners don't care and nothing on the vfsmount
* listeners list cares, nothing to do */

12
fs/notify/inotify/inotify_fsnotify.c
View File

@ -52,9 +52,9 @@ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new
!strcmp(old->file_name, new->file_name))
return true;
break;
case (FSNOTIFY_EVENT_PATH):
if ((old->path.mnt == new->path.mnt) &&
(old->path.dentry == new->path.dentry))
case (FSNOTIFY_EVENT_FILE):
if ((old->file->f_path.mnt == new->file->f_path.mnt) &&
(old->file->f_path.dentry == new->file->f_path.dentry))
return true;
break;
case (FSNOTIFY_EVENT_NONE):
@ -165,10 +165,10 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode
send = (fsn_mark->mask & mask);
if (send && (fsn_mark->mask & FS_EXCL_UNLINK) &&
(data_type == FSNOTIFY_EVENT_PATH)) {
struct path *path = data;
(data_type == FSNOTIFY_EVENT_FILE)) {
struct file *file = data;
if (d_unlinked(path->dentry))
if (d_unlinked(file->f_path.dentry))
send = false;
}

20
fs/notify/notification.c
View File

@ -31,6 +31,7 @@
* allocated and used.
*/
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
@ -89,8 +90,8 @@ void fsnotify_put_event(struct fsnotify_event *event)
if (atomic_dec_and_test(&event->refcnt)) {
pr_debug("%s: event=%p\n", __func__, event);
if (event->data_type == FSNOTIFY_EVENT_PATH)
path_put(&event->path);
if (event->data_type == FSNOTIFY_EVENT_FILE)
fput(event->file);
BUG_ON(!list_empty(&event->private_data_list));
@ -375,8 +376,8 @@ struct fsnotify_event *fsnotify_clone_event(struct fsnotify_event *old_event)
}
}
event->tgid = get_pid(old_event->tgid);
if (event->data_type == FSNOTIFY_EVENT_PATH)
path_get(&event->path);
if (event->data_type == FSNOTIFY_EVENT_FILE)
get_file(event->file);
return event;
}
@ -423,11 +424,9 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
event->data_type = data_type;
switch (data_type) {
case FSNOTIFY_EVENT_PATH: {
struct path *path = data;
event->path.dentry = path->dentry;
event->path.mnt = path->mnt;
path_get(&event->path);
case FSNOTIFY_EVENT_FILE: {
event->file = data;
get_file(event->file);
break;
}
case FSNOTIFY_EVENT_INODE:
@ -435,8 +434,7 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
break;
case FSNOTIFY_EVENT_NONE:
event->inode = NULL;
event->path.dentry = NULL;
event->path.mnt = NULL;
event->file = NULL;
break;
default:
BUG();

37
include/linux/fsnotify.h
View File

@ -26,19 +26,18 @@ static inline void fsnotify_d_instantiate(struct dentry *dentry,
}
/* Notify this dentry's parent about a child's events. */
static inline void fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
static inline void fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
{
if (!dentry)
dentry = path->dentry;
dentry = file->f_path.dentry;
__fsnotify_parent(path, dentry, mask);
__fsnotify_parent(file, dentry, mask);
}
/* simple call site for access decisions */
static inline int fsnotify_perm(struct file *file, int mask)
{
struct path *path = &file->f_path;
struct inode *inode = path->dentry->d_inode;
struct inode *inode = file->f_path.dentry->d_inode;
__u32 fsnotify_mask = 0;
if (file->f_mode & FMODE_NONOTIFY)
@ -52,7 +51,7 @@ static inline int fsnotify_perm(struct file *file, int mask)
else
BUG();
return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
return fsnotify(inode, fsnotify_mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
}
/*
@ -187,16 +186,15 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
*/
static inline void fsnotify_access(struct file *file)
{
struct path *path = &file->f_path;
struct inode *inode = path->dentry->d_inode;
struct inode *inode = file->f_path.dentry->d_inode;
__u32 mask = FS_ACCESS;
if (S_ISDIR(inode->i_mode))
mask |= FS_IN_ISDIR;
if (!(file->f_mode & FMODE_NONOTIFY)) {
fsnotify_parent(path, NULL, mask);
fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
fsnotify_parent(file, NULL, mask);
fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
}
}
@ -205,16 +203,15 @@ static inline void fsnotify_access(struct file *file)
*/
static inline void fsnotify_modify(struct file *file)
{
struct path *path = &file->f_path;
struct inode *inode = path->dentry->d_inode;
struct inode *inode = file->f_path.dentry->d_inode;
__u32 mask = FS_MODIFY;
if (S_ISDIR(inode->i_mode))
mask |= FS_IN_ISDIR;
if (!(file->f_mode & FMODE_NONOTIFY)) {
fsnotify_parent(path, NULL, mask);
fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
fsnotify_parent(file, NULL, mask);
fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
}
}
@ -223,16 +220,15 @@ static inline void fsnotify_modify(struct file *file)
*/
static inline void fsnotify_open(struct file *file)
{
struct path *path = &file->f_path;
struct inode *inode = path->dentry->d_inode;
struct inode *inode = file->f_path.dentry->d_inode;
__u32 mask = FS_OPEN;
if (S_ISDIR(inode->i_mode))
mask |= FS_IN_ISDIR;
if (!(file->f_mode & FMODE_NONOTIFY)) {
fsnotify_parent(path, NULL, mask);
fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
fsnotify_parent(file, NULL, mask);
fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
}
}
@ -241,7 +237,6 @@ static inline void fsnotify_open(struct file *file)
*/
static inline void fsnotify_close(struct file *file)
{
struct path *path = &file->f_path;
struct inode *inode = file->f_path.dentry->d_inode;
fmode_t mode = file->f_mode;
__u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
@ -250,8 +245,8 @@ static inline void fsnotify_close(struct file *file)
mask |= FS_IN_ISDIR;
if (!(file->f_mode & FMODE_NONOTIFY)) {
fsnotify_parent(path, NULL, mask);
fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
fsnotify_parent(file, NULL, mask);
fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
}
}

16
include/linux/fsnotify_backend.h
View File

@ -223,20 +223,20 @@ struct fsnotify_event {
/* to_tell may ONLY be dereferenced during handle_event(). */
struct inode *to_tell; /* either the inode the event happened to or its parent */
/*
* depending on the event type we should have either a path or inode
* We hold a reference on path, but NOT on inode. Since we have the ref on
* the path, it may be dereferenced at any point during this object's
* depending on the event type we should have either a file or inode
* We hold a reference on file, but NOT on inode. Since we have the ref on
* the file, it may be dereferenced at any point during this object's
* lifetime. That reference is dropped when this object's refcnt hits
* 0. If this event contains an inode instead of a path, the inode may
* 0. If this event contains an inode instead of a file, the inode may
* ONLY be used during handle_event().
*/
union {
struct path path;
struct file *file;
struct inode *inode;
};
/* when calling fsnotify tell it if the data is a path or inode */
#define FSNOTIFY_EVENT_NONE 0
#define FSNOTIFY_EVENT_PATH 1
#define FSNOTIFY_EVENT_FILE 1
#define FSNOTIFY_EVENT_INODE 2
int data_type; /* which of the above union we have */
atomic_t refcnt; /* how many groups still are using/need to send this event */
@ -311,7 +311,7 @@ struct fsnotify_mark {
/* main fsnotify call to send events */
extern int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
const unsigned char *name, u32 cookie);
extern void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask);
extern void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask);
extern void __fsnotify_inode_delete(struct inode *inode);
extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
extern u32 fsnotify_get_cookie(void);
@ -444,7 +444,7 @@ static inline int fsnotify(struct inode *to_tell, __u32 mask, void *data, int da
return 0;
}
static inline void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
static inline void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
{}
static inline void __fsnotify_inode_delete(struct inode *inode)

4
kernel/audit_watch.c
View File

@ -545,8 +545,8 @@ static int audit_watch_handle_event(struct fsnotify_group *group, struct fsnotif
return 0;
switch (event->data_type) {
case (FSNOTIFY_EVENT_PATH):
inode = event->path.dentry->d_inode;
case (FSNOTIFY_EVENT_FILE):
inode = event->file->f_path.dentry->d_inode;
break;
case (FSNOTIFY_EVENT_INODE):
inode = event->inode;