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authorJan Kara <jack@suse.cz>2020-03-24 19:04:20 +0300
committerJan Kara <jack@suse.cz>2020-03-25 12:27:16 +0300
commit7088f35720a55b99624ea36091538baec7ec611f (patch)
tree6e6d3eecaa9d3c239204477f6ab227dc4d8ee860 /fs/notify/fanotify
parentafc894c784c84cb3bb85a235feca2cb278f7b023 (diff)
downloadlinux-7088f35720a55b99624ea36091538baec7ec611f.tar.xz
fanotify: divorce fanotify_path_event and fanotify_fid_event
Breakup the union and make them both inherit from abstract fanotify_event. fanotify_path_event, fanotify_fid_event and fanotify_perm_event inherit from fanotify_event. type field in abstract fanotify_event determines the concrete event type. fanotify_path_event, fanotify_fid_event and fanotify_perm_event are allocated from separate memcache pools. Rename fanotify_perm_event casting macro to FANOTIFY_PERM(), so that FANOTIFY_PE() and FANOTIFY_FE() can be used as casting macros to fanotify_path_event and fanotify_fid_event. [JK: Cleanup FANOTIFY_PE() and FANOTIFY_FE() to be proper inline functions and remove requirement that fanotify_event is the first in event structures] Link: https://lore.kernel.org/r/20200319151022.31456-11-amir73il@gmail.com Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify/fanotify')
-rw-r--r--fs/notify/fanotify/fanotify.c126
-rw-r--r--fs/notify/fanotify/fanotify.h77
-rw-r--r--fs/notify/fanotify/fanotify_user.c71
3 files changed, 180 insertions, 94 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 64b05be4058d..39eb71f7c413 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -29,7 +29,7 @@ static inline bool fanotify_fsid_equal(__kernel_fsid_t *fsid1,
}
static bool fanotify_fh_equal(struct fanotify_fh *fh1,
- struct fanotify_fh *fh2)
+ struct fanotify_fh *fh2)
{
if (fh1->type != fh2->type || fh1->len != fh2->len)
return false;
@@ -42,6 +42,17 @@ static bool fanotify_fh_equal(struct fanotify_fh *fh1,
!memcmp(fanotify_fh_buf(fh1), fanotify_fh_buf(fh2), fh1->len);
}
+static bool fanotify_fid_event_equal(struct fanotify_fid_event *ffe1,
+ struct fanotify_fid_event *ffe2)
+{
+ /* Do not merge fid events without object fh */
+ if (!ffe1->object_fh.len)
+ return false;
+
+ return fanotify_fsid_equal(&ffe1->fsid, &ffe2->fsid) &&
+ fanotify_fh_equal(&ffe1->object_fh, &ffe2->object_fh);
+}
+
static bool should_merge(struct fsnotify_event *old_fsn,
struct fsnotify_event *new_fsn)
{
@@ -51,14 +62,15 @@ static bool should_merge(struct fsnotify_event *old_fsn,
old = FANOTIFY_E(old_fsn);
new = FANOTIFY_E(new_fsn);
- if (old_fsn->objectid != new_fsn->objectid || old->pid != new->pid ||
- old->fh.type != new->fh.type)
+ if (old_fsn->objectid != new_fsn->objectid ||
+ old->type != new->type || old->pid != new->pid)
return false;
- if (fanotify_event_has_path(old)) {
+ switch (old->type) {
+ case FANOTIFY_EVENT_TYPE_PATH:
return fanotify_path_equal(fanotify_event_path(old),
fanotify_event_path(new));
- } else if (fanotify_event_has_fid(old)) {
+ case FANOTIFY_EVENT_TYPE_FID:
/*
* We want to merge many dirent events in the same dir (i.e.
* creates/unlinks/renames), but we do not want to merge dirent
@@ -70,11 +82,12 @@ static bool should_merge(struct fsnotify_event *old_fsn,
if ((old->mask & FS_ISDIR) != (new->mask & FS_ISDIR))
return false;
- return fanotify_fsid_equal(&old->fsid, &new->fsid) &&
- fanotify_fh_equal(&old->fh, &new->fh);
+ return fanotify_fid_event_equal(FANOTIFY_FE(old),
+ FANOTIFY_FE(new));
+ default:
+ WARN_ON_ONCE(1);
}
- /* Do not merge events if we failed to encode fid */
return false;
}
@@ -310,6 +323,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
__kernel_fsid_t *fsid)
{
struct fanotify_event *event = NULL;
+ struct fanotify_fid_event *ffe = NULL;
gfp_t gfp = GFP_KERNEL_ACCOUNT;
struct inode *id = fanotify_fid_inode(inode, mask, data, data_type);
const struct path *path = fsnotify_data_path(data, data_type);
@@ -334,14 +348,32 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp);
if (!pevent)
goto out;
+
event = &pevent->fae;
+ event->type = FANOTIFY_EVENT_TYPE_PATH_PERM;
pevent->response = 0;
pevent->state = FAN_EVENT_INIT;
goto init;
}
- event = kmem_cache_alloc(fanotify_event_cachep, gfp);
- if (!event)
- goto out;
+
+ if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+ ffe = kmem_cache_alloc(fanotify_fid_event_cachep, gfp);
+ if (!ffe)
+ goto out;
+
+ event = &ffe->fae;
+ event->type = FANOTIFY_EVENT_TYPE_FID;
+ } else {
+ struct fanotify_path_event *pevent;
+
+ pevent = kmem_cache_alloc(fanotify_path_event_cachep, gfp);
+ if (!pevent)
+ goto out;
+
+ event = &pevent->fae;
+ event->type = FANOTIFY_EVENT_TYPE_PATH;
+ }
+
init: __maybe_unused
/*
* Use the victim inode instead of the watching inode as the id for
@@ -354,19 +386,23 @@ init: __maybe_unused
event->pid = get_pid(task_pid(current));
else
event->pid = get_pid(task_tgid(current));
- event->fh.len = 0;
- if (id && FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
- event->fsid = *fsid;
+
+ if (fanotify_event_has_fid(event)) {
+ ffe->object_fh.len = 0;
+ if (fsid)
+ ffe->fsid = *fsid;
if (id)
- fanotify_encode_fh(&event->fh, id, gfp);
- } else if (path) {
- event->fh.type = FILEID_ROOT;
- event->path = *path;
- path_get(path);
- } else {
- event->fh.type = FILEID_INVALID;
- event->path.mnt = NULL;
- event->path.dentry = NULL;
+ fanotify_encode_fh(&ffe->object_fh, id, gfp);
+ } else if (fanotify_event_has_path(event)) {
+ struct path *p = fanotify_event_path(event);
+
+ if (path) {
+ *p = *path;
+ path_get(path);
+ } else {
+ p->mnt = NULL;
+ p->dentry = NULL;
+ }
}
out:
memalloc_unuse_memcg();
@@ -486,7 +522,7 @@ static int fanotify_handle_event(struct fsnotify_group *group,
ret = 0;
} else if (fanotify_is_perm_event(mask)) {
- ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event),
+ ret = fanotify_get_response(group, FANOTIFY_PERM(event),
iter_info);
}
finish:
@@ -505,22 +541,46 @@ static void fanotify_free_group_priv(struct fsnotify_group *group)
free_uid(user);
}
+static void fanotify_free_path_event(struct fanotify_event *event)
+{
+ path_put(fanotify_event_path(event));
+ kmem_cache_free(fanotify_path_event_cachep, FANOTIFY_PE(event));
+}
+
+static void fanotify_free_perm_event(struct fanotify_event *event)
+{
+ path_put(fanotify_event_path(event));
+ kmem_cache_free(fanotify_perm_event_cachep, FANOTIFY_PERM(event));
+}
+
+static void fanotify_free_fid_event(struct fanotify_event *event)
+{
+ struct fanotify_fid_event *ffe = FANOTIFY_FE(event);
+
+ if (fanotify_fh_has_ext_buf(&ffe->object_fh))
+ kfree(fanotify_fh_ext_buf(&ffe->object_fh));
+ kmem_cache_free(fanotify_fid_event_cachep, ffe);
+}
+
static void fanotify_free_event(struct fsnotify_event *fsn_event)
{
struct fanotify_event *event;
event = FANOTIFY_E(fsn_event);
- if (fanotify_event_has_path(event))
- path_put(&event->path);
- else if (fanotify_fh_has_ext_buf(&event->fh))
- kfree(fanotify_fh_ext_buf(&event->fh));
put_pid(event->pid);
- if (fanotify_is_perm_event(event->mask)) {
- kmem_cache_free(fanotify_perm_event_cachep,
- FANOTIFY_PE(fsn_event));
- return;
+ switch (event->type) {
+ case FANOTIFY_EVENT_TYPE_PATH:
+ fanotify_free_path_event(event);
+ break;
+ case FANOTIFY_EVENT_TYPE_PATH_PERM:
+ fanotify_free_perm_event(event);
+ break;
+ case FANOTIFY_EVENT_TYPE_FID:
+ fanotify_free_fid_event(event);
+ break;
+ default:
+ WARN_ON_ONCE(1);
}
- kmem_cache_free(fanotify_event_cachep, event);
}
static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index f9da4481613d..3b50ee44a0cd 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -5,7 +5,8 @@
#include <linux/exportfs.h>
extern struct kmem_cache *fanotify_mark_cache;
-extern struct kmem_cache *fanotify_event_cachep;
+extern struct kmem_cache *fanotify_fid_event_cachep;
+extern struct kmem_cache *fanotify_path_event_cachep;
extern struct kmem_cache *fanotify_perm_event_cachep;
/* Possible states of the permission event */
@@ -52,43 +53,45 @@ static inline void *fanotify_fh_buf(struct fanotify_fh *fh)
}
/*
- * Structure for normal fanotify events. It gets allocated in
+ * Common structure for fanotify events. Concrete structs are allocated in
* fanotify_handle_event() and freed when the information is retrieved by
- * userspace
+ * userspace. The type of event determines how it was allocated, how it will
+ * be freed and which concrete struct it may be cast to.
*/
+enum fanotify_event_type {
+ FANOTIFY_EVENT_TYPE_FID,
+ FANOTIFY_EVENT_TYPE_PATH,
+ FANOTIFY_EVENT_TYPE_PATH_PERM,
+};
+
struct fanotify_event {
struct fsnotify_event fse;
u32 mask;
- /*
- * With FAN_REPORT_FID, we do not hold any reference on the
- * victim object. Instead we store its NFS file handle and its
- * filesystem's fsid as a unique identifier.
- */
- __kernel_fsid_t fsid;
- struct fanotify_fh fh;
- /*
- * We hold ref to this path so it may be dereferenced at any
- * point during this object's lifetime
- */
- struct path path;
+ enum fanotify_event_type type;
struct pid *pid;
};
-static inline bool fanotify_event_has_path(struct fanotify_event *event)
+struct fanotify_fid_event {
+ struct fanotify_event fae;
+ __kernel_fsid_t fsid;
+ struct fanotify_fh object_fh;
+};
+
+static inline struct fanotify_fid_event *
+FANOTIFY_FE(struct fanotify_event *event)
{
- return event->fh.type == FILEID_ROOT;
+ return container_of(event, struct fanotify_fid_event, fae);
}
static inline bool fanotify_event_has_fid(struct fanotify_event *event)
{
- return event->fh.type != FILEID_ROOT &&
- event->fh.type != FILEID_INVALID;
+ return event->type == FANOTIFY_EVENT_TYPE_FID;
}
static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event)
{
- if (fanotify_event_has_fid(event))
- return &event->fsid;
+ if (event->type == FANOTIFY_EVENT_TYPE_FID)
+ return &FANOTIFY_FE(event)->fsid;
else
return NULL;
}
@@ -96,8 +99,8 @@ static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event)
static inline struct fanotify_fh *fanotify_event_object_fh(
struct fanotify_event *event)
{
- if (fanotify_event_has_fid(event))
- return &event->fh;
+ if (event->type == FANOTIFY_EVENT_TYPE_FID)
+ return &FANOTIFY_FE(event)->object_fh;
else
return NULL;
}
@@ -109,6 +112,17 @@ static inline int fanotify_event_object_fh_len(struct fanotify_event *event)
return fh ? fh->len : 0;
}
+struct fanotify_path_event {
+ struct fanotify_event fae;
+ struct path path;
+};
+
+static inline struct fanotify_path_event *
+FANOTIFY_PE(struct fanotify_event *event)
+{
+ return container_of(event, struct fanotify_path_event, fae);
+}
+
/*
* Structure for permission fanotify events. It gets allocated and freed in
* fanotify_handle_event() since we wait there for user response. When the
@@ -118,15 +132,16 @@ static inline int fanotify_event_object_fh_len(struct fanotify_event *event)
*/
struct fanotify_perm_event {
struct fanotify_event fae;
+ struct path path;
unsigned short response; /* userspace answer to the event */
unsigned short state; /* state of the event */
int fd; /* fd we passed to userspace for this event */
};
static inline struct fanotify_perm_event *
-FANOTIFY_PE(struct fsnotify_event *fse)
+FANOTIFY_PERM(struct fanotify_event *event)
{
- return container_of(fse, struct fanotify_perm_event, fae.fse);
+ return container_of(event, struct fanotify_perm_event, fae);
}
static inline bool fanotify_is_perm_event(u32 mask)
@@ -140,10 +155,18 @@ static inline struct fanotify_event *FANOTIFY_E(struct fsnotify_event *fse)
return container_of(fse, struct fanotify_event, fse);
}
+static inline bool fanotify_event_has_path(struct fanotify_event *event)
+{
+ return event->type == FANOTIFY_EVENT_TYPE_PATH ||
+ event->type == FANOTIFY_EVENT_TYPE_PATH_PERM;
+}
+
static inline struct path *fanotify_event_path(struct fanotify_event *event)
{
- if (fanotify_event_has_path(event))
- return &event->path;
+ if (event->type == FANOTIFY_EVENT_TYPE_PATH)
+ return &FANOTIFY_PE(event)->path;
+ else if (event->type == FANOTIFY_EVENT_TYPE_PATH_PERM)
+ return &FANOTIFY_PERM(event)->path;
else
return NULL;
}
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 0b3b74fa3a27..6cb94a6bc980 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -46,7 +46,8 @@
extern const struct fsnotify_ops fanotify_fsnotify_ops;
struct kmem_cache *fanotify_mark_cache __read_mostly;
-struct kmem_cache *fanotify_event_cachep __read_mostly;
+struct kmem_cache *fanotify_fid_event_cachep __read_mostly;
+struct kmem_cache *fanotify_path_event_cachep __read_mostly;
struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
#define FANOTIFY_EVENT_ALIGN 4
@@ -64,16 +65,16 @@ static int fanotify_event_info_len(struct fanotify_event *event)
}
/*
- * Get an fsnotify notification event if one exists and is small
+ * Get an fanotify notification event if one exists and is small
* enough to fit in "count". Return an error pointer if the count
* is not large enough. When permission event is dequeued, its state is
* updated accordingly.
*/
-static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
+static struct fanotify_event *get_one_event(struct fsnotify_group *group,
size_t count)
{
size_t event_size = FAN_EVENT_METADATA_LEN;
- struct fsnotify_event *fsn_event = NULL;
+ struct fanotify_event *event = NULL;
pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
@@ -87,15 +88,15 @@ static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
}
if (event_size > count) {
- fsn_event = ERR_PTR(-EINVAL);
+ event = ERR_PTR(-EINVAL);
goto out;
}
- fsn_event = fsnotify_remove_first_event(group);
- if (fanotify_is_perm_event(FANOTIFY_E(fsn_event)->mask))
- FANOTIFY_PE(fsn_event)->state = FAN_EVENT_REPORTED;
+ event = FANOTIFY_E(fsnotify_remove_first_event(group));
+ if (fanotify_is_perm_event(event->mask))
+ FANOTIFY_PERM(event)->state = FAN_EVENT_REPORTED;
out:
spin_unlock(&group->notification_lock);
- return fsn_event;
+ return event;
}
static int create_fd(struct fsnotify_group *group, struct path *path,
@@ -252,19 +253,16 @@ static int copy_fid_to_user(struct fanotify_event *event, char __user *buf)
}
static ssize_t copy_event_to_user(struct fsnotify_group *group,
- struct fsnotify_event *fsn_event,
+ struct fanotify_event *event,
char __user *buf, size_t count)
{
struct fanotify_event_metadata metadata;
- struct fanotify_event *event;
- struct path *path;
+ struct path *path = fanotify_event_path(event);
struct file *f = NULL;
int ret, fd = FAN_NOFD;
- pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event);
+ pr_debug("%s: group=%p event=%p\n", __func__, group, event);
- event = container_of(fsn_event, struct fanotify_event, fse);
- path = fanotify_event_path(event);
metadata.event_len = FAN_EVENT_METADATA_LEN;
metadata.metadata_len = FAN_EVENT_METADATA_LEN;
metadata.vers = FANOTIFY_METADATA_VERSION;
@@ -293,9 +291,9 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
goto out_close_fd;
if (fanotify_is_perm_event(event->mask))
- FANOTIFY_PE(fsn_event)->fd = fd;
+ FANOTIFY_PERM(event)->fd = fd;
- if (fanotify_event_has_path(event)) {
+ if (f) {
fd_install(fd, f);
} else if (fanotify_event_has_fid(event)) {
ret = copy_fid_to_user(event, buf + FAN_EVENT_METADATA_LEN);
@@ -332,7 +330,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
size_t count, loff_t *pos)
{
struct fsnotify_group *group;
- struct fsnotify_event *kevent;
+ struct fanotify_event *event;
char __user *start;
int ret;
DEFINE_WAIT_FUNC(wait, woken_wake_function);
@@ -344,13 +342,13 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
add_wait_queue(&group->notification_waitq, &wait);
while (1) {
- kevent = get_one_event(group, count);
- if (IS_ERR(kevent)) {
- ret = PTR_ERR(kevent);
+ event = get_one_event(group, count);
+ if (IS_ERR(event)) {
+ ret = PTR_ERR(event);
break;
}
- if (!kevent) {
+ if (!event) {
ret = -EAGAIN;
if (file->f_flags & O_NONBLOCK)
break;
@@ -366,7 +364,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
continue;
}
- ret = copy_event_to_user(group, kevent, buf, count);
+ ret = copy_event_to_user(group, event, buf, count);
if (unlikely(ret == -EOPENSTALE)) {
/*
* We cannot report events with stale fd so drop it.
@@ -381,17 +379,17 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
* Permission events get queued to wait for response. Other
* events can be destroyed now.
*/
- if (!fanotify_is_perm_event(FANOTIFY_E(kevent)->mask)) {
- fsnotify_destroy_event(group, kevent);
+ if (!fanotify_is_perm_event(event->mask)) {
+ fsnotify_destroy_event(group, &event->fse);
} else {
if (ret <= 0) {
spin_lock(&group->notification_lock);
finish_permission_event(group,
- FANOTIFY_PE(kevent), FAN_DENY);
+ FANOTIFY_PERM(event), FAN_DENY);
wake_up(&group->fanotify_data.access_waitq);
} else {
spin_lock(&group->notification_lock);
- list_add_tail(&kevent->list,
+ list_add_tail(&event->fse.list,
&group->fanotify_data.access_list);
spin_unlock(&group->notification_lock);
}
@@ -437,8 +435,6 @@ static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t
static int fanotify_release(struct inode *ignored, struct file *file)
{
struct fsnotify_group *group = file->private_data;
- struct fanotify_perm_event *event;
- struct fsnotify_event *fsn_event;
/*
* Stop new events from arriving in the notification queue. since
@@ -453,6 +449,8 @@ static int fanotify_release(struct inode *ignored, struct file *file)
*/
spin_lock(&group->notification_lock);
while (!list_empty(&group->fanotify_data.access_list)) {
+ struct fanotify_perm_event *event;
+
event = list_first_entry(&group->fanotify_data.access_list,
struct fanotify_perm_event, fae.fse.list);
list_del_init(&event->fae.fse.list);
@@ -466,12 +464,14 @@ static int fanotify_release(struct inode *ignored, struct file *file)
* response is consumed and fanotify_get_response() returns.
*/
while (!fsnotify_notify_queue_is_empty(group)) {
- fsn_event = fsnotify_remove_first_event(group);
- if (!(FANOTIFY_E(fsn_event)->mask & FANOTIFY_PERM_EVENTS)) {
+ struct fanotify_event *event;
+
+ event = FANOTIFY_E(fsnotify_remove_first_event(group));
+ if (!(event->mask & FANOTIFY_PERM_EVENTS)) {
spin_unlock(&group->notification_lock);
- fsnotify_destroy_event(group, fsn_event);
+ fsnotify_destroy_event(group, &event->fse);
} else {
- finish_permission_event(group, FANOTIFY_PE(fsn_event),
+ finish_permission_event(group, FANOTIFY_PERM(event),
FAN_ALLOW);
}
spin_lock(&group->notification_lock);
@@ -1136,7 +1136,10 @@ static int __init fanotify_user_setup(void)
fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
SLAB_PANIC|SLAB_ACCOUNT);
- fanotify_event_cachep = KMEM_CACHE(fanotify_event, SLAB_PANIC);
+ fanotify_fid_event_cachep = KMEM_CACHE(fanotify_fid_event,
+ SLAB_PANIC);
+ fanotify_path_event_cachep = KMEM_CACHE(fanotify_path_event,
+ SLAB_PANIC);
if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
fanotify_perm_event_cachep =
KMEM_CACHE(fanotify_perm_event, SLAB_PANIC);