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Message-ID: <CAOQ4uxg9Jr0akOcvcJ3PQQBFzFaMXwOguSH5CZWHZ9ZhGMjjAQ@mail.gmail.com>
Date: Wed, 16 Jun 2021 12:26:00 +0300
From: Amir Goldstein <amir73il@...il.com>
To: Gabriel Krisman Bertazi <krisman@...labora.com>
Cc: kernel@...labora.com, "Darrick J. Wong" <djwong@...nel.org>,
Theodore Tso <tytso@....edu>,
Dave Chinner <david@...morbit.com>, Jan Kara <jack@...e.com>,
David Howells <dhowells@...hat.com>,
Khazhismel Kumykov <khazhy@...gle.com>,
linux-fsdevel <linux-fsdevel@...r.kernel.org>,
Ext4 <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH v2 07/14] fsnotify: pass arguments of fsnotify() in struct fsnotify_event_info
On Wed, Jun 16, 2021 at 2:56 AM Gabriel Krisman Bertazi
<krisman@...labora.com> wrote:
>
> From: Amir Goldstein <amir73il@...il.com>
>
> There are a lot of arguments to fsnotify() and the handle_event() method.
> Pass them in a const struct instead of on the argument list.
>
> Apart from being more tidy, this is needed for passing userns to backend.
Remove this line or change to "needed for <your thing>"
Because I don't know if passing userns to backend is ever going to happen.
Thanks,
Amir.
> __fsnotify_parent() argument list was intentionally left untouched,
> because its argument list is still short enough and because most of the
> event info arguments are initialized inside __fsnotify_parent().
>
> Signed-off-by: Amir Goldstein <amir73il@...il.com>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
> ---
> fs/notify/fanotify/fanotify.c | 59 +++++++++++------------
> fs/notify/fsnotify.c | 83 +++++++++++++++++---------------
> include/linux/fsnotify.h | 15 ++++--
> include/linux/fsnotify_backend.h | 73 +++++++++++++++++++++-------
> 4 files changed, 140 insertions(+), 90 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index f85efb24cfb4..3822e46fc18a 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -253,21 +253,22 @@ static int fanotify_get_response(struct fsnotify_group *group,
> * been included within the event mask, but have not been explicitly
> * requested by the user, will not be present in the returned mask.
> */
> -static u32 fanotify_group_event_mask(struct fsnotify_group *group,
> - struct fsnotify_iter_info *iter_info,
> - u32 event_mask, const void *data,
> - int data_type, struct inode *dir)
> +static u32 fanotify_group_event_mask(
> + struct fsnotify_group *group, u32 event_mask,
> + const struct fsnotify_event_info *event_info,
> + struct fsnotify_iter_info *iter_info)
> {
> __u32 marks_mask = 0, marks_ignored_mask = 0;
> __u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS |
> FANOTIFY_EVENT_FLAGS;
> - const struct path *path = fsnotify_data_path(data, data_type);
> + const struct path *path = fsnotify_event_info_path(event_info);
> unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
> struct fsnotify_mark *mark;
> int type;
>
> pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n",
> - __func__, iter_info->report_mask, event_mask, data, data_type);
> + __func__, iter_info->report_mask, event_mask,
> + event_info->data, event_info->data_type);
>
> if (!fid_mode) {
> /* Do we have path to open a file descriptor? */
> @@ -278,7 +279,7 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
> return 0;
> } else if (!(fid_mode & FAN_REPORT_FID)) {
> /* Do we have a directory inode to report? */
> - if (!dir && !(event_mask & FS_ISDIR))
> + if (!event_info->dir && !(event_mask & FS_ISDIR))
> return 0;
> }
>
> @@ -427,13 +428,13 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
> * FS_ATTRIB reports the child inode even if reported on a watched parent.
> * FS_CREATE reports the modified dir inode and not the created inode.
> */
> -static struct inode *fanotify_fid_inode(u32 event_mask, const void *data,
> - int data_type, struct inode *dir)
> +static struct inode *fanotify_fid_inode(u32 event_mask,
> + const struct fsnotify_event_info *event_info)
> {
> if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS)
> - return dir;
> + return event_info->dir;
>
> - return fsnotify_data_inode(data, data_type);
> + return fsnotify_event_info_inode(event_info);
> }
>
> /*
> @@ -444,18 +445,18 @@ static struct inode *fanotify_fid_inode(u32 event_mask, const void *data,
> * reported to parent.
> * Otherwise, do not report dir fid.
> */
> -static struct inode *fanotify_dfid_inode(u32 event_mask, const void *data,
> - int data_type, struct inode *dir)
> +static struct inode *fanotify_dfid_inode(u32 event_mask,
> + const struct fsnotify_event_info *event_info)
> {
> - struct inode *inode = fsnotify_data_inode(data, data_type);
> + struct inode *inode = fsnotify_event_info_inode(event_info);
>
> if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS)
> - return dir;
> + return event_info->dir;
>
> if (S_ISDIR(inode->i_mode))
> return inode;
>
> - return dir;
> + return event_info->dir;
> }
>
> static struct fanotify_event *fanotify_alloc_path_event(const struct path *path,
> @@ -563,17 +564,17 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id,
> return &fne->fae;
> }
>
> -static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
> - u32 mask, const void *data,
> - int data_type, struct inode *dir,
> - const struct qstr *file_name,
> - __kernel_fsid_t *fsid)
> +static struct fanotify_event *fanotify_alloc_event(
> + struct fsnotify_group *group, u32 mask,
> + const struct fsnotify_event_info *event_info,
> + __kernel_fsid_t *fsid)
> {
> struct fanotify_event *event = NULL;
> gfp_t gfp = GFP_KERNEL_ACCOUNT;
> - struct inode *id = fanotify_fid_inode(mask, data, data_type, dir);
> - struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir);
> - const struct path *path = fsnotify_data_path(data, data_type);
> + struct inode *id = fanotify_fid_inode(mask, event_info);
> + struct inode *dirid = fanotify_dfid_inode(mask, event_info);
> + const struct path *path = fsnotify_event_info_path(event_info);
> + const struct qstr *file_name = event_info->name;
> unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
> struct mem_cgroup *old_memcg;
> struct inode *child = NULL;
> @@ -709,9 +710,7 @@ static void fanotify_insert_event(struct fsnotify_group *group,
> }
>
> static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
> - const void *data, int data_type,
> - struct inode *dir,
> - const struct qstr *file_name, u32 cookie,
> + const struct fsnotify_event_info *event_info,
> struct fsnotify_iter_info *iter_info)
> {
> int ret = 0;
> @@ -741,8 +740,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
>
> BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19);
>
> - mask = fanotify_group_event_mask(group, iter_info, mask, data,
> - data_type, dir);
> + mask = fanotify_group_event_mask(group, mask, event_info, iter_info);
> if (!mask)
> return 0;
>
> @@ -764,8 +762,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
> return 0;
> }
>
> - event = fanotify_alloc_event(group, mask, data, data_type, dir,
> - file_name, &fsid);
> + event = fanotify_alloc_event(group, mask, event_info, &fsid);
> ret = -ENOMEM;
> if (unlikely(!event)) {
> /*
> diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> index 30d422b8c0fc..36205a769dde 100644
> --- a/fs/notify/fsnotify.c
> +++ b/fs/notify/fsnotify.c
> @@ -177,8 +177,8 @@ static bool fsnotify_event_needs_parent(struct inode *inode, struct mount *mnt,
> * Notify only the child without name info if parent is not watching and
> * inode/sb/mount are not interested in events with parent and name info.
> */
> -int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
> - int data_type)
> +int __fsnotify_parent(struct dentry *dentry, __u32 mask,
> + const void *data, int data_type)
> {
> const struct path *path = fsnotify_data_path(data, data_type);
> struct mount *mnt = path ? real_mount(path->mnt) : NULL;
> @@ -229,7 +229,11 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
> }
>
> notify:
> - ret = fsnotify(mask, data, data_type, p_inode, file_name, inode, 0);
> + ret = __fsnotify(mask, &(struct fsnotify_event_info) {
> + .data = data, .data_type = data_type,
> + .dir = p_inode, .name = file_name,
> + .inode = inode,
> + });
>
> if (file_name)
> release_dentry_name_snapshot(&name);
> @@ -240,13 +244,11 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
> EXPORT_SYMBOL_GPL(__fsnotify_parent);
>
> static int fsnotify_handle_inode_event(struct fsnotify_group *group,
> - struct fsnotify_mark *inode_mark,
> - u32 mask, const void *data, int data_type,
> - struct inode *dir, const struct qstr *name,
> - u32 cookie)
> + struct fsnotify_mark *inode_mark, u32 mask,
> + const struct fsnotify_event_info *event_info)
> {
> - const struct path *path = fsnotify_data_path(data, data_type);
> - struct inode *inode = fsnotify_data_inode(data, data_type);
> + const struct path *path = fsnotify_event_info_path(event_info);
> + struct inode *inode = fsnotify_event_info_inode(event_info);
> const struct fsnotify_ops *ops = group->ops;
>
> if (WARN_ON_ONCE(!ops->handle_inode_event))
> @@ -260,16 +262,17 @@ static int fsnotify_handle_inode_event(struct fsnotify_group *group,
> if (!(mask & inode_mark->mask & ALL_FSNOTIFY_EVENTS))
> return 0;
>
> - return ops->handle_inode_event(inode_mark, mask, inode, dir, name, cookie);
> + return ops->handle_inode_event(inode_mark, mask, inode, event_info->dir,
> + event_info->name, event_info->cookie);
> }
>
> static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
> - const void *data, int data_type,
> - struct inode *dir, const struct qstr *name,
> - u32 cookie, struct fsnotify_iter_info *iter_info)
> + const struct fsnotify_event_info *event_info,
> + struct fsnotify_iter_info *iter_info)
> {
> struct fsnotify_mark *inode_mark = fsnotify_iter_inode_mark(iter_info);
> struct fsnotify_mark *parent_mark = fsnotify_iter_parent_mark(iter_info);
> + struct fsnotify_event_info child_event_info = { };
> int ret;
>
> if (WARN_ON_ONCE(fsnotify_iter_sb_mark(iter_info)) ||
> @@ -284,8 +287,8 @@ static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
> * interested in this event?
> */
> if (parent_mark->mask & FS_EVENT_ON_CHILD) {
> - ret = fsnotify_handle_inode_event(group, parent_mark, mask,
> - data, data_type, dir, name, 0);
> + ret = fsnotify_handle_inode_event(group, parent_mark,
> + mask, event_info);
> if (ret)
> return ret;
> }
> @@ -302,18 +305,22 @@ static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
> * The child watcher is expecting an event without a file name
> * and without the FS_EVENT_ON_CHILD flag.
> */
> + if (WARN_ON_ONCE(!event_info->inode))
> + return 0;
> +
> mask &= ~FS_EVENT_ON_CHILD;
> - dir = NULL;
> - name = NULL;
> + child_event_info = *event_info;
> + child_event_info.dir = NULL;
> + child_event_info.name = NULL;
> + event_info = &child_event_info;
> }
>
> - return fsnotify_handle_inode_event(group, inode_mark, mask, data, data_type,
> - dir, name, cookie);
> + return fsnotify_handle_inode_event(group, inode_mark, mask, event_info);
> }
>
> -static int send_to_group(__u32 mask, const void *data, int data_type,
> - struct inode *dir, const struct qstr *file_name,
> - u32 cookie, struct fsnotify_iter_info *iter_info)
> +static int send_to_group(__u32 mask,
> + const struct fsnotify_event_info *event_info,
> + struct fsnotify_iter_info *iter_info)
> {
> struct fsnotify_group *group = NULL;
> __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
> @@ -351,18 +358,18 @@ static int send_to_group(__u32 mask, const void *data, int data_type,
>
> pr_debug("%s: group=%p mask=%x marks_mask=%x marks_ignored_mask=%x data=%p data_type=%d dir=%p cookie=%d\n",
> __func__, group, mask, marks_mask, marks_ignored_mask,
> - data, data_type, dir, cookie);
> + event_info->data, event_info->data_type, event_info->dir,
> + event_info->cookie);
>
> if (!(test_mask & marks_mask & ~marks_ignored_mask))
> return 0;
>
> if (group->ops->handle_event) {
> - return group->ops->handle_event(group, mask, data, data_type, dir,
> - file_name, cookie, iter_info);
> + return group->ops->handle_event(group, mask, event_info,
> + iter_info);
> }
>
> - return fsnotify_handle_event(group, mask, data, data_type, dir,
> - file_name, cookie, iter_info);
> + return fsnotify_handle_event(group, mask, event_info, iter_info);
> }
>
> static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp)
> @@ -448,21 +455,22 @@ static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info)
> * in whatever means they feel necessary.
> *
> * @mask: event type and flags
> + * Input args in struct fsnotify_event_info:
> * @data: object that event happened on
> * @data_type: type of object for fanotify_data_XXX() accessors
> * @dir: optional directory associated with event -
> - * if @file_name is not NULL, this is the directory that
> - * @file_name is relative to
> - * @file_name: optional file name associated with event
> + * if @name is not NULL, this is the directory that
> + * @name is relative to
> + * @name: optional file name associated with event
> * @inode: optional inode associated with event -
> * either @dir or @inode must be non-NULL.
> * if both are non-NULL event may be reported to both.
> * @cookie: inotify rename cookie
> */
> -int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
> - const struct qstr *file_name, struct inode *inode, u32 cookie)
> +int __fsnotify(__u32 mask, const struct fsnotify_event_info *event_info)
> {
> - const struct path *path = fsnotify_data_path(data, data_type);
> + const struct path *path = fsnotify_event_info_path(event_info);
> + struct inode *inode = event_info->inode;
> struct fsnotify_iter_info iter_info = {};
> struct super_block *sb;
> struct mount *mnt = NULL;
> @@ -475,13 +483,13 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
>
> if (!inode) {
> /* Dirent event - report on TYPE_INODE to dir */
> - inode = dir;
> + inode = event_info->dir;
> } else if (mask & FS_EVENT_ON_CHILD) {
> /*
> * Event on child - report on TYPE_PARENT to dir if it is
> * watching children and on TYPE_INODE to child.
> */
> - parent = dir;
> + parent = event_info->dir;
> }
> sb = inode->i_sb;
>
> @@ -538,8 +546,7 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
> * That's why this traversal is so complicated...
> */
> while (fsnotify_iter_select_report_types(&iter_info)) {
> - ret = send_to_group(mask, data, data_type, dir, file_name,
> - cookie, &iter_info);
> + ret = send_to_group(mask, event_info, &iter_info);
>
> if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
> goto out;
> @@ -552,7 +559,7 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
>
> return ret;
> }
> -EXPORT_SYMBOL_GPL(fsnotify);
> +EXPORT_SYMBOL_GPL(__fsnotify);
>
> static __init int fsnotify_init(void)
> {
> diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> index f8acddcf54fb..8c2c681b4495 100644
> --- a/include/linux/fsnotify.h
> +++ b/include/linux/fsnotify.h
> @@ -30,7 +30,10 @@ static inline void fsnotify_name(struct inode *dir, __u32 mask,
> struct inode *child,
> const struct qstr *name, u32 cookie)
> {
> - fsnotify(mask, child, FSNOTIFY_EVENT_INODE, dir, name, NULL, cookie);
> + __fsnotify(mask, &(struct fsnotify_event_info) {
> + .data = child, .data_type = FSNOTIFY_EVENT_INODE,
> + .dir = dir, .name = name, .cookie = cookie,
> + });
> }
>
> static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,
> @@ -44,7 +47,10 @@ static inline void fsnotify_inode(struct inode *inode, __u32 mask)
> if (S_ISDIR(inode->i_mode))
> mask |= FS_ISDIR;
>
> - fsnotify(mask, inode, FSNOTIFY_EVENT_INODE, NULL, NULL, inode, 0);
> + __fsnotify(mask, &(struct fsnotify_event_info) {
> + .data = inode, .data_type = FSNOTIFY_EVENT_INODE,
> + .inode = inode,
> + });
> }
>
> /* Notify this dentry's parent about a child's events. */
> @@ -68,7 +74,10 @@ static inline int fsnotify_parent(struct dentry *dentry, __u32 mask,
> return __fsnotify_parent(dentry, mask, data, data_type);
>
> notify_child:
> - return fsnotify(mask, data, data_type, NULL, NULL, inode, 0);
> + return __fsnotify(mask, &(struct fsnotify_event_info) {
> + .data = data, .data_type = data_type,
> + .inode = inode,
> + });
> }
>
> /*
> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index f9e2c6cd0f7d..b1590f654ade 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -112,6 +112,28 @@ struct fsnotify_iter_info;
>
> struct mem_cgroup;
>
> +/*
> + * Event info args passed to fsnotify() and to backends on handle_event():
> + * @data: object that event happened on
> + * @data_type: type of object for fanotify_data_XXX() accessors
> + * @dir: optional directory associated with event -
> + * if @name is not NULL, this is the directory that
> + * @name is relative to
> + * @name: optional file name associated with event
> + * @inode: optional inode associated with event -
> + * either @dir or @inode must be non-NULL.
> + * if both are non-NULL event may be reported to both.
> + * @cookie: inotify rename cookie
> + */
> +struct fsnotify_event_info {
> + const void *data;
> + int data_type;
> + struct inode *dir;
> + const struct qstr *name;
> + struct inode *inode;
> + u32 cookie;
> +};
> +
> /*
> * Each group much define these ops. The fsnotify infrastructure will call
> * these operations for each relevant group.
> @@ -119,13 +141,7 @@ struct mem_cgroup;
> * handle_event - main call for a group to handle an fs event
> * @group: group to notify
> * @mask: event type and flags
> - * @data: object that event happened on
> - * @data_type: type of object for fanotify_data_XXX() accessors
> - * @dir: optional directory associated with event -
> - * if @file_name is not NULL, this is the directory that
> - * @file_name is relative to
> - * @file_name: optional file name associated with event
> - * @cookie: inotify rename cookie
> + * @event_info: information attached to the event
> * @iter_info: array of marks from this group that are interested in the event
> *
> * handle_inode_event - simple variant of handle_event() for groups that only
> @@ -147,8 +163,7 @@ struct mem_cgroup;
> */
> struct fsnotify_ops {
> int (*handle_event)(struct fsnotify_group *group, u32 mask,
> - const void *data, int data_type, struct inode *dir,
> - const struct qstr *file_name, u32 cookie,
> + const struct fsnotify_event_info *event_info,
> struct fsnotify_iter_info *iter_info);
> int (*handle_inode_event)(struct fsnotify_mark *mark, u32 mask,
> struct inode *inode, struct inode *dir,
> @@ -262,6 +277,12 @@ static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
> }
> }
>
> +static inline struct inode *fsnotify_event_info_inode(
> + const struct fsnotify_event_info *event_info)
> +{
> + return fsnotify_data_inode(event_info->data, event_info->data_type);
> +}
> +
> static inline const struct path *fsnotify_data_path(const void *data,
> int data_type)
> {
> @@ -273,6 +294,12 @@ static inline const struct path *fsnotify_data_path(const void *data,
> }
> }
>
> +static inline const struct path *fsnotify_event_info_path(
> + const struct fsnotify_event_info *event_info)
> +{
> + return fsnotify_data_path(event_info->data, event_info->data_type);
> +}
> +
> enum fsnotify_obj_type {
> FSNOTIFY_OBJ_TYPE_INODE,
> FSNOTIFY_OBJ_TYPE_PARENT,
> @@ -410,11 +437,22 @@ struct fsnotify_mark {
> /* called from the vfs helpers */
>
> /* main fsnotify call to send events */
> -extern int fsnotify(__u32 mask, const void *data, int data_type,
> - struct inode *dir, const struct qstr *name,
> - struct inode *inode, u32 cookie);
> -extern int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
> - int data_type);
> +extern int __fsnotify(__u32 mask,
> + const struct fsnotify_event_info *event_info);
> +extern int __fsnotify_parent(struct dentry *dentry, __u32 mask,
> + const void *data, int data_type);
> +
> +static inline int fsnotify(__u32 mask, const void *data, int data_type,
> + struct inode *dir, const struct qstr *name,
> + struct inode *inode, u32 cookie)
> +{
> + return __fsnotify(mask, &(struct fsnotify_event_info) {
> + .data = data, .data_type = data_type,
> + .dir = dir, .name = name, .inode = inode,
> + .cookie = cookie,
> + });
> +}
> +
> extern void __fsnotify_inode_delete(struct inode *inode);
> extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt);
> extern void fsnotify_sb_delete(struct super_block *sb);
> @@ -594,15 +632,14 @@ static inline void fsnotify_init_event(struct fsnotify_event *event)
>
> #else
>
> -static inline int fsnotify(__u32 mask, const void *data, int data_type,
> - struct inode *dir, const struct qstr *name,
> - struct inode *inode, u32 cookie)
> +static inline int fsnotify(__u32 mask,
> + const struct fsnotify_event_info *event_info)
> {
> return 0;
> }
>
> static inline int __fsnotify_parent(struct dentry *dentry, __u32 mask,
> - const void *data, int data_type)
> + const void *data, int data_type)
> {
> return 0;
> }
> --
> 2.31.0
>
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