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fsnotify: pass optional file access range in pre-content event

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We would like to add file range information to pre-content events.

Pass a struct file_range with offset and length to event handler
along with pre-content permission event.

The offset and length are aligned to page size, but we may need to
align them to minimum folio size for filesystems with large block size.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/88eddee301231d814aede27fb4d5b41ae37c9702.1731684329.git.josef@toxicpanda.com
This commit is contained in:
Amir Goldstein 2024-11-15 10:30:21 -05:00 committed by Jan Kara
parent f156524e5d
commit 9740d17162
5 changed files with 71 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
fs/notify/fanotify/fanotify.c
View File

@ -548,9 +548,13 @@ static struct fanotify_event *fanotify_alloc_path_event(const struct path *path,
return &pevent->fae;
}
static struct fanotify_event *fanotify_alloc_perm_event(const struct path *path,
static struct fanotify_event *fanotify_alloc_perm_event(const void *data,
int data_type,
gfp_t gfp)
{
const struct path *path = fsnotify_data_path(data, data_type);
const struct file_range *range =
fsnotify_data_file_range(data, data_type);
struct fanotify_perm_event *pevent;
pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp);
@ -564,6 +568,9 @@ static struct fanotify_event *fanotify_alloc_perm_event(const struct path *path,
pevent->hdr.len = 0;
pevent->state = FAN_EVENT_INIT;
pevent->path = *path;
/* NULL ppos means no range info */
pevent->ppos = range ? &range->pos : NULL;
pevent->count = range ? range->count : 0;
path_get(path);
return &pevent->fae;
@ -801,7 +808,7 @@ static struct fanotify_event *fanotify_alloc_event(
old_memcg = set_active_memcg(group->memcg);
if (fanotify_is_perm_event(mask)) {
event = fanotify_alloc_perm_event(path, gfp);
event = fanotify_alloc_perm_event(data, data_type, gfp);
} else if (fanotify_is_error_event(mask)) {
event = fanotify_alloc_error_event(group, fsid, data,
data_type, &hash);

2
fs/notify/fanotify/fanotify.h
View File

@ -425,6 +425,8 @@ FANOTIFY_PE(struct fanotify_event *event)
struct fanotify_perm_event {
struct fanotify_event fae;
struct path path;
const loff_t *ppos; /* optional file range info */
size_t count;
u32 response; /* userspace answer to the event */
unsigned short state; /* state of the event */
int fd; /* fd we passed to userspace for this event */

18
fs/notify/fsnotify.c
View File

@ -203,6 +203,24 @@ static inline bool fsnotify_object_watched(struct inode *inode, __u32 mnt_mask,
return mask & marks_mask & ALL_FSNOTIFY_EVENTS;
}
/* Report pre-content event with optional range info */
int fsnotify_pre_content(const struct path *path, const loff_t *ppos,
size_t count)
{
struct file_range range;
/* Report page aligned range only when pos is known */
if (!ppos)
return fsnotify_path(path, FS_PRE_ACCESS);
range.path = path;
range.pos = PAGE_ALIGN_DOWN(*ppos);
range.count = PAGE_ALIGN(*ppos + count) - range.pos;
return fsnotify_parent(path->dentry, FS_PRE_ACCESS, &range,
FSNOTIFY_EVENT_FILE_RANGE);
}
/*
* Notify this dentry's parent about a child's events with child name info
* if parent is watching or if inode/sb/mount are interested in events with

4
include/linux/fsnotify.h
View File

@ -154,7 +154,7 @@ static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
* read()/write() and other types of access generate pre-content events.
*/
if (unlikely(FMODE_FSNOTIFY_HSM(file->f_mode))) {
int ret = fsnotify_path(&file->f_path, FS_PRE_ACCESS);
int ret = fsnotify_pre_content(&file->f_path, ppos, count);
if (ret)
return ret;
@ -171,7 +171,7 @@ static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
}
/*
* fsnotify_file_perm - permission hook before file access
* fsnotify_file_perm - permission hook before file access (unknown range)
*/
static inline int fsnotify_file_perm(struct file *file, int perm_mask)
{

40
include/linux/fsnotify_backend.h
View File

@ -294,6 +294,7 @@ static inline void fsnotify_group_assert_locked(struct fsnotify_group *group)
/* When calling fsnotify tell it if the data is a path or inode */
enum fsnotify_data_type {
FSNOTIFY_EVENT_NONE,
FSNOTIFY_EVENT_FILE_RANGE,
FSNOTIFY_EVENT_PATH,
FSNOTIFY_EVENT_INODE,
FSNOTIFY_EVENT_DENTRY,
@ -306,6 +307,17 @@ struct fs_error_report {
struct super_block *sb;
};
struct file_range {
const struct path *path;
loff_t pos;
size_t count;
};
static inline const struct path *file_range_path(const struct file_range *range)
{
return range->path;
}
static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
{
switch (data_type) {
@ -315,6 +327,8 @@ static inline struct inode *fsnotify_data_inode(const void *data, int data_type)
return d_inode(data);
case FSNOTIFY_EVENT_PATH:
return d_inode(((const struct path *)data)->dentry);
case FSNOTIFY_EVENT_FILE_RANGE:
return d_inode(file_range_path(data)->dentry);
case FSNOTIFY_EVENT_ERROR:
return ((struct fs_error_report *)data)->inode;
default:
@ -330,6 +344,8 @@ static inline struct dentry *fsnotify_data_dentry(const void *data, int data_typ
return (struct dentry *)data;
case FSNOTIFY_EVENT_PATH:
return ((const struct path *)data)->dentry;
case FSNOTIFY_EVENT_FILE_RANGE:
return file_range_path(data)->dentry;
default:
return NULL;
}
@ -341,6 +357,8 @@ static inline const struct path *fsnotify_data_path(const void *data,
switch (data_type) {
case FSNOTIFY_EVENT_PATH:
return data;
case FSNOTIFY_EVENT_FILE_RANGE:
return file_range_path(data);
default:
return NULL;
}
@ -356,6 +374,8 @@ static inline struct super_block *fsnotify_data_sb(const void *data,
return ((struct dentry *)data)->d_sb;
case FSNOTIFY_EVENT_PATH:
return ((const struct path *)data)->dentry->d_sb;
case FSNOTIFY_EVENT_FILE_RANGE:
return file_range_path(data)->dentry->d_sb;
case FSNOTIFY_EVENT_ERROR:
return ((struct fs_error_report *) data)->sb;
default:
@ -375,6 +395,18 @@ static inline struct fs_error_report *fsnotify_data_error_report(
}
}
static inline const struct file_range *fsnotify_data_file_range(
const void *data,
int data_type)
{
switch (data_type) {
case FSNOTIFY_EVENT_FILE_RANGE:
return (struct file_range *)data;
default:
return NULL;
}
}
/*
* Index to merged marks iterator array that correlates to a type of watch.
* The type of watched object can be deduced from the iterator type, but not
@ -863,9 +895,17 @@ static inline void fsnotify_init_event(struct fsnotify_event *event)
{
INIT_LIST_HEAD(&event->list);
}
int fsnotify_pre_content(const struct path *path, const loff_t *ppos,
size_t count);
#else
static inline int fsnotify_pre_content(const struct path *path,
const loff_t *ppos, size_t count)
{
return 0;
}
static inline int fsnotify(__u32 mask, const void *data, int data_type,
struct inode *dir, const struct qstr *name,
struct inode *inode, u32 cookie)