2021-07-20 16:13:34

by Gabriel Krisman Bertazi

[permalink] [raw]
Subject: [PATCH v4 05/16] fanotify: Split superblock marks out to a new cache

FAN_FS_ERROR will require an error structure to be stored per mark.
But, since FAN_FS_ERROR doesn't apply to inode/mount marks, it should
suffice to only expose this information for superblock marks. Therefore,
wrap this kind of marks into a container and plumb it for the future.

Reviewed-by: Amir Goldstein <[email protected]>
Signed-off-by: Gabriel Krisman Bertazi <[email protected]>

---
Changes since v2:
- Move mark initialization to fanotify_alloc_mark (Amir)

Changes since v1:
- Only extend superblock marks (Amir)
---
fs/notify/fanotify/fanotify.c | 10 ++++++--
fs/notify/fanotify/fanotify.h | 23 ++++++++++++++++++
fs/notify/fanotify/fanotify_user.c | 38 ++++++++++++++++++++++++++++--
3 files changed, 67 insertions(+), 4 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 310246f8d3f1..c3eefe3f6494 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -869,9 +869,15 @@ static void fanotify_freeing_mark(struct fsnotify_mark *mark,
dec_ucount(group->fanotify_data.ucounts, UCOUNT_FANOTIFY_MARKS);
}

-static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
+static void fanotify_free_mark(struct fsnotify_mark *mark)
{
- kmem_cache_free(fanotify_mark_cache, fsn_mark);
+ if (mark->flags & FANOTIFY_MARK_FLAG_SB_MARK) {
+ struct fanotify_sb_mark *fa_mark = FANOTIFY_SB_MARK(mark);
+
+ kmem_cache_free(fanotify_sb_mark_cache, fa_mark);
+ } else {
+ kmem_cache_free(fanotify_mark_cache, mark);
+ }
}

const struct fsnotify_ops fanotify_fsnotify_ops = {
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 4a5e555dc3d2..c548b96472dd 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -6,6 +6,7 @@
#include <linux/hashtable.h>

extern struct kmem_cache *fanotify_mark_cache;
+extern struct kmem_cache *fanotify_sb_mark_cache;
extern struct kmem_cache *fanotify_fid_event_cachep;
extern struct kmem_cache *fanotify_path_event_cachep;
extern struct kmem_cache *fanotify_perm_event_cachep;
@@ -129,6 +130,28 @@ static inline void fanotify_info_copy_name(struct fanotify_info *info,
name->name);
}

+#define FANOTIFY_MARK_FLAG(flag) \
+static const unsigned int FANOTIFY_MARK_FLAG_##flag = \
+ (1 << FANOTIFY_MARK_FLAG_BIT_##flag)
+
+enum fanotify_mark_bits {
+ FANOTIFY_MARK_FLAG_BIT_SB_MARK = FSN_MARK_PRIVATE_FLAGS,
+};
+
+FANOTIFY_MARK_FLAG(SB_MARK);
+
+struct fanotify_sb_mark {
+ struct fsnotify_mark fsn_mark;
+};
+
+static inline
+struct fanotify_sb_mark *FANOTIFY_SB_MARK(struct fsnotify_mark *mark)
+{
+ WARN_ON(!(mark->flags & FANOTIFY_MARK_FLAG_SB_MARK));
+
+ return container_of(mark, struct fanotify_sb_mark, fsn_mark);
+}
+
/*
* Common structure for fanotify events. Concrete structs are allocated in
* fanotify_handle_event() and freed when the information is retrieved by
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 67b18dfe0025..0696f2121781 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -99,6 +99,7 @@ struct ctl_table fanotify_table[] = {
extern const struct fsnotify_ops fanotify_fsnotify_ops;

struct kmem_cache *fanotify_mark_cache __read_mostly;
+struct kmem_cache *fanotify_sb_mark_cache __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;
@@ -915,6 +916,38 @@ static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
return mask & ~oldmask;
}

+static struct fsnotify_mark *fanotify_alloc_mark(struct fsnotify_group *group,
+ unsigned int type)
+{
+ struct fanotify_sb_mark *sb_mark;
+ struct fsnotify_mark *mark;
+
+ switch (type) {
+ case FSNOTIFY_OBJ_TYPE_SB:
+ sb_mark = kmem_cache_zalloc(fanotify_sb_mark_cache, GFP_KERNEL);
+ if (!sb_mark)
+ return NULL;
+ mark = &sb_mark->fsn_mark;
+ break;
+
+ case FSNOTIFY_OBJ_TYPE_INODE:
+ case FSNOTIFY_OBJ_TYPE_PARENT:
+ case FSNOTIFY_OBJ_TYPE_VFSMOUNT:
+ mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
+ break;
+ default:
+ WARN_ON(1);
+ return NULL;
+ }
+
+ fsnotify_init_mark(mark, group);
+
+ if (type == FSNOTIFY_OBJ_TYPE_SB)
+ mark->flags |= FANOTIFY_MARK_FLAG_SB_MARK;
+
+ return mark;
+}
+
static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
fsnotify_connp_t *connp,
unsigned int type,
@@ -933,13 +966,12 @@ static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
!inc_ucount(ucounts->ns, ucounts->uid, UCOUNT_FANOTIFY_MARKS))
return ERR_PTR(-ENOSPC);

- mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
+ mark = fanotify_alloc_mark(group, type);
if (!mark) {
ret = -ENOMEM;
goto out_dec_ucounts;
}

- fsnotify_init_mark(mark, group);
ret = fsnotify_add_mark_locked(mark, connp, type, 0, fsid);
if (ret) {
fsnotify_put_mark(mark);
@@ -1497,6 +1529,8 @@ static int __init fanotify_user_setup(void)

fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
SLAB_PANIC|SLAB_ACCOUNT);
+ fanotify_sb_mark_cache = KMEM_CACHE(fanotify_sb_mark,
+ SLAB_PANIC|SLAB_ACCOUNT);
fanotify_fid_event_cachep = KMEM_CACHE(fanotify_fid_event,
SLAB_PANIC);
fanotify_path_event_cachep = KMEM_CACHE(fanotify_path_event,
--
2.32.0