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Date: Mon, 16 Aug 2021 15:18:50 +0200
From: Jan Kara <jack@...e.cz>
To: Gabriel Krisman Bertazi <krisman@...labora.com>
Cc: amir73il@...il.com, jack@...e.com, linux-api@...r.kernel.org,
linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
khazhy@...gle.com, dhowells@...hat.com, david@...morbit.com,
tytso@....edu, djwong@...nel.org, repnop@...gle.com,
kernel@...labora.com
Subject: Re: [PATCH v6 05/21] fanotify: Split superblock marks out to a new
cache
On Thu 12-08-21 17:39:54, Gabriel Krisman Bertazi wrote:
> 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 <amir73il@...il.com>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@...e.cz>
Honza
> ---
> Changes since v5:
> - turn the flag bits into defines (jan)
> - don't use zalloc for consistency (jan)
> 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 | 20 ++++++++++++++++
> fs/notify/fanotify/fanotify_user.c | 38 ++++++++++++++++++++++++++++--
> 3 files changed, 64 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..3b11dd03df59 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 +130,25 @@ static inline void fanotify_info_copy_name(struct fanotify_info *info,
> name->name);
> }
>
> +enum fanotify_mark_bits {
> + FANOTIFY_MARK_FLAG_BIT_SB_MARK = FSN_MARK_PRIVATE_FLAGS,
> +};
> +
> +#define FANOTIFY_MARK_FLAG_SB_MARK \
> + (1 << FANOTIFY_MARK_FLAG_BIT_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..c47a5a45c0d3 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_alloc(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
>
--
Jan Kara <jack@...e.com>
SUSE Labs, CR
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