Introduce configurable generic interface for file system-wide event notifications to provide file systems with a common way of reporting any potential issues as they emerge. The notifications are to be issued through generic netlink interface, by a dedicated, for file system events, multicast group. The file systems might as well use this group to send their own custom messages. The events have been split into four base categories: information, warnings, errors and threshold notifications, with some very basic event types like running out of space or file system being remounted as read-only. Threshold notifications have been included to allow triggering an event whenever the amount of free space drops below a certain level - or levels to be more precise as two of them are being supported: the lower and the upper range. The notifications work both ways: once the threshold level has been reached, an event shall be generated whenever the number of available blocks goes up again re-activating the threshold. The interface has been exposed through a vfs. Once mounted, it serves as an entry point for the set-up where one can register for particular file system events. Signed-off-by: Beata Michalska <b.michalska@xxxxxxxxxxx> --- Documentation/filesystems/events.txt | 254 +++++++++++ fs/Makefile | 1 + fs/events/Makefile | 6 + fs/events/fs_event.c | 775 ++++++++++++++++++++++++++++++++++ fs/events/fs_event.h | 27 ++ fs/events/fs_event_netlink.c | 94 +++++ fs/namespace.c | 1 + include/linux/fs.h | 6 +- include/linux/fs_event.h | 69 +++ include/uapi/linux/fs_event.h | 62 +++ include/uapi/linux/genetlink.h | 1 + net/netlink/genetlink.c | 7 +- 12 files changed, 1301 insertions(+), 2 deletions(-) create mode 100644 Documentation/filesystems/events.txt create mode 100644 fs/events/Makefile create mode 100644 fs/events/fs_event.c create mode 100644 fs/events/fs_event.h create mode 100644 fs/events/fs_event_netlink.c create mode 100644 include/linux/fs_event.h create mode 100644 include/uapi/linux/fs_event.h diff --git a/Documentation/filesystems/events.txt b/Documentation/filesystems/events.txt new file mode 100644 index 0000000..c85dd88 --- /dev/null +++ b/Documentation/filesystems/events.txt @@ -0,0 +1,254 @@ + + Generic file system event notification interface + +Document created 09 April 2015 by Beata Michalska <b.michalska@xxxxxxxxxxx> + +1. The reason behind: +===================== + +There are many corner cases when things might get messy with the filesystems. +And it is not always obvious what and when went wrong. Sometimes you might +get some subtle hints that there is something going on - but by the time +you realise it, it might be too late as you are already out-of-space +or the filesystem has been remounted as read-only (i.e.). The generic +interface for the filesystem events fills the gap by providing a rather +easy way of real-time notifications triggered whenever something intreseting +happens, allowing filesystems to report events in a common way, as they occur. + +2. How does it work: +==================== + +The interface itself has been exposed as fstrace-type Virtual File System, +primarily to ease the process of setting up the configuration for the file +system notifications. So for starters it needs to get mounted (obviously): + + mount -t fstrace none /sys/fs/events + +This will unveil the single fstrace filesystem entry - the 'config' file, +through which the notification are being set-up. + +Activating notifications for particular filesystem is as straightforward +as writing into the 'config' file. Note that by default all events despite +the actual filesystem type are being disregarded. + +Synopsis of config: +------------------ + + MOUNT EVENT_TYPE [L1] [L2] + + MOUNT : the filesystem's mount point + EVENT_TYPE : type of events to be enabled: info,warn,err,thr; + at least one type needs to be specified; + note the comma delimiter and lack of spaces between + those options + L1 : the threshold limit - lower range + L2 : the threshold limit - upper range + case enabling threshold notifications the lower level is + mandatory, whereas the upper one remains optional; + note though, that as those refer to the number of available + blocks, the lower level needs to be higher than the upper one + +Sample request could look like the follwoing: + + echo /sample/mount/point warn,err,thr 710000 500000 > /sys/fs/events/config + +Multiple request might be specified provided they are separated with semicolon. + +The configuration itself might be modified at any time. One can add/remove +particilar event types for given fielsystem, modify the threshold levels, +and remove single or all entries from the 'config' file. + + - Adding new event type: + + $ echo MOUNT EVENT_TYPE > /sys/fs/events/config + +(Note that is is enough to provide the eventy type to be enabled without +the already set ones.) + + - Removing event type: + + $ echo '!MOUNT EVENT_TYPE' > /sys/fs/events/config + + - Updating threshold limits: + + $ echo MOUNT thres L1 L2 > /sys/fs/events/config + + - Removing single entry: + + $ echo '!MOUNT' > /sys/fs/events/config + + - Removing all entries: + + $ echo > /sys/fs/events/config + +Reading the file will list all registered entries with their current set-up +along with some additional info like the id of the entry (@see more on generic +netlink section), the filesystem type and the backing device name if available. + +Final, though a very important note on the configuration: when and if the +actual events are being triggered falls way beyond the scope of the generic +filesystem events interface. It is up to a particular filesystem +implementation which events are to be supported - if any at all. So if +given filesystem does not support the event notifications, an attempt to +enable those through 'config' file will fail. + + +3. The generic netlink interface support: +========================================= + +Whenever an event notification is triggered (by given filesystem) the current +configuration is being validated to decide whether a userpsace notification +should be launched. If there has been no request (in a mean of 'config' file +entry) for given event, one will be silently disreagrded. If, on the other +hand, someone is 'watching' given filesystem for specific events, a generic +netlink message will be sent. + +A dedicated multicast group has been provided solely for the purpose of +notifying any potential listeners of file system events. So in order to +receive such notifications, one should subscribe to this new mutlicast group. + +Each message type reflects the actual type of generated event (FS_EVENT_TYPE*) +Currently there are two supported message formats. + +There is a common message format representing an event generated by +a filesystem. The type of the event itself will be stored within +the generic netlink message header as the command filed. The messge +payload will provide more detailed info: the indentifier of the filesystem +trace (genereted upon registering the trace), the backing device major and +minor numbers, the event identifier and the id of the proccess which action +led to the event occurance. In case of threshold notifications, the current +number of available blocks will be included in the payload. + + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | NETLINK MESSAGE HEADER | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GENERIC NETLINK MESSAGE HEADER | + | (with event type as genlmsghdr cdm field) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Optional user specific message header | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GENERIC MESSAGE PAYLOAD: | + +---------------------------------------------------------------+ + | FS_EVENT_ATR_FS_ID (NLA_U32) | + +---------------------------------------------------------------+ + | FS_EVENT_ATR_DEV_MAJOR (NLA_U32) (if available) | + +---------------------------------------------------------------+ + | FS_EVENT_ATR_DEV_MINOR (NLA_U32) (if available) | + +---------------------------------------------------------------+ + | FS_EVENT_ATR_ID (NLA_U32) | + +---------------------------------------------------------------+ + | FS_EVENT_ATR_CAUSED_ID (NLA_U32) | + +---------------------------------------------------------------+ + | FS_EVENT_ATR_DATA (NLA_U64) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + +The second supported message format represents an event of a new trace being +registered. It contains two attributes within the payload: the trace id and the +mount point for which the trace has been registered. This message is of type +FS_EVENT_TYPE_NEW_TRACE and is being sent regardless the actual event types +being watched whenever new etnry for the 'config' file is being created. This +is supposed to ease parsing the messages by userpsace applications and to help +to identify the origin of the event. It also reduces the size of the payload +as there is no need to send additional data such as mount point and the file +system type for each possible event. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | NETLINK MESSAGE HEADER | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GENERIC NETLINK MESSAGE HEADER | + | (with event type as genlmsghdr cdm field) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Optional user specific message header | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | GENERIC MESSAGE PAYLOAD: | + + ------------------------------------------------------------- + + | FS_EVENT_ATR_FS_ID (NLA_U32) | + + ------------------------------------------------------------- + + | FS_EVENT_ATR_MOUNT (NLA_STRING) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +The above figures are based on: + http://www.linuxfoundation.org/collaborate/workgroups/networking/generic_netlink_howto#Message_Format + + + +4. API Reference: +================= + + 4.1 Generic file system event interface operations + + #include <linux/fs_event.h> + + struct fs_trace_operations { + int (*fs_trace_query)(struct super_block *, struct fs_trace_sdata *); + }; + + Each filesystem supporting the event notifications should register its + file system trace operations. This can be done through new entry in + the super_block structure: the s_trace_ops. The fs_trace_query shall + be called whenever new trace entry for given filesystem is being created + or when threshold notifications are being requested for the first time. + The filesystem should specify then, which event types are being supported. + In case of threshold notifications the current number of avaialble blocks + should be provided. + + 4.2 Event notification: + + #include <linux/fs_event.h> + void fs_event_notify(struct super_block *sb, unsigned int event_type, + unsigned int event_id); + + Notify the generic FS event interface of an occuring event. + This shall be used by any file system that wishes to inform any potenial + listeners/watchers of a particular event. + - sb: the filesystem's super block + - event_type: the type of an event (one of the FS_EVENT_*) + - event_id: an event identifier + + 4.3 Threshold notifications: + + #include <linux/fs_event.h> + void fs_event_alloc_space(struct super_block *sb, u64 ncount); + void fs_event_free_space(struct super_block *sb, u64 ncount); + + Each filesystme supporting the treshold notifiactions should call + fs_event_alloc_space/fs_event_free_space repsectively whenever the + ammount of availbale blocks changes. + - sb: the filesystem's super block + - ncount: number of blocks being acquired/released + + Note that to properly handle the treshold notifiactions the fs events + interface needs to be keept up to date by the filesystems. Each should + register fs_trace_operations to enable querying the basic trace data, + among which, is the current number of the available blocks (fs_trace_query). + + 4.4 Sending message through generic netlink interface + + #include <linux/fs_event.h> + int fs_netlink_send_event(size_t size, unsigned int event_type, + int (*compose_msg)(struct sk_buff *skb, unsigned int event_id, + void *data), + unsigned int event_id, void *data); + + Although the fs event interface is fully responsible for sending the messages + over the netlink, filesystems might use the FS_EVENT mutlicast group to send + their own custom messages. + - size: the size of the message payload + - event_type: the type of an event: stored as message header's command + - compose_msg: a custom callback handling composing the message payload + - event_id: the event identifier + - data: message custom data + + Calling fs_netlink_send_event will result in a message being sent through + the FS_EVENT muslicast group. Note that the body of the message should be + prepared (set-up )by the caller - through compose_msg callback. The message's + sk_buff will be allocated on behalf of the caller (thus the size parameter). + The compose_msg should only fill the payload with proper data. + + diff --git a/fs/Makefile b/fs/Makefile index a88ac48..798021d 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -126,3 +126,4 @@ obj-y += exofs/ # Multiple modules obj-$(CONFIG_CEPH_FS) += ceph/ obj-$(CONFIG_PSTORE) += pstore/ obj-$(CONFIG_EFIVAR_FS) += efivarfs/ +obj-y += events/ diff --git a/fs/events/Makefile b/fs/events/Makefile new file mode 100644 index 0000000..58d1454 --- /dev/null +++ b/fs/events/Makefile @@ -0,0 +1,6 @@ +# +# Makefile for the Linux Generic File System Event Interface +# + +obj-y := fs_event.o +obj-$(CONFIG_NET) += fs_event_netlink.o diff --git a/fs/events/fs_event.c b/fs/events/fs_event.c new file mode 100644 index 0000000..8ebe371 --- /dev/null +++ b/fs/events/fs_event.c @@ -0,0 +1,775 @@ +/* + * Generic File System Events Interface + * + * Copyright(c) 2015 Samsung Electronics. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2. + * + * The full GNU General Public License is included in this distribution in the + * file called COPYING. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include <linux/fs.h> +#include <linux/hashtable.h> +#include <linux/idr.h> +#include <linux/module.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/parser.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <net/genetlink.h> +#include "../mount.h" +#include "fs_event.h" + +#define FS_HASHTB_BITS 8 +#define FS_HASHTB_SIZE (1 << FS_HASHTB_BITS) + +/** + * The FS event trace entries are being stored in a hashtable + * for fast entry look-up, and in a doubly-linked list + * to ease all the paths that need to go through all + * the entries. + */ +static DEFINE_HASHTABLE(fs_trace_hashtbl, FS_HASHTB_BITS); +static LIST_HEAD(fs_trace_list); +static DEFINE_SPINLOCK(fs_trace_lock); + +static struct kmem_cache *fs_trace_cachep __read_mostly; + +/* + * Each registered FS event trace is being marked with + * a unique identifier managed by IDR + */ +static struct idr fs_trace_idr; +static DEFINE_SPINLOCK(fs_trace_idr_lock); + +/* + * Threshold notification state bits. + * Note the reverse as this refers to the number + * of available blocks. + */ +#define THRESH_LR_BELOW 0x0001 /* Falling below the lower range */ +#define THRESH_LR_BEYOND 0x0002 +#define THRESH_UR_BELOW 0x0004 +#define THRESH_UR_BEYOND 0x0008 /* Going beyond the upper range */ + +#define THRESH_LR_ON (THRESH_LR_BELOW | THRESH_LR_BEYOND) +#define THRESH_UR_ON (THRESH_UR_BELOW | THRESH_UR_BEYOND) + +#define FS_TRACE_ADD 0x100000 + +struct fs_trace_entry { + struct list_head node; + struct hlist_node hnode; + struct path path; + struct fs_trace_sdata data; + int mark; + unsigned int notify_mask; + struct fs_event_thresh { + u64 lrange; + u64 urange; + unsigned int state; + } thresh; + spinlock_t lock; +}; + +static const match_table_t fs_etypes = { + { FS_EVENT_INFO, "info" }, + { FS_EVENT_WARN, "warn" }, + { FS_EVENT_THRESH, "thr" }, + { FS_EVENT_ERR, "err" }, + { 0, NULL }, +}; + +#define fs_trace_sb(en) ((en)->path.mnt->mnt_sb) + +#define fs_trace_query_data(sb, arg) \ + (((sb)->s_trace_ops && (sb)->s_trace_ops->fs_trace_query) ? \ + (sb)->s_trace_ops->fs_trace_query((sb), arg) : -EINVAL) + +#define fs_event_type_cast(event_type) (ffs(event_type)) + +static inline unsigned int fs_trace_hasfn(const struct super_block *sb) +{ + return ((unsigned long)sb >> L1_CACHE_SHIFT) & (FS_HASHTB_SIZE - 1); +} + +static struct fs_trace_entry *fs_find_trace_entry(struct super_block *sb) +{ + struct fs_trace_entry *en; + unsigned long hash; + + if (list_empty(&fs_trace_list)) + return ERR_PTR(-EINVAL); + hash = fs_trace_hasfn(sb); + hash_for_each_possible(fs_trace_hashtbl, en, hnode, hash) + if (fs_trace_sb(en) == sb) + return en; + return ERR_PTR(-EINVAL); +} + +static inline void fs_trace_entry_list_del(struct fs_trace_entry *en) +{ + spin_lock(&en->lock); + list_del(&en->node); + hash_del(&en->hnode); + spin_unlock(&en->lock); +} + +static inline void fs_trace_entry_idr_remove(struct fs_trace_entry *en) +{ + spin_lock(&fs_trace_idr_lock); + idr_remove(&fs_trace_idr, en->mark); + spin_unlock(&fs_trace_idr_lock); +} + +static inline void fs_trace_entry_free(struct fs_trace_entry *en) +{ + kmem_cache_free(fs_trace_cachep, en); +} + +static inline void fs_destroy_trace_entry(struct fs_trace_entry *en) +{ + fs_trace_entry_list_del(en); + fs_trace_entry_idr_remove(en); + fs_trace_entry_free(en); +} + +static int fs_remove_trace_entry(struct super_block *sb) +{ + struct fs_trace_entry *en; + int ret = -EINVAL; + + spin_lock(&fs_trace_lock); + en = fs_find_trace_entry(sb); + if (!IS_ERR(en)) { + fs_destroy_trace_entry(en); + ret = 0; + } + spin_unlock(&fs_trace_lock); + return ret; +} + +static void fs_remove_all_traces(void) +{ + struct fs_trace_entry *en, *guard; + + spin_lock(&fs_trace_lock); + list_for_each_entry_safe(en, guard, &fs_trace_list, node) + fs_destroy_trace_entry(en); + spin_unlock(&fs_trace_lock); +} + +static int fs_event_new_trace_create_msg(struct sk_buff *skb, + unsigned int event_id, void *data) +{ + struct fs_trace_entry *en = (struct fs_trace_entry *)data; + char *path, *mount_dir; + int ret; + + path = kzalloc(PATH_MAX, GFP_KERNEL); + if (!path) + return -EINVAL; + mount_dir = d_path(&en->path, path, PATH_MAX - 1); + if (IS_ERR(mount_dir)) + mount_dir = "unknown"; + + ret = nla_put_u32(skb, FS_EVENT_ATR_FS_ID, en->mark); + if (ret) + goto leave; + ret = nla_put_string(skb, FS_EVENT_ATR_MOUNT, mount_dir); + +leave: + kfree(path); + return ret; +} + +static int fs_event_common_create_msg(struct sk_buff *skb, + unsigned int event_id, void *data) +{ + struct fs_trace_entry *en = (struct fs_trace_entry *)data; + struct super_block *sb = fs_trace_sb(en); + + if (nla_put_u32(skb, FS_EVENT_ATR_FS_ID, en->mark)) + return -EINVAL; + + /* In case there is no backing dev, so skip the followng */ + if (sb->s_bdev && MAJOR(sb->s_dev)) + if (nla_put_u32(skb, FS_EVENT_ATR_DEV_MAJOR, MAJOR(sb->s_dev)) + || nla_put_u32(skb, FS_EVENT_ATR_DEV_MINOR, MINOR(sb->s_dev))) + return -EINVAL; + + if (nla_put_u32(skb, FS_EVENT_ATR_ID, event_id)) + return -EINVAL; + if (nla_put_u64(skb, FS_EVENT_ATR_CAUSED_ID, pid_nr(task_pid(current)))) + return -EINVAL; + + if (event_id & (FS_THRESH_LR_REACHED | FS_THRESH_UR_REACHED)) + return nla_put_u64(skb, FS_EVENT_ATR_DATA, + en->data.available_blks); + + return 0; +} + +static void fs_event_new_trace(struct fs_trace_entry *en) +{ + fs_netlink_send_event(GENLMSG_DEFAULT_SIZE, FS_EVENT_TYPE_NEW_TRACE, + fs_event_new_trace_create_msg, 0, en); +} + +static void fs_event_send(struct fs_trace_entry *en, + unsigned int event_type, unsigned int event_id) +{ + size_t size = nla_total_size(sizeof(u32)) * 4 + + nla_total_size(sizeof(u64)) * 2; + + fs_netlink_send_event(size, fs_event_type_cast(event_type), + fs_event_common_create_msg, event_id, en); +} + +void fs_event_notify(struct super_block *sb, unsigned int event_type, + unsigned int event_id) +{ + struct fs_trace_entry *en; + + spin_lock(&fs_trace_lock); + en = fs_find_trace_entry(sb); + if (IS_ERR(en)) { + spin_unlock(&fs_trace_lock); + return; + } + + spin_lock(&en->lock); + /* Relase the main lock - it's enough to keep the entry lock here */ + spin_unlock(&fs_trace_lock); + if (en->notify_mask & event_type) + fs_event_send(en, event_type, event_id); + spin_unlock(&en->lock); +} +EXPORT_SYMBOL(fs_event_notify); + +void fs_event_alloc_space(struct super_block *sb, u64 ncount) +{ + struct fs_trace_entry *en; + s64 count; + + spin_lock(&fs_trace_lock); + en = fs_find_trace_entry(sb); + if (IS_ERR(en)) { + spin_unlock(&fs_trace_lock); + return; + } + + spin_lock(&en->lock); + spin_unlock(&fs_trace_lock); + + if (!(en->notify_mask & FS_EVENT_THRESH)) + goto leave; + /* we shouldn't drop below 0 here, unless there is a sync issue + somewhere (?) */ + count = en->data.available_blks - ncount; + en->data.available_blks = count < 0 ? 0 : count; + + if (en->data.available_blks > en->thresh.lrange) + /* Not 'even' close - leave */ + goto leave; + + if (en->data.available_blks > en->thresh.urange) { + /* Close enough - the lower range has been reached */ + if (!(en->thresh.state & THRESH_LR_BEYOND)) { + /* Send notificaton */ + fs_event_send(en, FS_EVENT_THRESH, + FS_THRESH_LR_REACHED); + en->thresh.state &= ~THRESH_LR_BELOW; + en->thresh.state |= THRESH_LR_BEYOND; + } + goto leave; + } + if (!(en->thresh.state & THRESH_UR_BEYOND)) { + fs_event_send(en, FS_EVENT_THRESH, FS_THRESH_UR_REACHED); + en->thresh.state &= ~THRESH_UR_BELOW; + en->thresh.state |= THRESH_UR_BEYOND; + } + +leave: + spin_unlock(&en->lock); +} +EXPORT_SYMBOL(fs_event_alloc_space); + +void fs_event_free_space(struct super_block *sb, u64 ncount) +{ + struct fs_trace_entry *en; + + spin_lock(&fs_trace_lock); + en = fs_find_trace_entry(sb); + if (IS_ERR(en)) { + spin_unlock(&fs_trace_lock); + return; + } + + spin_lock(&en->lock); + spin_unlock(&fs_trace_lock); + + if (!(en->notify_mask & FS_EVENT_THRESH)) + goto leave; + + en->data.available_blks += ncount; + + if (en->data.available_blks > en->thresh.lrange) { + if (!(en->thresh.state & THRESH_LR_BELOW) + && en->thresh.state & THRESH_LR_BEYOND) { + /* Send notificaton */ + fs_event_send(en, FS_EVENT_THRESH, + FS_THRESH_LR_REACHED); + en->thresh.state &= ~THRESH_LR_BEYOND; + en->thresh.state |= THRESH_LR_BELOW; + goto leave; + } + } + if (en->data.available_blks > en->thresh.urange) { + if (!(en->thresh.state & THRESH_UR_BELOW) + && en->thresh.state & THRESH_UR_BEYOND) { + /* Notify */ + fs_event_send(en, FS_EVENT_THRESH, + FS_THRESH_UR_REACHED); + en->thresh.state &= ~THRESH_UR_BEYOND; + en->thresh.state |= THRESH_UR_BELOW; + } + } +leave: + spin_unlock(&en->lock); +} +EXPORT_SYMBOL(fs_event_free_space); + +void fs_event_mount_dropped(struct vfsmount *mnt) +{ + struct fs_trace_entry *en; + + spin_lock(&fs_trace_lock); + en = fs_find_trace_entry(mnt->mnt_sb); + if (!IS_ERR(en)) { + spin_lock(&en->lock); + if (en->notify_mask & FS_EVENT_INFO) + fs_event_send(en, FS_EVENT_TYPE_INFO, FS_INFO_UMOUNT); + spin_unlock(&en->lock); + fs_destroy_trace_entry(en); + } + spin_unlock(&fs_trace_lock); +} + +static int fs_new_trace_entry(struct path *path, struct fs_event_thresh *thresh, + unsigned int nmask) +{ + struct fs_trace_entry *en; + struct super_block *sb; + struct mount *r_mnt; + + en = kmem_cache_zalloc(fs_trace_cachep, GFP_KERNEL); + if (unlikely(!en)) + return -ENOMEM; + /* + * Note that no reference is being taken here for the path as it would + * make the umount unnecessarily puzzling (due to an extra 'valid' + * reference for the mnt). + * This is *rather* safe as the notification on mount being dropped + * will get called prior to releasing the super block - so right + * in time to send the event and perform appropraite clean-up + */ + r_mnt = real_mount(path->mnt); + en->path.dentry = r_mnt->mnt.mnt_root; + en->path.mnt = &r_mnt->mnt; + + sb = fs_trace_sb(en); + spin_lock_init(&en->lock); + + spin_lock(&fs_trace_idr_lock); + idr_preload(GFP_KERNEL); + en->mark = idr_alloc_cyclic(&fs_trace_idr, en, 1, 0, GFP_KERNEL); + idr_preload_end(); + spin_unlock(&fs_trace_idr_lock); + + if (en->mark < 0) + goto leave; + if (fs_trace_query_data(sb, &en->data)) + goto leave; + + nmask = en->data.events_cap_mask & nmask; + if (!nmask) + goto leave; + en->notify_mask = nmask; + memcpy(&en->thresh, thresh, offsetof(struct fs_event_thresh, state)); + + spin_lock(&fs_trace_lock); + list_add(&en->node, &fs_trace_list); + hash_add(fs_trace_hashtbl, &en->hnode, fs_trace_hasfn(sb)); + spin_unlock(&fs_trace_lock); + + fs_event_new_trace(en); + return 0; +leave: + kmem_cache_free(fs_trace_cachep, en); + return -EINVAL; +} + +static int fs_update_trace_entry_locked(struct fs_trace_entry *en, + struct fs_event_thresh *thresh, + unsigned int nmask) +{ + int extend = nmask & FS_TRACE_ADD; + + nmask &= en->data.events_cap_mask; + if (!nmask) + return -EINVAL; + + if (nmask & FS_EVENT_THRESH) { + if (extend) { + /* Get the current state */ + if (!(en->notify_mask & FS_EVENT_THRESH)) + fs_trace_query_data(fs_trace_sb(en), + &en->data); + if (thresh->state & THRESH_LR_ON) { + en->thresh.lrange = thresh->lrange; + en->thresh.state &= ~THRESH_LR_ON; + } + if (thresh->state & THRESH_UR_ON) { + en->thresh.urange = thresh->urange; + en->thresh.state &= ~THRESH_UR_ON; + } + } else { + memset(&en->thresh, 0, sizeof(en->thresh)); + } + } + + if (extend) + en->notify_mask |= nmask; + else + en->notify_mask &= ~nmask; + return 0; +} + +static int fs_update_trace_entry(struct path *path, + struct fs_event_thresh *thresh, + unsigned int nmask) +{ + struct fs_trace_entry *en; + int ret; + + spin_lock(&fs_trace_lock); + en = fs_find_trace_entry(path->mnt->mnt_sb); + if (IS_ERR(en)) { + spin_unlock(&fs_trace_lock); + return (nmask & FS_TRACE_ADD) + ? fs_new_trace_entry(path, thresh, nmask) + : -EINVAL; + } + spin_lock(&en->lock); + spin_unlock(&fs_trace_lock); + + ret = fs_update_trace_entry_locked(en, thresh, nmask); + + spin_unlock(&en->lock); + return ret; +} + +static int fs_parse_trace_request(int argc, char **argv) +{ + struct fs_event_thresh thresh = {0}; + struct path path; + substring_t args[MAX_OPT_ARGS]; + unsigned int nmask = FS_TRACE_ADD; + int token; + char *s; + int ret = -EINVAL; + + if (!argc) { + fs_remove_all_traces(); + return 0; + } + + s = *(argv++); + if (*s == '!') { + /* Clear the trace entry */ + nmask &= ~FS_TRACE_ADD; + ++s; + } + + if (kern_path_mountpoint(AT_FDCWD, s, &path, LOOKUP_FOLLOW)) + return -EINVAL; + + if (!(--argc)) { + if (!(nmask & FS_TRACE_ADD)) + ret = fs_remove_trace_entry(path.mnt->mnt_sb); + goto leave; + } + + while ((s = strsep(argv, ",")) != NULL) { + if (!*s) + continue; + args[0].to = args[0].from = NULL; + token = match_token(s, fs_etypes, args); + nmask |= (token & FS_EVENTS_ALL); + } + + if (!(nmask & (~FS_TRACE_ADD)) || + (!(--argc) && (nmask & FS_EVENT_THRESH && nmask & FS_TRACE_ADD))) + goto leave; + + if ((nmask & FS_EVENT_THRESH) && (nmask & FS_TRACE_ADD)) { + /* + * Get the threshold config data: + * lower range + * upper range + */ + ret = kstrtoull(*(++argv), 10, &thresh.lrange); + if (ret) + goto leave; + + thresh.state |= THRESH_LR_ON; + + if ((--argc)) { + ret = kstrtoull(*(++argv), 10, &thresh.urange); + if (ret) + goto leave; + thresh.state |= THRESH_UR_ON; + } + /* The thresholds are based on number of available blocks */ + if (thresh.lrange < thresh.urange) { + ret = -EINVAL; + goto leave; + } + + } + ret = fs_update_trace_entry(&path, &thresh, nmask); +leave: + path_put(&path); + return ret; +} + +#define DEFAULT_BUF_SIZE PAGE_SIZE + +static ssize_t fs_trace_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + char **argv; + char *kern_buf, *next, *cfg; + size_t size, dcount = 0; + int argc; + + if (!count) + return 0; + + kern_buf = kmalloc(DEFAULT_BUF_SIZE, GFP_KERNEL); + if (!kern_buf) + return -ENOMEM; + + while (dcount < count) { + + size = count - dcount; + if (size >= DEFAULT_BUF_SIZE) + size = DEFAULT_BUF_SIZE - 1; + if (copy_from_user(kern_buf, buffer + dcount, size)) { + dcount = -EINVAL; + goto leave; + } + + kern_buf[size] = '\0'; + + next = cfg = kern_buf; + + do { + next = strchr(cfg, ';'); + if (next) + *next = '\0'; + + argv = argv_split(GFP_KERNEL, cfg, &argc); + if (!argv) { + dcount = -ENOMEM; + goto leave; + } + + if (fs_parse_trace_request(argc, argv)) { + dcount = -EINVAL; + argv_free(argv); + goto leave; + } + + argv_free(argv); + if (next) + cfg = ++next; + + } while (next); + dcount += size; + } +leave: + kfree(kern_buf); + return dcount; +} + +static void *fs_trace_seq_start(struct seq_file *m, loff_t *pos) +{ + spin_lock(&fs_trace_lock); + return seq_list_start(&fs_trace_list, *pos); +} + +static void *fs_trace_seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + return seq_list_next(v, &fs_trace_list, pos); +} + +static void fs_trace_seq_stop(struct seq_file *m, void *v) +{ + spin_unlock(&fs_trace_lock); +} + +static int fs_trace_seq_show(struct seq_file *m, void *v) +{ + struct fs_trace_entry *en; + struct super_block *sb; + struct mount *r_mnt; + const struct match_token *match; + unsigned int nmask; + + en = list_entry(v, struct fs_trace_entry, node); + sb = fs_trace_sb(en); + + seq_printf(m, "%d ", en->mark); + + seq_path(m, &en->path, "\t\n\\"); + seq_putc(m, ' '); + + seq_escape(m, sb->s_type->name, " \t\n\\"); + if (sb->s_subtype && sb->s_subtype[0]) { + seq_putc(m, '.'); + seq_escape(m, sb->s_subtype, " \t\n\\"); + } + + seq_putc(m, ' '); + if (sb->s_op->show_devname) { + sb->s_op->show_devname(m, en->path.mnt->mnt_root); + } else { + r_mnt = real_mount(en->path.mnt); + seq_escape(m, r_mnt->mnt_devname ? r_mnt->mnt_devname : "none", + " \t\n\\"); + } + seq_puts(m, " ("); + + nmask = en->notify_mask; + for (match = fs_etypes; match->pattern; ++match) { + if (match->token & nmask) { + seq_puts(m, match->pattern); + nmask &= ~match->token; + if (nmask) + seq_putc(m, ','); + } + } + seq_printf(m, " %llu %llu", en->thresh.lrange, + en->thresh.urange); + seq_puts(m, ")\n"); + return 0; +} + +static const struct seq_operations fs_trace_seq_ops = { + .start = fs_trace_seq_start, + .next = fs_trace_seq_next, + .stop = fs_trace_seq_stop, + .show = fs_trace_seq_show, +}; + +static int fs_trace_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &fs_trace_seq_ops); +} + +static const struct file_operations fs_trace_fops = { + .owner = THIS_MODULE, + .open = fs_trace_open, + .write = fs_trace_write, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static int fs_trace_init(void) +{ + fs_trace_cachep = KMEM_CACHE(fs_trace_entry, 0); + if (!fs_trace_cachep) + return -EINVAL; + if (!fs_event_netlink_register()) { + idr_init(&fs_trace_idr); + return 0; + } + kmem_cache_destroy(fs_trace_cachep); + return -EINVAL; +} + +/* VFS support */ +static int fs_trace_fill_super(struct super_block *sb, void *data, int silent) +{ + int ret; + static struct tree_descr desc[] = { + [2] = { + .name = "config", + .ops = &fs_trace_fops, + .mode = S_IWUSR | S_IRUGO, + }, + {""}, + }; + + ret = simple_fill_super(sb, 0x7246332, desc); + return !ret ? fs_trace_init() : ret; +} + +static struct dentry *fs_trace_do_mount(struct file_system_type *fs_type, + int ntype, const char *dev_name, void *data) +{ + return mount_single(fs_type, ntype, data, fs_trace_fill_super); +} + +static void fs_trace_kill_super(struct super_block *sb) +{ + fs_remove_all_traces(); + idr_destroy(&fs_trace_idr); + fs_event_netlink_unregister(); + kmem_cache_destroy(fs_trace_cachep); + kill_litter_super(sb); +} + +static struct kset *fs_trace_kset; +static struct vfsmount *fs_trace_mount; + +static struct file_system_type fs_trace_fstype = { + .name = "fstrace", + .mount = fs_trace_do_mount, + .kill_sb = fs_trace_kill_super, +}; + +static void __init fs_trace_vfs_init(void) +{ + fs_trace_kset = kset_create_and_add("events", NULL, fs_kobj); + + if (!fs_trace_kset) + return; + + if (!register_filesystem(&fs_trace_fstype)) { + fs_trace_mount = kern_mount(&fs_trace_fstype); + if (!IS_ERR(fs_trace_mount)) + return; + + unregister_filesystem(&fs_trace_fstype); + } + kset_unregister(fs_trace_kset); +} + +static int __init fs_trace_events_init(void) +{ + fs_trace_vfs_init(); + return 0; +}; +module_init(fs_trace_events_init); + diff --git a/fs/events/fs_event.h b/fs/events/fs_event.h new file mode 100644 index 0000000..4260ce5 --- /dev/null +++ b/fs/events/fs_event.h @@ -0,0 +1,27 @@ +/* + * Copyright(c) 2015 Samsung Electronics. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2. + * + * The full GNU General Public License is included in this distribution in the + * file called COPYING. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#ifndef __GENERIC_FS_EVENTS_H +#define __GENERIC_FS_EVENTS_H + +#ifdef CONFIG_NET +int fs_event_netlink_register(void); +void fs_event_netlink_unregister(void); +#else /* CONFIG_NET */ +static inline int fs_event_netlink_register(void) { return -ENOSYS; } +static inline void fs_event_netlink_unregister(void) {}; +#endif /* CONFIG_NET */ + +#endif /* __GENERIC_FS_EVENTS_H */ diff --git a/fs/events/fs_event_netlink.c b/fs/events/fs_event_netlink.c new file mode 100644 index 0000000..9c56e35 --- /dev/null +++ b/fs/events/fs_event_netlink.c @@ -0,0 +1,94 @@ +/* + * Copyright(c) 2015 Samsung Electronics. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2. + * + * The full GNU General Public License is included in this distribution in the + * file called COPYING. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <net/netlink.h> +#include <net/genetlink.h> + +static const struct genl_multicast_group fs_event_mcgroups[] = { + { .name = "event", }, +}; + +static struct genl_family fs_event_family = { + .id = GENL_ID_FS_EVENT, + .hdrsize = 0, + .name = "FS_EVENT", + .version = 1, + .maxattr = FS_EVENT_ATR_MAX, + .mcgrps = fs_event_mcgroups, + .n_mcgrps = ARRAY_SIZE(fs_event_mcgroups), +}; + +int fs_netlink_send_event(size_t size, unsigned int event_type, + int (*compose_msg)(struct sk_buff *skb, + unsigned int event_id, void *data), + unsigned int event_id, void *data) +{ + static atomic_t seq; + struct sk_buff *skb; + void *msg_head; + int ret = 0; + + if (!size || !compose_msg) + return -EINVAL; + + size += nla_total_size(sizeof(u64)); + skb = genlmsg_new(size, GFP_NOFS); + + if (!skb) { + pr_err("Failed to allocate new FS generic netlink message\n"); + return -ENOMEM; + } + + msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq), + &fs_event_family, 0, event_type); + if (!msg_head) + goto cleanup; + + ret = compose_msg(skb, event_id, data); + if (ret) { + genlmsg_cancel(skb, msg_head); + goto cleanup; + } + + genlmsg_end(skb, msg_head); + ret = genlmsg_multicast(&fs_event_family, skb, 0, 0, GFP_NOWAIT); + if (ret && ret != -ENOBUFS && ret != -ESRCH) + goto cleanup; + + return ret; +cleanup: + nlmsg_free(skb); + return ret; +} +EXPORT_SYMBOL(fs_netlink_send_event); + +int fs_event_netlink_register(void) +{ + int ret; + + ret = genl_register_family(&fs_event_family); + if (ret) + pr_err("Failed to register FS netlink interface\n"); + return ret; +} + +void fs_event_netlink_unregister(void) +{ + genl_unregister_family(&fs_event_family); +} diff --git a/fs/namespace.c b/fs/namespace.c index 82ef140..ec6e2ef 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1031,6 +1031,7 @@ static void cleanup_mnt(struct mount *mnt) if (unlikely(mnt->mnt_pins.first)) mnt_pin_kill(mnt); fsnotify_vfsmount_delete(&mnt->mnt); + fs_event_mount_dropped(&mnt->mnt); dput(mnt->mnt.mnt_root); deactivate_super(mnt->mnt.mnt_sb); mnt_free_id(mnt); diff --git a/include/linux/fs.h b/include/linux/fs.h index b4d71b5..bb529af 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -263,6 +263,10 @@ struct iattr { * Includes for diskquotas. */ #include <linux/quota.h> +/* + * Include for Generic File System Events Interface + */ +#include <linux/fs_event.h> /* * Maximum number of layers of fs stack. Needs to be limited to @@ -1233,6 +1237,7 @@ struct super_block { const struct dquot_operations *dq_op; const struct quotactl_ops *s_qcop; const struct export_operations *s_export_op; + const struct fs_trace_operations *s_trace_ops; unsigned long s_flags; unsigned long s_magic; struct dentry *s_root; @@ -1253,7 +1258,6 @@ struct super_block { struct hlist_node s_instances; unsigned int s_quota_types; /* Bitmask of supported quota types */ struct quota_info s_dquot; /* Diskquota specific options */ - struct sb_writers s_writers; char s_id[32]; /* Informational name */ diff --git a/include/linux/fs_event.h b/include/linux/fs_event.h new file mode 100644 index 0000000..1e128d8 --- /dev/null +++ b/include/linux/fs_event.h @@ -0,0 +1,69 @@ +/* + * Generic File System Events Interface + * + * Copyright(c) 2015 Samsung Electronics. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2. + * + * The full GNU General Public License is included in this distribution in the + * file called COPYING. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#ifndef _LINUX_GENERIC_FS_EVETS_ +#define _LINUX_GENERIC_FS_EVETS_ +#include <net/netlink.h> +#include <uapi/linux/fs_event.h> + +/* + * Those event flags match the event types send though the netlink interface + * so mind in case making any modifications. + */ +#define FS_EVENT_INFO 0x001 +#define FS_EVENT_WARN 0x002 +#define FS_EVENT_ERR 0x004 +#define FS_EVENT_THRESH 0x008 + +#define FS_EVENTS_ALL \ + (FS_EVENT_INFO | FS_EVENT_WARN | FS_EVENT_THRESH | FS_EVENT_ERR) + +struct fs_trace_sdata { + /* Supported notification types */ + unsigned int events_cap_mask; + /* Number of available/reachable blocks */ + u64 available_blks; +}; + +struct fs_trace_operations { + int (*fs_trace_query)(struct super_block *, struct fs_trace_sdata *); +}; + + +void fs_event_notify(struct super_block *sb, unsigned int event_type, + unsigned int event_id); +void fs_event_alloc_space(struct super_block *sb, u64 ncount); +void fs_event_free_space(struct super_block *sb, u64 ncount); +void fs_event_mount_dropped(struct vfsmount *mnt); + +#ifdef CONFIG_NET +int fs_netlink_send_event(size_t size, unsigned int event_type, + int (*compose_msg)(struct sk_buff *skb, unsigned int event_id, + void *data), + unsigned int event_id, void *data); +#else /* CONFIG_NET */ +static inline +int fs_netlink_send_event(size_t size, unsigned int event_type, + int (*compose_msg)(struct sk_buff *skb, unsigned int event_id, + void *data), + unsigned int event_idid, void *data) +{ + return -ENOSYS; +} +#endif /* CONFIG_NET */ + +#endif /* _LINUX_GENERIC_FS_EVENTS_ */ + diff --git a/include/uapi/linux/fs_event.h b/include/uapi/linux/fs_event.h new file mode 100644 index 0000000..dd79953 --- /dev/null +++ b/include/uapi/linux/fs_event.h @@ -0,0 +1,62 @@ +/* + * Generic netlink support for Generic File System Events Interface + * + * Copyright(c) 2015 Samsung Electronics. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2. + * + * The full GNU General Public License is included in this distribution in the + * file called COPYING. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#ifndef _UAPI_LINUX_GENERIC_FS_EVENTS_ +#define _UAPI_LINUX_GENERIC_FS_EVENTS_ +/* + * Generic FS event types + */ +enum { + FS_EVENT_TYPE_NONE, + FS_EVENT_TYPE_INFO, + FS_EVENT_TYPE_WARN, + FS_EVENT_TYPE_ERR, + FS_EVENT_TYPE_THRESH, + FS_EVENT_TYPE_NEW_TRACE, + __FS_EVENT_TYPE_MAX, +}; +#define FS_EVENT_TYPE_MAX (__FS_EVENT_TYPE_MAX - 1) +/* + * Generic netlink attribute types + */ +enum { + FS_EVENT_ATR_NONE, + FS_EVENT_ATR_FS_ID, /* An identifier of traced fs */ + FS_EVENT_ATR_MOUNT, /* Mount point directory name */ + FS_EVENT_ATR_DEV_MAJOR, + FS_EVENT_ATR_DEV_MINOR, + FS_EVENT_ATR_ID, + FS_EVENT_ATR_CAUSED_ID, + FS_EVENT_ATR_DATA, + __FS_EVENT_ATR_MAX, +}; +#define FS_EVENT_ATR_MAX (__FS_EVENT_ATR_MAX - 1) + +/* + * Supported set of FS events ids + */ +#define FS_INFO_UMOUNT 0x00000001 /* File system unmounted */ +#define FS_WARN_UNKNOWN 0x00000004 /* Unknown warning */ +#define FS_WARN_ENOSPC 0x00000008 /* No space left to reserve data blks */ +#define FS_WANR_ENOSPC_META 0x00000010 /* No space left for metadata */ +#define FS_THRESH_LR_REACHED 0x00000020 /* The lower range of threshold has been reached */ +#define FS_THRESH_UR_REACHED 0x00000040 /* The upper range of threshold has been reached */ +#define FS_ERR_UNKNOWN 0x00000080 /* Unknown error */ +#define FS_ERR_RO_REMOUT 0x00000100 /* The file system has been remounted as red-only */ +#define FS_ERR_ITERNAL 0x00000200 /* File system's internal error */ + +#endif /* _UAPI_LINUX_GENERIC_FS_EVENTS_ */ + diff --git a/include/uapi/linux/genetlink.h b/include/uapi/linux/genetlink.h index c3363ba..6464129 100644 --- a/include/uapi/linux/genetlink.h +++ b/include/uapi/linux/genetlink.h @@ -29,6 +29,7 @@ struct genlmsghdr { #define GENL_ID_CTRL NLMSG_MIN_TYPE #define GENL_ID_VFS_DQUOT (NLMSG_MIN_TYPE + 1) #define GENL_ID_PMCRAID (NLMSG_MIN_TYPE + 2) +#define GENL_ID_FS_EVENT (NLMSG_MIN_TYPE + 3) /************************************************************************** * Controller diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 2ed5f96..e8e0bd68 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -82,7 +82,8 @@ static struct list_head family_ht[GENL_FAM_TAB_SIZE]; */ static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | BIT(GENL_ID_VFS_DQUOT) | - BIT(GENL_ID_PMCRAID); + BIT(GENL_ID_PMCRAID) | + BIT(GENL_ID_FS_EVENT); static unsigned long *mc_groups = &mc_group_start; static unsigned long mc_groups_longs = 1; @@ -146,6 +147,7 @@ static u16 genl_generate_id(void) for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) { if (id_gen_idx != GENL_ID_VFS_DQUOT && id_gen_idx != GENL_ID_PMCRAID && + id_gen_idx != GENL_ID_FS_EVENT && !genl_family_find_byid(id_gen_idx)) return id_gen_idx; if (++id_gen_idx > GENL_MAX_ID) @@ -249,6 +251,9 @@ static int genl_validate_assign_mc_groups(struct genl_family *family) } else if (family->id == GENL_ID_PMCRAID) { first_id = GENL_ID_PMCRAID; BUG_ON(n_groups != 1); + } else if (family->id == GENL_ID_FS_EVENT) { + first_id = GENL_ID_FS_EVENT; + BUG_ON(n_groups != 1); } else { groups_allocated = true; err = genl_allocate_reserve_groups(n_groups, &first_id); -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>