On Wed, Apr 15, 2015 at 09:15:44AM +0200, Beata Michalska wrote: > 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) FS_EVENT_ATTR_ ? Most of the time, the kernel seems to use "attr" as shorthand for "attribute". > + > +/* > + * 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 */ Why WANR, as opposed to WARN? > +#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 */ _REMOUNT... read-only... > +#define FS_ERR_ITERNAL 0x00000200 /* File system's internal error */ _INTERNAL... What does FS_ERR_ITERNAL mean? "programming error"? How about a separate FS_ERR_CORRUPTED to mean "go run fsck"? Hmm, these are bit flags... it doesn't make sense that I can send things like FS_INFO_UMOUNT | FS_ERR_RO_REMOUT. > + > +#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 from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
