On 04/15/2015 09:25 PM, Darrick J. Wong wrote: > 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". That actually varies. For netlink message attributes it is smt more like *_NL_A_*. Nevertheless, I'm totally fine with possibly renaming those. > >> + >> +/* >> + * 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? That's me misspelling. > >> +#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"? > FS_ERR_ITERNAL is supposed to mean smth than can not be easily translated into generic event code - so smth that is specific for given file system type. > How about a separate FS_ERR_CORRUPTED to mean "go run fsck"? Sounds like a good idea. > > Hmm, these are bit flags... it doesn't make sense that I can send things like > FS_INFO_UMOUNT | FS_ERR_RO_REMOUT. > You can but you shouldn't. Possibly some sanity checks could be added for such cases. I was thinking of possibly merging events for the same file system and sending them in one go - so a single message could contain multiple events. Though this requires some more thoughts. BR Beata >> + >> +#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
