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SubjectRe: [RFC 0/4] Generic file system events interface

Hi,

On 04/17/2015 10:17 AM, Jan Kara wrote:
> Hello,
>
> On Wed 15-04-15 09:15:43, Beata Michalska wrote:
>> The following patchset is a result of previous discussions regarding
>> file system threshold notifiactions. It introduces support for file
>> system event notifications, sent through generic netlinik interface
>> whenever an fs-related event occurs. Included are also some shmem
>> and ext4 changes showing how the new interface might actually be used.
>>
>> The vary idea of using the generic netlink interface has been previoulsy
>> suggested here: https://lkml.org/lkml/2011/8/18/169
>>
>> The basic description of the new functionality can be found in
>> the first patch from this set - both in the commit message and
>> in the doc file.
>>
>> Some very basic tests have been performed though still this is
>> a PoC version. Below though is a sample user space application
>> which subscribes to the new multicast group and listens for
>> potential fs-related events. The code has been based on libnl 3.4
>> and its test application for the generic netlink.
> Thanks for the patches! As a general note for the next posting, please CC
> also linux-fsdevel@vger.kernel.org (since this has implications for other
> filesystems as well, specifically I know about XFS guys thinking about some
> notification system as well) and linux-api@vger.kernel.org (since this is a
> new kernel interface to userspace).
>
> Honza

My bad - with the CC list. Apologies for that.

BR
Beata

>>
>> ---
>>
>> Beata Michalska (4):
>> fs: Add generic file system event notifications
>> ext4: Add helper function to mark group as corrupted
>> ext4: Add support for generic FS events
>> shmem: Add support for generic FS events
>>
>> 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/ext4/balloc.c | 26 +-
>> fs/ext4/ext4.h | 10 +
>> fs/ext4/ialloc.c | 5 +-
>> fs/ext4/inode.c | 2 +-
>> fs/ext4/mballoc.c | 17 +-
>> fs/ext4/resize.c | 1 +
>> fs/ext4/super.c | 43 ++
>> 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 +
>> mm/shmem.c | 39 +-
>> net/netlink/genetlink.c | 7 +-
>> 20 files changed, 1412 insertions(+), 34 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
>>
>> ---
>> Sample application:
>>
>> #include <netlink/cli/utils.h>
>> #include <fs_event.h>
>>
>> #define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
>> #define LOG(args...) fprintf(stderr, args)
>>
>> static int parse_info(struct nl_cache_ops *unused, struct genl_cmd *cmd,
>> struct genl_info *info, void *arg)
>> {
>> LOG("New trace %d:\n",
>> info->attrs[FS_EVENT_ATR_FS_ID]
>> ? nla_get_u32(info->attrs[FS_EVENT_ATR_FS_ID])
>> : -1);
>> LOG("Mout point: %s\n", info->attrs[FS_EVENT_ATR_MOUNT]
>> ? nla_get_string(info->attrs[FS_EVENT_ATR_MOUNT])
>> : "unknown");
>> return 0;
>> }
>>
>> static int parse_thres(struct nl_cache_ops *unused, struct genl_cmd *cmd,
>> struct genl_info *info, void *arg)
>> {
>>
>> LOG("Threshold notification received for trace %d:\n",
>> info->attrs[FS_EVENT_ATR_FS_ID]
>> ? nla_get_u32(info->attrs[FS_EVENT_ATR_FS_ID])
>> : -1);
>>
>> if (info->attrs[FS_EVENT_ATR_DEV_MAJOR])
>> LOG("Backing dev major: %u\n",
>> nla_get_u32(info->attrs[FS_EVENT_ATR_DEV_MAJOR]));
>> if (info->attrs[FS_EVENT_ATR_DEV_MINOR])
>> LOG("Backing dev minor: %u\n",
>> nla_get_u32(info->attrs[FS_EVENT_ATR_DEV_MINOR]));
>> LOG("Proc: %u\n", info->attrs[FS_EVENT_ATR_CAUSED_ID] ?
>> nla_get_u32(info->attrs[FS_EVENT_ATR_CAUSED_ID]) : -1);
>> LOG("Threshold data: %llu\n", info->attrs[FS_EVENT_ATR_DATA]
>> ? nla_get_u64(info->attrs[FS_EVENT_ATR_DATA])
>> : 0);
>>
>> return 0;
>> }
>>
>> static int parse_warning(struct nl_cache_ops *unused, struct genl_cmd *cmd,
>> struct genl_info *info, void *arg)
>> {
>>
>> LOG("Warning recieved for trace %d\n", info->attrs[FS_EVENT_ATR_FS_ID] ?
>> nla_get_u32(info->attrs[FS_EVENT_ATR_FS_ID]) : -1);
>> if (info->attrs[FS_EVENT_ATR_DEV_MAJOR])
>> LOG("Backing dev major: %u\n",
>> nla_get_u32(info->attrs[FS_EVENT_ATR_DEV_MAJOR]));
>> if (info->attrs[FS_EVENT_ATR_DEV_MINOR])
>> LOG("Backing dev minor: %u\n",
>> nla_get_u32(info->attrs[FS_EVENT_ATR_DEV_MINOR]));
>> LOG("Proc: %u\n", info->attrs[FS_EVENT_ATR_CAUSED_ID] ?
>> nla_get_u32(info->attrs[FS_EVENT_ATR_CAUSED_ID]) : -1);
>> LOG("Warning: %u\n", info->attrs[FS_EVENT_ATR_ID] ?
>> nla_get_u32(info->attrs[FS_EVENT_ATR_ID]) : -1);
>>
>> return 0;
>> }
>>
>> static struct genl_cmd cmd[] = {
>> {
>> .c_id = FS_EVENT_TYPE_NEW_TRACE,
>> .c_name = "info",
>> .c_maxattr = 2,
>> .c_msg_parser = parse_info,
>> }, {
>> .c_id = FS_EVENT_TYPE_THRESH,
>> .c_name = "thres",
>> .c_maxattr = 6,
>> .c_msg_parser = parse_thres,
>> }, {
>> .c_id = FS_EVENT_TYPE_WARN,
>> .c_name = "warn",
>> .c_maxattr = 5,
>> .c_msg_parser = parse_warning,
>> },
>> };
>>
>> static struct genl_ops ops = {
>> .o_id = GENL_ID_FS_EVENT,
>> .o_name = "FS_EVENT",
>> .o_hdrsize = 0,
>> .o_cmds = cmd,
>> .o_ncmds = ARRAY_SIZE(cmd),
>> };
>>
>>
>> int events_cb(struct nl_msg *msg, void *arg)
>> {
>> return genl_handle_msg(msg, arg);
>> }
>>
>> int main(int argc, char **argv)
>> {
>> struct nl_sock *sock;
>> int ret;
>>
>> sock = nl_cli_alloc_socket();
>> nl_socket_set_local_port(sock, 0);
>> nl_socket_disable_seq_check(sock);
>>
>> nl_socket_modify_cb(sock, NL_CB_VALID, NL_CB_CUSTOM, events_cb, NULL);
>>
>> nl_cli_connect(sock, NETLINK_GENERIC);
>>
>> if ((ret = nl_socket_add_membership(sock, GENL_ID_FS_EVENT))) {
>> LOG("Failed to add membership\n");
>> goto leave;
>> }
>>
>> if((ret = genl_register_family(&ops))) {
>> LOG("Failed to register protocol family\n");
>> goto leave;
>> }
>>
>> if ((ret = genl_ops_resolve(sock, &ops) < 0)) {
>> LOG("Unable to resolve the family name\n");
>> goto leave;
>> }
>>
>> if (genl_ctrl_resolve(sock, "FS_EVENT") < 0) {
>> LOG("Failed to resolve the family name\n");
>> goto leave;
>> }
>>
>> while (1) {
>> if ((ret = nl_recvmsgs_default(sock)) < 0)
>> LOG("Unable to receive message: %s\n", nl_geterror(ret));
>> }
>>
>> leave:
>> nl_close(sock);
>> nl_socket_free(sock);
>> return 0;
>> }
>>
>> --
>> 1.7.9.5
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html



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