Re: [systemd-devel] About autofs: no handling of expire??
On Wed, 02.05.12 07:45, Stef Bon (stef...@gmail.com) wrote:
Hi,
I've been looking into the code how systemd handles the automounting.
Heya,
I've got two issues:
a. I've found the handling of the missing packet
(autofs_ptype_missing_direct), which triggers the
mounting. But I did not found the handling of the expire packet
(autofs_ptype_expire_direct). Is this on purpose?
I see a timeout set, so I guess it was the intention to handle the
expire.
We currently don't do expiration, since this wasn't intended as a full
autofs implementation, but just a way to parallelize and delay load
things at boot.
That said, we could support expire easily I guess, and so I have now
added this to the TODO list.
b. the packet read from the pipe is of type union
autofs_v5_packet_union which looks like:
union autofs_v5_packet_union {
struct autofs_packet_hdr hdr;
struct autofs_v5_packet v5_packet;
autofs_packet_missing_indirect_t missing_indirect;
autofs_packet_expire_indirect_t expire_indirect;
autofs_packet_missing_direct_t missing_direct;
autofs_packet_expire_direct_t expire_direct;
};
where autofs_v5_packet is:
struct autofs_v5_packet {
struct autofs_packet_hdr hdr;
autofs_wqt_t wait_queue_token;
__u32 dev;
__u64 ino;
__u32 uid;
__u32 gid;
__u32 pid;
__u32 tgid;
__u32 len;
char name[NAME_MAX+1];
};
now in the code of automount_fd_event, the selection is based upon
packet.hdr.type, and futher the fields
packet.v5_packet.pid are used. Now this while packet is an union: it's
used as hdr OR as autofs_v5_packet, not both at the same time.
It works, so here probably happens something strange: while using the
field packet.hdr, actually the field packet.v5_packet.hdr is used. Is
this correct?
In Autofs5 all packets have the same format which exposes
pid. i.e. autofs_packet_xxx_yyy_t are all typedef'ed to the same packet
struct. Hence accessing this this way is safe.
Lennart
--
Lennart Poettering - Red Hat, Inc.
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Re: [systemd-devel] About autofs: no handling of expire??
2012/5/2 Lennart Poettering lenn...@poettering.net: (autofs_ptype_expire_direct). Is this on purpose? I see a timeout set, so I guess it was the intention to handle the expire. We currently don't do expiration, since this wasn't intended as a full autofs implementation, but just a way to parallelize and delay load things at boot. That said, we could support expire easily I guess, and so I have now added this to the TODO list. Well you do not have to. I'm just asking. It works, so here probably happens something strange: while using the field packet.hdr, actually the field packet.v5_packet.hdr is used. Is this correct? In Autofs5 all packets have the same format which exposes pid. i.e. autofs_packet_xxx_yyy_t are all typedef'ed to the same packet struct. Hence accessing this this way is safe. Well yes every autofs packet starts with a header. If it's a autofsv5 pakket, it also starts with a header. Probably because it's the first struct in the union AND the first field part of autofs_v5_packet, it works. I'm just checking the code and see I understand it to write my own autofs implementation using FUSE. The FUSE fs will somehow be what now is the browseable map with indirect maps with the automounter, and somehow I have to find a way to make a specific directory a direct autofs mountpoint. Thanks, Stef Bon ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] About autofs: no handling of expire??
Hi,
I've been looking into the code how systemd handles the automounting.
I've got two issues:
a. I've found the handling of the missing packet
(autofs_ptype_missing_direct), which triggers the
mounting. But I did not found the handling of the expire packet
(autofs_ptype_expire_direct). Is this on purpose?
I see a timeout set, so I guess it was the intention to handle the expire.
b. the packet read from the pipe is of type union
autofs_v5_packet_union which looks like:
union autofs_v5_packet_union {
struct autofs_packet_hdr hdr;
struct autofs_v5_packet v5_packet;
autofs_packet_missing_indirect_t missing_indirect;
autofs_packet_expire_indirect_t expire_indirect;
autofs_packet_missing_direct_t missing_direct;
autofs_packet_expire_direct_t expire_direct;
};
where autofs_v5_packet is:
struct autofs_v5_packet {
struct autofs_packet_hdr hdr;
autofs_wqt_t wait_queue_token;
__u32 dev;
__u64 ino;
__u32 uid;
__u32 gid;
__u32 pid;
__u32 tgid;
__u32 len;
char name[NAME_MAX+1];
};
now in the code of automount_fd_event, the selection is based upon
packet.hdr.type, and futher the fields
packet.v5_packet.pid are used. Now this while packet is an union: it's
used as hdr OR as autofs_v5_packet, not both at the same time.
It works, so here probably happens something strange: while using the
field packet.hdr, actually the field packet.v5_packet.hdr is used. Is
this correct?
Stef
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