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Commit e64be33c authored by Ian Kent's avatar Ian Kent Committed by Linus Torvalds
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autofs4: check kernel communication pipe is valid for write 



It is possible for an autofs mount to become catatonic (and for the daemon
communication pipe to become NULL) after a wait has been initiallized but
before the request has been sent to the daemon.  We need to check for this
before sending the request packet.

Signed-off-by: default avatarIan Kent <raven@themaw.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f4c7da02

fs/autofs4/waitq.c

+14 −2
Original line number Diff line number Diff line
@@ -99,6 +99,7 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi, 
		union autofs_packet_union v4_pkt;

		union autofs_v5_packet_union v5_pkt;

	} pkt;

	struct file *pipe = NULL;

	size_t pktsz;



	DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
@@ -164,8 +165,19 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi, 
		return;

	}



	if (autofs4_write(sbi->pipe, &pkt, pktsz))

	/* Check if we have become catatonic */

	mutex_lock(&sbi->wq_mutex);

	if (!sbi->catatonic) {

		pipe = sbi->pipe;

		get_file(pipe);

	}

	mutex_unlock(&sbi->wq_mutex);



	if (pipe) {

		if (autofs4_write(pipe, &pkt, pktsz))

			autofs4_catatonic_mode(sbi);

		fput(pipe);

	}

}



static int autofs4_getpath(struct autofs_sb_info *sbi,