From b4c20166dcfca106f0f416bfce200099ed76ab18 Mon Sep 17 00:00:00 2001 From: Abhijith Das Date: Thu, 13 Sep 2007 23:35:27 -0500 Subject: [GFS2] flocks from same process trip kernel BUG at fs/gfs2/glock.c:1118! This patch adds a new flag to the gfs2_holder structure GL_FLOCK. It is set on holders of glocks representing flocks. This flag is checked in add_to_queue() and a process is permitted to queue more than one holder onto a glock if it is set. This solves the issue of a process not being able to do multiple flocks on the same file. Through a single descriptor, a process can now promote and demote flocks. Through multiple descriptors a process can now queue multiple flocks on the same file. There's still the problem of a process deadlocking itself (because gfs2 blocking locks are not interruptible) by queueing incompatible deadlock. Signed-off-by: Abhijith Das Signed-off-by: Steven Whitehouse --- fs/gfs2/glock.c | 43 +++++++++++++++++++++++++------------------ 1 file changed, 25 insertions(+), 18 deletions(-) (limited to 'fs/gfs2/glock.c') diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 931368a385c8..d631cad0aeee 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1106,24 +1106,31 @@ static void add_to_queue(struct gfs2_holder *gh) if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags)) BUG(); - existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner_pid); - if (existing) { - print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip); - printk(KERN_INFO "pid : %d\n", existing->gh_owner_pid); - printk(KERN_INFO "lock type : %d lock state : %d\n", - existing->gh_gl->gl_name.ln_type, existing->gh_gl->gl_state); - print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip); - printk(KERN_INFO "pid : %d\n", gh->gh_owner_pid); - printk(KERN_INFO "lock type : %d lock state : %d\n", - gl->gl_name.ln_type, gl->gl_state); - BUG(); - } - - existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner_pid); - if (existing) { - print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip); - print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip); - BUG(); + if (!(gh->gh_flags & GL_FLOCK)) { + existing = find_holder_by_owner(&gl->gl_holders, + gh->gh_owner_pid); + if (existing) { + print_symbol(KERN_WARNING "original: %s\n", + existing->gh_ip); + printk(KERN_INFO "pid : %d\n", existing->gh_owner_pid); + printk(KERN_INFO "lock type : %d lock state : %d\n", + existing->gh_gl->gl_name.ln_type, + existing->gh_gl->gl_state); + print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip); + printk(KERN_INFO "pid : %d\n", gh->gh_owner_pid); + printk(KERN_INFO "lock type : %d lock state : %d\n", + gl->gl_name.ln_type, gl->gl_state); + BUG(); + } + + existing = find_holder_by_owner(&gl->gl_waiters3, + gh->gh_owner_pid); + if (existing) { + print_symbol(KERN_WARNING "original: %s\n", + existing->gh_ip); + print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip); + BUG(); + } } if (gh->gh_flags & LM_FLAG_PRIORITY) -- cgit v1.2.3