Commit 4b09ec4b authored Jan 05, 2017 by Benjamin Coddington Committed by Trond Myklebust Jan 12, 2017

nfs: Don't take a reference on fl->fl_file for LOCK operation



I have reports of a crash that look like __fput() was called twice for
a NFSv4.0 file.  It seems possible that the state manager could try to
reclaim a lock and take a reference on the fl->fl_file at the same time the
file is being released if, during the close(), a signal interrupts the wait
for outstanding IO while removing locks which then skips the removal
of that lock.

Since 83bfff23 ("nfs4: have do_vfs_lock take an inode pointer") has
removed the need to traverse fl->fl_file->f_inode in nfs4_lock_done(),
taking that reference is no longer necessary.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

parent a121103c

fs/nfs/nfs4proc.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -38,7 +38,6 @@
		#include <linux/mm.h>
		#include <linux/delay.h>
		#include <linux/errno.h>
		#include <linux/file.h>
		#include <linux/string.h>
		#include <linux/ratelimit.h>
		#include <linux/printk.h>
		@@ -6127,7 +6126,6 @@ static struct nfs4_lockdata nfs4_alloc_lockdata(struct file_lock fl,
		p->server = server;
		atomic_inc(&lsp->ls_count);
		p->ctx = get_nfs_open_context(ctx);
		get_file(fl->fl_file);
		memcpy(&p->fl, fl, sizeof(p->fl));
		return p;
		out_free_seqid:
		@@ -6240,7 +6238,6 @@ static void nfs4_lock_release(void *calldata)
		nfs_free_seqid(data->arg.lock_seqid);
		nfs4_put_lock_state(data->lsp);
		put_nfs_open_context(data->ctx);
		fput(data->fl.fl_file);
		kfree(data);
		dprintk("%s: done!\n", __func__);
		}

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