NFSv4 fix CLOSE not waiting for direct IO compeletion (d03727b2) · Commits · 戴 / test

Figuring out the root case for the REMOVE/CLOSE race and suggesting the solution was done by Neil Brown. Currently what happens is that direct IO calls hold a reference on the open context which is decremented as an asynchronous task in the nfs_direct_complete(). Before reference is decremented, control is returned to the application which is free to close the file. When close is being processed, it decrements its reference on the open_context but since directIO still holds one, it doesn't sent a close on the wire. It returns control to the application which is free to do other operations. For instance, it can delete a file. Direct IO is finally releasing its reference and triggering an asynchronous close. Which races with the REMOVE. On the server, REMOVE can be processed before the CLOSE, failing the REMOVE with EACCES as the file is still opened. Signed-off-by:

Olga Kornievskaia <kolga@netapp.com> Suggested-by:

Neil Brown <neilb@suse.com> CC: stable@vger.kernel.org Signed-off-by:

Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/direct.c

+9 −4

Original line number	Diff line number	Diff line
		@@ -267,8 +267,6 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq)
		{
		struct inode *inode = dreq->inode;

		inode_dio_end(inode);

		if (dreq->iocb) {
		long res = (long) dreq->error;
		if (dreq->count != 0) {
		@@ -280,7 +278,10 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq)

		complete(&dreq->completion);

		igrab(inode);
		nfs_direct_req_release(dreq);
		inode_dio_end(inode);
		iput(inode);
		}

		static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
		@@ -410,8 +411,10 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
		* generic layer handle the completion.
		*/
		if (requested_bytes == 0) {
		inode_dio_end(inode);
		igrab(inode);
		nfs_direct_req_release(dreq);
		inode_dio_end(inode);
		iput(inode);
		return result < 0 ? result : -EIO;
		}

		@@ -864,8 +867,10 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
		* generic layer handle the completion.
		*/
		if (requested_bytes == 0) {
		inode_dio_end(inode);
		igrab(inode);
		nfs_direct_req_release(dreq);
		inode_dio_end(inode);
		iput(inode);
		return result < 0 ? result : -EIO;
		}

fs/nfs/file.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -83,6 +83,7 @@ nfs_file_release(struct inode inode, struct file filp)
		dprintk("NFS: release(%pD2)\n", filp);

		nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
		inode_dio_wait(inode);
		nfs_file_clear_open_context(filp);
		return 0;
		}

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