staging: lustre: fid: fix up debugfs access to ->lcs_space (8689a502) · Commits · 戴 / test

lcs_space can change while the lock is not held if an RPC in underway. This can be detected by seq->ls_update being set. In this case, reading or writing the value should return -EBUSY. Also, the D_INFO CDEBUG() which reports the lcs_space being updated never fires, as it tests the wrong value - ldebugfs_fid_write_common() returns 'count' on success. Finally, this return value should be returned from ldebugfs_fid_space_seq_write(), rather than always returning 'count', so that errors can be detected. Signed-off-by:

NeilBrown <neilb@suse.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/fid/lproc_fid.c

+11 −4

Original line number	Diff line number	Diff line
		@@ -106,28 +106,35 @@ ldebugfs_fid_space_seq_write(struct file *file,
		rc = ldebugfs_fid_write_common(buffer, count, &range);

		spin_lock(&seq->lcs_lock);
		if (seq->lcs_update)
		/* An RPC call is active to update lcs_space */
		rc = -EBUSY;
		if (rc > 0)
		seq->lcs_space = range;
		spin_unlock(&seq->lcs_lock);

		if (rc == 0) {
		if (rc > 0) {
		CDEBUG(D_INFO, "%s: Space: " DRANGE "\n",
		seq->lcs_name, PRANGE(&range));
		}

		return count;
		return rc;
		}

		static int
		ldebugfs_fid_space_seq_show(struct seq_file m, void unused)
		{
		struct lu_client_seq seq = (struct lu_client_seq )m->private;
		int rc = 0;

		spin_lock(&seq->lcs_lock);
		if (seq->lcs_update)
		rc = -EBUSY;
		else
		seq_printf(m, "[%#llx - %#llx]:%x:%s\n", PRANGE(&seq->lcs_space));
		spin_unlock(&seq->lcs_lock);

		return 0;
		return rc;
		}

		static ssize_t

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