From 8689a5027c7cfb8ee25318127262fbc974662d26 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 20 Feb 2018 13:23:38 +1100 Subject: [PATCH] staging: lustre: fid: fix up debugfs access to ->lcs_space 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 Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lustre/lustre/fid/lproc_fid.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/staging/lustre/lustre/fid/lproc_fid.c b/drivers/staging/lustre/lustre/fid/lproc_fid.c index e05487662afd..a1e5bf9f36ec 100644 --- a/drivers/staging/lustre/lustre/fid/lproc_fid.c +++ b/drivers/staging/lustre/lustre/fid/lproc_fid.c @@ -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); - seq_printf(m, "[%#llx - %#llx]:%x:%s\n", PRANGE(&seq->lcs_space)); + 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 -- GitLab