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 <neilb@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -106,28 +106,35 @@ ldebugfs_fid_space_seq_write(struct file *file,
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rc = ldebugfs_fid_write_common(buffer, count, &range);
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spin_lock(&seq->lcs_lock);
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if (seq->lcs_update)
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/* An RPC call is active to update lcs_space */
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rc = -EBUSY;
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if (rc > 0)
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seq->lcs_space = range;
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spin_unlock(&seq->lcs_lock);
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if (rc == 0) {
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if (rc > 0) {
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CDEBUG(D_INFO, "%s: Space: " DRANGE "\n",
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seq->lcs_name, PRANGE(&range));
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}
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return count;
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return rc;
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}
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static int
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ldebugfs_fid_space_seq_show(struct seq_file *m, void *unused)
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{
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struct lu_client_seq *seq = (struct lu_client_seq *)m->private;
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int rc = 0;
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spin_lock(&seq->lcs_lock);
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seq_printf(m, "[%#llx - %#llx]:%x:%s\n", PRANGE(&seq->lcs_space));
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if (seq->lcs_update)
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rc = -EBUSY;
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else
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seq_printf(m, "[%#llx - %#llx]:%x:%s\n", PRANGE(&seq->lcs_space));
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spin_unlock(&seq->lcs_lock);
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return 0;
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return rc;
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}
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static ssize_t
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