mdadm/0004-Incremental-Simplify-remove-logic.patch

From b9888145987e273a7613209721a68f75e060263e Mon Sep 17 00:00:00 2001
From: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
Date: Tue, 5 Nov 2024 13:07:16 +0100
Subject: [PATCH 04/37] Incremental: Simplify remove logic

Incremental_remove() does not execute Manage_subdevs() now.

Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
---
 Incremental.c | 116 ++++++++++++++++++++++++++++++++------------------
 Manage.c      |  10 ++---
 mdadm.h       |   1 +
 sysfs.c       |  23 ++++++++++
 4 files changed, 102 insertions(+), 48 deletions(-)

diff --git a/Incremental.c b/Incremental.c
index 60d6f8cb..228d2bdd 100644
--- a/Incremental.c
+++ b/Incremental.c
@@ -1610,22 +1610,6 @@ release:
 	return rv;
 }
 
-static void remove_from_member_array(struct mdstat_ent *memb,
-				    struct mddev_dev *devlist, int verbose)
-{
-	int subfd = open_dev(memb->devnm);
-
-	if (subfd >= 0) {
-		/*
-		 * Ignore the return value because it's necessary
-		 * to handle failure condition here.
-		 */
-		Manage_subdevs(memb->devnm, subfd, devlist, verbose,
-			       0, UOPT_UNDEFINED, 0);
-		close(subfd);
-	}
-}
-
 /**
  * is_devnode_path() - check if the devname passed might be devnode path.
  * @devnode: the path to check.
@@ -1646,25 +1630,81 @@ static bool is_devnode_path(char *devnode)
 	return false;
 }
 
+/**
+ * Incremental_remove_external() - Remove the device from external container.
+ * @device_devnm: block device to remove.
+ * @container_devnm: the parent container
+ * @mdstat: mdstat file content.
+ * @verbose: verbose flag.
+ *
+ * Fail member device in each subarray and remove member device from external container.
+ * The resposibility of removing member disks from external subararys belongs to mdmon.
+ */
+static mdadm_status_t Incremental_remove_external(char *device_devnm, char *container_devnm,
+						  struct mdstat_ent *mdstat, int verbose)
+{
+	mdadm_status_t rv = MDADM_STATUS_SUCCESS;
+	struct mdstat_ent *memb;
+
+	for (memb = mdstat ; memb ; memb = memb->next) {
+		mdadm_status_t ret = MDADM_STATUS_SUCCESS;
+		int state_fd;
+
+		if (!is_container_member(memb, container_devnm))
+			continue;
+
+		/*
+		 * Checking mdstat is pointles because it might be outdated, try open descriptor
+		 * instead. If it fails, we are fine with that, device is already gone.
+		 */
+		state_fd = sysfs_open_memb_attr(memb->devnm, device_devnm, "state", O_RDWR);
+		if (!is_fd_valid(state_fd))
+			continue;
+
+		ret = sysfs_set_memb_state_fd(state_fd, MEMB_STATE_FAULTY, NULL);
+		if (ret && verbose >= 0)
+			pr_err("Cannot fail member device %s in external subarray %s.\n",
+				device_devnm, memb->devnm);
+
+		close_fd(&state_fd);
+
+		/*
+		 * Don't remove member device from container if it failed to remove it
+		 * from any member array.
+		 */
+		rv |= ret;
+	}
+
+	if (rv == MDADM_STATUS_SUCCESS)
+		rv = sysfs_set_memb_state(container_devnm, device_devnm, MEMB_STATE_REMOVE);
+
+	if (rv && verbose >= 0)
+		pr_err("Cannot remove member device %s from container %s.\n", device_devnm,
+		       container_devnm);
+
+	return rv;
+}
+
 /**
  * Incremental_remove() - Remove the device from all raid arrays.
  * @devname: the device we want to remove, it could be kernel device name or devnode.
  * @id_path: optional, /dev/disk/by-path path to save for bare scenarios support.
  * @verbose: verbose flag.
  *
- * First, fail the device (if needed) and then remove the device from native raid array or external
- * container.  If it is external container, the device is removed from each subarray first.
+ * First, fail the device (if needed) and then remove the device. This code is critical for system
+ * funtionality and that is why it is keept as simple as possible. We do not load devices using
+ * sysfs_read() because any unerelated failure may lead us to abort. We also do not call
+ * Manage_Subdevs().
  */
 int Incremental_remove(char *devname, char *id_path, int verbose)
 {
+	mdadm_status_t rv = MDADM_STATUS_SUCCESS;
 	char *devnm = basename(devname);
-	struct mddev_dev devlist = {0};
 	char buf[SYSFS_MAX_BUF_SIZE];
 	struct mdstat_ent *mdstat;
 	struct mdstat_ent *ent;
 	struct mdinfo mdi;
-	int rv = 1;
-	int mdfd;
+	int mdfd = -1;
 
 	if (strcmp(devnm, devname) != 0)
 		if (!is_devnode_path(devname)) {
@@ -1733,32 +1773,24 @@ int Incremental_remove(char *devname, char *id_path, int verbose)
 		map_free(map);
 	}
 
-	devlist.devname = devnm;
-	devlist.disposition = 'I';
-	/* for a container, we must fail each member array */
 	if (is_mdstat_ent_external(ent)) {
-		struct mdstat_ent *memb;
-		for (memb = mdstat ; memb ; memb = memb->next) {
-			if (is_container_member(memb, ent->devnm))
-				remove_from_member_array(memb,
-					&devlist, verbose);
-		}
-	} else {
-		/*
-		 * This 'I' incremental remove is a try-best effort,
-		 * the failure condition can be safely ignored
-		 * because of the following up 'r' remove.
-		 */
-		Manage_subdevs(ent->devnm, mdfd, &devlist,
-			       verbose, 0, UOPT_UNDEFINED, 0);
+		rv = Incremental_remove_external(devnm, ent->devnm, mdstat, verbose);
+		goto out;
 	}
 
-	devlist.disposition = 'r';
-	rv = Manage_subdevs(ent->devnm, mdfd, &devlist,
-			    verbose, 0, UOPT_UNDEFINED, 0);
+	/* Native arrays are handled separatelly to provide more detailed error handling */
+	rv = sysfs_set_memb_state(ent->devnm, devnm, MEMB_STATE_FAULTY);
+	if (rv && verbose >= 0)
+		pr_err("Cannot fail member device %s in array %s.\n", devnm, ent->devnm);
+
+	if (rv == MDADM_STATUS_SUCCESS)
+		rv = sysfs_set_memb_state(ent->devnm, devnm, MEMB_STATE_REMOVE);
+
+	if (rv && verbose >= 0)
+		pr_err("Cannot remove member device %s from %s.\n", devnm, ent->devnm);
 
-	close_fd(&mdfd);
 out:
+	close_fd(&mdfd);
 	free_mdstat(mdstat);
 	return rv;
 }
diff --git a/Manage.c b/Manage.c
index d618a2f0..034eb00c 100644
--- a/Manage.c
+++ b/Manage.c
@@ -1381,8 +1381,6 @@ bool is_remove_safe(mdu_array_info_t *array, const int fd, char *devname, const
  * 'f' - set the device faulty SET_DISK_FAULTY
  *       device can be 'detached' in which case any device that
  *       is inaccessible will be marked faulty.
- * 'I' - remove device by using incremental fail
- *       which is executed when device is removed surprisingly.
  * 'R' - mark this device as wanting replacement.
  * 'W' - this device is added if necessary and activated as
  *       a replacement for a previous 'R' device.
@@ -1544,9 +1542,9 @@ int Manage_subdevs(char *devname, int fd,
 
 			/* This is a kernel-internal name like 'sda1' */
 
-			if (!strchr("rfI", dv->disposition)) {
-				pr_err("%s only meaningful with -r, -f or -I, not -%c\n",
-					dv->devname, dv->disposition);
+			if (!strchr("rf", dv->disposition)) {
+				pr_err("%s only meaningful with -r, -f, not -%c\n", dv->devname,
+				       dv->disposition);
 				goto abort;
 			}
 
@@ -1673,7 +1671,7 @@ int Manage_subdevs(char *devname, int fd,
 				close_fd(&sysfd);
 				goto abort;
 			}
-		case 'I':
+
 			if (is_fd_valid(sysfd)) {
 				rv = sysfs_set_memb_state_fd(sysfd, MEMB_STATE_FAULTY, &err);
 			} else {
diff --git a/mdadm.h b/mdadm.h
index 218056c8..77705b11 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -829,6 +829,7 @@ extern mdadm_status_t sysfs_write_descriptor(const int fd, const char *value,
 					     const ssize_t len, int *errno_p);
 extern mdadm_status_t write_attr(const char *value, const int fd);
 extern mdadm_status_t sysfs_set_memb_state_fd(int fd, memb_state_t state, int *err);
+extern mdadm_status_t sysfs_set_memb_state(char *array_devnm, char *memb_devnm, memb_state_t state);
 extern void sysfs_get_container_devnm(struct mdinfo *mdi, char *buf);
 
 extern int sysfs_open(char *devnm, char *devname, char *attr);
diff --git a/sysfs.c b/sysfs.c
index 60b27459..c030d634 100644
--- a/sysfs.c
+++ b/sysfs.c
@@ -149,6 +149,29 @@ mdadm_status_t sysfs_set_memb_state_fd(int fd, memb_state_t state, int *err)
 	return sysfs_write_descriptor(fd, val, strlen(val), err);
 }
 
+/**
+ * sysfs_set_memb_state() - write to member disk state file.
+ * @array_devnm: kernel name of the array.
+ * @memb_devnm: kernel name of member device.
+ * @state: value to write.
+ *
+ * Function expects that the device exists, error is unconditionally printed.
+ */
+mdadm_status_t sysfs_set_memb_state(char *array_devnm, char *memb_devnm, memb_state_t state)
+{
+	int state_fd = sysfs_open_memb_attr(array_devnm, memb_devnm, "state", O_RDWR);
+
+	if (!is_fd_valid(state_fd)) {
+		pr_err("Cannot open file descriptor to %s in array %s, aborting.\n",
+		       memb_devnm, array_devnm);
+			return MDADM_STATUS_ERROR;
+	}
+
+	return sysfs_set_memb_state_fd(state_fd, state, NULL);
+
+	close_fd(&state_fd);
+}
+
 /**
  * sysfs_get_container_devnm() - extract container device name.
  * @mdi: md_info describes member array, with GET_VERSION option.
-- 
2.41.0