* [PATCH 1/3] badblocks: Add core badblock management code
2015-11-21 0:49 [PATCH 0/3] Badblock tracking for gendisks Vishal Verma
@ 2015-11-21 0:49 ` Vishal Verma
2015-11-24 19:19 ` Jens Axboe
2015-11-21 0:49 ` [PATCH 2/3] block: Add badblock management for gendisks Vishal Verma
2015-11-21 0:49 ` [PATCH 3/3] md: convert to use the generic badblocks code Vishal Verma
2 siblings, 1 reply; 13+ messages in thread
From: Vishal Verma @ 2015-11-21 0:49 UTC (permalink / raw)
To: linux-nvdimm
Cc: Vishal Verma, linux-block, linux-raid, linux-scsi, Jens Axboe,
NeilBrown, Jeff Moyer
Take the core badblocks implementation from md, and make it generally
available. This follows the same style as kernel implementations of
linked lists, rb-trees etc, where you can have a structure that can be
embedded anywhere, and accessor functions to manipulate the data.
The only changes in this copy of the code are ones to generalize
function/variable names from md-specific ones. Also add init and free
functions.
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
include/linux/badblocks.h | 512 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 512 insertions(+)
create mode 100644 include/linux/badblocks.h
diff --git a/include/linux/badblocks.h b/include/linux/badblocks.h
new file mode 100644
index 0000000..94fa348
--- /dev/null
+++ b/include/linux/badblocks.h
@@ -0,0 +1,512 @@
+#ifndef _LINUX_BADBLOCKS_H
+#define _LINUX_BADBLOCKS_H
+
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+
+#define BB_LEN_MASK (0x00000000000001FFULL)
+#define BB_OFFSET_MASK (0x7FFFFFFFFFFFFE00ULL)
+#define BB_ACK_MASK (0x8000000000000000ULL)
+#define BB_MAX_LEN 512
+#define BB_OFFSET(x) (((x) & BB_OFFSET_MASK) >> 9)
+#define BB_LEN(x) (((x) & BB_LEN_MASK) + 1)
+#define BB_ACK(x) (!!((x) & BB_ACK_MASK))
+#define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
+
+/* Bad block numbers are stored sorted in a single page.
+ * 64bits is used for each block or extent.
+ * 54 bits are sector number, 9 bits are extent size,
+ * 1 bit is an 'acknowledged' flag.
+ */
+#define MAX_BADBLOCKS (PAGE_SIZE/8)
+
+struct badblocks {
+ int count; /* count of bad blocks */
+ int unacked_exist; /* there probably are unacknowledged
+ * bad blocks. This is only cleared
+ * when a read discovers none
+ */
+ int shift; /* shift from sectors to block size
+ * a -ve shift means badblocks are
+ * disabled.*/
+ u64 *page; /* badblock list */
+ int changed;
+ seqlock_t lock;
+ sector_t sector;
+ sector_t size; /* in sectors */
+};
+
+/* Bad block management.
+ * We can record which blocks on each device are 'bad' and so just
+ * fail those blocks, or that stripe, rather than the whole device.
+ * Entries in the bad-block table are 64bits wide. This comprises:
+ * Length of bad-range, in sectors: 0-511 for lengths 1-512
+ * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
+ * A 'shift' can be set so that larger blocks are tracked and
+ * consequently larger devices can be covered.
+ * 'Acknowledged' flag - 1 bit. - the most significant bit.
+ *
+ * Locking of the bad-block table uses a seqlock so badblocks_check
+ * might need to retry if it is very unlucky.
+ * We will sometimes want to check for bad blocks in a bi_end_io function,
+ * so we use the write_seqlock_irq variant.
+ *
+ * When looking for a bad block we specify a range and want to
+ * know if any block in the range is bad. So we binary-search
+ * to the last range that starts at-or-before the given endpoint,
+ * (or "before the sector after the target range")
+ * then see if it ends after the given start.
+ * We return
+ * 0 if there are no known bad blocks in the range
+ * 1 if there are known bad block which are all acknowledged
+ * -1 if there are bad blocks which have not yet been acknowledged in metadata.
+ * plus the start/length of the first bad section we overlap.
+ */
+static inline int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
+ sector_t *first_bad, int *bad_sectors)
+{
+ int hi;
+ int lo;
+ u64 *p = bb->page;
+ int rv;
+ sector_t target = s + sectors;
+ unsigned seq;
+
+ if (bb->shift > 0) {
+ /* round the start down, and the end up */
+ s >>= bb->shift;
+ target += (1<<bb->shift) - 1;
+ target >>= bb->shift;
+ sectors = target - s;
+ }
+ /* 'target' is now the first block after the bad range */
+
+retry:
+ seq = read_seqbegin(&bb->lock);
+ lo = 0;
+ rv = 0;
+ hi = bb->count;
+
+ /* Binary search between lo and hi for 'target'
+ * i.e. for the last range that starts before 'target'
+ */
+ /* INVARIANT: ranges before 'lo' and at-or-after 'hi'
+ * are known not to be the last range before target.
+ * VARIANT: hi-lo is the number of possible
+ * ranges, and decreases until it reaches 1
+ */
+ while (hi - lo > 1) {
+ int mid = (lo + hi) / 2;
+ sector_t a = BB_OFFSET(p[mid]);
+ if (a < target)
+ /* This could still be the one, earlier ranges
+ * could not. */
+ lo = mid;
+ else
+ /* This and later ranges are definitely out. */
+ hi = mid;
+ }
+ /* 'lo' might be the last that started before target, but 'hi' isn't */
+ if (hi > lo) {
+ /* need to check all range that end after 's' to see if
+ * any are unacknowledged.
+ */
+ while (lo >= 0 &&
+ BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
+ if (BB_OFFSET(p[lo]) < target) {
+ /* starts before the end, and finishes after
+ * the start, so they must overlap
+ */
+ if (rv != -1 && BB_ACK(p[lo]))
+ rv = 1;
+ else
+ rv = -1;
+ *first_bad = BB_OFFSET(p[lo]);
+ *bad_sectors = BB_LEN(p[lo]);
+ }
+ lo--;
+ }
+ }
+
+ if (read_seqretry(&bb->lock, seq))
+ goto retry;
+
+ return rv;
+}
+
+/*
+ * Add a range of bad blocks to the table.
+ * This might extend the table, or might contract it
+ * if two adjacent ranges can be merged.
+ * We binary-search to find the 'insertion' point, then
+ * decide how best to handle it.
+ */
+static inline int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
+ int acknowledged)
+{
+ u64 *p;
+ int lo, hi;
+ int rv = 1;
+ unsigned long flags;
+
+ if (bb->shift < 0)
+ /* badblocks are disabled */
+ return 0;
+
+ if (bb->shift) {
+ /* round the start down, and the end up */
+ sector_t next = s + sectors;
+ s >>= bb->shift;
+ next += (1<<bb->shift) - 1;
+ next >>= bb->shift;
+ sectors = next - s;
+ }
+
+ write_seqlock_irqsave(&bb->lock, flags);
+
+ p = bb->page;
+ lo = 0;
+ hi = bb->count;
+ /* Find the last range that starts at-or-before 's' */
+ while (hi - lo > 1) {
+ int mid = (lo + hi) / 2;
+ sector_t a = BB_OFFSET(p[mid]);
+ if (a <= s)
+ lo = mid;
+ else
+ hi = mid;
+ }
+ if (hi > lo && BB_OFFSET(p[lo]) > s)
+ hi = lo;
+
+ if (hi > lo) {
+ /* we found a range that might merge with the start
+ * of our new range
+ */
+ sector_t a = BB_OFFSET(p[lo]);
+ sector_t e = a + BB_LEN(p[lo]);
+ int ack = BB_ACK(p[lo]);
+ if (e >= s) {
+ /* Yes, we can merge with a previous range */
+ if (s == a && s + sectors >= e)
+ /* new range covers old */
+ ack = acknowledged;
+ else
+ ack = ack && acknowledged;
+
+ if (e < s + sectors)
+ e = s + sectors;
+ if (e - a <= BB_MAX_LEN) {
+ p[lo] = BB_MAKE(a, e-a, ack);
+ s = e;
+ } else {
+ /* does not all fit in one range,
+ * make p[lo] maximal
+ */
+ if (BB_LEN(p[lo]) != BB_MAX_LEN)
+ p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
+ s = a + BB_MAX_LEN;
+ }
+ sectors = e - s;
+ }
+ }
+ if (sectors && hi < bb->count) {
+ /* 'hi' points to the first range that starts after 's'.
+ * Maybe we can merge with the start of that range */
+ sector_t a = BB_OFFSET(p[hi]);
+ sector_t e = a + BB_LEN(p[hi]);
+ int ack = BB_ACK(p[hi]);
+ if (a <= s + sectors) {
+ /* merging is possible */
+ if (e <= s + sectors) {
+ /* full overlap */
+ e = s + sectors;
+ ack = acknowledged;
+ } else
+ ack = ack && acknowledged;
+
+ a = s;
+ if (e - a <= BB_MAX_LEN) {
+ p[hi] = BB_MAKE(a, e-a, ack);
+ s = e;
+ } else {
+ p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
+ s = a + BB_MAX_LEN;
+ }
+ sectors = e - s;
+ lo = hi;
+ hi++;
+ }
+ }
+ if (sectors == 0 && hi < bb->count) {
+ /* we might be able to combine lo and hi */
+ /* Note: 's' is at the end of 'lo' */
+ sector_t a = BB_OFFSET(p[hi]);
+ int lolen = BB_LEN(p[lo]);
+ int hilen = BB_LEN(p[hi]);
+ int newlen = lolen + hilen - (s - a);
+ if (s >= a && newlen < BB_MAX_LEN) {
+ /* yes, we can combine them */
+ int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
+ p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
+ memmove(p + hi, p + hi + 1,
+ (bb->count - hi - 1) * 8);
+ bb->count--;
+ }
+ }
+ while (sectors) {
+ /* didn't merge (it all).
+ * Need to add a range just before 'hi' */
+ if (bb->count >= MAX_BADBLOCKS) {
+ /* No room for more */
+ rv = 0;
+ break;
+ } else {
+ int this_sectors = sectors;
+ memmove(p + hi + 1, p + hi,
+ (bb->count - hi) * 8);
+ bb->count++;
+
+ if (this_sectors > BB_MAX_LEN)
+ this_sectors = BB_MAX_LEN;
+ p[hi] = BB_MAKE(s, this_sectors, acknowledged);
+ sectors -= this_sectors;
+ s += this_sectors;
+ }
+ }
+
+ bb->changed = 1;
+ if (!acknowledged)
+ bb->unacked_exist = 1;
+ write_sequnlock_irqrestore(&bb->lock, flags);
+
+ return rv;
+}
+
+/*
+ * Remove a range of bad blocks from the table.
+ * This may involve extending the table if we spilt a region,
+ * but it must not fail. So if the table becomes full, we just
+ * drop the remove request.
+ */
+static inline int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
+{
+ u64 *p;
+ int lo, hi;
+ sector_t target = s + sectors;
+ int rv = 0;
+
+ if (bb->shift > 0) {
+ /* When clearing we round the start up and the end down.
+ * This should not matter as the shift should align with
+ * the block size and no rounding should ever be needed.
+ * However it is better the think a block is bad when it
+ * isn't than to think a block is not bad when it is.
+ */
+ s += (1<<bb->shift) - 1;
+ s >>= bb->shift;
+ target >>= bb->shift;
+ sectors = target - s;
+ }
+
+ write_seqlock_irq(&bb->lock);
+
+ p = bb->page;
+ lo = 0;
+ hi = bb->count;
+ /* Find the last range that starts before 'target' */
+ while (hi - lo > 1) {
+ int mid = (lo + hi) / 2;
+ sector_t a = BB_OFFSET(p[mid]);
+ if (a < target)
+ lo = mid;
+ else
+ hi = mid;
+ }
+ if (hi > lo) {
+ /* p[lo] is the last range that could overlap the
+ * current range. Earlier ranges could also overlap,
+ * but only this one can overlap the end of the range.
+ */
+ if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) {
+ /* Partial overlap, leave the tail of this range */
+ int ack = BB_ACK(p[lo]);
+ sector_t a = BB_OFFSET(p[lo]);
+ sector_t end = a + BB_LEN(p[lo]);
+
+ if (a < s) {
+ /* we need to split this range */
+ if (bb->count >= MAX_BADBLOCKS) {
+ rv = -ENOSPC;
+ goto out;
+ }
+ memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
+ bb->count++;
+ p[lo] = BB_MAKE(a, s-a, ack);
+ lo++;
+ }
+ p[lo] = BB_MAKE(target, end - target, ack);
+ /* there is no longer an overlap */
+ hi = lo;
+ lo--;
+ }
+ while (lo >= 0 &&
+ BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
+ /* This range does overlap */
+ if (BB_OFFSET(p[lo]) < s) {
+ /* Keep the early parts of this range. */
+ int ack = BB_ACK(p[lo]);
+ sector_t start = BB_OFFSET(p[lo]);
+ p[lo] = BB_MAKE(start, s - start, ack);
+ /* now low doesn't overlap, so.. */
+ break;
+ }
+ lo--;
+ }
+ /* 'lo' is strictly before, 'hi' is strictly after,
+ * anything between needs to be discarded
+ */
+ if (hi - lo > 1) {
+ memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
+ bb->count -= (hi - lo - 1);
+ }
+ }
+
+ bb->changed = 1;
+out:
+ write_sequnlock_irq(&bb->lock);
+ return rv;
+}
+
+/*
+ * Acknowledge all bad blocks in a list.
+ * This only succeeds if ->changed is clear. It is used by
+ * in-kernel metadata updates
+ */
+static inline void ack_all_badblocks(struct badblocks *bb)
+{
+ if (bb->page == NULL || bb->changed)
+ /* no point even trying */
+ return;
+ write_seqlock_irq(&bb->lock);
+
+ if (bb->changed == 0 && bb->unacked_exist) {
+ u64 *p = bb->page;
+ int i;
+ for (i = 0; i < bb->count ; i++) {
+ if (!BB_ACK(p[i])) {
+ sector_t start = BB_OFFSET(p[i]);
+ int len = BB_LEN(p[i]);
+ p[i] = BB_MAKE(start, len, 1);
+ }
+ }
+ bb->unacked_exist = 0;
+ }
+ write_sequnlock_irq(&bb->lock);
+}
+
+/* sysfs access to bad-blocks list. */
+static inline ssize_t badblocks_show(struct badblocks *bb, char *page,
+ int unack)
+{
+ size_t len;
+ int i;
+ u64 *p = bb->page;
+ unsigned seq;
+
+ if (bb->shift < 0)
+ return 0;
+
+retry:
+ seq = read_seqbegin(&bb->lock);
+
+ len = 0;
+ i = 0;
+
+ while (len < PAGE_SIZE && i < bb->count) {
+ sector_t s = BB_OFFSET(p[i]);
+ unsigned int length = BB_LEN(p[i]);
+ int ack = BB_ACK(p[i]);
+ i++;
+
+ if (unack && ack)
+ continue;
+
+ len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
+ (unsigned long long)s << bb->shift,
+ length << bb->shift);
+ }
+ if (unack && len == 0)
+ bb->unacked_exist = 0;
+
+ if (read_seqretry(&bb->lock, seq))
+ goto retry;
+
+ return len;
+}
+
+#define DO_DEBUG 1
+
+static inline ssize_t badblocks_store(struct badblocks *bb, const char *page,
+ size_t len, int unack)
+{
+ unsigned long long sector;
+ int length;
+ char newline;
+#ifdef DO_DEBUG
+ /* Allow clearing via sysfs *only* for testing/debugging.
+ * Normally only a successful write may clear a badblock
+ */
+ int clear = 0;
+ if (page[0] == '-') {
+ clear = 1;
+ page++;
+ }
+#endif /* DO_DEBUG */
+
+ switch (sscanf(page, "%llu %d%c", §or, &length, &newline)) {
+ case 3:
+ if (newline != '\n')
+ return -EINVAL;
+ case 2:
+ if (length <= 0)
+ return -EINVAL;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+#ifdef DO_DEBUG
+ if (clear) {
+ badblocks_clear(bb, sector, length);
+ return len;
+ }
+#endif /* DO_DEBUG */
+ if (badblocks_set(bb, sector, length, !unack))
+ return len;
+ else
+ return -ENOSPC;
+}
+
+static inline int badblocks_init(struct badblocks *bb, int enable)
+{
+ bb->count = 0;
+ if (enable)
+ bb->shift = 0;
+ else
+ bb->shift = -1;
+ bb->page = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (bb->page == NULL)
+ return -ENOMEM;
+ seqlock_init(&bb->lock);
+
+ return 0;
+}
+
+static inline void badblocks_free(struct badblocks *bb)
+{
+ kfree(bb->page);
+}
+
+#endif
--
2.5.0
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 2/3] block: Add badblock management for gendisks
2015-11-21 0:49 [PATCH 0/3] Badblock tracking for gendisks Vishal Verma
2015-11-21 0:49 ` [PATCH 1/3] badblocks: Add core badblock management code Vishal Verma
@ 2015-11-21 0:49 ` Vishal Verma
2015-11-24 15:34 ` Jeff Moyer
2015-11-21 0:49 ` [PATCH 3/3] md: convert to use the generic badblocks code Vishal Verma
2 siblings, 1 reply; 13+ messages in thread
From: Vishal Verma @ 2015-11-21 0:49 UTC (permalink / raw)
To: linux-nvdimm
Cc: Vishal Verma, linux-block, linux-raid, linux-scsi, Jens Axboe,
NeilBrown, Jeff Moyer
NVDIMM devices, which can behave more like DRAM rather than block
devices, may develop bad cache lines, or 'poison'. A block device
exposed by the pmem driver can then consume poison via a read (or
write), and cause a machine check. On platforms without machine
check recovery features, this would mean a crash.
The block device maintaining a runtime list of all known sectors that
have poison can directly avoid this, and also provide a path forward
to enable proper handling/recovery for DAX faults on such a device.
Use the new badblock management interfaces to add a badblocks list to
gendisks.
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
block/genhd.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/genhd.h | 6 +++++
2 files changed, 70 insertions(+)
diff --git a/block/genhd.c b/block/genhd.c
index 0c706f3..4209c32 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -20,6 +20,7 @@
#include <linux/idr.h>
#include <linux/log2.h>
#include <linux/pm_runtime.h>
+#include <linux/badblocks.h>
#include "blk.h"
@@ -505,6 +506,20 @@ static int exact_lock(dev_t devt, void *data)
return 0;
}
+static void disk_alloc_badblocks(struct gendisk *disk)
+{
+ disk->bb = kzalloc(sizeof(disk->bb), GFP_KERNEL);
+ if (!disk->bb) {
+ pr_warn("%s: failed to allocate space for badblocks\n",
+ disk->disk_name);
+ return;
+ }
+
+ if (badblocks_init(disk->bb, 1))
+ pr_warn("%s: failed to initialize badblocks\n",
+ disk->disk_name);
+}
+
static void register_disk(struct gendisk *disk)
{
struct device *ddev = disk_to_dev(disk);
@@ -609,6 +624,7 @@ void add_disk(struct gendisk *disk)
disk->first_minor = MINOR(devt);
disk_alloc_events(disk);
+ disk_alloc_badblocks(disk);
/* Register BDI before referencing it from bdev */
bdi = &disk->queue->backing_dev_info;
@@ -657,6 +673,9 @@ void del_gendisk(struct gendisk *disk)
blk_unregister_queue(disk);
blk_unregister_region(disk_devt(disk), disk->minors);
+ badblocks_free(disk->bb);
+ kfree(disk->bb);
+
part_stat_set_all(&disk->part0, 0);
disk->part0.stamp = 0;
@@ -670,6 +689,48 @@ void del_gendisk(struct gendisk *disk)
}
EXPORT_SYMBOL(del_gendisk);
+/*
+ * The gendisk usage of badblocks does not track acknowledgements for
+ * badblocks. We always assume they are acknowledged.
+ */
+int disk_check_badblocks(struct gendisk *disk, sector_t s, int sectors,
+ sector_t *first_bad, int *bad_sectors)
+{
+ return badblocks_check(disk->bb, s, sectors, first_bad, bad_sectors);
+}
+EXPORT_SYMBOL(disk_check_badblocks);
+
+int disk_set_badblocks(struct gendisk *disk, sector_t s, int sectors)
+{
+ return badblocks_set(disk->bb, s, sectors, 1);
+}
+EXPORT_SYMBOL(disk_set_badblocks);
+
+int disk_clear_badblocks(struct gendisk *disk, sector_t s, int sectors)
+{
+ return badblocks_clear(disk->bb, s, sectors);
+}
+EXPORT_SYMBOL(disk_clear_badblocks);
+
+/* sysfs access to bad-blocks list. */
+static ssize_t disk_badblocks_show(struct device *dev,
+ struct device_attribute *attr,
+ char *page)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return badblocks_show(disk->bb, page, 0);
+}
+
+static ssize_t disk_badblocks_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *page, size_t len)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return badblocks_store(disk->bb, page, len, 0);
+}
+
/**
* get_gendisk - get partitioning information for a given device
* @devt: device to get partitioning information for
@@ -988,6 +1049,8 @@ static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show,
static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
+static DEVICE_ATTR(badblocks, S_IRUGO | S_IWUSR, disk_badblocks_show,
+ disk_badblocks_store);
#ifdef CONFIG_FAIL_MAKE_REQUEST
static struct device_attribute dev_attr_fail =
__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
@@ -1009,6 +1072,7 @@ static struct attribute *disk_attrs[] = {
&dev_attr_capability.attr,
&dev_attr_stat.attr,
&dev_attr_inflight.attr,
+ &dev_attr_badblocks.attr,
#ifdef CONFIG_FAIL_MAKE_REQUEST
&dev_attr_fail.attr,
#endif
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 2adbfa6..5563bde 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -162,6 +162,7 @@ struct disk_part_tbl {
};
struct disk_events;
+struct badblocks;
struct gendisk {
/* major, first_minor and minors are input parameters only,
@@ -201,6 +202,7 @@ struct gendisk {
struct blk_integrity *integrity;
#endif
int node_id;
+ struct badblocks *bb;
};
static inline struct gendisk *part_to_disk(struct hd_struct *part)
@@ -421,6 +423,10 @@ extern void add_disk(struct gendisk *disk);
extern void del_gendisk(struct gendisk *gp);
extern struct gendisk *get_gendisk(dev_t dev, int *partno);
extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
+extern int disk_check_badblocks(struct gendisk *disk, sector_t s, int sectors,
+ sector_t *first_bad, int *bad_sectors);
+extern int disk_set_badblocks(struct gendisk *disk, sector_t s, int sectors);
+extern int disk_clear_badblocks(struct gendisk *disk, sector_t s, int sectors);
extern void set_device_ro(struct block_device *bdev, int flag);
extern void set_disk_ro(struct gendisk *disk, int flag);
--
2.5.0
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 3/3] md: convert to use the generic badblocks code
2015-11-21 0:49 [PATCH 0/3] Badblock tracking for gendisks Vishal Verma
2015-11-21 0:49 ` [PATCH 1/3] badblocks: Add core badblock management code Vishal Verma
2015-11-21 0:49 ` [PATCH 2/3] block: Add badblock management for gendisks Vishal Verma
@ 2015-11-21 0:49 ` Vishal Verma
2 siblings, 0 replies; 13+ messages in thread
From: Vishal Verma @ 2015-11-21 0:49 UTC (permalink / raw)
To: linux-nvdimm
Cc: Vishal Verma, linux-block, linux-raid, linux-scsi, Jens Axboe,
NeilBrown, Jeff Moyer
Retain badblocks as part of rdev, but use the accessor functions from
include/linux/badblocks for all manipulation.
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
drivers/md/md.c | 495 +++-----------------------------------------------------
drivers/md/md.h | 31 +---
2 files changed, 21 insertions(+), 505 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c702de1..82994d7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -34,6 +34,7 @@
#include <linux/kthread.h>
#include <linux/blkdev.h>
+#include <linux/badblocks.h>
#include <linux/sysctl.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
@@ -1358,8 +1359,6 @@ static __le32 calc_sb_1_csum(struct mdp_superblock_1 *sb)
return cpu_to_le32(csum);
}
-static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
- int acknowledged);
static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
{
struct mdp_superblock_1 *sb;
@@ -1484,7 +1483,7 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
count <<= sb->bblog_shift;
if (bb + 1 == 0)
break;
- if (md_set_badblocks(&rdev->badblocks,
+ if (badblocks_set(&rdev->badblocks,
sector, count, 1) == 0)
return -EINVAL;
}
@@ -2226,7 +2225,7 @@ repeat:
rdev_for_each(rdev, mddev) {
if (rdev->badblocks.changed) {
rdev->badblocks.changed = 0;
- md_ack_all_badblocks(&rdev->badblocks);
+ ack_all_badblocks(&rdev->badblocks);
md_error(mddev, rdev);
}
clear_bit(Blocked, &rdev->flags);
@@ -2352,7 +2351,7 @@ repeat:
clear_bit(Blocked, &rdev->flags);
if (any_badblocks_changed)
- md_ack_all_badblocks(&rdev->badblocks);
+ ack_all_badblocks(&rdev->badblocks);
clear_bit(BlockedBadBlocks, &rdev->flags);
wake_up(&rdev->blocked_wait);
}
@@ -2944,11 +2943,17 @@ static ssize_t recovery_start_store(struct md_rdev *rdev, const char *buf, size_
static struct rdev_sysfs_entry rdev_recovery_start =
__ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);
-static ssize_t
-badblocks_show(struct badblocks *bb, char *page, int unack);
-static ssize_t
-badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack);
-
+/* sysfs access to bad-blocks list.
+ * We present two files.
+ * 'bad-blocks' lists sector numbers and lengths of ranges that
+ * are recorded as bad. The list is truncated to fit within
+ * the one-page limit of sysfs.
+ * Writing "sector length" to this file adds an acknowledged
+ * bad block list.
+ * 'unacknowledged-bad-blocks' lists bad blocks that have not yet
+ * been acknowledged. Writing to this file adds bad blocks
+ * without acknowledging them. This is largely for testing.
+ */
static ssize_t bb_show(struct md_rdev *rdev, char *page)
{
return badblocks_show(&rdev->badblocks, page, 0);
@@ -8348,253 +8353,7 @@ void md_finish_reshape(struct mddev *mddev)
}
EXPORT_SYMBOL(md_finish_reshape);
-/* Bad block management.
- * We can record which blocks on each device are 'bad' and so just
- * fail those blocks, or that stripe, rather than the whole device.
- * Entries in the bad-block table are 64bits wide. This comprises:
- * Length of bad-range, in sectors: 0-511 for lengths 1-512
- * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
- * A 'shift' can be set so that larger blocks are tracked and
- * consequently larger devices can be covered.
- * 'Acknowledged' flag - 1 bit. - the most significant bit.
- *
- * Locking of the bad-block table uses a seqlock so md_is_badblock
- * might need to retry if it is very unlucky.
- * We will sometimes want to check for bad blocks in a bi_end_io function,
- * so we use the write_seqlock_irq variant.
- *
- * When looking for a bad block we specify a range and want to
- * know if any block in the range is bad. So we binary-search
- * to the last range that starts at-or-before the given endpoint,
- * (or "before the sector after the target range")
- * then see if it ends after the given start.
- * We return
- * 0 if there are no known bad blocks in the range
- * 1 if there are known bad block which are all acknowledged
- * -1 if there are bad blocks which have not yet been acknowledged in metadata.
- * plus the start/length of the first bad section we overlap.
- */
-int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
- sector_t *first_bad, int *bad_sectors)
-{
- int hi;
- int lo;
- u64 *p = bb->page;
- int rv;
- sector_t target = s + sectors;
- unsigned seq;
-
- if (bb->shift > 0) {
- /* round the start down, and the end up */
- s >>= bb->shift;
- target += (1<<bb->shift) - 1;
- target >>= bb->shift;
- sectors = target - s;
- }
- /* 'target' is now the first block after the bad range */
-
-retry:
- seq = read_seqbegin(&bb->lock);
- lo = 0;
- rv = 0;
- hi = bb->count;
-
- /* Binary search between lo and hi for 'target'
- * i.e. for the last range that starts before 'target'
- */
- /* INVARIANT: ranges before 'lo' and at-or-after 'hi'
- * are known not to be the last range before target.
- * VARIANT: hi-lo is the number of possible
- * ranges, and decreases until it reaches 1
- */
- while (hi - lo > 1) {
- int mid = (lo + hi) / 2;
- sector_t a = BB_OFFSET(p[mid]);
- if (a < target)
- /* This could still be the one, earlier ranges
- * could not. */
- lo = mid;
- else
- /* This and later ranges are definitely out. */
- hi = mid;
- }
- /* 'lo' might be the last that started before target, but 'hi' isn't */
- if (hi > lo) {
- /* need to check all range that end after 's' to see if
- * any are unacknowledged.
- */
- while (lo >= 0 &&
- BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
- if (BB_OFFSET(p[lo]) < target) {
- /* starts before the end, and finishes after
- * the start, so they must overlap
- */
- if (rv != -1 && BB_ACK(p[lo]))
- rv = 1;
- else
- rv = -1;
- *first_bad = BB_OFFSET(p[lo]);
- *bad_sectors = BB_LEN(p[lo]);
- }
- lo--;
- }
- }
-
- if (read_seqretry(&bb->lock, seq))
- goto retry;
-
- return rv;
-}
-EXPORT_SYMBOL_GPL(md_is_badblock);
-
-/*
- * Add a range of bad blocks to the table.
- * This might extend the table, or might contract it
- * if two adjacent ranges can be merged.
- * We binary-search to find the 'insertion' point, then
- * decide how best to handle it.
- */
-static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
- int acknowledged)
-{
- u64 *p;
- int lo, hi;
- int rv = 1;
- unsigned long flags;
-
- if (bb->shift < 0)
- /* badblocks are disabled */
- return 0;
-
- if (bb->shift) {
- /* round the start down, and the end up */
- sector_t next = s + sectors;
- s >>= bb->shift;
- next += (1<<bb->shift) - 1;
- next >>= bb->shift;
- sectors = next - s;
- }
-
- write_seqlock_irqsave(&bb->lock, flags);
-
- p = bb->page;
- lo = 0;
- hi = bb->count;
- /* Find the last range that starts at-or-before 's' */
- while (hi - lo > 1) {
- int mid = (lo + hi) / 2;
- sector_t a = BB_OFFSET(p[mid]);
- if (a <= s)
- lo = mid;
- else
- hi = mid;
- }
- if (hi > lo && BB_OFFSET(p[lo]) > s)
- hi = lo;
-
- if (hi > lo) {
- /* we found a range that might merge with the start
- * of our new range
- */
- sector_t a = BB_OFFSET(p[lo]);
- sector_t e = a + BB_LEN(p[lo]);
- int ack = BB_ACK(p[lo]);
- if (e >= s) {
- /* Yes, we can merge with a previous range */
- if (s == a && s + sectors >= e)
- /* new range covers old */
- ack = acknowledged;
- else
- ack = ack && acknowledged;
-
- if (e < s + sectors)
- e = s + sectors;
- if (e - a <= BB_MAX_LEN) {
- p[lo] = BB_MAKE(a, e-a, ack);
- s = e;
- } else {
- /* does not all fit in one range,
- * make p[lo] maximal
- */
- if (BB_LEN(p[lo]) != BB_MAX_LEN)
- p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
- s = a + BB_MAX_LEN;
- }
- sectors = e - s;
- }
- }
- if (sectors && hi < bb->count) {
- /* 'hi' points to the first range that starts after 's'.
- * Maybe we can merge with the start of that range */
- sector_t a = BB_OFFSET(p[hi]);
- sector_t e = a + BB_LEN(p[hi]);
- int ack = BB_ACK(p[hi]);
- if (a <= s + sectors) {
- /* merging is possible */
- if (e <= s + sectors) {
- /* full overlap */
- e = s + sectors;
- ack = acknowledged;
- } else
- ack = ack && acknowledged;
-
- a = s;
- if (e - a <= BB_MAX_LEN) {
- p[hi] = BB_MAKE(a, e-a, ack);
- s = e;
- } else {
- p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
- s = a + BB_MAX_LEN;
- }
- sectors = e - s;
- lo = hi;
- hi++;
- }
- }
- if (sectors == 0 && hi < bb->count) {
- /* we might be able to combine lo and hi */
- /* Note: 's' is at the end of 'lo' */
- sector_t a = BB_OFFSET(p[hi]);
- int lolen = BB_LEN(p[lo]);
- int hilen = BB_LEN(p[hi]);
- int newlen = lolen + hilen - (s - a);
- if (s >= a && newlen < BB_MAX_LEN) {
- /* yes, we can combine them */
- int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
- p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
- memmove(p + hi, p + hi + 1,
- (bb->count - hi - 1) * 8);
- bb->count--;
- }
- }
- while (sectors) {
- /* didn't merge (it all).
- * Need to add a range just before 'hi' */
- if (bb->count >= MD_MAX_BADBLOCKS) {
- /* No room for more */
- rv = 0;
- break;
- } else {
- int this_sectors = sectors;
- memmove(p + hi + 1, p + hi,
- (bb->count - hi) * 8);
- bb->count++;
-
- if (this_sectors > BB_MAX_LEN)
- this_sectors = BB_MAX_LEN;
- p[hi] = BB_MAKE(s, this_sectors, acknowledged);
- sectors -= this_sectors;
- s += this_sectors;
- }
- }
-
- bb->changed = 1;
- if (!acknowledged)
- bb->unacked_exist = 1;
- write_sequnlock_irqrestore(&bb->lock, flags);
-
- return rv;
-}
+/* Bad block management */
int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
int is_new)
@@ -8604,8 +8363,7 @@ int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
s += rdev->new_data_offset;
else
s += rdev->data_offset;
- rv = md_set_badblocks(&rdev->badblocks,
- s, sectors, 0);
+ rv = badblocks_set(&rdev->badblocks, s, sectors, 0);
if (rv) {
/* Make sure they get written out promptly */
sysfs_notify_dirent_safe(rdev->sysfs_state);
@@ -8617,101 +8375,6 @@ int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
}
EXPORT_SYMBOL_GPL(rdev_set_badblocks);
-/*
- * Remove a range of bad blocks from the table.
- * This may involve extending the table if we spilt a region,
- * but it must not fail. So if the table becomes full, we just
- * drop the remove request.
- */
-static int md_clear_badblocks(struct badblocks *bb, sector_t s, int sectors)
-{
- u64 *p;
- int lo, hi;
- sector_t target = s + sectors;
- int rv = 0;
-
- if (bb->shift > 0) {
- /* When clearing we round the start up and the end down.
- * This should not matter as the shift should align with
- * the block size and no rounding should ever be needed.
- * However it is better the think a block is bad when it
- * isn't than to think a block is not bad when it is.
- */
- s += (1<<bb->shift) - 1;
- s >>= bb->shift;
- target >>= bb->shift;
- sectors = target - s;
- }
-
- write_seqlock_irq(&bb->lock);
-
- p = bb->page;
- lo = 0;
- hi = bb->count;
- /* Find the last range that starts before 'target' */
- while (hi - lo > 1) {
- int mid = (lo + hi) / 2;
- sector_t a = BB_OFFSET(p[mid]);
- if (a < target)
- lo = mid;
- else
- hi = mid;
- }
- if (hi > lo) {
- /* p[lo] is the last range that could overlap the
- * current range. Earlier ranges could also overlap,
- * but only this one can overlap the end of the range.
- */
- if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) {
- /* Partial overlap, leave the tail of this range */
- int ack = BB_ACK(p[lo]);
- sector_t a = BB_OFFSET(p[lo]);
- sector_t end = a + BB_LEN(p[lo]);
-
- if (a < s) {
- /* we need to split this range */
- if (bb->count >= MD_MAX_BADBLOCKS) {
- rv = -ENOSPC;
- goto out;
- }
- memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
- bb->count++;
- p[lo] = BB_MAKE(a, s-a, ack);
- lo++;
- }
- p[lo] = BB_MAKE(target, end - target, ack);
- /* there is no longer an overlap */
- hi = lo;
- lo--;
- }
- while (lo >= 0 &&
- BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
- /* This range does overlap */
- if (BB_OFFSET(p[lo]) < s) {
- /* Keep the early parts of this range. */
- int ack = BB_ACK(p[lo]);
- sector_t start = BB_OFFSET(p[lo]);
- p[lo] = BB_MAKE(start, s - start, ack);
- /* now low doesn't overlap, so.. */
- break;
- }
- lo--;
- }
- /* 'lo' is strictly before, 'hi' is strictly after,
- * anything between needs to be discarded
- */
- if (hi - lo > 1) {
- memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
- bb->count -= (hi - lo - 1);
- }
- }
-
- bb->changed = 1;
-out:
- write_sequnlock_irq(&bb->lock);
- return rv;
-}
-
int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
int is_new)
{
@@ -8719,133 +8382,11 @@ int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
s += rdev->new_data_offset;
else
s += rdev->data_offset;
- return md_clear_badblocks(&rdev->badblocks,
+ return badblocks_clear(&rdev->badblocks,
s, sectors);
}
EXPORT_SYMBOL_GPL(rdev_clear_badblocks);
-/*
- * Acknowledge all bad blocks in a list.
- * This only succeeds if ->changed is clear. It is used by
- * in-kernel metadata updates
- */
-void md_ack_all_badblocks(struct badblocks *bb)
-{
- if (bb->page == NULL || bb->changed)
- /* no point even trying */
- return;
- write_seqlock_irq(&bb->lock);
-
- if (bb->changed == 0 && bb->unacked_exist) {
- u64 *p = bb->page;
- int i;
- for (i = 0; i < bb->count ; i++) {
- if (!BB_ACK(p[i])) {
- sector_t start = BB_OFFSET(p[i]);
- int len = BB_LEN(p[i]);
- p[i] = BB_MAKE(start, len, 1);
- }
- }
- bb->unacked_exist = 0;
- }
- write_sequnlock_irq(&bb->lock);
-}
-EXPORT_SYMBOL_GPL(md_ack_all_badblocks);
-
-/* sysfs access to bad-blocks list.
- * We present two files.
- * 'bad-blocks' lists sector numbers and lengths of ranges that
- * are recorded as bad. The list is truncated to fit within
- * the one-page limit of sysfs.
- * Writing "sector length" to this file adds an acknowledged
- * bad block list.
- * 'unacknowledged-bad-blocks' lists bad blocks that have not yet
- * been acknowledged. Writing to this file adds bad blocks
- * without acknowledging them. This is largely for testing.
- */
-
-static ssize_t
-badblocks_show(struct badblocks *bb, char *page, int unack)
-{
- size_t len;
- int i;
- u64 *p = bb->page;
- unsigned seq;
-
- if (bb->shift < 0)
- return 0;
-
-retry:
- seq = read_seqbegin(&bb->lock);
-
- len = 0;
- i = 0;
-
- while (len < PAGE_SIZE && i < bb->count) {
- sector_t s = BB_OFFSET(p[i]);
- unsigned int length = BB_LEN(p[i]);
- int ack = BB_ACK(p[i]);
- i++;
-
- if (unack && ack)
- continue;
-
- len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
- (unsigned long long)s << bb->shift,
- length << bb->shift);
- }
- if (unack && len == 0)
- bb->unacked_exist = 0;
-
- if (read_seqretry(&bb->lock, seq))
- goto retry;
-
- return len;
-}
-
-#define DO_DEBUG 1
-
-static ssize_t
-badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack)
-{
- unsigned long long sector;
- int length;
- char newline;
-#ifdef DO_DEBUG
- /* Allow clearing via sysfs *only* for testing/debugging.
- * Normally only a successful write may clear a badblock
- */
- int clear = 0;
- if (page[0] == '-') {
- clear = 1;
- page++;
- }
-#endif /* DO_DEBUG */
-
- switch (sscanf(page, "%llu %d%c", §or, &length, &newline)) {
- case 3:
- if (newline != '\n')
- return -EINVAL;
- case 2:
- if (length <= 0)
- return -EINVAL;
- break;
- default:
- return -EINVAL;
- }
-
-#ifdef DO_DEBUG
- if (clear) {
- md_clear_badblocks(bb, sector, length);
- return len;
- }
-#endif /* DO_DEBUG */
- if (md_set_badblocks(bb, sector, length, !unack))
- return len;
- else
- return -ENOSPC;
-}
-
static int md_notify_reboot(struct notifier_block *this,
unsigned long code, void *x)
{
diff --git a/drivers/md/md.h b/drivers/md/md.h
index ab33957..dd9fab8 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -17,6 +17,7 @@
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
+#include <linux/badblocks.h>
#include <linux/kobject.h>
#include <linux/list.h>
#include <linux/mm.h>
@@ -28,13 +29,6 @@
#define MaxSector (~(sector_t)0)
-/* Bad block numbers are stored sorted in a single page.
- * 64bits is used for each block or extent.
- * 54 bits are sector number, 9 bits are extent size,
- * 1 bit is an 'acknowledged' flag.
- */
-#define MD_MAX_BADBLOCKS (PAGE_SIZE/8)
-
/*
* MD's 'extended' device
*/
@@ -111,22 +105,7 @@ struct md_rdev {
struct kernfs_node *sysfs_state; /* handle for 'state'
* sysfs entry */
- struct badblocks {
- int count; /* count of bad blocks */
- int unacked_exist; /* there probably are unacknowledged
- * bad blocks. This is only cleared
- * when a read discovers none
- */
- int shift; /* shift from sectors to block size
- * a -ve shift means badblocks are
- * disabled.*/
- u64 *page; /* badblock list */
- int changed;
- seqlock_t lock;
-
- sector_t sector;
- sector_t size; /* in sectors */
- } badblocks;
+ struct badblocks badblocks;
};
enum flag_bits {
Faulty, /* device is known to have a fault */
@@ -183,13 +162,11 @@ enum flag_bits {
#define BB_ACK(x) (!!((x) & BB_ACK_MASK))
#define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
-extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
- sector_t *first_bad, int *bad_sectors);
static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
sector_t *first_bad, int *bad_sectors)
{
if (unlikely(rdev->badblocks.count)) {
- int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
+ int rv = badblocks_check(&rdev->badblocks, rdev->data_offset + s,
sectors,
first_bad, bad_sectors);
if (rv)
@@ -202,8 +179,6 @@ extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
int is_new);
extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
int is_new);
-extern void md_ack_all_badblocks(struct badblocks *bb);
-
struct md_cluster_info;
struct mddev {
--
2.5.0
^ permalink raw reply related [flat|nested] 13+ messages in thread