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-rw-r--r--drivers/md/bitmap.c39
-rw-r--r--drivers/md/md.c33
-rw-r--r--drivers/md/md.h3
3 files changed, 73 insertions, 2 deletions
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index c7784a98567..ac688fb54e1 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1934,6 +1934,44 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
static struct md_sysfs_entry bitmap_location =
__ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
+/* 'bitmap/space' is the space available at 'location' for the
+ * bitmap. This allows the kernel to know when it is safe to
+ * resize the bitmap to match a resized array.
+ */
+static ssize_t
+space_show(struct mddev *mddev, char *page)
+{
+ return sprintf(page, "%lu\n", mddev->bitmap_info.space);
+}
+
+static ssize_t
+space_store(struct mddev *mddev, const char *buf, size_t len)
+{
+ unsigned long sectors;
+ int rv;
+
+ rv = kstrtoul(buf, 10, &sectors);
+ if (rv)
+ return rv;
+
+ if (sectors == 0)
+ return -EINVAL;
+
+ if (mddev->bitmap &&
+ sectors < ((mddev->bitmap->file_pages - 1) * PAGE_SIZE
+ + mddev->bitmap->last_page_size + 511) >> 9)
+ return -EFBIG; /* Bitmap is too big for this small space */
+
+ /* could make sure it isn't too big, but that isn't really
+ * needed - user-space should be careful.
+ */
+ mddev->bitmap_info.space = sectors;
+ return len;
+}
+
+static struct md_sysfs_entry bitmap_space =
+__ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
+
static ssize_t
timeout_show(struct mddev *mddev, char *page)
{
@@ -2109,6 +2147,7 @@ __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
static struct attribute *md_bitmap_attrs[] = {
&bitmap_location.attr,
+ &bitmap_space.attr,
&bitmap_timeout.attr,
&bitmap_backlog.attr,
&bitmap_chunksize.attr,
diff --git a/drivers/md/md.c b/drivers/md/md.c
index ac99616f48d..9a677f2078a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1197,7 +1197,10 @@ static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
mddev->dev_sectors = ((sector_t)sb->size) * 2;
mddev->events = ev1;
mddev->bitmap_info.offset = 0;
+ mddev->bitmap_info.space = 0;
+ /* bitmap can use 60 K after the 4K superblocks */
mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
+ mddev->bitmap_info.default_space = 64*2 - (MD_SB_BYTES >> 9);
mddev->reshape_backwards = 0;
if (mddev->minor_version >= 91) {
@@ -1234,9 +1237,12 @@ static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
mddev->max_disks = MD_SB_DISKS;
if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
- mddev->bitmap_info.file == NULL)
+ mddev->bitmap_info.file == NULL) {
mddev->bitmap_info.offset =
mddev->bitmap_info.default_offset;
+ mddev->bitmap_info.space =
+ mddev->bitmap_info.space;
+ }
} else if (mddev->pers == NULL) {
/* Insist on good event counter while assembling, except
@@ -1677,7 +1683,12 @@ static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
mddev->dev_sectors = le64_to_cpu(sb->size);
mddev->events = ev1;
mddev->bitmap_info.offset = 0;
+ mddev->bitmap_info.space = 0;
+ /* Default location for bitmap is 1K after superblock
+ * using 3K - total of 4K
+ */
mddev->bitmap_info.default_offset = 1024 >> 9;
+ mddev->bitmap_info.default_space = (4096-1024) >> 9;
mddev->reshape_backwards = 0;
mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
@@ -1686,9 +1697,23 @@ static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
mddev->max_disks = (4096-256)/2;
if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
- mddev->bitmap_info.file == NULL )
+ mddev->bitmap_info.file == NULL) {
mddev->bitmap_info.offset =
(__s32)le32_to_cpu(sb->bitmap_offset);
+ /* Metadata doesn't record how much space is available.
+ * For 1.0, we assume we can use up to the superblock
+ * if before, else to 4K beyond superblock.
+ * For others, assume no change is possible.
+ */
+ if (mddev->minor_version > 0)
+ mddev->bitmap_info.space = 0;
+ else if (mddev->bitmap_info.offset > 0)
+ mddev->bitmap_info.space =
+ 8 - mddev->bitmap_info.offset;
+ else
+ mddev->bitmap_info.space =
+ -mddev->bitmap_info.offset;
+ }
if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
mddev->reshape_position = le64_to_cpu(sb->reshape_position);
@@ -5280,6 +5305,7 @@ static void md_clean(struct mddev *mddev)
mddev->merge_check_needed = 0;
mddev->bitmap_info.offset = 0;
mddev->bitmap_info.default_offset = 0;
+ mddev->bitmap_info.default_space = 0;
mddev->bitmap_info.chunksize = 0;
mddev->bitmap_info.daemon_sleep = 0;
mddev->bitmap_info.max_write_behind = 0;
@@ -6076,6 +6102,7 @@ static int set_array_info(struct mddev * mddev, mdu_array_info_t *info)
set_bit(MD_CHANGE_DEVS, &mddev->flags);
mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
+ mddev->bitmap_info.default_space = 64*2 - (MD_SB_BYTES >> 9);
mddev->bitmap_info.offset = 0;
mddev->reshape_position = MaxSector;
@@ -6258,6 +6285,8 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
return -EINVAL;
mddev->bitmap_info.offset =
mddev->bitmap_info.default_offset;
+ mddev->bitmap_info.space =
+ mddev->bitmap_info.default_space;
mddev->pers->quiesce(mddev, 1);
rv = bitmap_create(mddev);
if (!rv)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 360937389e6..7b4a3c318ca 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -393,10 +393,13 @@ struct mddev {
* For external metadata, offset
* from start of device.
*/
+ unsigned long space; /* space available at this offset */
loff_t default_offset; /* this is the offset to use when
* hot-adding a bitmap. It should
* eventually be settable by sysfs.
*/
+ unsigned long default_space; /* space available at
+ * default offset */
struct mutex mutex;
unsigned long chunksize;
unsigned long daemon_sleep; /* how many jiffies between updates? */
generated by cgit v1.2.3-70-g09d2 (git 2.51.2) at 2025-11-04 11:42:26 +0000