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Avoid confusing with 'blocks' number. 

The 'blocks' number computed by analyse_change is the number of
blocks that it makes sense to back-up at a time.
It is the smallest number of blocks that is a whole number of
stripes in both the old and the new layout.

However we are also using it as the smallest amount of progress
that can be made at a time, which is wrong as it is always valid
to progress a single stripe in the new layout.

So change 'blocks' to be called 'backup_blocks' to make it more clear.
And pass new_chunk size down so it can be used for 'minimum forward
progress' calculations.

Also set 'stripes' (the amount actually backed up) from the
possibly-scaled 'blocks' number rather than ignoring it and using
backup_blocks.

Finally, get rid of 'read_range' as it isn't used (or needed).

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2011-01-11 14:51:09 +11:00
parent 6eb48844a5
commit b4f8e38b94
1 changed files with 18 additions and 17 deletions
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35
Grow.c
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@ -886,7 +886,7 @@ struct reshape {
int layout;
int data_disks;
} before, after;
unsigned long long blocks;
unsigned long long backup_blocks;
unsigned long long stripes; /* number of old stripes that comprise 'blocks'*/
unsigned long long new_size; /* New size of array in sectors */
};
@ -947,7 +947,7 @@ char *analyse_change(struct mdinfo *info, struct reshape *re)
re->before.data_disks = (info->array.raid_disks +
info->delta_disks);
re->before.layout = 0;
re->blocks = 0;
re->backup_blocks = 0;
re->parity = 0;
return NULL;
}
@ -958,7 +958,7 @@ char *analyse_change(struct mdinfo *info, struct reshape *re)
re->parity = 1;
re->before.data_disks = 1;
re->before.layout = ALGORITHM_LEFT_SYMMETRIC;
re->blocks = 0;
re->backup_blocks = 0;
return NULL;
}
/* Could do some multi-stage conversions, but leave that to
@ -995,7 +995,7 @@ char *analyse_change(struct mdinfo *info, struct reshape *re)
re->parity = 0;
re->before.data_disks = new_disks;
re->before.layout = 0;
re->blocks = 0;
re->backup_blocks = 0;
return NULL;
case 0:
@ -1032,7 +1032,7 @@ char *analyse_change(struct mdinfo *info, struct reshape *re)
re->before.data_disks = (info->array.raid_disks +
info->delta_disks);
re->before.layout = info->new_layout;
re->blocks = 0;
re->backup_blocks = 0;
return NULL;
}
@ -1242,12 +1242,12 @@ char *analyse_change(struct mdinfo *info, struct reshape *re)
re->after.layout == re->before.layout &&
info->new_chunk == info->array.chunk_size) {
/* Nothing to change */
re->blocks = 0;
re->backup_blocks = 0;
return NULL;
}
if (re->after.data_disks == 1 && re->before.data_disks == 1) {
/* chunks can layout changes make no difference */
re->blocks = 0;
re->backup_blocks = 0;
return NULL;
}
@ -1259,7 +1259,7 @@ char *analyse_change(struct mdinfo *info, struct reshape *re)
get_linux_version() < 2006030)
return "reshape to fewer devices is not supported before 2.6.32 - sorry.";
re->blocks = compute_backup_blocks(
re->backup_blocks = compute_backup_blocks(
info->new_chunk, info->array.chunk_size,
re->after.data_disks,
re->before.data_disks);
@ -1706,7 +1706,7 @@ static int reshape_array(char *container, int fd, char *devname,
sysfs_free(info2);
}
if (reshape.blocks == 0) {
if (reshape.backup_blocks == 0) {
/* No restriping needed, but we might need to impose
* some more changes: layout, raid_disks, chunk_size
*/
@ -1804,7 +1804,7 @@ static int reshape_array(char *container, int fd, char *devname,
/* Decide how many blocks (sectors) for a reshape
* unit. The number we have so far is just a minimum
*/
blocks = reshape.blocks;
blocks = reshape.backup_blocks;
if (reshape.before.data_disks ==
reshape.after.data_disks) {
/* Make 'blocks' bigger for better throughput, but
@ -1892,6 +1892,8 @@ static int reshape_array(char *container, int fd, char *devname,
*/
sync_metadata(st);
sra->new_chunk = info->new_chunk;
if (info->array.chunk_size == info->new_chunk &&
reshape.before.layout == reshape.after.layout &&
st->ss->external == 0) {
@ -1983,7 +1985,7 @@ static int reshape_array(char *container, int fd, char *devname,
bsb.mtime = __cpu_to_le64(time(0));
bsb.devstart2 = blocks;
stripes = reshape.blocks / (info->array.chunk_size/512) /
stripes = blocks / (info->array.chunk_size/512) /
reshape.before.data_disks;
/* Now we just need to kick off the reshape and watch, while
@ -2278,7 +2280,7 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
int need_backup = (reshape->after.data_disks
== reshape->before.data_disks);
unsigned long long read_offset, write_offset;
unsigned long long read_range, write_range;
unsigned long long write_range;
unsigned long long max_progress, target, completed;
int fd;
@ -2313,8 +2315,7 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
*/
write_offset = info->reshape_progress / reshape->before.data_disks;
read_offset = info->reshape_progress / reshape->after.data_disks;
write_range = reshape->blocks / reshape->before.data_disks;
read_range = reshape->blocks / reshape->after.data_disks;
write_range = info->new_chunk/512;
if (advancing) {
if (read_offset < write_offset + write_range) {
max_progress = backup_point;
@ -2353,10 +2354,10 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
*/
target = 64*1024*2 * min(reshape->before.data_disks,
reshape->after.data_disks);
target /= reshape->blocks;
target /= reshape->backup_blocks;
if (target < 2)
target = 2;
target *= reshape->blocks;
target *= reshape->backup_blocks;
/* For externally managed metadata we always need to suspend IO to
* the area being reshaped so we regularly push suspend_point forward.
@ -2447,7 +2448,7 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
close(fd);
/* We return the need_backup flag. Caller will decide
* how much (a multiple of ->blocks) and will adjust
* how much (a multiple of ->backup_blocks) and will adjust
* suspend_{lo,hi} and suspend_point.
*/
return need_backup;