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md/raid5: unite fetch_block5 and fetch_block6
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Provided that ->failed_num[1] is not a valid device number (which is
easily achieved) fetch_block6 provides all the functionality of
fetch_block5.

So remove the latter and rename the former to simply "fetch_block".

Then handle_stripe_fill5 and handle_stripe_fill6 become the same and
can similarly be united.

Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
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NeilBrown committed Jul 27, 2011
1 parent 5d35e09 commit 93b3dbc
Showing 1 changed file with 23 additions and 84 deletions.
107 changes: 23 additions & 84 deletions drivers/md/raid5.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2308,99 +2308,30 @@ handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh,
md_wakeup_thread(conf->mddev->thread);
}

/* fetch_block5 - checks the given member device to see if its data needs
/* fetch_block - checks the given member device to see if its data needs
* to be read or computed to satisfy a request.
*
* Returns 1 when no more member devices need to be checked, otherwise returns
* 0 to tell the loop in handle_stripe_fill5 to continue
* 0 to tell the loop in handle_stripe_fill to continue
*/
static int fetch_block5(struct stripe_head *sh, struct stripe_head_state *s,
int disk_idx, int disks)
{
struct r5dev *dev = &sh->dev[disk_idx];
struct r5dev *failed_dev = &sh->dev[s->failed_num[0]];

/* is the data in this block needed, and can we get it? */
if (!test_bit(R5_LOCKED, &dev->flags) &&
!test_bit(R5_UPTODATE, &dev->flags) &&
(dev->toread ||
(dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
s->syncing || s->expanding ||
(s->failed && failed_dev->toread) ||
(s->failed && failed_dev->towrite &&
!test_bit(R5_OVERWRITE, &failed_dev->flags)))))) {
/* We would like to get this block, possibly by computing it,
* otherwise read it if the backing disk is insync
*/
if ((s->uptodate == disks - 1) &&
(s->failed && disk_idx == s->failed_num[0])) {
set_bit(STRIPE_COMPUTE_RUN, &sh->state);
set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
set_bit(R5_Wantcompute, &dev->flags);
sh->ops.target = disk_idx;
sh->ops.target2 = -1;
s->req_compute = 1;
/* Careful: from this point on 'uptodate' is in the eye
* of raid_run_ops which services 'compute' operations
* before writes. R5_Wantcompute flags a block that will
* be R5_UPTODATE by the time it is needed for a
* subsequent operation.
*/
s->uptodate++;
return 1; /* uptodate + compute == disks */
} else if (test_bit(R5_Insync, &dev->flags)) {
set_bit(R5_LOCKED, &dev->flags);
set_bit(R5_Wantread, &dev->flags);
s->locked++;
pr_debug("Reading block %d (sync=%d)\n", disk_idx,
s->syncing);
}
}

return 0;
}

/**
* handle_stripe_fill5 - read or compute data to satisfy pending requests.
*/
static void handle_stripe_fill5(struct stripe_head *sh,
struct stripe_head_state *s, int disks)
{
int i;

/* look for blocks to read/compute, skip this if a compute
* is already in flight, or if the stripe contents are in the
* midst of changing due to a write
*/
if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
!sh->reconstruct_state)
for (i = disks; i--; )
if (fetch_block5(sh, s, i, disks))
break;
set_bit(STRIPE_HANDLE, &sh->state);
}

/* fetch_block6 - checks the given member device to see if its data needs
* to be read or computed to satisfy a request.
*
* Returns 1 when no more member devices need to be checked, otherwise returns
* 0 to tell the loop in handle_stripe_fill6 to continue
*/
static int fetch_block6(struct stripe_head *sh, struct stripe_head_state *s,
int disk_idx, int disks)
static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
int disk_idx, int disks)
{
struct r5dev *dev = &sh->dev[disk_idx];
struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
&sh->dev[s->failed_num[1]] };

/* is the data in this block needed, and can we get it? */
if (!test_bit(R5_LOCKED, &dev->flags) &&
!test_bit(R5_UPTODATE, &dev->flags) &&
(dev->toread ||
(dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
s->syncing || s->expanding ||
(s->failed >= 1 && fdev[0]->toread) ||
(s->failed >= 2 && fdev[1]->toread) ||
(s->failed && s->to_write)) {
(sh->raid_conf->level <= 5 && s->failed && fdev[0]->towrite &&
!test_bit(R5_OVERWRITE, &fdev[0]->flags)) ||
(sh->raid_conf->level == 6 && s->failed && s->to_write))) {
/* we would like to get this block, possibly by computing it,
* otherwise read it if the backing disk is insync
*/
Expand All @@ -2420,6 +2351,12 @@ static int fetch_block6(struct stripe_head *sh, struct stripe_head_state *s,
sh->ops.target = disk_idx;
sh->ops.target2 = -1; /* no 2nd target */
s->req_compute = 1;
/* Careful: from this point on 'uptodate' is in the eye
* of raid_run_ops which services 'compute' operations
* before writes. R5_Wantcompute flags a block that will
* be R5_UPTODATE by the time it is needed for a
* subsequent operation.
*/
s->uptodate++;
return 1;
} else if (s->uptodate == disks-2 && s->failed >= 2) {
Expand Down Expand Up @@ -2460,11 +2397,11 @@ static int fetch_block6(struct stripe_head *sh, struct stripe_head_state *s,
}

/**
* handle_stripe_fill6 - read or compute data to satisfy pending requests.
* handle_stripe_fill - read or compute data to satisfy pending requests.
*/
static void handle_stripe_fill6(struct stripe_head *sh,
struct stripe_head_state *s,
int disks)
static void handle_stripe_fill(struct stripe_head *sh,
struct stripe_head_state *s,
int disks)
{
int i;

Expand All @@ -2475,7 +2412,7 @@ static void handle_stripe_fill6(struct stripe_head *sh,
if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
!sh->reconstruct_state)
for (i = disks; i--; )
if (fetch_block6(sh, s, i, disks))
if (fetch_block(sh, s, i, disks))
break;
set_bit(STRIPE_HANDLE, &sh->state);
}
Expand Down Expand Up @@ -3122,7 +3059,7 @@ static int handle_stripe5(struct stripe_head *sh, struct stripe_head_state *s)
*/
if (s->to_read || s->non_overwrite ||
(s->syncing && (s->uptodate + s->compute < disks)) || s->expanding)
handle_stripe_fill5(sh, s, disks);
handle_stripe_fill(sh, s, disks);

/* Now we check to see if any write operations have recently
* completed
Expand Down Expand Up @@ -3313,7 +3250,7 @@ static int handle_stripe6(struct stripe_head *sh, struct stripe_head_state *s)
*/
if (s->to_read || s->non_overwrite || (s->to_write && s->failed) ||
(s->syncing && (s->uptodate + s->compute < disks)) || s->expanding)
handle_stripe_fill6(sh, s, disks);
handle_stripe_fill(sh, s, disks);

/* Now we check to see if any write operations have recently
* completed
Expand Down Expand Up @@ -3397,6 +3334,8 @@ static void handle_stripe(struct stripe_head *sh)
s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
s.failed_num[0] = -1;
s.failed_num[1] = -1;

if (conf->level == 6)
done = handle_stripe6(sh, &s);
Expand Down

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