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md: rationalize raid5 function names
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From: Dan Williams <dan.j.williams@intel.com>

Commit a445685 refactored some of the deep code paths in raid5.c into separate
functions.  The names chosen at the time do not consistently indicate what is
going to happen to the stripe.  So, update the names, and since a stripe is a
cache element use cache semantics like fill, dirty, and clean.

(also, fix up the indentation in fetch_block5)

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>
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Dan Williams authored and Neil Brown committed Jun 27, 2008
1 parent 7b3a871 commit 1fe797e
Showing 1 changed file with 40 additions and 36 deletions.
76 changes: 40 additions & 36 deletions drivers/md/raid5.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1618,7 +1618,7 @@ static void compute_block_2(struct stripe_head *sh, int dd_idx1, int dd_idx2)
}

static void
handle_write_operations5(struct stripe_head *sh, struct stripe_head_state *s,
schedule_reconstruction5(struct stripe_head *sh, struct stripe_head_state *s,
int rcw, int expand)
{
int i, pd_idx = sh->pd_idx, disks = sh->disks;
Expand Down Expand Up @@ -1783,7 +1783,7 @@ static int stripe_to_pdidx(sector_t stripe, raid5_conf_t *conf, int disks)
}

static void
handle_requests_to_failed_array(raid5_conf_t *conf, struct stripe_head *sh,
handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh,
struct stripe_head_state *s, int disks,
struct bio **return_bi)
{
Expand Down Expand Up @@ -1874,23 +1874,28 @@ handle_requests_to_failed_array(raid5_conf_t *conf, struct stripe_head *sh,
md_wakeup_thread(conf->mddev->thread);
}

/* __handle_issuing_new_read_requests5 - returns 0 if there are no more disks
* to process
/* fetch_block5 - 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
*/
static int __handle_issuing_new_read_requests5(struct stripe_head *sh,
struct stripe_head_state *s, int disk_idx, int disks)
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];

/* 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 || (failed_dev->towrite &&
!test_bit(R5_OVERWRITE, &failed_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 ||
(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
*/
Expand All @@ -1908,7 +1913,7 @@ static int __handle_issuing_new_read_requests5(struct stripe_head *sh,
* subsequent operation.
*/
s->uptodate++;
return 0; /* uptodate + compute == disks */
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);
Expand All @@ -1918,10 +1923,13 @@ static int __handle_issuing_new_read_requests5(struct stripe_head *sh,
}
}

return ~0;
return 0;
}

static void handle_issuing_new_read_requests5(struct stripe_head *sh,
/**
* 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;
Expand All @@ -1931,16 +1939,14 @@ static void handle_issuing_new_read_requests5(struct stripe_head *sh,
* midst of changing due to a write
*/
if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
!sh->reconstruct_state) {
!sh->reconstruct_state)
for (i = disks; i--; )
if (__handle_issuing_new_read_requests5(
sh, s, i, disks) == 0)
if (fetch_block5(sh, s, i, disks))
break;
}
set_bit(STRIPE_HANDLE, &sh->state);
}

static void handle_issuing_new_read_requests6(struct stripe_head *sh,
static void handle_stripe_fill6(struct stripe_head *sh,
struct stripe_head_state *s, struct r6_state *r6s,
int disks)
{
Expand Down Expand Up @@ -1999,12 +2005,12 @@ static void handle_issuing_new_read_requests6(struct stripe_head *sh,
}


/* handle_completed_write_requests
/* handle_stripe_clean_event
* any written block on an uptodate or failed drive can be returned.
* Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
* never LOCKED, so we don't need to test 'failed' directly.
*/
static void handle_completed_write_requests(raid5_conf_t *conf,
static void handle_stripe_clean_event(raid5_conf_t *conf,
struct stripe_head *sh, int disks, struct bio **return_bi)
{
int i;
Expand Down Expand Up @@ -2049,7 +2055,7 @@ static void handle_completed_write_requests(raid5_conf_t *conf,
md_wakeup_thread(conf->mddev->thread);
}

static void handle_issuing_new_write_requests5(raid5_conf_t *conf,
static void handle_stripe_dirtying5(raid5_conf_t *conf,
struct stripe_head *sh, struct stripe_head_state *s, int disks)
{
int rmw = 0, rcw = 0, i;
Expand Down Expand Up @@ -2136,10 +2142,10 @@ static void handle_issuing_new_write_requests5(raid5_conf_t *conf,
if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
(s->locked == 0 && (rcw == 0 || rmw == 0) &&
!test_bit(STRIPE_BIT_DELAY, &sh->state)))
handle_write_operations5(sh, s, rcw == 0, 0);
schedule_reconstruction5(sh, s, rcw == 0, 0);
}

static void handle_issuing_new_write_requests6(raid5_conf_t *conf,
static void handle_stripe_dirtying6(raid5_conf_t *conf,
struct stripe_head *sh, struct stripe_head_state *s,
struct r6_state *r6s, int disks)
{
Expand Down Expand Up @@ -2597,8 +2603,7 @@ static void handle_stripe5(struct stripe_head *sh)
* need to be failed
*/
if (s.failed > 1 && s.to_read+s.to_write+s.written)
handle_requests_to_failed_array(conf, sh, &s, disks,
&return_bi);
handle_failed_stripe(conf, sh, &s, disks, &return_bi);
if (s.failed > 1 && s.syncing) {
md_done_sync(conf->mddev, STRIPE_SECTORS,0);
clear_bit(STRIPE_SYNCING, &sh->state);
Expand All @@ -2614,15 +2619,15 @@ static void handle_stripe5(struct stripe_head *sh)
!test_bit(R5_LOCKED, &dev->flags) &&
test_bit(R5_UPTODATE, &dev->flags)) ||
(s.failed == 1 && s.failed_num == sh->pd_idx)))
handle_completed_write_requests(conf, sh, disks, &return_bi);
handle_stripe_clean_event(conf, sh, disks, &return_bi);

/* Now we might consider reading some blocks, either to check/generate
* parity, or to satisfy requests
* or to load a block that is being partially written.
*/
if (s.to_read || s.non_overwrite ||
(s.syncing && (s.uptodate + s.compute < disks)) || s.expanding)
handle_issuing_new_read_requests5(sh, &s, disks);
handle_stripe_fill5(sh, &s, disks);

/* Now we check to see if any write operations have recently
* completed
Expand Down Expand Up @@ -2666,7 +2671,7 @@ static void handle_stripe5(struct stripe_head *sh)
* block.
*/
if (s.to_write && !sh->reconstruct_state && !sh->check_state)
handle_issuing_new_write_requests5(conf, sh, &s, disks);
handle_stripe_dirtying5(conf, sh, &s, disks);

/* maybe we need to check and possibly fix the parity for this stripe
* Any reads will already have been scheduled, so we just see if enough
Expand Down Expand Up @@ -2722,7 +2727,7 @@ static void handle_stripe5(struct stripe_head *sh)
sh->disks = conf->raid_disks;
sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
conf->raid_disks);
handle_write_operations5(sh, &s, 1, 1);
schedule_reconstruction5(sh, &s, 1, 1);
} else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
clear_bit(STRIPE_EXPAND_READY, &sh->state);
atomic_dec(&conf->reshape_stripes);
Expand Down Expand Up @@ -2854,8 +2859,7 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
* might need to be failed
*/
if (s.failed > 2 && s.to_read+s.to_write+s.written)
handle_requests_to_failed_array(conf, sh, &s, disks,
&return_bi);
handle_failed_stripe(conf, sh, &s, disks, &return_bi);
if (s.failed > 2 && s.syncing) {
md_done_sync(conf->mddev, STRIPE_SECTORS,0);
clear_bit(STRIPE_SYNCING, &sh->state);
Expand All @@ -2880,19 +2884,19 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
( r6s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
&& !test_bit(R5_LOCKED, &qdev->flags)
&& test_bit(R5_UPTODATE, &qdev->flags)))))
handle_completed_write_requests(conf, sh, disks, &return_bi);
handle_stripe_clean_event(conf, sh, disks, &return_bi);

/* Now we might consider reading some blocks, either to check/generate
* parity, or to satisfy requests
* or to load a block that is being partially written.
*/
if (s.to_read || s.non_overwrite || (s.to_write && s.failed) ||
(s.syncing && (s.uptodate < disks)) || s.expanding)
handle_issuing_new_read_requests6(sh, &s, &r6s, disks);
handle_stripe_fill6(sh, &s, &r6s, disks);

/* now to consider writing and what else, if anything should be read */
if (s.to_write)
handle_issuing_new_write_requests6(conf, sh, &s, &r6s, disks);
handle_stripe_dirtying6(conf, sh, &s, &r6s, disks);

/* maybe we need to check and possibly fix the parity for this stripe
* Any reads will already have been scheduled, so we just see if enough
Expand Down

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