exofs: Prepare for groups

* Rename _offset_dev_unit_off() to _calc_stripe_info() and recieve a struct for the output params * In _prepare_for_striping we only need to call _calc_stripe_info() once. The other componets are easy to calculate from that. This code was inspired by what's done in truncate. * Some code shifts that make sense now but will make more sense when group support is added. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>

exofs: Prepare for groups
* Rename _offset_dev_unit_off() to _calc_stripe_info() and recieve a struct for the output params * In _prepare_for_striping we only need to call _calc_stripe_info() once. The other componets are easy to calculate from that. This code was inspired by what's done in truncate. * Some code shifts that make sense now but will make more sense when group support is added. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Boaz Harrosh
1 parent 96391e2bae
Showing 1 changed file with 99 additions and 60 deletions Side-by-side Diff
fs/exofs/ios.c
@@ -259,28 +259,46 @@
 	return acumulated_lin_err;
 }
  
-/* REMOVEME: After review
-   Some quoteing from the standard
+/*
+ * L - logical offset into the file
+ *
+ * U - The number of bytes in a full stripe
+ *
+ *	U = stripe_unit * group_width
+ *
+ * N - The stripe number
+ *
+ *	N = L / U
+ *
+ * C - The component index coresponding to L
+ *
+ *	C = (L - (N*U)) / stripe_unit
+ *
+ * O - The component offset coresponding to L
+ *
+ *	(N*stripe_unit)+(L%stripe_unit)
+ */
  
-   L = logical offset into the file
-   W = number of data components in a stripe
-   S = W * stripe_unit (S is Stripe length)
-   N = L / S (N is the stripe Number)
-   C = (L-(N*S)) / stripe_unit (C is the component)
-   O = (N*stripe_unit)+(L%stripe_unit) (O is the object's offset)
-*/
+struct _striping_info {
+	u64 obj_offset;
+	unsigned dev;
+	unsigned unit_off;
+};
  
-static void _offset_dev_unit_off(struct exofs_io_state *ios, u64 file_offset,
-			u64 *obj_offset, unsigned *dev, unsigned *unit_off)
+static void _calc_stripe_info(struct exofs_io_state *ios, u64 file_offset,
+			      struct _striping_info *si)
 {
-	unsigned stripe_unit = ios->layout->stripe_unit;
-	unsigned stripe_length = stripe_unit * ios->layout->group_width;
-	u64 stripe_no = file_offset;
-	unsigned stripe_mod = do_div(stripe_no, stripe_length);
+	u32	stripe_unit = ios->layout->stripe_unit;
+	u32	group_width = ios->layout->group_width;
+	u32	U = stripe_unit * group_width;
  
-	*unit_off = stripe_mod % stripe_unit;
-	*obj_offset = stripe_no * stripe_unit + *unit_off;
-	*dev = stripe_mod / stripe_unit * ios->layout->mirrors_p1;
+	u32	LmodU;
+	u64 	N = div_u64_rem(file_offset, U, &LmodU);
+
+	si->unit_off = LmodU % stripe_unit;
+	si->obj_offset = N * stripe_unit + si->unit_off;
+	si->dev = LmodU / stripe_unit;
+	si->dev *= ios->layout->mirrors_p1;
 }
  
 static int _add_stripe_unit(struct exofs_io_state *ios,  unsigned *cur_pg,
  
  
  
  
  
  
  
  
  
  
  
  
@@ -327,65 +345,88 @@
 	return 0;
 }
  
-static int _prepare_for_striping(struct exofs_io_state *ios)
+static int _prepare_pages(struct exofs_io_state *ios,
+			  struct _striping_info *si)
 {
 	u64 length = ios->length;
-	u64 offset = ios->offset;
 	unsigned stripe_unit = ios->layout->stripe_unit;
+	unsigned mirrors_p1 = ios->layout->mirrors_p1;
+	unsigned dev = si->dev;
 	unsigned comp = 0;
 	unsigned stripes = 0;
 	unsigned cur_pg = 0;
 	int ret = 0;
  
-	if (!ios->pages) {
-		if (ios->kern_buff) {
-			struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
-			unsigned unit_off;
-
-			_offset_dev_unit_off(ios, offset, &per_dev->offset,
-					     &per_dev->dev, &unit_off);
-			/* no cross device without page array */
-			BUG_ON((ios->layout->group_width > 1) &&
-			       (unit_off + length > stripe_unit));
-		}
-		ios->numdevs = ios->layout->mirrors_p1;
-		return 0;
-	}
-
 	while (length) {
 		struct exofs_per_dev_state *per_dev = &ios->per_dev[comp];
-		unsigned cur_len, page_off;
+		unsigned cur_len, page_off = 0;
  
 		if (!per_dev->length) {
-			unsigned unit_off;
+			per_dev->dev = dev;
+			if (dev < si->dev) {
+				per_dev->offset = si->obj_offset + stripe_unit -
+								   si->unit_off;
+				cur_len = stripe_unit;
+			} else if (dev == si->dev) {
+				per_dev->offset = si->obj_offset;
+				cur_len = stripe_unit - si->unit_off;
+				page_off = si->unit_off & ~PAGE_MASK;
+				BUG_ON(page_off && (page_off != ios->pgbase));
+			} else { /* dev > si->dev */
+				per_dev->offset = si->obj_offset - si->unit_off;
+				cur_len = stripe_unit;
+			}
  
-			_offset_dev_unit_off(ios, offset, &per_dev->offset,
-					     &per_dev->dev, &unit_off);
 			stripes++;
-			cur_len = min_t(u64, stripe_unit - unit_off, length);
-			offset += cur_len;
-			page_off = unit_off & ~PAGE_MASK;
-			BUG_ON(page_off != ios->pgbase);
+
+			dev += mirrors_p1;
+			dev %= ios->layout->s_numdevs;
 		} else {
-			cur_len = min_t(u64, stripe_unit, length);
-			page_off = 0;
+			cur_len = stripe_unit;
 		}
+		if (cur_len >= length)
+			cur_len = length;
  
 		ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
 				       cur_len);
 		if (unlikely(ret))
 			goto out;
  
-		comp += ios->layout->mirrors_p1;
+		comp += mirrors_p1;
 		comp %= ios->layout->s_numdevs;
  
 		length -= cur_len;
 	}
 out:
-	ios->numdevs = stripes * ios->layout->mirrors_p1;
+	ios->numdevs = stripes * mirrors_p1;
 	return ret;
 }
  
+static int _prepare_for_striping(struct exofs_io_state *ios)
+{
+	struct _striping_info si;
+
+	_calc_stripe_info(ios, ios->offset, &si);
+
+	if (!ios->pages) {
+		if (ios->kern_buff) {
+			struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
+
+			per_dev->offset = si.obj_offset;
+			per_dev->dev = si.dev;
+
+			/* no cross device without page array */
+			BUG_ON((ios->layout->group_width > 1) &&
+			       (si.unit_off + ios->length >
+				ios->layout->stripe_unit));
+		}
+		ios->numdevs = ios->layout->mirrors_p1;
+		return 0;
+	}
+
+	return _prepare_pages(ios, &si);
+}
+
 int exofs_sbi_create(struct exofs_io_state *ios)
 {
 	int i, ret;
@@ -648,9 +689,7 @@
 		struct osd_attr attr;
 		__be64 newsize;
 	} *size_attrs;
-	u64 this_obj_size;
-	unsigned dev;
-	unsigned unit_off;
+	struct _striping_info si;
 	int i, ret;
  
 	ret = exofs_get_io_state(&sbi->layout, &ios);
  
@@ -668,19 +707,19 @@
 	ios->cred = oi->i_cred;
  
 	ios->numdevs = ios->layout->s_numdevs;
-	_offset_dev_unit_off(ios, size, &this_obj_size, &dev, &unit_off);
+	_calc_stripe_info(ios, size, &si);
  
 	for (i = 0; i < ios->layout->group_width; ++i) {
 		struct exofs_trunc_attr *size_attr = &size_attrs[i];
 		u64 obj_size;
  
-		if (i < dev)
-			obj_size = this_obj_size +
-					ios->layout->stripe_unit - unit_off;
-		else if (i == dev)
-			obj_size = this_obj_size;
-		else /* i > dev */
-			obj_size = this_obj_size - unit_off;
+		if (i < si.dev)
+			obj_size = si.obj_offset +
+					ios->layout->stripe_unit - si.unit_off;
+		else if (i == si.dev)
+			obj_size = si.obj_offset;
+		else /* i > si.dev */
+			obj_size = si.obj_offset - si.unit_off;
  
 		size_attr->newsize = cpu_to_be64(obj_size);
 		size_attr->attr = g_attr_logical_length;
...	...	@@ -259,28 +259,46 @@
259	259	return acumulated_lin_err;
260	260	}
261	261
262		-/* REMOVEME: After review
263		- Some quoteing from the standard
	262	+/*
	263	+ * L - logical offset into the file
	264	+ *
	265	+ * U - The number of bytes in a full stripe
	266	+ *
	267	+ * U = stripe_unit * group_width
	268	+ *
	269	+ * N - The stripe number
	270	+ *
	271	+ * N = L / U
	272	+ *
	273	+ * C - The component index coresponding to L
	274	+ *
	275	+ * C = (L - (N*U)) / stripe_unit
	276	+ *
	277	+ * O - The component offset coresponding to L
	278	+ *
	279	+ * (N*stripe_unit)+(L%stripe_unit)
	280	+ */
264	281
265		- L = logical offset into the file
266		- W = number of data components in a stripe
267		- S = W * stripe_unit (S is Stripe length)
268		- N = L / S (N is the stripe Number)
269		- C = (L-(N*S)) / stripe_unit (C is the component)
270		- O = (N*stripe_unit)+(L%stripe_unit) (O is the object's offset)
271		-*/
	282	+struct _striping_info {
	283	+ u64 obj_offset;
	284	+ unsigned dev;
	285	+ unsigned unit_off;
	286	+};
272	287
273		-static void _offset_dev_unit_off(struct exofs_io_state *ios, u64 file_offset,
274		- u64 obj_offset, unsigned dev, unsigned *unit_off)
	288	+static void _calc_stripe_info(struct exofs_io_state *ios, u64 file_offset,
	289	+ struct _striping_info *si)
275	290	{
276		- unsigned stripe_unit = ios->layout->stripe_unit;
277		- unsigned stripe_length = stripe_unit * ios->layout->group_width;
278		- u64 stripe_no = file_offset;
279		- unsigned stripe_mod = do_div(stripe_no, stripe_length);
	291	+ u32 stripe_unit = ios->layout->stripe_unit;
	292	+ u32 group_width = ios->layout->group_width;
	293	+ u32 U = stripe_unit * group_width;
280	294
281		- *unit_off = stripe_mod % stripe_unit;
282		- obj_offset = stripe_no stripe_unit + *unit_off;
283		- dev = stripe_mod / stripe_unit ios->layout->mirrors_p1;
	295	+ u32 LmodU;
	296	+ u64 N = div_u64_rem(file_offset, U, &LmodU);
	297	+
	298	+ si->unit_off = LmodU % stripe_unit;
	299	+ si->obj_offset = N * stripe_unit + si->unit_off;
	300	+ si->dev = LmodU / stripe_unit;
	301	+ si->dev *= ios->layout->mirrors_p1;
284	302	}
285	303
286	304	static int _add_stripe_unit(struct exofs_io_state ios, unsigned cur_pg,
287	305
288	306
289	307
290	308
291	309
292	310
293	311
294	312
295	313
296	314
297	315
298	316
...	...	@@ -327,65 +345,88 @@
327	345	return 0;
328	346	}
329	347
330		-static int _prepare_for_striping(struct exofs_io_state *ios)
	348	+static int _prepare_pages(struct exofs_io_state *ios,
	349	+ struct _striping_info *si)
331	350	{
332	351	u64 length = ios->length;
333		- u64 offset = ios->offset;
334	352	unsigned stripe_unit = ios->layout->stripe_unit;
	353	+ unsigned mirrors_p1 = ios->layout->mirrors_p1;
	354	+ unsigned dev = si->dev;
335	355	unsigned comp = 0;
336	356	unsigned stripes = 0;
337	357	unsigned cur_pg = 0;
338	358	int ret = 0;
339	359
340		- if (!ios->pages) {
341		- if (ios->kern_buff) {
342		- struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
343		- unsigned unit_off;
344		-
345		- _offset_dev_unit_off(ios, offset, &per_dev->offset,
346		- &per_dev->dev, &unit_off);
347		- /* no cross device without page array */
348		- BUG_ON((ios->layout->group_width > 1) &&
349		- (unit_off + length > stripe_unit));
350		- }
351		- ios->numdevs = ios->layout->mirrors_p1;
352		- return 0;
353		- }
354		-
355	360	while (length) {
356	361	struct exofs_per_dev_state *per_dev = &ios->per_dev[comp];
357		- unsigned cur_len, page_off;
	362	+ unsigned cur_len, page_off = 0;
358	363
359	364	if (!per_dev->length) {
360		- unsigned unit_off;
	365	+ per_dev->dev = dev;
	366	+ if (dev < si->dev) {
	367	+ per_dev->offset = si->obj_offset + stripe_unit -
	368	+ si->unit_off;
	369	+ cur_len = stripe_unit;
	370	+ } else if (dev == si->dev) {
	371	+ per_dev->offset = si->obj_offset;
	372	+ cur_len = stripe_unit - si->unit_off;
	373	+ page_off = si->unit_off & ~PAGE_MASK;
	374	+ BUG_ON(page_off && (page_off != ios->pgbase));
	375	+ } else { /* dev > si->dev */
	376	+ per_dev->offset = si->obj_offset - si->unit_off;
	377	+ cur_len = stripe_unit;
	378	+ }
361	379
362		- _offset_dev_unit_off(ios, offset, &per_dev->offset,
363		- &per_dev->dev, &unit_off);
364	380	stripes++;
365		- cur_len = min_t(u64, stripe_unit - unit_off, length);
366		- offset += cur_len;
367		- page_off = unit_off & ~PAGE_MASK;
368		- BUG_ON(page_off != ios->pgbase);
	381	+
	382	+ dev += mirrors_p1;
	383	+ dev %= ios->layout->s_numdevs;
369	384	} else {
370		- cur_len = min_t(u64, stripe_unit, length);
371		- page_off = 0;
	385	+ cur_len = stripe_unit;
372	386	}
	387	+ if (cur_len >= length)
	388	+ cur_len = length;
373	389
374	390	ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
375	391	cur_len);
376	392	if (unlikely(ret))
377	393	goto out;
378	394
379		- comp += ios->layout->mirrors_p1;
	395	+ comp += mirrors_p1;
380	396	comp %= ios->layout->s_numdevs;
381	397
382	398	length -= cur_len;
383	399	}
384	400	out:
385		- ios->numdevs = stripes * ios->layout->mirrors_p1;
	401	+ ios->numdevs = stripes * mirrors_p1;
386	402	return ret;
387	403	}
388	404
	405	+static int _prepare_for_striping(struct exofs_io_state *ios)
	406	+{
	407	+ struct _striping_info si;
	408	+
	409	+ _calc_stripe_info(ios, ios->offset, &si);
	410	+
	411	+ if (!ios->pages) {
	412	+ if (ios->kern_buff) {
	413	+ struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
	414	+
	415	+ per_dev->offset = si.obj_offset;
	416	+ per_dev->dev = si.dev;
	417	+
	418	+ /* no cross device without page array */
	419	+ BUG_ON((ios->layout->group_width > 1) &&
	420	+ (si.unit_off + ios->length >
	421	+ ios->layout->stripe_unit));
	422	+ }
	423	+ ios->numdevs = ios->layout->mirrors_p1;
	424	+ return 0;
	425	+ }
	426	+
	427	+ return _prepare_pages(ios, &si);
	428	+}
	429	+
389	430	int exofs_sbi_create(struct exofs_io_state *ios)
390	431	{
391	432	int i, ret;
...	...	@@ -648,9 +689,7 @@
648	689	struct osd_attr attr;
649	690	__be64 newsize;
650	691	} *size_attrs;
651		- u64 this_obj_size;
652		- unsigned dev;
653		- unsigned unit_off;
	692	+ struct _striping_info si;
654	693	int i, ret;
655	694
656	695	ret = exofs_get_io_state(&sbi->layout, &ios);
657	696
...	...	@@ -668,19 +707,19 @@
668	707	ios->cred = oi->i_cred;
669	708
670	709	ios->numdevs = ios->layout->s_numdevs;
671		- _offset_dev_unit_off(ios, size, &this_obj_size, &dev, &unit_off);
	710	+ _calc_stripe_info(ios, size, &si);
672	711
673	712	for (i = 0; i < ios->layout->group_width; ++i) {
674	713	struct exofs_trunc_attr *size_attr = &size_attrs[i];
675	714	u64 obj_size;
676	715
677		- if (i < dev)
678		- obj_size = this_obj_size +
679		- ios->layout->stripe_unit - unit_off;
680		- else if (i == dev)
681		- obj_size = this_obj_size;
682		- else /* i > dev */
683		- obj_size = this_obj_size - unit_off;
	716	+ if (i < si.dev)
	717	+ obj_size = si.obj_offset +
	718	+ ios->layout->stripe_unit - si.unit_off;
	719	+ else if (i == si.dev)
	720	+ obj_size = si.obj_offset;
	721	+ else /* i > si.dev */
	722	+ obj_size = si.obj_offset - si.unit_off;
684	723
685	724	size_attr->newsize = cpu_to_be64(obj_size);
686	725	size_attr->attr = g_attr_logical_length;