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-rw-r--r--meta/recipes-bsp/grub/files/lvm-Add-LVM-cache-logical-volume-handling.patch287
1 files changed, 287 insertions, 0 deletions
diff --git a/meta/recipes-bsp/grub/files/lvm-Add-LVM-cache-logical-volume-handling.patch b/meta/recipes-bsp/grub/files/lvm-Add-LVM-cache-logical-volume-handling.patch
new file mode 100644
index 0000000000..2b8157f592
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/lvm-Add-LVM-cache-logical-volume-handling.patch
@@ -0,0 +1,287 @@
1From 8eb02bcb5897b238b29ff762402bb0c3028f0eab Mon Sep 17 00:00:00 2001
2From: Michael Chang <mchang@suse.com>
3Date: Thu, 19 Mar 2020 13:56:13 +0800
4Subject: [PATCH 3/9] lvm: Add LVM cache logical volume handling
5
6The LVM cache logical volume is the logical volume consisting of the original
7and the cache pool logical volume. The original is usually on a larger and
8slower storage device while the cache pool is on a smaller and faster one. The
9performance of the original volume can be improved by storing the frequently
10used data on the cache pool to utilize the greater performance of faster
11device.
12
13The default cache mode "writethrough" ensures that any data written will be
14stored both in the cache and on the origin LV, therefore grub can be straight
15to read the original lv as no data loss is guarenteed.
16
17The second cache mode is "writeback", which delays writing from the cache pool
18back to the origin LV to have increased performance. The drawback is potential
19data loss if losing the associated cache device.
20
21During the boot time grub reads the LVM offline i.e. LVM volumes are not
22activated and mounted, hence it should be fine to read directly from original
23lv since all cached data should have been flushed back in the process of taking
24it offline.
25
26It is also not much helpful to the situation by adding fsync calls to the
27install code. The fsync did not force to write back dirty cache to the original
28device and rather it would update associated cache metadata to complete the
29write transaction with the cache device. IOW the writes to cached blocks still
30go only to the cache device.
31
32To write back dirty cache, as LVM cache did not support dirty cache flush per
33block range, there'no way to do it for file. On the other hand the "cleaner"
34policy is implemented and can be used to write back "all" dirty blocks in a
35cache, which effectively drain all dirty cache gradually to attain and last in
36the "clean" state, which can be useful for shrinking or decommissioning a
37cache. The result and effect is not what we are looking for here.
38
39In conclusion, as it seems no way to enforce file writes to the original
40device, grub may suffer from power failure as it cannot assemble the cache
41device and read the dirty data from it. However since the case is only
42applicable to writeback mode which is sensitive to data lost in nature, I'd
43still like to propose my (relatively simple) patch and treat reading dirty
44cache as improvement.
45
46Upstream-Status: Backport [commit 0454b0445393aafc5600e92ef0c39494e333b135
47from https://git.savannah.gnu.org/git/grub.git]
48
49Signed-off-by: Michael Chang <mchang@suse.com>
50Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
51Signed-off-by: Yongxin Liu <yongxin.liu@windriver.com>
52---
53 grub-core/disk/lvm.c | 190 +++++++++++++++++++++++++++++++++++++++++++++++++++
54 1 file changed, 190 insertions(+)
55
56diff --git a/grub-core/disk/lvm.c b/grub-core/disk/lvm.c
57index 7b265c7..dc6b83b 100644
58--- a/grub-core/disk/lvm.c
59+++ b/grub-core/disk/lvm.c
60@@ -33,6 +33,14 @@
61
62 GRUB_MOD_LICENSE ("GPLv3+");
63
64+struct cache_lv
65+{
66+ struct grub_diskfilter_lv *lv;
67+ char *cache_pool;
68+ char *origin;
69+ struct cache_lv *next;
70+};
71+
72
73 /* Go the string STR and return the number after STR. *P will point
74 at the number. In case STR is not found, *P will be NULL and the
75@@ -95,6 +103,34 @@ grub_lvm_check_flag (char *p, const char *str, const char *flag)
76 }
77 }
78
79+static void
80+grub_lvm_free_cache_lvs (struct cache_lv *cache_lvs)
81+{
82+ struct cache_lv *cache;
83+
84+ while ((cache = cache_lvs))
85+ {
86+ cache_lvs = cache_lvs->next;
87+
88+ if (cache->lv)
89+ {
90+ unsigned int i;
91+
92+ for (i = 0; i < cache->lv->segment_count; ++i)
93+ if (cache->lv->segments)
94+ grub_free (cache->lv->segments[i].nodes);
95+ grub_free (cache->lv->segments);
96+ grub_free (cache->lv->fullname);
97+ grub_free (cache->lv->idname);
98+ grub_free (cache->lv->name);
99+ }
100+ grub_free (cache->lv);
101+ grub_free (cache->origin);
102+ grub_free (cache->cache_pool);
103+ grub_free (cache);
104+ }
105+}
106+
107 static struct grub_diskfilter_vg *
108 grub_lvm_detect (grub_disk_t disk,
109 struct grub_diskfilter_pv_id *id,
110@@ -242,6 +278,8 @@ grub_lvm_detect (grub_disk_t disk,
111
112 if (! vg)
113 {
114+ struct cache_lv *cache_lvs = NULL;
115+
116 /* First time we see this volume group. We've to create the
117 whole volume group structure. */
118 vg = grub_malloc (sizeof (*vg));
119@@ -671,6 +709,106 @@ grub_lvm_detect (grub_disk_t disk,
120 seg->nodes[seg->node_count - 1].name = tmp;
121 }
122 }
123+ else if (grub_memcmp (p, "cache\"",
124+ sizeof ("cache\"") - 1) == 0)
125+ {
126+ struct cache_lv *cache = NULL;
127+
128+ char *p2, *p3;
129+ grub_size_t sz;
130+
131+ cache = grub_zalloc (sizeof (*cache));
132+ if (!cache)
133+ goto cache_lv_fail;
134+ cache->lv = grub_zalloc (sizeof (*cache->lv));
135+ if (!cache->lv)
136+ goto cache_lv_fail;
137+ grub_memcpy (cache->lv, lv, sizeof (*cache->lv));
138+
139+ if (lv->fullname)
140+ {
141+ cache->lv->fullname = grub_strdup (lv->fullname);
142+ if (!cache->lv->fullname)
143+ goto cache_lv_fail;
144+ }
145+ if (lv->idname)
146+ {
147+ cache->lv->idname = grub_strdup (lv->idname);
148+ if (!cache->lv->idname)
149+ goto cache_lv_fail;
150+ }
151+ if (lv->name)
152+ {
153+ cache->lv->name = grub_strdup (lv->name);
154+ if (!cache->lv->name)
155+ goto cache_lv_fail;
156+ }
157+
158+ skip_lv = 1;
159+
160+ p2 = grub_strstr (p, "cache_pool = \"");
161+ if (!p2)
162+ goto cache_lv_fail;
163+
164+ p2 = grub_strchr (p2, '"');
165+ if (!p2)
166+ goto cache_lv_fail;
167+
168+ p3 = ++p2;
169+ p3 = grub_strchr (p3, '"');
170+ if (!p3)
171+ goto cache_lv_fail;
172+
173+ sz = p3 - p2;
174+
175+ cache->cache_pool = grub_malloc (sz + 1);
176+ if (!cache->cache_pool)
177+ goto cache_lv_fail;
178+ grub_memcpy (cache->cache_pool, p2, sz);
179+ cache->cache_pool[sz] = '\0';
180+
181+ p2 = grub_strstr (p, "origin = \"");
182+ if (!p2)
183+ goto cache_lv_fail;
184+
185+ p2 = grub_strchr (p2, '"');
186+ if (!p2)
187+ goto cache_lv_fail;
188+
189+ p3 = ++p2;
190+ p3 = grub_strchr (p3, '"');
191+ if (!p3)
192+ goto cache_lv_fail;
193+
194+ sz = p3 - p2;
195+
196+ cache->origin = grub_malloc (sz + 1);
197+ if (!cache->origin)
198+ goto cache_lv_fail;
199+ grub_memcpy (cache->origin, p2, sz);
200+ cache->origin[sz] = '\0';
201+
202+ cache->next = cache_lvs;
203+ cache_lvs = cache;
204+ break;
205+
206+ cache_lv_fail:
207+ if (cache)
208+ {
209+ grub_free (cache->origin);
210+ grub_free (cache->cache_pool);
211+ if (cache->lv)
212+ {
213+ grub_free (cache->lv->fullname);
214+ grub_free (cache->lv->idname);
215+ grub_free (cache->lv->name);
216+ }
217+ grub_free (cache->lv);
218+ grub_free (cache);
219+ }
220+ grub_lvm_free_cache_lvs (cache_lvs);
221+ goto fail4;
222+ }
223 else
224 {
225 #ifdef GRUB_UTIL
226@@ -747,6 +885,58 @@ grub_lvm_detect (grub_disk_t disk,
227 }
228
229 }
230+
231+ {
232+ struct cache_lv *cache;
233+
234+ for (cache = cache_lvs; cache; cache = cache->next)
235+ {
236+ struct grub_diskfilter_lv *lv;
237+
238+ for (lv = vg->lvs; lv; lv = lv->next)
239+ if (grub_strcmp (lv->name, cache->origin) == 0)
240+ break;
241+ if (lv)
242+ {
243+ cache->lv->segments = grub_malloc (lv->segment_count * sizeof (*lv->segments));
244+ if (!cache->lv->segments)
245+ {
246+ grub_lvm_free_cache_lvs (cache_lvs);
247+ goto fail4;
248+ }
249+ grub_memcpy (cache->lv->segments, lv->segments, lv->segment_count * sizeof (*lv->segments));
250+
251+ for (i = 0; i < lv->segment_count; ++i)
252+ {
253+ struct grub_diskfilter_node *nodes = lv->segments[i].nodes;
254+ grub_size_t node_count = lv->segments[i].node_count;
255+
256+ cache->lv->segments[i].nodes = grub_malloc (node_count * sizeof (*nodes));
257+ if (!cache->lv->segments[i].nodes)
258+ {
259+ for (j = 0; j < i; ++j)
260+ grub_free (cache->lv->segments[j].nodes);
261+ grub_free (cache->lv->segments);
262+ cache->lv->segments = NULL;
263+ grub_lvm_free_cache_lvs (cache_lvs);
264+ goto fail4;
265+ }
266+ grub_memcpy (cache->lv->segments[i].nodes, nodes, node_count * sizeof (*nodes));
267+ }
268+
269+ if (cache->lv->segments)
270+ {
271+ cache->lv->segment_count = lv->segment_count;
272+ cache->lv->vg = vg;
273+ cache->lv->next = vg->lvs;
274+ vg->lvs = cache->lv;
275+ cache->lv = NULL;
276+ }
277+ }
278+ }
279+ }
280+
281+ grub_lvm_free_cache_lvs (cache_lvs);
282 if (grub_diskfilter_vg_register (vg))
283 goto fail4;
284 }
285--
2862.14.4
287
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