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authorNeilBrown <neilb@suse.de>2006-03-27 04:18:11 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-27 11:45:01 -0500
commitf67055780caac6a99f43834795c43acf99eba6a6 (patch)
tree6b80e7b4cb300edb0910dbad1d840ff8e2f36ae5 /include/linux/raid
parent292695531ae4019bb15deedc121b218d1908b648 (diff)
[PATCH] md: Checkpoint and allow restart of raid5 reshape
We allow the superblock to record an 'old' and a 'new' geometry, and a position where any conversion is up to. The geometry allows for changing chunksize, layout and level as well as number of devices. When using verion-0.90 superblock, we convert the version to 0.91 while the conversion is happening so that an old kernel will refuse the assemble the array. For version-1, we use a feature bit for the same effect. When starting an array we check for an incomplete reshape and restart the reshape process if needed. If the reshape stopped at an awkward time (like when updating the first stripe) we refuse to assemble the array, and let user-space worry about it. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/raid')
-rw-r--r--include/linux/raid/md.h2
-rw-r--r--include/linux/raid/md_k.h8
-rw-r--r--include/linux/raid/md_p.h32
-rw-r--r--include/linux/raid/raid5.h1
4 files changed, 40 insertions, 3 deletions
diff --git a/include/linux/raid/md.h b/include/linux/raid/md.h
index 9c77cde5a79..66b44e5e0d6 100644
--- a/include/linux/raid/md.h
+++ b/include/linux/raid/md.h
@@ -95,6 +95,8 @@ extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
95extern void md_do_sync(mddev_t *mddev); 95extern void md_do_sync(mddev_t *mddev);
96extern void md_new_event(mddev_t *mddev); 96extern void md_new_event(mddev_t *mddev);
97 97
98extern void md_update_sb(mddev_t * mddev);
99
98#define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); } 100#define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
99 101
100#endif 102#endif
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index 4e26ef2cacc..1a6f9f2f628 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -132,6 +132,14 @@ struct mddev_s
132 132
133 char uuid[16]; 133 char uuid[16];
134 134
135 /* If the array is being reshaped, we need to record the
136 * new shape and an indication of where we are up to.
137 * This is written to the superblock.
138 * If reshape_position is MaxSector, then no reshape is happening (yet).
139 */
140 sector_t reshape_position;
141 int delta_disks, new_level, new_layout, new_chunk;
142
135 struct mdk_thread_s *thread; /* management thread */ 143 struct mdk_thread_s *thread; /* management thread */
136 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */ 144 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
137 sector_t curr_resync; /* blocks scheduled */ 145 sector_t curr_resync; /* blocks scheduled */
diff --git a/include/linux/raid/md_p.h b/include/linux/raid/md_p.h
index c100fa5d4bf..774e1acfb8c 100644
--- a/include/linux/raid/md_p.h
+++ b/include/linux/raid/md_p.h
@@ -102,6 +102,18 @@ typedef struct mdp_device_descriptor_s {
102#define MD_SB_ERRORS 1 102#define MD_SB_ERRORS 1
103 103
104#define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */ 104#define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */
105
106/*
107 * Notes:
108 * - if an array is being reshaped (restriped) in order to change the
109 * the number of active devices in the array, 'raid_disks' will be
110 * the larger of the old and new numbers. 'delta_disks' will
111 * be the "new - old". So if +ve, raid_disks is the new value, and
112 * "raid_disks-delta_disks" is the old. If -ve, raid_disks is the
113 * old value and "raid_disks+delta_disks" is the new (smaller) value.
114 */
115
116
105typedef struct mdp_superblock_s { 117typedef struct mdp_superblock_s {
106 /* 118 /*
107 * Constant generic information 119 * Constant generic information
@@ -146,7 +158,13 @@ typedef struct mdp_superblock_s {
146 __u32 cp_events_hi; /* 10 high-order of checkpoint update count */ 158 __u32 cp_events_hi; /* 10 high-order of checkpoint update count */
147#endif 159#endif
148 __u32 recovery_cp; /* 11 recovery checkpoint sector count */ 160 __u32 recovery_cp; /* 11 recovery checkpoint sector count */
149 __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 12]; 161 /* There are only valid for minor_version > 90 */
162 __u64 reshape_position; /* 12,13 next address in array-space for reshape */
163 __u32 new_level; /* 14 new level we are reshaping to */
164 __u32 delta_disks; /* 15 change in number of raid_disks */
165 __u32 new_layout; /* 16 new layout */
166 __u32 new_chunk; /* 17 new chunk size (bytes) */
167 __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18];
150 168
151 /* 169 /*
152 * Personality information 170 * Personality information
@@ -207,7 +225,14 @@ struct mdp_superblock_1 {
207 * NOTE: signed, so bitmap can be before superblock 225 * NOTE: signed, so bitmap can be before superblock
208 * only meaningful of feature_map[0] is set. 226 * only meaningful of feature_map[0] is set.
209 */ 227 */
210 __u8 pad1[128-100]; /* set to 0 when written */ 228
229 /* These are only valid with feature bit '4' */
230 __u64 reshape_position; /* next address in array-space for reshape */
231 __u32 new_level; /* new level we are reshaping to */
232 __u32 delta_disks; /* change in number of raid_disks */
233 __u32 new_layout; /* new layout */
234 __u32 new_chunk; /* new chunk size (bytes) */
235 __u8 pad1[128-124]; /* set to 0 when written */
211 236
212 /* constant this-device information - 64 bytes */ 237 /* constant this-device information - 64 bytes */
213 __u64 data_offset; /* sector start of data, often 0 */ 238 __u64 data_offset; /* sector start of data, often 0 */
@@ -240,8 +265,9 @@ struct mdp_superblock_1 {
240 265
241/* feature_map bits */ 266/* feature_map bits */
242#define MD_FEATURE_BITMAP_OFFSET 1 267#define MD_FEATURE_BITMAP_OFFSET 1
268#define MD_FEATURE_RESHAPE_ACTIVE 4
243 269
244#define MD_FEATURE_ALL 1 270#define MD_FEATURE_ALL 5
245 271
246#endif 272#endif
247 273
diff --git a/include/linux/raid/raid5.h b/include/linux/raid/raid5.h
index 55c738d5050..abcdf0d0658 100644
--- a/include/linux/raid/raid5.h
+++ b/include/linux/raid/raid5.h
@@ -224,6 +224,7 @@ struct raid5_private_data {
224 struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */ 224 struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */
225 atomic_t preread_active_stripes; /* stripes with scheduled io */ 225 atomic_t preread_active_stripes; /* stripes with scheduled io */
226 226
227 atomic_t reshape_stripes; /* stripes with pending writes for reshape */
227 /* unfortunately we need two cache names as we temporarily have 228 /* unfortunately we need two cache names as we temporarily have
228 * two caches. 229 * two caches.
229 */ 230 */