Paranoia patch. In theory this operation can fail, but in practise it
never does because we're careful to check what size buffer is needed.
---
drivers/md/dm-cache-metadata.c | 60 +++++++++++++++++++-----------
drivers/md/dm-era-target.c | 68 +++++++++++++++++++++-------------
drivers/md/dm-thin-metadata.c | 80 +++++++++++++++++++++++-----------------
3 files changed, 127 insertions(+), 81 deletions(-)
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 3e7fd7d..53ab31e 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -120,6 +120,12 @@ struct dm_cache_metadata {
unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
size_t policy_hint_size;
struct dm_cache_statistics stats;
+
+ /*
+ * Reading the space map root can fail, so we read it into this
+ * buffer before the superblock is locked and updated.
+ */
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
};
/*-------------------------------------------------------------------
@@ -260,11 +266,31 @@ static void __setup_mapping_info(struct dm_cache_metadata *cmd)
}
}
+static int __save_sm_root(struct dm_cache_metadata *cmd)
+{
+ int r;
+ size_t metadata_len;
+
+ r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
+ if (r < 0)
+ return r;
+
+ return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
+ metadata_len);
+}
+
+static void __copy_sm_root(struct dm_cache_metadata *cmd,
+ struct cache_disk_superblock *disk_super)
+{
+ memcpy(&disk_super->metadata_space_map_root,
+ &cmd->metadata_space_map_root,
+ sizeof(cmd->metadata_space_map_root));
+}
+
static int __write_initial_superblock(struct dm_cache_metadata *cmd)
{
int r;
struct dm_block *sblock;
- size_t metadata_len;
struct cache_disk_superblock *disk_super;
sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
@@ -272,12 +298,16 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
- r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
+ r = dm_tm_pre_commit(cmd->tm);
if (r < 0)
return r;
- r = dm_tm_pre_commit(cmd->tm);
- if (r < 0)
+ /*
+ * dm_sm_copy_root() can fail. So we need to do it before we start
+ * updating the superblock.
+ */
+ r = __save_sm_root(cmd);
+ if (r)
return r;
r = superblock_lock_zero(cmd, &sblock);
@@ -293,10 +323,7 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
disk_super->policy_hint_size = 0;
- r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
- metadata_len);
- if (r < 0)
- goto bad_locked;
+ __copy_sm_root(cmd, disk_super);
disk_super->mapping_root = cpu_to_le64(cmd->root);
disk_super->hint_root = cpu_to_le64(cmd->hint_root);
@@ -313,10 +340,6 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
disk_super->write_misses = cpu_to_le32(0);
return dm_tm_commit(cmd->tm, sblock);
-
-bad_locked:
- dm_bm_unlock(sblock);
- return r;
}
static int __format_metadata(struct dm_cache_metadata *cmd)
@@ -560,7 +583,6 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
flags_mutator mutator)
{
int r;
- size_t metadata_len;
struct cache_disk_superblock *disk_super;
struct dm_block *sblock;
@@ -578,8 +600,8 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
if (r < 0)
return r;
- r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
- if (r < 0)
+ r = __save_sm_root(cmd);
+ if (r)
return r;
r = superblock_lock(cmd, &sblock);
@@ -606,13 +628,7 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
-
- r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
- metadata_len);
- if (r < 0) {
- dm_bm_unlock(sblock);
- return r;
- }
+ __copy_sm_root(cmd, disk_super);
return dm_tm_commit(cmd->tm, sblock);
}
diff --git a/drivers/md/dm-era-target.c b/drivers/md/dm-era-target.c
index ca65f90..0254b6d 100644
--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -289,6 +289,12 @@ struct era_metadata {
* A flag that is set whenever a writeset has been archived.
*/
bool archived_writesets;
+
+ /*
+ * Reading the space map root can fail, so we read it into this
+ * buffer before the superblock is locked and updated.
+ */
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
};
static int superblock_read_lock(struct era_metadata *md,
@@ -453,16 +459,33 @@ bad:
return r;
}
+static int save_sm_root(struct era_metadata *md)
+{
+ int r;
+ size_t metadata_len;
+
+ r = dm_sm_root_size(md->sm, &metadata_len);
+ if (r < 0)
+ return r;
+
+ return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
+ metadata_len);
+}
+
+static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
+{
+ memcpy(&disk->metadata_space_map_root,
+ &md->metadata_space_map_root,
+ sizeof(md->metadata_space_map_root));
+}
+
/*
* Writes a superblock, including the static fields that don't get updated
* with every commit (possible optimisation here). 'md' should be fully
* constructed when this is called.
*/
-static int prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
+static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
{
- int r;
- size_t metadata_len;
-
disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
disk->flags = cpu_to_le32(0ul);
@@ -470,14 +493,7 @@ static int prepare_superblock(struct era_metadata *md, struct superblock_disk *d
memset(disk->uuid, 0, sizeof(disk->uuid));
disk->version = cpu_to_le32(MAX_ERA_VERSION);
- r = dm_sm_root_size(md->sm, &metadata_len);
- if (r < 0)
- return r;
-
- r = dm_sm_copy_root(md->sm, &disk->metadata_space_map_root,
- metadata_len);
- if (r < 0)
- return r;
+ copy_sm_root(md, disk);
disk->data_block_size = cpu_to_le32(md->block_size);
disk->metadata_block_size = cpu_to_le32(METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
@@ -488,8 +504,6 @@ static int prepare_superblock(struct era_metadata *md, struct superblock_disk *d
disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
disk->era_array_root = cpu_to_le64(md->era_array_root);
disk->metadata_snap = cpu_to_le64(md->metadata_snap);
-
- return 0;
}
static int write_superblock(struct era_metadata *md)
@@ -498,17 +512,18 @@ static int write_superblock(struct era_metadata *md)
struct dm_block *sblock;
struct superblock_disk *disk;
+ r = save_sm_root(md);
+ if (r) {
+ DMERR("%s: save_sm_root failed", __func__);
+ return r;
+ }
+
r = superblock_lock_zero(md, &sblock);
if (r)
return r;
disk = dm_block_data(sblock);
- r = prepare_superblock(md, disk);
- if (r) {
- DMERR("%s: prepare_superblock failed", __func__);
- dm_bm_unlock(sblock); /* FIXME: does this commit? */
- return r;
- }
+ prepare_superblock(md, disk);
return dm_tm_commit(md->tm, sblock);
}
@@ -930,6 +945,12 @@ static int metadata_commit(struct era_metadata *md)
}
}
+ r = save_sm_root(md);
+ if (r) {
+ DMERR("%s: save_sm_root failed", __func__);
+ return r;
+ }
+
r = dm_tm_pre_commit(md->tm);
if (r) {
DMERR("%s: pre commit failed", __func__);
@@ -942,12 +963,7 @@ static int metadata_commit(struct era_metadata *md)
return r;
}
- r = prepare_superblock(md, dm_block_data(sblock));
- if (r) {
- DMERR("%s: prepare_superblock failed", __func__);
- dm_bm_unlock(sblock); /* FIXME: does this commit? */
- return r;
- }
+ prepare_superblock(md, dm_block_data(sblock));
return dm_tm_commit(md->tm, sblock);
}
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 8bc585c..10c0f67 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -192,6 +192,13 @@ struct dm_pool_metadata {
* operation possible in this state is the closing of the device.
*/
bool fail_io:1;
+
+ /*
+ * Reading the space map roots can fail, so we read it into these
+ * buffers before the superblock is locked and updated.
+ */
+ __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
};
struct dm_thin_device {
@@ -431,26 +438,53 @@ static void __setup_btree_details(struct dm_pool_metadata *pmd)
pmd->details_info.value_type.equal = NULL;
}
+static int save_sm_roots(struct dm_pool_metadata *pmd)
+{
+ int r;
+ size_t len;
+
+ r = dm_sm_root_size(pmd->metadata_sm, &len);
+ if (r < 0)
+ return r;
+
+ r = dm_sm_copy_root(pmd->metadata_sm, &pmd->metadata_space_map_root, len);
+ if (r < 0)
+ return r;
+
+ r = dm_sm_root_size(pmd->data_sm, &len);
+ if (r < 0)
+ return r;
+
+ return dm_sm_copy_root(pmd->data_sm, &pmd->data_space_map_root, len);
+}
+
+static void copy_sm_roots(struct dm_pool_metadata *pmd,
+ struct thin_disk_superblock *disk)
+{
+ memcpy(&disk->metadata_space_map_root,
+ &pmd->metadata_space_map_root,
+ sizeof(pmd->metadata_space_map_root));
+
+ memcpy(&disk->data_space_map_root,
+ &pmd->data_space_map_root,
+ sizeof(pmd->data_space_map_root));
+}
+
static int __write_initial_superblock(struct dm_pool_metadata *pmd)
{
int r;
struct dm_block *sblock;
- size_t metadata_len, data_len;
struct thin_disk_superblock *disk_super;
sector_t bdev_size = i_size_read(pmd->bdev->bd_inode) >> SECTOR_SHIFT;
if (bdev_size > THIN_METADATA_MAX_SECTORS)
bdev_size = THIN_METADATA_MAX_SECTORS;
- r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
- if (r < 0)
- return r;
-
- r = dm_sm_root_size(pmd->data_sm, &data_len);
+ r = dm_sm_commit(pmd->data_sm);
if (r < 0)
return r;
- r = dm_sm_commit(pmd->data_sm);
+ r = save_sm_roots(pmd);
if (r < 0)
return r;
@@ -471,15 +505,7 @@ static int __write_initial_superblock(struct dm_pool_metadata *pmd)
disk_super->trans_id = 0;
disk_super->held_root = 0;
- r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
- metadata_len);
- if (r < 0)
- goto bad_locked;
-
- r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
- data_len);
- if (r < 0)
- goto bad_locked;
+ copy_sm_roots(pmd, disk_super);
disk_super->data_mapping_root = cpu_to_le64(pmd->root);
disk_super->device_details_root = cpu_to_le64(pmd->details_root);
@@ -488,10 +514,6 @@ static int __write_initial_superblock(struct dm_pool_metadata *pmd)
disk_super->data_block_size = cpu_to_le32(pmd->data_block_size);
return dm_tm_commit(pmd->tm, sblock);
-
-bad_locked:
- dm_bm_unlock(sblock);
- return r;
}
static int __format_metadata(struct dm_pool_metadata *pmd)
@@ -769,6 +791,10 @@ static int __commit_transaction(struct dm_pool_metadata *pmd)
if (r < 0)
return r;
+ r = save_sm_roots(pmd);
+ if (r < 0)
+ return r;
+
r = superblock_lock(pmd, &sblock);
if (r)
return r;
@@ -780,21 +806,9 @@ static int __commit_transaction(struct dm_pool_metadata *pmd)
disk_super->trans_id = cpu_to_le64(pmd->trans_id);
disk_super->flags = cpu_to_le32(pmd->flags);
- r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
- metadata_len);
- if (r < 0)
- goto out_locked;
-
- r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
- data_len);
- if (r < 0)
- goto out_locked;
+ copy_sm_roots(pmd, disk_super);
return dm_tm_commit(pmd->tm, sblock);
-
-out_locked:
- dm_bm_unlock(sblock);
- return r;
}
struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
--
1.7.10.4
--
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