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scoutfs: add inode index item locking

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Add a locking wrapper for the inode index items.  It maps the index
fields to a lock name for each index type.

Signed-off-by: Zach Brown <zab@versity.com>
This commit is contained in:
Zach Brown
2017-07-13 09:00:03 -07:00
parent c80dd579e1
commit 4f6f842efa
2 changed files with 73 additions and 0 deletions
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70
kmod/src/lock.c
View File

@@ -439,6 +439,76 @@ int scoutfs_lock_ino_group(struct super_block *sb, int mode, u64 ino,
return lock_name_keys(sb, mode, &lock_name, &start, &end, ret_lock);
}
/*
* map inode index items to locks. The idea is to not have to
* constantly get locks over a reasonable distribution of items, but
* also not have an insane amount of items covered by locks. time and
* seq indexes have natural batching and limits on the number of keys
* per major value. Size keys are very different. For them we use a
* mix of a sort of linear-log distribution (top 4 bits of size), and
* then also a lot of inodes per size.
*/
int scoutfs_lock_inode_index(struct super_block *sb, int mode,
u8 type, u64 major, u64 ino,
struct scoutfs_lock **ret_lock)
{
struct scoutfs_lock_name lock_name;
struct scoutfs_inode_index_key start_ikey;
struct scoutfs_inode_index_key end_ikey;
struct scoutfs_key_buf start;
struct scoutfs_key_buf end;
u64 major_mask;
u64 ino_mask;
int bit;
switch(type) {
case SCOUTFS_INODE_INDEX_CTIME_TYPE:
case SCOUTFS_INODE_INDEX_MTIME_TYPE:
major_mask = (1 << 5) - 1;
ino_mask = ~0ULL;
break;
case SCOUTFS_INODE_INDEX_SIZE_TYPE:
major_mask = 0;
if (major) {
bit = fls64(major);
if (bit > 4)
major_mask = (1 << (bit - 4)) - 1;
}
ino_mask = (1 << 12) - 1;
break;
case SCOUTFS_INODE_INDEX_META_SEQ_TYPE:
case SCOUTFS_INODE_INDEX_DATA_SEQ_TYPE:
major_mask = (1 << 10) - 1;
ino_mask = ~0ULL;
break;
default:
BUG();
}
lock_name.zone = SCOUTFS_INODE_INDEX_ZONE;
lock_name.type = type;
lock_name.first = cpu_to_le64(major & ~major_mask);
lock_name.second = cpu_to_le64(ino & ~ino_mask);
start_ikey.zone = SCOUTFS_INODE_INDEX_ZONE;
start_ikey.type = type;
start_ikey.major = cpu_to_be64(major & ~major_mask);
start_ikey.minor = cpu_to_be32(0);
start_ikey.ino = cpu_to_be64(ino & ~ino_mask);
scoutfs_key_init(&start, &start_ikey, sizeof(start_ikey));
end_ikey.zone = SCOUTFS_INODE_INDEX_ZONE;
end_ikey.type = type;
end_ikey.major = cpu_to_be64(major | major_mask);
end_ikey.minor = cpu_to_be32(U32_MAX);
end_ikey.ino = cpu_to_be64(ino | ino_mask);
scoutfs_key_init(&end, &end_ikey, sizeof(end_ikey));
return lock_name_keys(sb, mode, &lock_name, &start, &end, ret_lock);
}
void scoutfs_unlock(struct super_block *sb, struct scoutfs_lock *lock)
{
DECLARE_LOCK_INFO(sb, linfo);

3
kmod/src/lock.h
View File

@@ -26,6 +26,9 @@ struct scoutfs_lock {
int scoutfs_lock_ino_group(struct super_block *sb, int mode, u64 ino,
struct scoutfs_lock **ret_lock);
int scoutfs_lock_inode_index(struct super_block *sb, int mode,
u8 type, u64 major, u64 ino,
struct scoutfs_lock **ret_lock);
void scoutfs_unlock(struct super_block *sb, struct scoutfs_lock *lock);
int scoutfs_lock_addr(struct super_block *sb, int wanted_mode,