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Wrap decrease btree height in a transaction #15

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Wrap decrease btree height in a transaction #15

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21 changes: 10 additions & 11 deletions Linux-5.1/fs/winefs/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -564,16 +564,8 @@ static void pmfs_decrease_btree_height(struct super_block *sb,
height--;
}
update_root_and_height:
/* pi->height and pi->root need to be atomically updated. use
* cmpxchg16 here. The following is dependent on a specific layout of
* inode fields */
*(u64 *)b = *(u64 *)pi;
/* pi->height is at offset 2 from pi */
b[2] = (u8)new_height;
/* TODO: the following function assumes cmpxchg16b instruction writes
* 16 bytes atomically. Confirm if it is really true. */
cmpxchg_double_local((u64 *)pi, &pi->root, *(u64 *)pi, pi->root,
*(u64 *)b, newroot);
pi->root = newroot;
pi->height = height;
}

static unsigned long pmfs_inode_count_iblocks_recursive(struct super_block *sb,
Expand Down Expand Up @@ -630,6 +622,7 @@ static void __pmfs_truncate_blocks(struct inode *inode, loff_t start,
unsigned int freed = 0;
unsigned int data_bits = blk_type_to_shift[pi->i_blk_type];
unsigned int meta_bits = META_BLK_SHIFT;
struct pmfs_transaction *trans;
bool mpty;

inode->i_mtime = inode->i_ctime = current_time(inode);
Expand Down Expand Up @@ -681,6 +674,11 @@ static void __pmfs_truncate_blocks(struct inode *inode, loff_t start,
inode->i_blocks -= (freed * (1 << (data_bits -
sb->s_blocksize_bits)));

PERSISTENT_BARRIER();
BUG_ON(pmfs_current_transaction());
trans = pmfs_new_transaction(sb, MAX_INODE_LENTRIES, pmfs_get_cpuid(sb));
pmfs_add_logentry(sb, trans, pi, sizeof(*pi), LE_DATA);

pmfs_memunlock_inode(sb, pi);
pi->i_blocks = cpu_to_le64(inode->i_blocks);
pi->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
Expand All @@ -690,7 +688,8 @@ static void __pmfs_truncate_blocks(struct inode *inode, loff_t start,
check_eof_blocks(sb, pi, inode->i_size);
pmfs_memlock_inode(sb, pi);
/* now flush the inode's first cacheline which was modified */
pmfs_flush_buffer(pi, 1, false);
pmfs_flush_buffer(pi, 1, true);
pmfs_commit_transaction(sb, trans);
return;
end_truncate_blocks:
/* we still need to update ctime and mtime */
Expand Down