new_inode used to have the following:
spin_lock(&inode_lock);
inodes_stat.nr_inodes++;
list_add(&inode->i_list, &inode_in_use);
list_add(&inode->i_sb_list, &sb->s_inodes);
inode->i_ino = ++last_ino;
inode->i_state = 0;
spin_unlock(&inode_lock);
over time things disappeared, got moved around or got replaced (global
inode lock with a per-inode lock), eventually this got reduced to:
spin_lock(&inode->i_lock);
inode->i_state = 0;
spin_unlock(&inode->i_lock);
But the lock acquire here does not synchronize against anyone.
Additionally iget5_locked performs i_state = 0 assignment without any
locks to begin with, the two combined look confusing at best.
It looks like the current state is a leftover which was not cleaned up.
Ideally it would be an invariant that i_state == 0 to begin with, but
achieving that would require dealing with all filesystem alloc handlers
one by one.
In the meantime drop the misleading locking and move i_state zeroing to
inode_init_always so that others don't need to deal with it by hand.
Signed-off-by: Mateusz Guzik <mjguzik@xxxxxxxxx>
---
fs/inode.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 3a4c67bfe085..8f05d79de01d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -231,6 +231,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
if (unlikely(security_inode_alloc(inode)))
return -ENOMEM;
+
+ inode->i_state = 0;
this_cpu_inc(nr_inodes);
return 0;
@@ -1023,14 +1025,7 @@ EXPORT_SYMBOL(get_next_ino);
*/
struct inode *new_inode_pseudo(struct super_block *sb)
{
- struct inode *inode = alloc_inode(sb);
-
- if (inode) {
- spin_lock(&inode->i_lock);
- inode->i_state = 0;
- spin_unlock(&inode->i_lock);
- }
- return inode;
+ return alloc_inode(sb);
}
/**
@@ -1254,7 +1249,6 @@ struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
struct inode *new = alloc_inode(sb);
if (new) {
- new->i_state = 0;
inode = inode_insert5(new, hashval, test, set, data);
if (unlikely(inode != new))
destroy_inode(new);
@@ -1285,7 +1279,6 @@ struct inode *iget5_locked_rcu(struct super_block *sb, unsigned long hashval,
struct inode *new = alloc_inode(sb);
if (new) {
- new->i_state = 0;
inode = inode_insert5(new, hashval, test, set, data);
if (unlikely(inode != new))
destroy_inode(new);
--
2.43.0
