From: Dave Chinner <dchinner@xxxxxxxxxx>
Now that inode state changes are protected by the inode->i_lock and
the inode LRU manipulations by the inode_lru_lock, we can remove the
inode_lock from prune_icache and the initial part of iput_final().
instead of using the inode_lock to protect the inode during
iput_final, use the inode->i_lock instead. This protects the inode
against new references being taken while we change the inode state
to I_FREEING, as well as preventing prune_icache from grabbing the
inode while we are manipulating it. Hence we no longer need the
inode_lock in iput_final prior to setting I_FREEING on the inode.
For prune_icache, we no longer need the inode_lock to protect the
LRU list, and the inodes themselves are protected against freeing
races by the inode->i_lock. Hence we can lift the inode_lock from
prune_icache as well.
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
fs/inode.c | 17 +++--------------
1 files changed, 3 insertions(+), 14 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index ef376d0..fd635c0 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -620,7 +620,6 @@ static void prune_icache(int nr_to_scan)
unsigned long reap = 0;
down_read(&iprune_sem);
- spin_lock(&inode_lock);
spin_lock(&inode_lru_lock);
for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
struct inode *inode;
@@ -646,8 +645,8 @@ static void prune_icache(int nr_to_scan)
*/
if (atomic_read(&inode->i_count) ||
(inode->i_state & ~I_REFERENCED)) {
- spin_unlock(&inode->i_lock);
list_del_init(&inode->i_lru);
+ spin_unlock(&inode->i_lock);
percpu_counter_dec(&nr_inodes_unused);
continue;
}
@@ -655,20 +654,18 @@ static void prune_icache(int nr_to_scan)
/* recently referenced inodes get one more pass */
if (inode->i_state & I_REFERENCED) {
inode->i_state &= ~I_REFERENCED;
- spin_unlock(&inode->i_lock);
list_move(&inode->i_lru, &inode_lru);
+ spin_unlock(&inode->i_lock);
continue;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
__iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lru_lock);
- spin_unlock(&inode_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
0, -1);
iput(inode);
- spin_lock(&inode_lock);
spin_lock(&inode_lru_lock);
if (inode != list_entry(inode_lru.next,
@@ -694,7 +691,6 @@ static void prune_icache(int nr_to_scan)
else
__count_vm_events(PGINODESTEAL, reap);
spin_unlock(&inode_lru_lock);
- spin_unlock(&inode_lock);
dispose_list(&freeable);
up_read(&iprune_sem);
@@ -1052,7 +1048,6 @@ EXPORT_SYMBOL(iunique);
struct inode *igrab(struct inode *inode)
{
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
__iget(inode);
@@ -1066,7 +1061,6 @@ struct inode *igrab(struct inode *inode)
*/
inode = NULL;
}
- spin_unlock(&inode_lock);
return inode;
}
EXPORT_SYMBOL(igrab);
@@ -1409,7 +1403,6 @@ static void iput_final(struct inode *inode)
const struct super_operations *op = inode->i_sb->s_op;
int drop;
- spin_lock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
if (op && op->drop_inode)
@@ -1422,16 +1415,13 @@ static void iput_final(struct inode *inode)
if (!(inode->i_state & (I_DIRTY|I_SYNC)))
inode_lru_list_add(inode);
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
return;
}
if (!drop) {
inode->i_state |= I_WILL_FREE;
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
write_inode_now(inode, 1);
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
@@ -1440,7 +1430,6 @@ static void iput_final(struct inode *inode)
inode->i_state |= I_FREEING;
inode_lru_list_del(inode);
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
evict(inode);
}
@@ -1459,7 +1448,7 @@ void iput(struct inode *inode)
if (inode) {
BUG_ON(inode->i_state & I_CLEAR);
- if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
+ if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock))
iput_final(inode);
}
}
--
1.7.1
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