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Date: Wed, 27 Oct 2010 15:23:02 +1100
From: Dave Chinner <david@...morbit.com>
To: viro@...IV.linux.org.uk
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] fs: factor inode disposal
From: Dave Chinner <dchinner@...hat.com>
We have a couple of places that dispose of inodes. factor the
disposal into a common helper dispose_one_inode() to isolate this
code and make it simpler to peel away the inode_lock from the code.
While doing this, change the logic flow in iput_final() to separate
the different cases that need to be handled to make the transitions
the inode goes through more obvious.
Signed-off-by: Dave Chinner <dchinner@...hat.com>
---
fs/inode.c | 75 +++++++++++++++++++++++++++++++----------------------------
1 files changed, 39 insertions(+), 36 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index eaba6ce..f134aa4 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -464,6 +464,32 @@ static void evict(struct inode *inode)
}
/*
+ * Free the inode passed in, removing it from the lists it is still connected
+ * to but avoiding unnecessary lock round-trips for the lists it is no longer
+ * on.
+ *
+ * An inode must already be marked I_FREEING so that we avoid the inode being
+ * moved back onto lists if we race with other code that manipulates the lists
+ * (e.g. writeback_single_inode_inode). The caller is responsisble for setting this.
+ */
+static void dispose_one_inode(struct inode *inode)
+{
+ BUG_ON(!(inode->i_state & I_FREEING));
+
+ spin_lock(&inode_lock);
+ list_del_init(&inode->i_wb_list);
+ __remove_inode_hash(inode);
+ __inode_sb_list_del(inode);
+ spin_unlock(&inode_lock);
+
+ evict(inode);
+
+ wake_up_inode(inode);
+ BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
+ destroy_inode(inode);
+}
+
+/*
* dispose_list - dispose of the contents of a local list
* @head: the head of the list to free
*
@@ -478,15 +504,7 @@ static void dispose_list(struct list_head *head)
inode = list_first_entry(head, struct inode, i_lru);
list_del_init(&inode->i_lru);
- evict(inode);
-
- spin_lock(&inode_lock);
- __remove_inode_hash(inode);
- __inode_sb_list_del(inode);
- spin_unlock(&inode_lock);
-
- wake_up_inode(inode);
- destroy_inode(inode);
+ dispose_one_inode(inode);
}
}
@@ -528,7 +546,6 @@ void evict_inodes(struct super_block *sb)
* set so that it won't get moved back on there if it is dirty.
*/
list_move(&inode->i_lru, &dispose);
- list_del_init(&inode->i_wb_list);
}
spin_unlock(&inode_lock);
@@ -574,7 +591,6 @@ int invalidate_inodes(struct super_block *sb)
* set so that it won't get moved back on there if it is dirty.
*/
list_move(&inode->i_lru, &dispose);
- list_del_init(&inode->i_wb_list);
}
spin_unlock(&inode_lock);
@@ -677,7 +693,6 @@ static void prune_icache(int nr_to_scan)
* set so that it won't get moved back on there if it is dirty.
*/
list_move(&inode->i_lru, &freeable);
- list_del_init(&inode->i_wb_list);
percpu_counter_dec(&nr_inodes_unused);
}
if (current_is_kswapd())
@@ -1409,16 +1424,16 @@ static void iput_final(struct inode *inode)
else
drop = generic_drop_inode(inode);
+ if (!drop && (sb->s_flags & MS_ACTIVE)) {
+ inode->i_state |= I_REFERENCED;
+ 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) {
- if (sb->s_flags & MS_ACTIVE) {
- inode->i_state |= I_REFERENCED;
- if (!(inode->i_state & (I_DIRTY|I_SYNC))) {
- inode_lru_list_add(inode);
- }
- spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
- return;
- }
inode->i_state |= I_WILL_FREE;
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
@@ -1427,26 +1442,14 @@ static void iput_final(struct inode *inode)
spin_lock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
- __remove_inode_hash(inode);
}
inode->i_state |= I_FREEING;
- spin_unlock(&inode->i_lock);
-
- /*
- * Move the inode off the IO lists and LRU once I_FREEING is
- * set so that it won't get moved back on there if it is dirty.
- */
inode_lru_list_del(inode);
- list_del_init(&inode->i_wb_list);
-
- __inode_sb_list_del(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
- evict(inode);
- remove_inode_hash(inode);
- wake_up_inode(inode);
- BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
- destroy_inode(inode);
+
+ dispose_one_inode(inode);
}
/**
--
1.7.1
--
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