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Message-Id: <1286515292-15882-13-git-send-email-david@fromorbit.com>
Date: Fri, 8 Oct 2010 16:21:26 +1100
From: Dave Chinner <david@...morbit.com>
To: linux-fsdevel@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 12/18] fs: add a per-superblock lock for the inode list
From: Dave Chinner <dchinner@...hat.com>
To allow removal of the inode_lock, we first need to protect the
superblock inode list with its own lock instead of using the
inode_lock. Add a lock to the superblock to protect this list and
nest the new lock inside the inode_lock around the list operations
it needs to protect.
Based on a patch originally from Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@...hat.com>
---
fs/drop_caches.c | 4 ++++
fs/fs-writeback.c | 4 ++++
fs/inode.c | 22 +++++++++++++++++++---
fs/notify/inode_mark.c | 3 +++
fs/quota/dquot.c | 6 ++++++
fs/super.c | 1 +
include/linux/fs.h | 1 +
7 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index c4f3e06..c808ca8 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -17,18 +17,22 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
struct inode *inode, *toput_inode = NULL;
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;
if (inode->i_mapping->nrpages == 0)
continue;
iref_locked(inode);
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
toput_inode = inode;
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
}
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
iput(toput_inode);
}
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index d63ab47..29f8032 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1026,6 +1026,7 @@ static void wait_sb_inodes(struct super_block *sb)
WARN_ON(!rwsem_is_locked(&sb->s_umount));
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
/*
* Data integrity sync. Must wait for all pages under writeback,
@@ -1043,6 +1044,7 @@ static void wait_sb_inodes(struct super_block *sb)
if (mapping->nrpages == 0)
continue;
iref_locked(inode);
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
/*
* We hold a reference to 'inode' so it couldn't have
@@ -1060,7 +1062,9 @@ static void wait_sb_inodes(struct super_block *sb)
cond_resched();
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
}
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
iput(old_inode);
}
diff --git a/fs/inode.c b/fs/inode.c
index 3c07719..e6bb36d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -33,13 +33,18 @@
* i_ref
* inode_hash_bucket lock protects:
* inode hash table, i_hash
+ * sb inode lock protects:
+ * s_inodes, i_sb_list
*
* Lock orders
* inode_lock
* inode hash bucket lock
* inode->i_lock
+ *
+ * inode_lock
+ * sb inode lock
+ * inode->i_lock
*/
-
/*
* This is needed for the following functions:
* - inode_has_buffers
@@ -488,7 +493,9 @@ static void dispose_list(struct list_head *head)
spin_lock(&inode_lock);
__remove_inode_hash(inode);
+ spin_lock(&inode->i_sb->s_inodes_lock);
list_del_init(&inode->i_sb_list);
+ spin_unlock(&inode->i_sb->s_inodes_lock);
spin_unlock(&inode_lock);
wake_up_inode(inode);
@@ -499,7 +506,8 @@ static void dispose_list(struct list_head *head)
/*
* Invalidate all inodes for a device.
*/
-static int invalidate_list(struct list_head *head, struct list_head *dispose)
+static int invalidate_list(struct super_block *sb, struct list_head *head,
+ struct list_head *dispose)
{
struct list_head *next;
int busy = 0;
@@ -516,6 +524,7 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
* shrink_icache_memory() away.
*/
cond_resched_lock(&inode_lock);
+ cond_resched_lock(&sb->s_inodes_lock);
next = next->next;
if (tmp == head)
@@ -555,8 +564,10 @@ int invalidate_inodes(struct super_block *sb)
down_write(&iprune_sem);
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
fsnotify_unmount_inodes(&sb->s_inodes);
- busy = invalidate_list(&sb->s_inodes, &throw_away);
+ busy = invalidate_list(sb, &sb->s_inodes, &throw_away);
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
dispose_list(&throw_away);
@@ -753,7 +764,9 @@ static inline void
__inode_add_to_lists(struct super_block *sb, struct inode_hash_bucket *b,
struct inode *inode)
{
+ spin_lock(&sb->s_inodes_lock);
list_add(&inode->i_sb_list, &sb->s_inodes);
+ spin_unlock(&sb->s_inodes_lock);
if (b) {
spin_lock_bucket(b);
hlist_bl_add_head(&inode->i_hash, &b->head);
@@ -1397,7 +1410,10 @@ static void iput_final(struct inode *inode)
percpu_counter_dec(&nr_inodes_unused);
}
+ spin_lock(&sb->s_inodes_lock);
list_del_init(&inode->i_sb_list);
+ spin_unlock(&sb->s_inodes_lock);
+
spin_unlock(&inode_lock);
evict(inode);
remove_inode_hash(inode);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 2fe319b..3389ff0 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -242,6 +242,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
struct inode *need_iput_tmp;
+ struct super_block *sb = inode->i_sb;
/*
* We cannot iref() an inode in state I_FREEING,
@@ -288,6 +289,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
* will be added since the umount has begun. Finally,
* iprune_mutex keeps shrink_icache_memory() away.
*/
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
if (need_iput_tmp)
@@ -301,5 +303,6 @@ void fsnotify_unmount_inodes(struct list_head *list)
iput(inode);
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
}
}
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 5199418..b7cbc41 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -897,6 +897,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
#endif
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;
@@ -910,6 +911,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
continue;
iref_locked(inode);
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
iput(old_inode);
@@ -921,7 +923,9 @@ static void add_dquot_ref(struct super_block *sb, int type)
* keep the reference and iput it later. */
old_inode = inode;
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
}
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
iput(old_inode);
@@ -1004,6 +1008,7 @@ static void remove_dquot_ref(struct super_block *sb, int type,
int reserved = 0;
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
/*
* We have to scan also I_NEW inodes because they can already
@@ -1017,6 +1022,7 @@ static void remove_dquot_ref(struct super_block *sb, int type,
remove_inode_dquot_ref(inode, type, tofree_head);
}
}
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
#ifdef CONFIG_QUOTA_DEBUG
if (reserved) {
diff --git a/fs/super.c b/fs/super.c
index 8819e3a..d826214 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -76,6 +76,7 @@ static struct super_block *alloc_super(struct file_system_type *type)
INIT_LIST_HEAD(&s->s_dentry_lru);
init_rwsem(&s->s_umount);
mutex_init(&s->s_lock);
+ spin_lock_init(&(s->s_inodes_lock);
lockdep_set_class(&s->s_umount, &type->s_umount_key);
/*
* The locking rules for s_lock are up to the
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 34f983f..54c4e86 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1342,6 +1342,7 @@ struct super_block {
#endif
const struct xattr_handler **s_xattr;
+ spinlock_t s_inodes_lock; /* lock for s_inodes */
struct list_head s_inodes; /* all inodes */
struct hlist_head s_anon; /* anonymous dentries for (nfs) exporting */
#ifdef CONFIG_SMP
--
1.7.1
--
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