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authorDave Chinner <dchinner@redhat.com>2011-03-22 22:23:36 +1100
committerAl Viro <viro@zeniv.linux.org.uk>2011-03-24 21:16:31 -0400
commit250df6ed274d767da844a5d9f05720b804240197 (patch)
treeb74f49a86c4451d9e3e82f90e3f791163025be21 /fs/drop_caches.c
parent3dc8fe4dca9cd3e4aa828ed36451e2bcfd2350da (diff)
downloadlinux-250df6ed274d767da844a5d9f05720b804240197.tar.gz
fs: protect inode->i_state with inode->i_lock
Protect inode state transitions and validity checks with the inode->i_lock. This enables us to make inode state transitions independently of the inode_lock and is the first step to peeling away the inode_lock from the code. This requires that __iget() is done atomically with i_state checks during list traversals so that we don't race with another thread marking the inode I_FREEING between the state check and grabbing the reference. Also remove the unlock_new_inode() memory barrier optimisation required to avoid taking the inode_lock when clearing I_NEW. Simplify the code by simply taking the inode->i_lock around the state change and wakeup. Because the wakeup is no longer tricky, remove the wake_up_inode() function and open code the wakeup where necessary. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/drop_caches.c')
-rw-r--r--fs/drop_caches.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 816f88e6b9c..6c6f73ba086 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -18,11 +18,14 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
spin_lock(&inode_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)
+ spin_lock(&inode->i_lock);
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ (inode->i_mapping->nrpages == 0)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
__iget(inode);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);