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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/notify/inode_mark.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/notify/inode_mark.c')
-rw-r--r--fs/notify/inode_mark.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 4c29fcf557d..4dd53fb4412 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -254,8 +254,11 @@ void fsnotify_unmount_inodes(struct list_head *list)
* I_WILL_FREE, or I_NEW which is fine because by that point
* the inode cannot have any associated watches.
*/
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
/*
* If i_count is zero, the inode cannot have any watches and
@@ -263,8 +266,10 @@ void fsnotify_unmount_inodes(struct list_head *list)
* evict all inodes with zero i_count from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
- if (!atomic_read(&inode->i_count))
+ if (!atomic_read(&inode->i_count)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
need_iput_tmp = need_iput;
need_iput = NULL;
@@ -274,13 +279,17 @@ void fsnotify_unmount_inodes(struct list_head *list)
__iget(inode);
else
need_iput_tmp = NULL;
+ spin_unlock(&inode->i_lock);
/* In case the dropping of a reference would nuke next_i. */
if ((&next_i->i_sb_list != list) &&
- atomic_read(&next_i->i_count) &&
- !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
- __iget(next_i);
- need_iput = next_i;
+ atomic_read(&next_i->i_count)) {
+ spin_lock(&next_i->i_lock);
+ if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
+ __iget(next_i);
+ need_iput = next_i;
+ }
+ spin_unlock(&next_i->i_lock);
}
/*