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authorNick Piggin <npiggin@kernel.dk>2011-01-07 17:49:34 +1100
committerNick Piggin <npiggin@kernel.dk>2011-01-07 17:50:21 +1100
commit2fd6b7f50797f2e993eea59e0a0b8c6399c811dc (patch)
treece33b94b34844c09103836cf4cfa4364b742f217 /security
parentda5029563a0a026c64821b09e8e7b4fd81d3fe1b (diff)
downloadlinux-linaro-2fd6b7f50797f2e993eea59e0a0b8c6399c811dc.tar.gz
fs: dcache scale subdirs
Protect d_subdirs and d_child with d_lock, except in filesystems that aren't using dcache_lock for these anyway (eg. using i_mutex). Note: if we change the locking rule in future so that ->d_child protection is provided only with ->d_parent->d_lock, it may allow us to reduce some locking. But it would be an exception to an otherwise regular locking scheme, so we'd have to see some good results. Probably not worthwhile. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/selinuxfs.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 073fd5b0a53..017ec096446 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -1146,22 +1146,30 @@ static void sel_remove_entries(struct dentry *de)
struct list_head *node;
spin_lock(&dcache_lock);
+ spin_lock(&de->d_lock);
node = de->d_subdirs.next;
while (node != &de->d_subdirs) {
struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
+
+ spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
list_del_init(node);
if (d->d_inode) {
- d = dget_locked(d);
+ dget_locked_dlock(d);
+ spin_unlock(&de->d_lock);
+ spin_unlock(&d->d_lock);
spin_unlock(&dcache_lock);
d_delete(d);
simple_unlink(de->d_inode, d);
dput(d);
spin_lock(&dcache_lock);
- }
+ spin_lock(&de->d_lock);
+ } else
+ spin_unlock(&d->d_lock);
node = de->d_subdirs.next;
}
+ spin_unlock(&de->d_lock);
spin_unlock(&dcache_lock);
}