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-rw-r--r--fs/fuse/dir.c70
-rw-r--r--fs/fuse/fuse_i.h3
-rw-r--r--fs/fuse/inode.c5
3 files changed, 51 insertions, 27 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 7ecfe95795cd..9d0ef5e18740 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -177,22 +177,6 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
return 1;
}
-/*
- * Check if there's already a hashed alias of this directory inode.
- * If yes, then lookup and mkdir must not create a new alias.
- */
-static int dir_alias(struct inode *inode)
-{
- if (S_ISDIR(inode->i_mode)) {
- struct dentry *alias = d_find_alias(inode);
- if (alias) {
- dput(alias);
- return 1;
- }
- }
- return 0;
-}
-
static int invalid_nodeid(u64 nodeid)
{
return !nodeid || nodeid == FUSE_ROOT_ID;
@@ -208,6 +192,24 @@ static int valid_mode(int m)
S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
}
+/*
+ * Add a directory inode to a dentry, ensuring that no other dentry
+ * refers to this inode. Called with fc->inst_mutex.
+ */
+static int fuse_d_add_directory(struct dentry *entry, struct inode *inode)
+{
+ struct dentry *alias = d_find_alias(inode);
+ if (alias) {
+ /* This tries to shrink the subtree below alias */
+ fuse_invalidate_entry(alias);
+ dput(alias);
+ if (!list_empty(&inode->i_dentry))
+ return -EBUSY;
+ }
+ d_add(entry, inode);
+ return 0;
+}
+
static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
struct nameidata *nd)
{
@@ -243,11 +245,17 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
if (err && err != -ENOENT)
return ERR_PTR(err);
- if (inode && dir_alias(inode)) {
- iput(inode);
- return ERR_PTR(-EIO);
- }
- d_add(entry, inode);
+ if (inode && S_ISDIR(inode->i_mode)) {
+ mutex_lock(&fc->inst_mutex);
+ err = fuse_d_add_directory(entry, inode);
+ mutex_unlock(&fc->inst_mutex);
+ if (err) {
+ iput(inode);
+ return ERR_PTR(err);
+ }
+ } else
+ d_add(entry, inode);
+
entry->d_op = &fuse_dentry_operations;
if (!err)
fuse_change_timeout(entry, &outarg);
@@ -403,12 +411,22 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
}
fuse_put_request(fc, req);
- if (dir_alias(inode)) {
- iput(inode);
- return -EIO;
- }
+ if (S_ISDIR(inode->i_mode)) {
+ struct dentry *alias;
+ mutex_lock(&fc->inst_mutex);
+ alias = d_find_alias(inode);
+ if (alias) {
+ /* New directory must have moved since mkdir */
+ mutex_unlock(&fc->inst_mutex);
+ dput(alias);
+ iput(inode);
+ return -EBUSY;
+ }
+ d_instantiate(entry, inode);
+ mutex_unlock(&fc->inst_mutex);
+ } else
+ d_instantiate(entry, inode);
- d_instantiate(entry, inode);
fuse_change_timeout(entry, &outarg);
fuse_invalidate_attr(dir);
return 0;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 69c7750d55b8..91edb8932d90 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -239,6 +239,9 @@ struct fuse_conn {
/** Lock protecting accessess to members of this structure */
spinlock_t lock;
+ /** Mutex protecting against directory alias creation */
+ struct mutex inst_mutex;
+
/** Refcount */
atomic_t count;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 4ee8f72e6380..fc4203570370 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -379,6 +379,7 @@ static struct fuse_conn *new_conn(void)
fc = kzalloc(sizeof(*fc), GFP_KERNEL);
if (fc) {
spin_lock_init(&fc->lock);
+ mutex_init(&fc->inst_mutex);
atomic_set(&fc->count, 1);
init_waitqueue_head(&fc->waitq);
init_waitqueue_head(&fc->blocked_waitq);
@@ -398,8 +399,10 @@ static struct fuse_conn *new_conn(void)
void fuse_conn_put(struct fuse_conn *fc)
{
- if (atomic_dec_and_test(&fc->count))
+ if (atomic_dec_and_test(&fc->count)) {
+ mutex_destroy(&fc->inst_mutex);
kfree(fc);
+ }
}
struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)