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authorMiklos Szeredi <mszeredi@redhat.com>2018-07-26 17:13:11 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-07-26 17:13:11 +0300
commit63576c13bd17848376c8ba4a98f5d5151140c4ac (patch)
tree2b33da7010c6d8a18f0736cf80a967a4ce8ad50c /fs/fuse
parente8f3bd773d22f488724dffb886a1618da85c2966 (diff)
downloadlinux-63576c13bd17848376c8ba4a98f5d5151140c4ac.tar.xz
fuse: fix initial parallel dirops
If parallel dirops are enabled in FUSE_INIT reply, then first operation may leave fi->mutex held. Reported-by: syzbot <syzbot+3f7b29af1baa9d0a55be@syzkaller.appspotmail.com> Fixes: 5c672ab3f0ee ("fuse: serialize dirops by default") Cc: <stable@vger.kernel.org> # v4.7 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/dir.c10
-rw-r--r--fs/fuse/fuse_i.h4
-rw-r--r--fs/fuse/inode.c14
3 files changed, 18 insertions, 10 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 56231b31f806..606909ed5f21 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -355,11 +355,12 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
struct inode *inode;
struct dentry *newent;
bool outarg_valid = true;
+ bool locked;
- fuse_lock_inode(dir);
+ locked = fuse_lock_inode(dir);
err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
&outarg, &inode);
- fuse_unlock_inode(dir);
+ fuse_unlock_inode(dir, locked);
if (err == -ENOENT) {
outarg_valid = false;
err = 0;
@@ -1340,6 +1341,7 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx)
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
u64 attr_version = 0;
+ bool locked;
if (is_bad_inode(inode))
return -EIO;
@@ -1367,9 +1369,9 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx)
fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
FUSE_READDIR);
}
- fuse_lock_inode(inode);
+ locked = fuse_lock_inode(inode);
fuse_request_send(fc, req);
- fuse_unlock_inode(inode);
+ fuse_unlock_inode(inode, locked);
nbytes = req->out.args[0].size;
err = req->out.h.error;
fuse_put_request(fc, req);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 582b1756a011..f78e9614bb5f 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -975,8 +975,8 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
void fuse_set_initialized(struct fuse_conn *fc);
-void fuse_unlock_inode(struct inode *inode);
-void fuse_lock_inode(struct inode *inode);
+void fuse_unlock_inode(struct inode *inode, bool locked);
+bool fuse_lock_inode(struct inode *inode);
int fuse_setxattr(struct inode *inode, const char *name, const void *value,
size_t size, int flags);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 0115c2f0a428..2dbd487390a3 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -357,15 +357,21 @@ int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
return 0;
}
-void fuse_lock_inode(struct inode *inode)
+bool fuse_lock_inode(struct inode *inode)
{
- if (!get_fuse_conn(inode)->parallel_dirops)
+ bool locked = false;
+
+ if (!get_fuse_conn(inode)->parallel_dirops) {
mutex_lock(&get_fuse_inode(inode)->mutex);
+ locked = true;
+ }
+
+ return locked;
}
-void fuse_unlock_inode(struct inode *inode)
+void fuse_unlock_inode(struct inode *inode, bool locked)
{
- if (!get_fuse_conn(inode)->parallel_dirops)
+ if (locked)
mutex_unlock(&get_fuse_inode(inode)->mutex);
}