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fuse: fix initial parallel dirops

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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: 5c672ab3f0 ("fuse: serialize dirops by default")
Cc: <stable@vger.kernel.org> # v4.7
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2018-07-26 16:13:11 +02:00
parent e8f3bd773d
commit 63576c13bd
3 changed files with 18 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
fs/fuse/dir.c
View File

@ -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);

4
fs/fuse/fuse_i.h
View File

@ -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);

14
fs/fuse/inode.c
View File

@ -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);
}