/*
* Grab the exclusive iolock for a data copy from src to dest, making
* sure to abide vfs locking order (lowest pointer value goes first) and
* breaking the pnfs layout leases on dest before proceeding. The loop
* is needed because we cannot call the blocking break_layout() with the
* src iolock held, and therefore have to back out both locks.
*/
static int
xfs_iolock_two_inodes_and_break_layout(
struct inode *src,
struct inode *dest)
{
int error;
retry:
if (src < dest) {
inode_lock_shared(src);
inode_lock_nested(dest, I_MUTEX_NONDIR2);
} else {
/* src >= dest */
inode_lock(dest);
}
error = break_layout(dest, false);
if (error == -EWOULDBLOCK) {
inode_unlock(dest);
if (src < dest)
inode_unlock_shared(src);
error = break_layout(dest, true);
if (error)
return error;
goto retry;
}
if (error) {
inode_unlock(dest);
if (src < dest)
inode_unlock_shared(src);
return error;
}
if (src > dest)
inode_lock_shared_nested(src, I_MUTEX_NONDIR2);
return 0;
}
static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
ssize_t ret;
if (!iov_iter_count(to))
return 0; /* skip atime */
inode_lock_shared(inode);
ret = dax_iomap_rw(iocb, to, &ext2_iomap_ops);
inode_unlock_shared(inode);
file_accessed(iocb->ki_filp);
return ret;
}
/* Unlock both inodes after they've been prepped for a range clone. */
void
xfs_reflink_remap_unlock(
struct file *file_in,
struct file *file_out)
{
struct inode *inode_in = file_inode(file_in);
struct xfs_inode *src = XFS_I(inode_in);
struct inode *inode_out = file_inode(file_out);
struct xfs_inode *dest = XFS_I(inode_out);
bool same_inode = (inode_in == inode_out);
xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);
if (!same_inode)
xfs_iunlock(src, XFS_MMAPLOCK_SHARED);
inode_unlock(inode_out);
if (!same_inode)
inode_unlock_shared(inode_in);
}
int iterate_dir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
bool shared = false;
int res = -ENOTDIR;
if (file->f_op->iterate_shared)
shared = true;
else if (!file->f_op->iterate)
goto out;
res = security_file_permission(file, MAY_READ);
if (res)
goto out;
if (shared)
res = down_read_killable(&inode->i_rwsem);
else
res = down_write_killable(&inode->i_rwsem);
if (res)
goto out;
res = -ENOENT;
if (!IS_DEADDIR(inode)) {
ctx->pos = file->f_pos;
if (shared)
res = file->f_op->iterate_shared(file, ctx);
else
res = file->f_op->iterate(file, ctx);
file->f_pos = ctx->pos;
fsnotify_access(file);
file_accessed(file);
}
if (shared)
inode_unlock_shared(inode);
else
inode_unlock(inode);
out:
return res;
}
