path: root/fs/ceph/dir.c

#include <linux/ceph/ceph_debug.h>

#include <linux/spinlock.h>
#include <linux/fs_struct.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <linux/sched.h>

#include "super.h"
#include "mds_client.h"

/*
 * Directory operations: readdir, lookup, create, link, unlink,
 * rename, etc.
 */

/*
 * Ceph MDS operations are specified in terms of a base ino and
 * relative path.  Thus, the client can specify an operation on a
 * specific inode (e.g., a getattr due to fstat(2)), or as a path
 * relative to, say, the root directory.
 *
 * Normally, we limit ourselves to strict inode ops (no path component)
 * or dentry operations (a single path component relative to an ino).  The
 * exception to this is open_root_dentry(), which will open the mount
 * point by name.
 */

const struct inode_operations ceph_dir_iops;
const struct file_operations ceph_dir_fops;
const struct dentry_operations ceph_dentry_ops;

/*
 * Initialize ceph dentry state.
 */
int ceph_init_dentry(struct dentry *dentry)
{
	struct ceph_dentry_info *di;

	if (dentry->d_fsdata)
		return 0;

	if (dentry->d_parent == NULL ||   /* nfs fh_to_dentry */
	    ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP)
		d_set_d_op(dentry, &ceph_dentry_ops);
	else if (ceph_snap(dentry->d_parent->d_inode) == CEPH_SNAPDIR)
		d_set_d_op(dentry, &ceph_snapdir_dentry_ops);
	else
		d_set_d_op(dentry, &ceph_snap_dentry_ops);

	di = kmem_cache_alloc(ceph_dentry_cachep, GFP_NOFS | __GFP_ZERO);
	if (!di)
		return -ENOMEM;          /* oh well */

	spin_lock(&dentry->d_lock);
	if (dentry->d_fsdata) {
		/* lost a race */
		kmem_cache_free(ceph_dentry_cachep, di);
		goto out_unlock;
	}
	di->dentry = dentry;
	di->lease_session = NULL;
	dentry->d_fsdata = di;
	dentry->d_time = jiffies;
	ceph_dentry_lru_add(dentry);
out_unlock:
	spin_unlock(&dentry->d_lock);
	return 0;
}



/*
 * for readdir, we encode the directory frag and offset within that
 * frag into f_pos.
 */
static unsigned fpos_frag(loff_t p)
{
	return p >> 32;
}
static unsigned fpos_off(loff_t p)
{
	return p & 0xffffffff;
}

/*
 * When possible, we try to satisfy a readdir by peeking at the
 * dcache.  We make this work by carefully ordering dentries on
 * d_u.d_child when we initially get results back from the MDS, and
 * falling back to a "normal" sync readdir if any dentries in the dir
 * are dropped.
 *
 * I_COMPLETE tells indicates we have all dentries in the dir.  It is
 * defined IFF we hold CEPH_CAP_FILE_SHARED (which will be revoked by
 * the MDS if/when the directory is modified).
 */
static int __dcache_readdir(struct file *filp,
			    void *dirent, filldir_t filldir)
{
	struct ceph_file_info *fi = filp->private_data;
	struct dentry *parent = filp->f_dentry;
	struct inode *dir = parent->d_inode;