linux/fs/ceph/quota.c

// SPDX-License-Identifier: GPL-2.0
/*
 * quota.c - CephFS quota
 *
 * Copyright (C) 2017-2018 SUSE
 */

#include <linux/statfs.h>

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

void ceph_adjust_quota_realms_count(struct inode *inode, bool inc)
{ … }

static inline bool ceph_has_realms_with_quotas(struct inode *inode)
{ … }

void ceph_handle_quota(struct ceph_mds_client *mdsc,
		       struct ceph_mds_session *session,
		       struct ceph_msg *msg)
{ … }

static struct ceph_quotarealm_inode *
find_quotarealm_inode(struct ceph_mds_client *mdsc, u64 ino)
{ … }

/*
 * This function will try to lookup a realm inode which isn't visible in the
 * filesystem mountpoint.  A list of these kind of inodes (not visible) is
 * maintained in the mdsc and freed only when the filesystem is umounted.
 *
 * Note that these inodes are kept in this list even if the lookup fails, which
 * allows to prevent useless lookup requests.
 */
static struct inode *lookup_quotarealm_inode(struct ceph_mds_client *mdsc,
					     struct super_block *sb,
					     struct ceph_snap_realm *realm)
{ … }

void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc)
{ … }

/*
 * This function walks through the snaprealm for an inode and set the
 * realmp with the first snaprealm that has quotas set (max_files,
 * max_bytes, or any, depending on the 'which_quota' argument).  If the root is
 * reached, set the realmp with the root ceph_snap_realm instead.
 *
 * Note that the caller is responsible for calling ceph_put_snap_realm() on the
 * returned realm.
 *
 * Callers of this function need to hold mdsc->snap_rwsem.  However, if there's
 * a need to do an inode lookup, this rwsem will be temporarily dropped.  Hence
 * the 'retry' argument: if rwsem needs to be dropped and 'retry' is 'false'
 * this function will return -EAGAIN; otherwise, the snaprealms walk-through
 * will be restarted.
 */
static int get_quota_realm(struct ceph_mds_client *mdsc, struct inode *inode,
			   enum quota_get_realm which_quota,
			   struct ceph_snap_realm **realmp, bool retry)
{ … }

bool ceph_quota_is_same_realm(struct inode *old, struct inode *new)
{ … }

enum quota_check_op { … };

/*
 * check_quota_exceeded() will walk up the snaprealm hierarchy and, for each
 * realm, it will execute quota check operation defined by the 'op' parameter.
 * The snaprealm walk is interrupted if the quota check detects that the quota
 * is exceeded or if the root inode is reached.
 */
static bool check_quota_exceeded(struct inode *inode, enum quota_check_op op,
				 loff_t delta)
{ … }

/*
 * ceph_quota_is_max_files_exceeded - check if we can create a new file
 * @inode:	directory where a new file is being created
 *
 * This functions returns true is max_files quota allows a new file to be
 * created.  It is necessary to walk through the snaprealm hierarchy (until the
 * FS root) to check all realms with quotas set.
 */
bool ceph_quota_is_max_files_exceeded(struct inode *inode)
{ … }

/*
 * ceph_quota_is_max_bytes_exceeded - check if we can write to a file
 * @inode:	inode being written
 * @newsize:	new size if write succeeds
 *
 * This functions returns true is max_bytes quota allows a file size to reach
 * @newsize; it returns false otherwise.
 */
bool ceph_quota_is_max_bytes_exceeded(struct inode *inode, loff_t newsize)
{ … }

/*
 * ceph_quota_is_max_bytes_approaching - check if we're reaching max_bytes
 * @inode:	inode being written
 * @newsize:	new size if write succeeds
 *
 * This function returns true if the new file size @newsize will be consuming
 * more than 1/16th of the available quota space; it returns false otherwise.
 */
bool ceph_quota_is_max_bytes_approaching(struct inode *inode, loff_t newsize)
{ … }

/*
 * ceph_quota_update_statfs - if root has quota update statfs with quota status
 * @fsc:	filesystem client instance
 * @buf:	statfs to update
 *
 * If the mounted filesystem root has max_bytes quota set, update the filesystem
 * statistics with the quota status.
 *
 * This function returns true if the stats have been updated, false otherwise.
 */
bool ceph_quota_update_statfs(struct ceph_fs_client *fsc, struct kstatfs *buf)
{ … }