linux/fs/ceph/quota.c
Wenchao Hao 0f4cf64eab ceph: fix invalid pointer access if get_quota_realm return ERR_PTR
This issue is reported by smatch that get_quota_realm() might return
ERR_PTR but we did not handle it. It's not a immediate bug, while we
still should address it to avoid potential bugs if get_quota_realm()
is changed to return other ERR_PTR in future.

Set ceph_snap_realm's pointer in get_quota_realm()'s to address this
issue, the pointer would be set to NULL if get_quota_realm() failed
to get struct ceph_snap_realm, so no ERR_PTR would happen any more.

[ xiubli: minor code style clean up ]

Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2024-01-15 15:40:51 +01:00

548 lines
15 KiB
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)
{
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
if (inc)
atomic64_inc(&mdsc->quotarealms_count);
else
atomic64_dec(&mdsc->quotarealms_count);
}
static inline bool ceph_has_realms_with_quotas(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(sb);
struct inode *root = d_inode(sb->s_root);
if (atomic64_read(&mdsc->quotarealms_count) > 0)
return true;
/* if root is the real CephFS root, we don't have quota realms */
if (root && ceph_ino(root) == CEPH_INO_ROOT)
return false;
/* MDS stray dirs have no quota realms */
if (ceph_vino_is_reserved(ceph_inode(inode)->i_vino))
return false;
/* otherwise, we can't know for sure */
return true;
}
void ceph_handle_quota(struct ceph_mds_client *mdsc,
struct ceph_mds_session *session,
struct ceph_msg *msg)
{
struct super_block *sb = mdsc->fsc->sb;
struct ceph_mds_quota *h = msg->front.iov_base;
struct ceph_client *cl = mdsc->fsc->client;
struct ceph_vino vino;
struct inode *inode;
struct ceph_inode_info *ci;
if (!ceph_inc_mds_stopping_blocker(mdsc, session))
return;
if (msg->front.iov_len < sizeof(*h)) {
pr_err_client(cl, "corrupt message mds%d len %d\n",
session->s_mds, (int)msg->front.iov_len);
ceph_msg_dump(msg);
goto out;
}
/* lookup inode */
vino.ino = le64_to_cpu(h->ino);
vino.snap = CEPH_NOSNAP;
inode = ceph_find_inode(sb, vino);
if (!inode) {
pr_warn_client(cl, "failed to find inode %llx\n", vino.ino);
goto out;
}
ci = ceph_inode(inode);
spin_lock(&ci->i_ceph_lock);
ci->i_rbytes = le64_to_cpu(h->rbytes);
ci->i_rfiles = le64_to_cpu(h->rfiles);
ci->i_rsubdirs = le64_to_cpu(h->rsubdirs);
__ceph_update_quota(ci, le64_to_cpu(h->max_bytes),
le64_to_cpu(h->max_files));
spin_unlock(&ci->i_ceph_lock);
iput(inode);
out:
ceph_dec_mds_stopping_blocker(mdsc);
}
static struct ceph_quotarealm_inode *
find_quotarealm_inode(struct ceph_mds_client *mdsc, u64 ino)
{
struct ceph_quotarealm_inode *qri = NULL;
struct rb_node **node, *parent = NULL;
struct ceph_client *cl = mdsc->fsc->client;
mutex_lock(&mdsc->quotarealms_inodes_mutex);
node = &(mdsc->quotarealms_inodes.rb_node);
while (*node) {
parent = *node;
qri = container_of(*node, struct ceph_quotarealm_inode, node);
if (ino < qri->ino)
node = &((*node)->rb_left);
else if (ino > qri->ino)
node = &((*node)->rb_right);
else
break;
}
if (!qri || (qri->ino != ino)) {
/* Not found, create a new one and insert it */
qri = kmalloc(sizeof(*qri), GFP_KERNEL);
if (qri) {
qri->ino = ino;
qri->inode = NULL;
qri->timeout = 0;
mutex_init(&qri->mutex);
rb_link_node(&qri->node, parent, node);
rb_insert_color(&qri->node, &mdsc->quotarealms_inodes);
} else
pr_warn_client(cl, "Failed to alloc quotarealms_inode\n");
}
mutex_unlock(&mdsc->quotarealms_inodes_mutex);
return qri;
}
/*
* 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)
{
struct ceph_client *cl = mdsc->fsc->client;
struct ceph_quotarealm_inode *qri;
struct inode *in;
qri = find_quotarealm_inode(mdsc, realm->ino);
if (!qri)
return NULL;
mutex_lock(&qri->mutex);
if (qri->inode && ceph_is_any_caps(qri->inode)) {
/* A request has already returned the inode */
mutex_unlock(&qri->mutex);
return qri->inode;
}
/* Check if this inode lookup has failed recently */
if (qri->timeout &&
time_before_eq(jiffies, qri->timeout)) {
mutex_unlock(&qri->mutex);
return NULL;
}
if (qri->inode) {
/* get caps */
int ret = __ceph_do_getattr(qri->inode, NULL,
CEPH_STAT_CAP_INODE, true);
if (ret >= 0)
in = qri->inode;
else
in = ERR_PTR(ret);
} else {
in = ceph_lookup_inode(sb, realm->ino);
}
if (IS_ERR(in)) {
doutc(cl, "Can't lookup inode %llx (err: %ld)\n", realm->ino,
PTR_ERR(in));
qri->timeout = jiffies + msecs_to_jiffies(60 * 1000); /* XXX */
} else {
qri->timeout = 0;
qri->inode = in;
}
mutex_unlock(&qri->mutex);
return in;
}
void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc)
{
struct ceph_quotarealm_inode *qri;
struct rb_node *node;
/*
* It should now be safe to clean quotarealms_inode tree without holding
* mdsc->quotarealms_inodes_mutex...
*/
mutex_lock(&mdsc->quotarealms_inodes_mutex);
while (!RB_EMPTY_ROOT(&mdsc->quotarealms_inodes)) {
node = rb_first(&mdsc->quotarealms_inodes);
qri = rb_entry(node, struct ceph_quotarealm_inode, node);
rb_erase(node, &mdsc->quotarealms_inodes);
iput(qri->inode);
kfree(qri);
}
mutex_unlock(&mdsc->quotarealms_inodes_mutex);
}
/*
* 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)
{
struct ceph_client *cl = mdsc->fsc->client;
struct ceph_inode_info *ci = NULL;
struct ceph_snap_realm *realm, *next;
struct inode *in;
bool has_quota;
if (realmp)
*realmp = NULL;
if (ceph_snap(inode) != CEPH_NOSNAP)
return 0;
restart:
realm = ceph_inode(inode)->i_snap_realm;
if (realm)
ceph_get_snap_realm(mdsc, realm);
else
pr_err_ratelimited_client(cl,
"%p %llx.%llx null i_snap_realm\n",
inode, ceph_vinop(inode));
while (realm) {
bool has_inode;
spin_lock(&realm->inodes_with_caps_lock);
has_inode = realm->inode;
in = has_inode ? igrab(realm->inode) : NULL;
spin_unlock(&realm->inodes_with_caps_lock);
if (has_inode && !in)
break;
if (!in) {
up_read(&mdsc->snap_rwsem);
in = lookup_quotarealm_inode(mdsc, inode->i_sb, realm);
down_read(&mdsc->snap_rwsem);
if (IS_ERR_OR_NULL(in))
break;
ceph_put_snap_realm(mdsc, realm);
if (!retry)
return -EAGAIN;
goto restart;
}
ci = ceph_inode(in);
has_quota = __ceph_has_quota(ci, which_quota);
iput(in);
next = realm->parent;
if (has_quota || !next) {
if (realmp)
*realmp = realm;
return 0;
}
ceph_get_snap_realm(mdsc, next);
ceph_put_snap_realm(mdsc, realm);
realm = next;
}
if (realm)
ceph_put_snap_realm(mdsc, realm);
return 0;
}
bool ceph_quota_is_same_realm(struct inode *old, struct inode *new)
{
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(old->i_sb);
struct ceph_snap_realm *old_realm, *new_realm;
bool is_same;
int ret;
restart:
/*
* We need to lookup 2 quota realms atomically, i.e. with snap_rwsem.
* However, get_quota_realm may drop it temporarily. By setting the
* 'retry' parameter to 'false', we'll get -EAGAIN if the rwsem was
* dropped and we can then restart the whole operation.
*/
down_read(&mdsc->snap_rwsem);
get_quota_realm(mdsc, old, QUOTA_GET_ANY, &old_realm, true);
ret = get_quota_realm(mdsc, new, QUOTA_GET_ANY, &new_realm, false);
if (ret == -EAGAIN) {
up_read(&mdsc->snap_rwsem);
if (old_realm)
ceph_put_snap_realm(mdsc, old_realm);
goto restart;
}
is_same = (old_realm == new_realm);
up_read(&mdsc->snap_rwsem);
if (old_realm)
ceph_put_snap_realm(mdsc, old_realm);
if (new_realm)
ceph_put_snap_realm(mdsc, new_realm);
return is_same;
}
enum quota_check_op {
QUOTA_CHECK_MAX_FILES_OP, /* check quota max_files limit */
QUOTA_CHECK_MAX_BYTES_OP, /* check quota max_files limit */
QUOTA_CHECK_MAX_BYTES_APPROACHING_OP /* check if quota max_files
limit is approaching */
};
/*
* 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)
{
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
struct ceph_client *cl = mdsc->fsc->client;
struct ceph_inode_info *ci;
struct ceph_snap_realm *realm, *next;
struct inode *in;
u64 max, rvalue;
bool exceeded = false;
if (ceph_snap(inode) != CEPH_NOSNAP)
return false;
down_read(&mdsc->snap_rwsem);
restart:
realm = ceph_inode(inode)->i_snap_realm;
if (realm)
ceph_get_snap_realm(mdsc, realm);
else
pr_err_ratelimited_client(cl,
"%p %llx.%llx null i_snap_realm\n",
inode, ceph_vinop(inode));
while (realm) {
bool has_inode;
spin_lock(&realm->inodes_with_caps_lock);
has_inode = realm->inode;
in = has_inode ? igrab(realm->inode) : NULL;
spin_unlock(&realm->inodes_with_caps_lock);
if (has_inode && !in)
break;
if (!in) {
up_read(&mdsc->snap_rwsem);
in = lookup_quotarealm_inode(mdsc, inode->i_sb, realm);
down_read(&mdsc->snap_rwsem);
if (IS_ERR_OR_NULL(in))
break;
ceph_put_snap_realm(mdsc, realm);
goto restart;
}
ci = ceph_inode(in);
spin_lock(&ci->i_ceph_lock);
if (op == QUOTA_CHECK_MAX_FILES_OP) {
max = ci->i_max_files;
rvalue = ci->i_rfiles + ci->i_rsubdirs;
} else {
max = ci->i_max_bytes;
rvalue = ci->i_rbytes;
}
spin_unlock(&ci->i_ceph_lock);
switch (op) {
case QUOTA_CHECK_MAX_FILES_OP:
case QUOTA_CHECK_MAX_BYTES_OP:
exceeded = (max && (rvalue + delta > max));
break;
case QUOTA_CHECK_MAX_BYTES_APPROACHING_OP:
if (max) {
if (rvalue >= max)
exceeded = true;
else {
/*
* when we're writing more that 1/16th
* of the available space
*/
exceeded =
(((max - rvalue) >> 4) < delta);
}
}
break;
default:
/* Shouldn't happen */
pr_warn_client(cl, "Invalid quota check op (%d)\n", op);
exceeded = true; /* Just break the loop */
}
iput(in);
next = realm->parent;
if (exceeded || !next)
break;
ceph_get_snap_realm(mdsc, next);
ceph_put_snap_realm(mdsc, realm);
realm = next;
}
if (realm)
ceph_put_snap_realm(mdsc, realm);
up_read(&mdsc->snap_rwsem);
return exceeded;
}
/*
* 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)
{
if (!ceph_has_realms_with_quotas(inode))
return false;
WARN_ON(!S_ISDIR(inode->i_mode));
return check_quota_exceeded(inode, QUOTA_CHECK_MAX_FILES_OP, 1);
}
/*
* 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)
{
loff_t size = i_size_read(inode);
if (!ceph_has_realms_with_quotas(inode))
return false;
/* return immediately if we're decreasing file size */
if (newsize <= size)
return false;
return check_quota_exceeded(inode, QUOTA_CHECK_MAX_BYTES_OP, (newsize - size));
}
/*
* 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)
{
loff_t size = ceph_inode(inode)->i_reported_size;
if (!ceph_has_realms_with_quotas(inode))
return false;
/* return immediately if we're decreasing file size */
if (newsize <= size)
return false;
return check_quota_exceeded(inode, QUOTA_CHECK_MAX_BYTES_APPROACHING_OP,
(newsize - size));
}
/*
* 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)
{
struct ceph_mds_client *mdsc = fsc->mdsc;
struct ceph_inode_info *ci;
struct ceph_snap_realm *realm;
struct inode *in;
u64 total = 0, used, free;
bool is_updated = false;
down_read(&mdsc->snap_rwsem);
get_quota_realm(mdsc, d_inode(fsc->sb->s_root), QUOTA_GET_MAX_BYTES,
&realm, true);
up_read(&mdsc->snap_rwsem);
if (!realm)
return false;
spin_lock(&realm->inodes_with_caps_lock);
in = realm->inode ? igrab(realm->inode) : NULL;
spin_unlock(&realm->inodes_with_caps_lock);
if (in) {
ci = ceph_inode(in);
spin_lock(&ci->i_ceph_lock);
if (ci->i_max_bytes) {
total = ci->i_max_bytes >> CEPH_BLOCK_SHIFT;
used = ci->i_rbytes >> CEPH_BLOCK_SHIFT;
/* For quota size less than 4MB, use 4KB block size */
if (!total) {
total = ci->i_max_bytes >> CEPH_4K_BLOCK_SHIFT;
used = ci->i_rbytes >> CEPH_4K_BLOCK_SHIFT;
buf->f_frsize = 1 << CEPH_4K_BLOCK_SHIFT;
}
/* It is possible for a quota to be exceeded.
* Report 'zero' in that case
*/
free = total > used ? total - used : 0;
/* For quota size less than 4KB, report the
* total=used=4KB,free=0 when quota is full
* and total=free=4KB, used=0 otherwise */
if (!total) {
total = 1;
free = ci->i_max_bytes > ci->i_rbytes ? 1 : 0;
buf->f_frsize = 1 << CEPH_4K_BLOCK_SHIFT;
}
}
spin_unlock(&ci->i_ceph_lock);
if (total) {
buf->f_blocks = total;
buf->f_bfree = free;
buf->f_bavail = free;
is_updated = true;
}
iput(in);
}
ceph_put_snap_realm(mdsc, realm);
return is_updated;
}