linux-stable/fs/quota/quota_tree.c
Eric W. Biederman 4c376dcae8 userns: Convert struct dquot dq_id to be a struct kqid
Change struct dquot dq_id to a struct kqid and remove the now
unecessary dq_type.

Make minimal changes to dquot, quota_tree, quota_v1, quota_v2, ext3,
ext4, and ocfs2 to deal with the change in quota structures and
signatures.  The ocfs2 changes are larger than most because of the
extensive tracing throughout the ocfs2 quota code that prints out
dq_id.

quota_tree.c:get_index is modified to take a struct kqid instead of a
qid_t because all of it's callers pass in dquot->dq_id and it allows
me to introduce only a single conversion.

The rest of the changes are either just replacing dq_type with dq_id.type,
adding conversions to deal with the change in type and occassionally
adding qid_eq to allow quota id comparisons in a user namespace safe way.

Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Theodore Tso <tytso@mit.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-09-18 01:01:41 -07:00

663 lines
17 KiB
C

/*
* vfsv0 quota IO operations on file
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/dqblk_v2.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/quotaops.h>
#include <asm/byteorder.h>
#include "quota_tree.h"
MODULE_AUTHOR("Jan Kara");
MODULE_DESCRIPTION("Quota trie support");
MODULE_LICENSE("GPL");
#define __QUOTA_QT_PARANOIA
static int get_index(struct qtree_mem_dqinfo *info, struct kqid qid, int depth)
{
unsigned int epb = info->dqi_usable_bs >> 2;
qid_t id = from_kqid(&init_user_ns, qid);
depth = info->dqi_qtree_depth - depth - 1;
while (depth--)
id /= epb;
return id % epb;
}
/* Number of entries in one blocks */
static int qtree_dqstr_in_blk(struct qtree_mem_dqinfo *info)
{
return (info->dqi_usable_bs - sizeof(struct qt_disk_dqdbheader))
/ info->dqi_entry_size;
}
static char *getdqbuf(size_t size)
{
char *buf = kmalloc(size, GFP_NOFS);
if (!buf)
printk(KERN_WARNING
"VFS: Not enough memory for quota buffers.\n");
return buf;
}
static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
{
struct super_block *sb = info->dqi_sb;
memset(buf, 0, info->dqi_usable_bs);
return sb->s_op->quota_read(sb, info->dqi_type, buf,
info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
}
static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
{
struct super_block *sb = info->dqi_sb;
ssize_t ret;
ret = sb->s_op->quota_write(sb, info->dqi_type, buf,
info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
if (ret != info->dqi_usable_bs) {
quota_error(sb, "dquota write failed");
if (ret >= 0)
ret = -EIO;
}
return ret;
}
/* Remove empty block from list and return it */
static int get_free_dqblk(struct qtree_mem_dqinfo *info)
{
char *buf = getdqbuf(info->dqi_usable_bs);
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
int ret, blk;
if (!buf)
return -ENOMEM;
if (info->dqi_free_blk) {
blk = info->dqi_free_blk;
ret = read_blk(info, blk, buf);
if (ret < 0)
goto out_buf;
info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
}
else {
memset(buf, 0, info->dqi_usable_bs);
/* Assure block allocation... */
ret = write_blk(info, info->dqi_blocks, buf);
if (ret < 0)
goto out_buf;
blk = info->dqi_blocks++;
}
mark_info_dirty(info->dqi_sb, info->dqi_type);
ret = blk;
out_buf:
kfree(buf);
return ret;
}
/* Insert empty block to the list */
static int put_free_dqblk(struct qtree_mem_dqinfo *info, char *buf, uint blk)
{
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
int err;
dh->dqdh_next_free = cpu_to_le32(info->dqi_free_blk);
dh->dqdh_prev_free = cpu_to_le32(0);
dh->dqdh_entries = cpu_to_le16(0);
err = write_blk(info, blk, buf);
if (err < 0)
return err;
info->dqi_free_blk = blk;
mark_info_dirty(info->dqi_sb, info->dqi_type);
return 0;
}
/* Remove given block from the list of blocks with free entries */
static int remove_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
uint blk)
{
char *tmpbuf = getdqbuf(info->dqi_usable_bs);
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
uint nextblk = le32_to_cpu(dh->dqdh_next_free);
uint prevblk = le32_to_cpu(dh->dqdh_prev_free);
int err;
if (!tmpbuf)
return -ENOMEM;
if (nextblk) {
err = read_blk(info, nextblk, tmpbuf);
if (err < 0)
goto out_buf;
((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
dh->dqdh_prev_free;
err = write_blk(info, nextblk, tmpbuf);
if (err < 0)
goto out_buf;
}
if (prevblk) {
err = read_blk(info, prevblk, tmpbuf);
if (err < 0)
goto out_buf;
((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_next_free =
dh->dqdh_next_free;
err = write_blk(info, prevblk, tmpbuf);
if (err < 0)
goto out_buf;
} else {
info->dqi_free_entry = nextblk;
mark_info_dirty(info->dqi_sb, info->dqi_type);
}
kfree(tmpbuf);
dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
/* No matter whether write succeeds block is out of list */
if (write_blk(info, blk, buf) < 0)
quota_error(info->dqi_sb, "Can't write block (%u) "
"with free entries", blk);
return 0;
out_buf:
kfree(tmpbuf);
return err;
}
/* Insert given block to the beginning of list with free entries */
static int insert_free_dqentry(struct qtree_mem_dqinfo *info, char *buf,
uint blk)
{
char *tmpbuf = getdqbuf(info->dqi_usable_bs);
struct qt_disk_dqdbheader *dh = (struct qt_disk_dqdbheader *)buf;
int err;
if (!tmpbuf)
return -ENOMEM;
dh->dqdh_next_free = cpu_to_le32(info->dqi_free_entry);
dh->dqdh_prev_free = cpu_to_le32(0);
err = write_blk(info, blk, buf);
if (err < 0)
goto out_buf;
if (info->dqi_free_entry) {
err = read_blk(info, info->dqi_free_entry, tmpbuf);
if (err < 0)
goto out_buf;
((struct qt_disk_dqdbheader *)tmpbuf)->dqdh_prev_free =
cpu_to_le32(blk);
err = write_blk(info, info->dqi_free_entry, tmpbuf);
if (err < 0)
goto out_buf;
}
kfree(tmpbuf);
info->dqi_free_entry = blk;
mark_info_dirty(info->dqi_sb, info->dqi_type);
return 0;
out_buf:
kfree(tmpbuf);
return err;
}
/* Is the entry in the block free? */
int qtree_entry_unused(struct qtree_mem_dqinfo *info, char *disk)
{
int i;
for (i = 0; i < info->dqi_entry_size; i++)
if (disk[i])
return 0;
return 1;
}
EXPORT_SYMBOL(qtree_entry_unused);
/* Find space for dquot */
static uint find_free_dqentry(struct qtree_mem_dqinfo *info,
struct dquot *dquot, int *err)
{
uint blk, i;
struct qt_disk_dqdbheader *dh;
char *buf = getdqbuf(info->dqi_usable_bs);
char *ddquot;
*err = 0;
if (!buf) {
*err = -ENOMEM;
return 0;
}
dh = (struct qt_disk_dqdbheader *)buf;
if (info->dqi_free_entry) {
blk = info->dqi_free_entry;
*err = read_blk(info, blk, buf);
if (*err < 0)
goto out_buf;
} else {
blk = get_free_dqblk(info);
if ((int)blk < 0) {
*err = blk;
kfree(buf);
return 0;
}
memset(buf, 0, info->dqi_usable_bs);
/* This is enough as the block is already zeroed and the entry
* list is empty... */
info->dqi_free_entry = blk;
mark_info_dirty(dquot->dq_sb, dquot->dq_id.type);
}
/* Block will be full? */
if (le16_to_cpu(dh->dqdh_entries) + 1 >= qtree_dqstr_in_blk(info)) {
*err = remove_free_dqentry(info, buf, blk);
if (*err < 0) {
quota_error(dquot->dq_sb, "Can't remove block (%u) "
"from entry free list", blk);
goto out_buf;
}
}
le16_add_cpu(&dh->dqdh_entries, 1);
/* Find free structure in block */
ddquot = buf + sizeof(struct qt_disk_dqdbheader);
for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
if (qtree_entry_unused(info, ddquot))
break;
ddquot += info->dqi_entry_size;
}
#ifdef __QUOTA_QT_PARANOIA
if (i == qtree_dqstr_in_blk(info)) {
quota_error(dquot->dq_sb, "Data block full but it shouldn't");
*err = -EIO;
goto out_buf;
}
#endif
*err = write_blk(info, blk, buf);
if (*err < 0) {
quota_error(dquot->dq_sb, "Can't write quota data block %u",
blk);
goto out_buf;
}
dquot->dq_off = (blk << info->dqi_blocksize_bits) +
sizeof(struct qt_disk_dqdbheader) +
i * info->dqi_entry_size;
kfree(buf);
return blk;
out_buf:
kfree(buf);
return 0;
}
/* Insert reference to structure into the trie */
static int do_insert_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
uint *treeblk, int depth)
{
char *buf = getdqbuf(info->dqi_usable_bs);
int ret = 0, newson = 0, newact = 0;
__le32 *ref;
uint newblk;
if (!buf)
return -ENOMEM;
if (!*treeblk) {
ret = get_free_dqblk(info);
if (ret < 0)
goto out_buf;
*treeblk = ret;
memset(buf, 0, info->dqi_usable_bs);
newact = 1;
} else {
ret = read_blk(info, *treeblk, buf);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't read tree quota "
"block %u", *treeblk);
goto out_buf;
}
}
ref = (__le32 *)buf;
newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
if (!newblk)
newson = 1;
if (depth == info->dqi_qtree_depth - 1) {
#ifdef __QUOTA_QT_PARANOIA
if (newblk) {
quota_error(dquot->dq_sb, "Inserting already present "
"quota entry (block %u)",
le32_to_cpu(ref[get_index(info,
dquot->dq_id, depth)]));
ret = -EIO;
goto out_buf;
}
#endif
newblk = find_free_dqentry(info, dquot, &ret);
} else {
ret = do_insert_tree(info, dquot, &newblk, depth+1);
}
if (newson && ret >= 0) {
ref[get_index(info, dquot->dq_id, depth)] =
cpu_to_le32(newblk);
ret = write_blk(info, *treeblk, buf);
} else if (newact && ret < 0) {
put_free_dqblk(info, buf, *treeblk);
}
out_buf:
kfree(buf);
return ret;
}
/* Wrapper for inserting quota structure into tree */
static inline int dq_insert_tree(struct qtree_mem_dqinfo *info,
struct dquot *dquot)
{
int tmp = QT_TREEOFF;
return do_insert_tree(info, dquot, &tmp, 0);
}
/*
* We don't have to be afraid of deadlocks as we never have quotas on quota
* files...
*/
int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
{
int type = dquot->dq_id.type;
struct super_block *sb = dquot->dq_sb;
ssize_t ret;
char *ddquot = getdqbuf(info->dqi_entry_size);
if (!ddquot)
return -ENOMEM;
/* dq_off is guarded by dqio_mutex */
if (!dquot->dq_off) {
ret = dq_insert_tree(info, dquot);
if (ret < 0) {
quota_error(sb, "Error %zd occurred while creating "
"quota", ret);
kfree(ddquot);
return ret;
}
}
spin_lock(&dq_data_lock);
info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
spin_unlock(&dq_data_lock);
ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
dquot->dq_off);
if (ret != info->dqi_entry_size) {
quota_error(sb, "dquota write failed");
if (ret >= 0)
ret = -ENOSPC;
} else {
ret = 0;
}
dqstats_inc(DQST_WRITES);
kfree(ddquot);
return ret;
}
EXPORT_SYMBOL(qtree_write_dquot);
/* Free dquot entry in data block */
static int free_dqentry(struct qtree_mem_dqinfo *info, struct dquot *dquot,
uint blk)
{
struct qt_disk_dqdbheader *dh;
char *buf = getdqbuf(info->dqi_usable_bs);
int ret = 0;
if (!buf)
return -ENOMEM;
if (dquot->dq_off >> info->dqi_blocksize_bits != blk) {
quota_error(dquot->dq_sb, "Quota structure has offset to "
"other block (%u) than it should (%u)", blk,
(uint)(dquot->dq_off >> info->dqi_blocksize_bits));
goto out_buf;
}
ret = read_blk(info, blk, buf);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't read quota data block %u",
blk);
goto out_buf;
}
dh = (struct qt_disk_dqdbheader *)buf;
le16_add_cpu(&dh->dqdh_entries, -1);
if (!le16_to_cpu(dh->dqdh_entries)) { /* Block got free? */
ret = remove_free_dqentry(info, buf, blk);
if (ret >= 0)
ret = put_free_dqblk(info, buf, blk);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't move quota data block "
"(%u) to free list", blk);
goto out_buf;
}
} else {
memset(buf +
(dquot->dq_off & ((1 << info->dqi_blocksize_bits) - 1)),
0, info->dqi_entry_size);
if (le16_to_cpu(dh->dqdh_entries) ==
qtree_dqstr_in_blk(info) - 1) {
/* Insert will write block itself */
ret = insert_free_dqentry(info, buf, blk);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't insert quota "
"data block (%u) to free entry list", blk);
goto out_buf;
}
} else {
ret = write_blk(info, blk, buf);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't write quota "
"data block %u", blk);
goto out_buf;
}
}
}
dquot->dq_off = 0; /* Quota is now unattached */
out_buf:
kfree(buf);
return ret;
}
/* Remove reference to dquot from tree */
static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
uint *blk, int depth)
{
char *buf = getdqbuf(info->dqi_usable_bs);
int ret = 0;
uint newblk;
__le32 *ref = (__le32 *)buf;
if (!buf)
return -ENOMEM;
ret = read_blk(info, *blk, buf);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't read quota data block %u",
*blk);
goto out_buf;
}
newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
if (depth == info->dqi_qtree_depth - 1) {
ret = free_dqentry(info, dquot, newblk);
newblk = 0;
} else {
ret = remove_tree(info, dquot, &newblk, depth+1);
}
if (ret >= 0 && !newblk) {
int i;
ref[get_index(info, dquot->dq_id, depth)] = cpu_to_le32(0);
/* Block got empty? */
for (i = 0; i < (info->dqi_usable_bs >> 2) && !ref[i]; i++)
;
/* Don't put the root block into the free block list */
if (i == (info->dqi_usable_bs >> 2)
&& *blk != QT_TREEOFF) {
put_free_dqblk(info, buf, *blk);
*blk = 0;
} else {
ret = write_blk(info, *blk, buf);
if (ret < 0)
quota_error(dquot->dq_sb,
"Can't write quota tree block %u",
*blk);
}
}
out_buf:
kfree(buf);
return ret;
}
/* Delete dquot from tree */
int qtree_delete_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
{
uint tmp = QT_TREEOFF;
if (!dquot->dq_off) /* Even not allocated? */
return 0;
return remove_tree(info, dquot, &tmp, 0);
}
EXPORT_SYMBOL(qtree_delete_dquot);
/* Find entry in block */
static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info,
struct dquot *dquot, uint blk)
{
char *buf = getdqbuf(info->dqi_usable_bs);
loff_t ret = 0;
int i;
char *ddquot;
if (!buf)
return -ENOMEM;
ret = read_blk(info, blk, buf);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't read quota tree "
"block %u", blk);
goto out_buf;
}
ddquot = buf + sizeof(struct qt_disk_dqdbheader);
for (i = 0; i < qtree_dqstr_in_blk(info); i++) {
if (info->dqi_ops->is_id(ddquot, dquot))
break;
ddquot += info->dqi_entry_size;
}
if (i == qtree_dqstr_in_blk(info)) {
quota_error(dquot->dq_sb,
"Quota for id %u referenced but not present",
from_kqid(&init_user_ns, dquot->dq_id));
ret = -EIO;
goto out_buf;
} else {
ret = (blk << info->dqi_blocksize_bits) + sizeof(struct
qt_disk_dqdbheader) + i * info->dqi_entry_size;
}
out_buf:
kfree(buf);
return ret;
}
/* Find entry for given id in the tree */
static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
struct dquot *dquot, uint blk, int depth)
{
char *buf = getdqbuf(info->dqi_usable_bs);
loff_t ret = 0;
__le32 *ref = (__le32 *)buf;
if (!buf)
return -ENOMEM;
ret = read_blk(info, blk, buf);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't read quota tree block %u",
blk);
goto out_buf;
}
ret = 0;
blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
if (!blk) /* No reference? */
goto out_buf;
if (depth < info->dqi_qtree_depth - 1)
ret = find_tree_dqentry(info, dquot, blk, depth+1);
else
ret = find_block_dqentry(info, dquot, blk);
out_buf:
kfree(buf);
return ret;
}
/* Find entry for given id in the tree - wrapper function */
static inline loff_t find_dqentry(struct qtree_mem_dqinfo *info,
struct dquot *dquot)
{
return find_tree_dqentry(info, dquot, QT_TREEOFF, 0);
}
int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
{
int type = dquot->dq_id.type;
struct super_block *sb = dquot->dq_sb;
loff_t offset;
char *ddquot;
int ret = 0;
#ifdef __QUOTA_QT_PARANOIA
/* Invalidated quota? */
if (!sb_dqopt(dquot->dq_sb)->files[type]) {
quota_error(sb, "Quota invalidated while reading!");
return -EIO;
}
#endif
/* Do we know offset of the dquot entry in the quota file? */
if (!dquot->dq_off) {
offset = find_dqentry(info, dquot);
if (offset <= 0) { /* Entry not present? */
if (offset < 0)
quota_error(sb,"Can't read quota structure "
"for id %u",
from_kqid(&init_user_ns,
dquot->dq_id));
dquot->dq_off = 0;
set_bit(DQ_FAKE_B, &dquot->dq_flags);
memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
ret = offset;
goto out;
}
dquot->dq_off = offset;
}
ddquot = getdqbuf(info->dqi_entry_size);
if (!ddquot)
return -ENOMEM;
ret = sb->s_op->quota_read(sb, type, ddquot, info->dqi_entry_size,
dquot->dq_off);
if (ret != info->dqi_entry_size) {
if (ret >= 0)
ret = -EIO;
quota_error(sb, "Error while reading quota structure for id %u",
from_kqid(&init_user_ns, dquot->dq_id));
set_bit(DQ_FAKE_B, &dquot->dq_flags);
memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
kfree(ddquot);
goto out;
}
spin_lock(&dq_data_lock);
info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
if (!dquot->dq_dqb.dqb_bhardlimit &&
!dquot->dq_dqb.dqb_bsoftlimit &&
!dquot->dq_dqb.dqb_ihardlimit &&
!dquot->dq_dqb.dqb_isoftlimit)
set_bit(DQ_FAKE_B, &dquot->dq_flags);
spin_unlock(&dq_data_lock);
kfree(ddquot);
out:
dqstats_inc(DQST_READS);
return ret;
}
EXPORT_SYMBOL(qtree_read_dquot);
/* Check whether dquot should not be deleted. We know we are
* the only one operating on dquot (thanks to dq_lock) */
int qtree_release_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
{
if (test_bit(DQ_FAKE_B, &dquot->dq_flags) &&
!(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
return qtree_delete_dquot(info, dquot);
return 0;
}
EXPORT_SYMBOL(qtree_release_dquot);