/*
* 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, qid_t id, int depth)
{
unsigned int epb = info->dqi_usable_bs >> 2;
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;
return sb->s_op->quota_write(sb, info->dqi_type, buf,
info->dqi_usable_bs, blk << info->dqi_blocksize_bits);
}
/* 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)
printk(KERN_ERR
"VFS: Can't write block (%u) with free entries.\n",
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_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) {
printk(KERN_ERR "VFS: find_free_dqentry(): Can't "
"remove block (%u) from entry free list.\n",
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)) {
printk(KERN_ERR "VFS: find_free_dqentry(): Data block full "
"but it shouldn't.\n");
*err = -EIO;
goto out_buf;
}
#endif
*err = write_blk(info, blk, buf);
if (*err < 0) {
printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota "
"data block %u.\n", 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) {
printk(KERN_ERR "VFS: Can't read tree quota block "
"%u.\n", *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) {
printk(KERN_ERR "VFS: Inserting already present quota "
"entry (block %u).\n",
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_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) {
printk(KERN_ERR "VFS: Error %zd occurred while "
"creating quota.\n", 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) {
printk(KERN_WARNING "VFS: dquota write failed on dev %s\n",
sb->s_id);
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) {
printk(KERN_ERR "VFS: Quota structure has offset to other "
"block (%u) than it should (%u).\n", blk,
(uint)(dquot->dq_off >> info->dqi_blocksize_bits));
goto out_buf;
}
ret = read_blk(info, blk, buf);
if (ret < 0) {
printk(KERN_ERR "VFS: Can't read quota data block %u\n", 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) {
printk(KERN_ERR "VFS: Can't move quota data block (%u) "
"to free list.\n", 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) {
printk(KERN_ERR "VFS: Can't insert quota data "
"block (%u) to free entry list.\n", blk);
goto out_buf;
}
} else {
ret = write_blk(info, blk, buf);
if (ret < 0) {
printk(KERN_ERR "VFS: Can't write quota data "
"block %u\n", 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) {
printk(KERN_ERR "VFS: Can't read quota data block %u\n", *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)
printk(KERN_ERR "VFS: Can't write quota tree "
"block %u.\n", *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) {
printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", 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)) {
printk(KERN_ERR "VFS: Quota for id %u referenced "
"but not present.\n", 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) {
printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", 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_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]) {
printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
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)
printk(KERN_ERR "VFS: Can't read quota "
"structure for id %u.\n", 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;
printk(KERN_ERR "VFS: Error while reading quota "
"structure for id %u.\n", 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);
