Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 693 insertions, 0 deletions

diff --git a/fs/quota_v2.c b/fs/quota_v2.c
new file mode 100644
index 000000000000..19bdb7b86ca7
--- /dev/null
+++ b/fs/quota_v2.c
@@ -0,0 +1,693 @@
+/*
+ *      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/quotaio_v2.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include <asm/byteorder.h>
+
+MODULE_AUTHOR("Jan Kara");
+MODULE_DESCRIPTION("Quota format v2 support");
+MODULE_LICENSE("GPL");
+
+#define __QUOTA_V2_PARANOIA
+
+typedef char *dqbuf_t;
+
+#define GETIDINDEX(id, depth) (((id) >> ((V2_DQTREEDEPTH-(depth)-1)*8)) & 0xff)
+#define GETENTRIES(buf) ((struct v2_disk_dqblk *)(((char *)buf)+sizeof(struct v2_disk_dqdbheader)))
+
+/* Check whether given file is really vfsv0 quotafile */
+static int v2_check_quota_file(struct super_block *sb, int type)
+{
+        struct v2_disk_dqheader dqhead;
+        ssize_t size;
+        static const uint quota_magics[] = V2_INITQMAGICS;
+        static const uint quota_versions[] = V2_INITQVERSIONS;
+ 
+        size = sb->s_op->quota_read(sb, type, (char *)&dqhead, sizeof(struct v2_disk_dqheader), 0);
+        if (size != sizeof(struct v2_disk_dqheader)) {
+                printk("failed read\n");
+                return 0;
+        }
+        if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
+            le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
+                return 0;
+        return 1;
+}
+
+/* Read information header from quota file */
+static int v2_read_file_info(struct super_block *sb, int type)
+{
+        struct v2_disk_dqinfo dinfo;
+        struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
+        ssize_t size;
+
+        size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
+               sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
+        if (size != sizeof(struct v2_disk_dqinfo)) {
+                printk(KERN_WARNING "Can't read info structure on device %s.\n",
+                        sb->s_id);
+                return -1;
+        }
+        info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
+        info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
+        info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
+        info->u.v2_i.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
+        info->u.v2_i.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
+        info->u.v2_i.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
+        return 0;
+}
+
+/* Write information header to quota file */
+static int v2_write_file_info(struct super_block *sb, int type)
+{
+        struct v2_disk_dqinfo dinfo;
+        struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
+        ssize_t size;
+
+        spin_lock(&dq_data_lock);
+        info->dqi_flags &= ~DQF_INFO_DIRTY;
+        dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
+        dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
+        dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
+        spin_unlock(&dq_data_lock);
+        dinfo.dqi_blocks = cpu_to_le32(info->u.v2_i.dqi_blocks);
+        dinfo.dqi_free_blk = cpu_to_le32(info->u.v2_i.dqi_free_blk);
+        dinfo.dqi_free_entry = cpu_to_le32(info->u.v2_i.dqi_free_entry);
+        size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
+               sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
+        if (size != sizeof(struct v2_disk_dqinfo)) {
+                printk(KERN_WARNING "Can't write info structure on device %s.\n",
+                        sb->s_id);
+                return -1;
+        }
+        return 0;
+}
+
+static void disk2memdqb(struct mem_dqblk *m, struct v2_disk_dqblk *d)
+{
+        m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
+        m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
+        m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
+        m->dqb_itime = le64_to_cpu(d->dqb_itime);
+        m->dqb_bhardlimit = le32_to_cpu(d->dqb_bhardlimit);
+        m->dqb_bsoftlimit = le32_to_cpu(d->dqb_bsoftlimit);
+        m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
+        m->dqb_btime = le64_to_cpu(d->dqb_btime);
+}
+
+static void mem2diskdqb(struct v2_disk_dqblk *d, struct mem_dqblk *m, qid_t id)
+{
+        d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
+        d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
+        d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
+        d->dqb_itime = cpu_to_le64(m->dqb_itime);
+        d->dqb_bhardlimit = cpu_to_le32(m->dqb_bhardlimit);
+        d->dqb_bsoftlimit = cpu_to_le32(m->dqb_bsoftlimit);
+        d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
+        d->dqb_btime = cpu_to_le64(m->dqb_btime);
+        d->dqb_id = cpu_to_le32(id);
+}
+
+static dqbuf_t getdqbuf(void)
+{
+        dqbuf_t buf = kmalloc(V2_DQBLKSIZE, GFP_NOFS);
+        if (!buf)
+                printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n");
+        return buf;
+}
+
+static inline void freedqbuf(dqbuf_t buf)
+{
+        kfree(buf);
+}
+
+static inline ssize_t read_blk(struct super_block *sb, int type, uint blk, dqbuf_t buf)
+{
+        memset(buf, 0, V2_DQBLKSIZE);
+        return sb->s_op->quota_read(sb, type, (char *)buf,
+               V2_DQBLKSIZE, blk << V2_DQBLKSIZE_BITS);
+}
+
+static inline ssize_t write_blk(struct super_block *sb, int type, uint blk, dqbuf_t buf)
+{
+        return sb->s_op->quota_write(sb, type, (char *)buf,
+               V2_DQBLKSIZE, blk << V2_DQBLKSIZE_BITS);
+}
+
+/* Remove empty block from list and return it */
+static int get_free_dqblk(struct super_block *sb, int type)
+{
+        dqbuf_t buf = getdqbuf();
+        struct mem_dqinfo *info = sb_dqinfo(sb, type);
+        struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
+        int ret, blk;
+
+        if (!buf)
+                return -ENOMEM;
+        if (info->u.v2_i.dqi_free_blk) {
+                blk = info->u.v2_i.dqi_free_blk;
+                if ((ret = read_blk(sb, type, blk, buf)) < 0)
+                        goto out_buf;
+                info->u.v2_i.dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
+        }
+        else {
+                memset(buf, 0, V2_DQBLKSIZE);
+                /* Assure block allocation... */
+                if ((ret = write_blk(sb, type, info->u.v2_i.dqi_blocks, buf)) < 0)
+                        goto out_buf;
+                blk = info->u.v2_i.dqi_blocks++;
+        }
+        mark_info_dirty(sb, type);
+        ret = blk;
+out_buf:
+        freedqbuf(buf);
+        return ret;
+}
+
+/* Insert empty block to the list */
+static int put_free_dqblk(struct super_block *sb, int type, dqbuf_t buf, uint blk)
+{
+        struct mem_dqinfo *info = sb_dqinfo(sb, type);
+        struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
+        int err;
+
+        dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_blk);
+        dh->dqdh_prev_free = cpu_to_le32(0);
+        dh->dqdh_entries = cpu_to_le16(0);
+        info->u.v2_i.dqi_free_blk = blk;
+        mark_info_dirty(sb, type);
+        /* Some strange block. We had better leave it... */
+        if ((err = write_blk(sb, type, blk, buf)) < 0)
+                return err;
+        return 0;
+}
+
+/* Remove given block from the list of blocks with free entries */
+static int remove_free_dqentry(struct super_block *sb, int type, dqbuf_t buf, uint blk)
+{
+        dqbuf_t tmpbuf = getdqbuf();
+        struct mem_dqinfo *info = sb_dqinfo(sb, type);
+        struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
+        uint nextblk = le32_to_cpu(dh->dqdh_next_free), prevblk = le32_to_cpu(dh->dqdh_prev_free);
+        int err;
+
+        if (!tmpbuf)
+                return -ENOMEM;
+        if (nextblk) {
+                if ((err = read_blk(sb, type, nextblk, tmpbuf)) < 0)
+                        goto out_buf;
+                ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free;
+                if ((err = write_blk(sb, type, nextblk, tmpbuf)) < 0)
+                        goto out_buf;
+        }
+        if (prevblk) {
+                if ((err = read_blk(sb, type, prevblk, tmpbuf)) < 0)
+                        goto out_buf;
+                ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free;
+                if ((err = write_blk(sb, type, prevblk, tmpbuf)) < 0)
+                        goto out_buf;
+        }
+        else {
+                info->u.v2_i.dqi_free_entry = nextblk;
+                mark_info_dirty(sb, type);
+        }
+        freedqbuf(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(sb, type, blk, buf) < 0)
+                printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk);
+        return 0;
+out_buf:
+        freedqbuf(tmpbuf);
+        return err;
+}
+
+/* Insert given block to the beginning of list with free entries */
+static int insert_free_dqentry(struct super_block *sb, int type, dqbuf_t buf, uint blk)
+{
+        dqbuf_t tmpbuf = getdqbuf();
+        struct mem_dqinfo *info = sb_dqinfo(sb, type);
+        struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
+        int err;
+
+        if (!tmpbuf)
+                return -ENOMEM;
+        dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_entry);
+        dh->dqdh_prev_free = cpu_to_le32(0);
+        if ((err = write_blk(sb, type, blk, buf)) < 0)
+                goto out_buf;
+        if (info->u.v2_i.dqi_free_entry) {
+                if ((err = read_blk(sb, type, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
+                        goto out_buf;
+                ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk);
+                if ((err = write_blk(sb, type, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
+                        goto out_buf;
+        }
+        freedqbuf(tmpbuf);
+        info->u.v2_i.dqi_free_entry = blk;
+        mark_info_dirty(sb, type);
+        return 0;
+out_buf:
+        freedqbuf(tmpbuf);
+        return err;
+}
+
+/* Find space for dquot */
+static uint find_free_dqentry(struct dquot *dquot, int *err)
+{
+        struct super_block *sb = dquot->dq_sb;
+        struct mem_dqinfo *info = sb_dqopt(sb)->info+dquot->dq_type;
+        uint blk, i;
+        struct v2_disk_dqdbheader *dh;
+        struct v2_disk_dqblk *ddquot;
+        struct v2_disk_dqblk fakedquot;
+        dqbuf_t buf;
+
+        *err = 0;
+        if (!(buf = getdqbuf())) {
+                *err = -ENOMEM;
+                return 0;
+        }
+        dh = (struct v2_disk_dqdbheader *)buf;
+        ddquot = GETENTRIES(buf);
+        if (info->u.v2_i.dqi_free_entry) {
+                blk = info->u.v2_i.dqi_free_entry;
+                if ((*err = read_blk(sb, dquot->dq_type, blk, buf)) < 0)
+                        goto out_buf;
+        }
+        else {
+                blk = get_free_dqblk(sb, dquot->dq_type);
+                if ((int)blk < 0) {
+                        *err = blk;
+                        freedqbuf(buf);
+                        return 0;
+                }
+                memset(buf, 0, V2_DQBLKSIZE);
+                /* This is enough as block is already zeroed and entry list is empty... */
+                info->u.v2_i.dqi_free_entry = blk;
+                mark_info_dirty(sb, dquot->dq_type);
+        }
+        if (le16_to_cpu(dh->dqdh_entries)+1 >= V2_DQSTRINBLK)   /* Block will be full? */
+                if ((*err = remove_free_dqentry(sb, dquot->dq_type, buf, blk)) < 0) {
+                        printk(KERN_ERR "VFS: find_free_dqentry(): Can't remove block (%u) from entry free list.\n", blk);
+                        goto out_buf;
+                }
+        dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)+1);
+        memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
+        /* Find free structure in block */
+        for (i = 0; i < V2_DQSTRINBLK && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)); i++);
+#ifdef __QUOTA_V2_PARANOIA
+        if (i == V2_DQSTRINBLK) {
+                printk(KERN_ERR "VFS: find_free_dqentry(): Data block full but it shouldn't.\n");
+                *err = -EIO;
+                goto out_buf;
+        }
+#endif
+        if ((*err = write_blk(sb, dquot->dq_type, blk, buf)) < 0) {
+                printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota data block %u.\n", blk);
+                goto out_buf;
+        }
+        dquot->dq_off = (blk<<V2_DQBLKSIZE_BITS)+sizeof(struct v2_disk_dqdbheader)+i*sizeof(struct v2_disk_dqblk);
+        freedqbuf(buf);
+        return blk;
+out_buf:
+        freedqbuf(buf);
+        return 0;
+}
+
+/* Insert reference to structure into the trie */
+static int do_insert_tree(struct dquot *dquot, uint *treeblk, int depth)
+{
+        struct super_block *sb = dquot->dq_sb;
+        dqbuf_t buf;
+        int ret = 0, newson = 0, newact = 0;
+        __le32 *ref;
+        uint newblk;
+
+        if (!(buf = getdqbuf()))
+                return -ENOMEM;
+        if (!*treeblk) {
+                ret = get_free_dqblk(sb, dquot->dq_type);
+                if (ret < 0)
+                        goto out_buf;
+                *treeblk = ret;
+                memset(buf, 0, V2_DQBLKSIZE);
+                newact = 1;
+        }
+        else {
+                if ((ret = read_blk(sb, dquot->dq_type, *treeblk, buf)) < 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[GETIDINDEX(dquot->dq_id, depth)]);
+        if (!newblk)
+                newson = 1;
+        if (depth == V2_DQTREEDEPTH-1) {
+#ifdef __QUOTA_V2_PARANOIA
+                if (newblk) {
+                        printk(KERN_ERR "VFS: Inserting already present quota entry (block %u).\n", le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]));
+                        ret = -EIO;
+                        goto out_buf;
+                }
+#endif
+                newblk = find_free_dqentry(dquot, &ret);
+        }
+        else
+                ret = do_insert_tree(dquot, &newblk, depth+1);
+        if (newson && ret >= 0) {
+                ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(newblk);
+                ret = write_blk(sb, dquot->dq_type, *treeblk, buf);
+        }
+        else if (newact && ret < 0)
+                put_free_dqblk(sb, dquot->dq_type, buf, *treeblk);
+out_buf:
+        freedqbuf(buf);
+        return ret;
+}
+
+/* Wrapper for inserting quota structure into tree */
+static inline int dq_insert_tree(struct dquot *dquot)
+{
+        int tmp = V2_DQTREEOFF;
+        return do_insert_tree(dquot, &tmp, 0);
+}
+
+/*
+ *      We don't have to be afraid of deadlocks as we never have quotas on quota files...
+ */
+static int v2_write_dquot(struct dquot *dquot)
+{
+        int type = dquot->dq_type;
+        ssize_t ret;
+        struct v2_disk_dqblk ddquot, empty;
+
+        /* dq_off is guarded by dqio_sem */
+        if (!dquot->dq_off)
+                if ((ret = dq_insert_tree(dquot)) < 0) {
+                        printk(KERN_ERR "VFS: Error %zd occurred while creating quota.\n", ret);
+                        return ret;
+                }
+        spin_lock(&dq_data_lock);
+        mem2diskdqb(&ddquot, &dquot->dq_dqb, dquot->dq_id);
+        /* Argh... We may need to write structure full of zeroes but that would be
+         * treated as an empty place by the rest of the code. Format change would
+         * be definitely cleaner but the problems probably are not worth it */
+        memset(&empty, 0, sizeof(struct v2_disk_dqblk));
+        if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
+                ddquot.dqb_itime = cpu_to_le64(1);
+        spin_unlock(&dq_data_lock);
+        ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
+              (char *)&ddquot, sizeof(struct v2_disk_dqblk), dquot->dq_off);
+        if (ret != sizeof(struct v2_disk_dqblk)) {
+                printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", dquot->dq_sb->s_id);
+                if (ret >= 0)
+                        ret = -ENOSPC;
+        }
+        else
+                ret = 0;
+        dqstats.writes++;
+
+        return ret;
+}
+
+/* Free dquot entry in data block */
+static int free_dqentry(struct dquot *dquot, uint blk)
+{
+        struct super_block *sb = dquot->dq_sb;
+        int type = dquot->dq_type;
+        struct v2_disk_dqdbheader *dh;
+        dqbuf_t buf = getdqbuf();
+        int ret = 0;
+
+        if (!buf)
+                return -ENOMEM;
+        if (dquot->dq_off >> V2_DQBLKSIZE_BITS != blk) {
+                printk(KERN_ERR "VFS: Quota structure has offset to other "
+                  "block (%u) than it should (%u).\n", blk,
+                  (uint)(dquot->dq_off >> V2_DQBLKSIZE_BITS));
+                goto out_buf;
+        }
+        if ((ret = read_blk(sb, type, blk, buf)) < 0) {
+                printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
+                goto out_buf;
+        }
+        dh = (struct v2_disk_dqdbheader *)buf;
+        dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)-1);
+        if (!le16_to_cpu(dh->dqdh_entries)) {   /* Block got free? */
+                if ((ret = remove_free_dqentry(sb, type, buf, blk)) < 0 ||
+                    (ret = put_free_dqblk(sb, type, buf, blk)) < 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 << V2_DQBLKSIZE_BITS)-1)), 0,
+                  sizeof(struct v2_disk_dqblk));
+                if (le16_to_cpu(dh->dqdh_entries) == V2_DQSTRINBLK-1) {
+                        /* Insert will write block itself */
+                        if ((ret = insert_free_dqentry(sb, type, buf, blk)) < 0) {
+                                printk(KERN_ERR "VFS: Can't insert quota data block (%u) to free entry list.\n", blk);
+                                goto out_buf;
+                        }
+                }
+                else
+                        if ((ret = write_blk(sb, type, blk, buf)) < 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:
+        freedqbuf(buf);
+        return ret;
+}
+
+/* Remove reference to dquot from tree */
+static int remove_tree(struct dquot *dquot, uint *blk, int depth)
+{
+        struct super_block *sb = dquot->dq_sb;
+        int type = dquot->dq_type;
+        dqbuf_t buf = getdqbuf();
+        int ret = 0;
+        uint newblk;
+        __le32 *ref = (__le32 *)buf;
+        
+        if (!buf)
+                return -ENOMEM;
+        if ((ret = read_blk(sb, type, *blk, buf)) < 0) {
+                printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
+                goto out_buf;
+        }
+        newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
+        if (depth == V2_DQTREEDEPTH-1) {
+                ret = free_dqentry(dquot, newblk);
+                newblk = 0;
+        }
+        else
+                ret = remove_tree(dquot, &newblk, depth+1);
+        if (ret >= 0 && !newblk) {
+                int i;
+                ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
+                for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++);  /* Block got empty? */
+                if (i == V2_DQBLKSIZE) {
+                        put_free_dqblk(sb, type, buf, *blk);
+                        *blk = 0;
+                }
+                else
+                        if ((ret = write_blk(sb, type, *blk, buf)) < 0)
+                                printk(KERN_ERR "VFS: Can't write quota tree "
+                                  "block %u.\n", *blk);
+        }
+out_buf:
+        freedqbuf(buf);
+        return ret;     
+}
+
+/* Delete dquot from tree */
+static int v2_delete_dquot(struct dquot *dquot)
+{
+        uint tmp = V2_DQTREEOFF;
+
+        if (!dquot->dq_off)     /* Even not allocated? */
+                return 0;
+        return remove_tree(dquot, &tmp, 0);
+}
+
+/* Find entry in block */
+static loff_t find_block_dqentry(struct dquot *dquot, uint blk)
+{
+        dqbuf_t buf = getdqbuf();
+        loff_t ret = 0;
+        int i;
+        struct v2_disk_dqblk *ddquot = GETENTRIES(buf);
+
+        if (!buf)
+                return -ENOMEM;
+        if ((ret = read_blk(dquot->dq_sb, dquot->dq_type, blk, buf)) < 0) {
+                printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
+                goto out_buf;
+        }
+        if (dquot->dq_id)
+                for (i = 0; i < V2_DQSTRINBLK &&
+                     le32_to_cpu(ddquot[i].dqb_id) != dquot->dq_id; i++);
+        else {  /* ID 0 as a bit more complicated searching... */
+                struct v2_disk_dqblk fakedquot;
+
+                memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
+                for (i = 0; i < V2_DQSTRINBLK; i++)
+                        if (!le32_to_cpu(ddquot[i].dqb_id) &&
+                            memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)))
+                                break;
+        }
+        if (i == V2_DQSTRINBLK) {
+                printk(KERN_ERR "VFS: Quota for id %u referenced "
+                  "but not present.\n", dquot->dq_id);
+                ret = -EIO;
+                goto out_buf;
+        }
+        else
+                ret = (blk << V2_DQBLKSIZE_BITS) + sizeof(struct
+                  v2_disk_dqdbheader) + i * sizeof(struct v2_disk_dqblk);
+out_buf:
+        freedqbuf(buf);
+        return ret;
+}
+
+/* Find entry for given id in the tree */
+static loff_t find_tree_dqentry(struct dquot *dquot, uint blk, int depth)
+{
+        dqbuf_t buf = getdqbuf();
+        loff_t ret = 0;
+        __le32 *ref = (__le32 *)buf;
+
+        if (!buf)
+                return -ENOMEM;
+        if ((ret = read_blk(dquot->dq_sb, dquot->dq_type, blk, buf)) < 0) {
+                printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
+                goto out_buf;
+        }
+        ret = 0;
+        blk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
+        if (!blk)       /* No reference? */
+                goto out_buf;
+        if (depth < V2_DQTREEDEPTH-1)
+                ret = find_tree_dqentry(dquot, blk, depth+1);
+        else
+                ret = find_block_dqentry(dquot, blk);
+out_buf:
+        freedqbuf(buf);
+        return ret;
+}
+
+/* Find entry for given id in the tree - wrapper function */
+static inline loff_t find_dqentry(struct dquot *dquot)
+{
+        return find_tree_dqentry(dquot, V2_DQTREEOFF, 0);
+}
+
+static int v2_read_dquot(struct dquot *dquot)
+{
+        int type = dquot->dq_type;
+        loff_t offset;
+        struct v2_disk_dqblk ddquot, empty;
+        int ret = 0;
+
+#ifdef __QUOTA_V2_PARANOIA
+        /* Invalidated quota? */
+        if (!dquot->dq_sb || !sb_dqopt(dquot->dq_sb)->files[type]) {
+                printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
+                return -EIO;
+        }
+#endif
+        offset = find_dqentry(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;
+        }
+        else {
+                dquot->dq_off = offset;
+                if ((ret = dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type,
+                    (char *)&ddquot, sizeof(struct v2_disk_dqblk), offset))
+                    != sizeof(struct v2_disk_dqblk)) {
+                        if (ret >= 0)
+                                ret = -EIO;
+                        printk(KERN_ERR "VFS: Error while reading quota "
+                          "structure for id %u.\n", dquot->dq_id);
+                        memset(&ddquot, 0, sizeof(struct v2_disk_dqblk));
+                }
+                else {
+                        ret = 0;
+                        /* We need to escape back all-zero structure */
+                        memset(&empty, 0, sizeof(struct v2_disk_dqblk));
+                        empty.dqb_itime = cpu_to_le64(1);
+                        if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
+                                ddquot.dqb_itime = 0;
+                }
+                disk2memdqb(&dquot->dq_dqb, &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);
+        }
+        dqstats.reads++;
+
+        return ret;
+}
+
+/* Check whether dquot should not be deleted. We know we are
+ * the only one operating on dquot (thanks to dq_lock) */
+static int v2_release_dquot(struct dquot *dquot)
+{
+        if (test_bit(DQ_FAKE_B, &dquot->dq_flags) && !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
+                return v2_delete_dquot(dquot);
+        return 0;
+}
+
+static struct quota_format_ops v2_format_ops = {
+        .check_quota_file       = v2_check_quota_file,
+        .read_file_info         = v2_read_file_info,
+        .write_file_info        = v2_write_file_info,
+        .free_file_info         = NULL,
+        .read_dqblk             = v2_read_dquot,
+        .commit_dqblk           = v2_write_dquot,
+        .release_dqblk          = v2_release_dquot,
+};
+
+static struct quota_format_type v2_quota_format = {
+        .qf_fmt_id      = QFMT_VFS_V0,
+        .qf_ops         = &v2_format_ops,
+        .qf_owner       = THIS_MODULE
+};
+
+static int __init init_v2_quota_format(void)
+{
+        return register_quota_format(&v2_quota_format);
+}
+
+static void __exit exit_v2_quota_format(void)
+{
+        unregister_quota_format(&v2_quota_format);
+}
+
+module_init(init_v2_quota_format);
+module_exit(exit_v2_quota_format);