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-rw-r--r--fs/quota_v2.c693
1 files changed, 693 insertions, 0 deletions
diff --git a/fs/quota_v2.c b/fs/quota_v2.c
new file mode 100644
index 00000000000..19bdb7b86ca
--- /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);