summaryrefslogtreecommitdiff
path: root/fs/quota/quota_tree.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/quota/quota_tree.c')
-rw-r--r--fs/quota/quota_tree.c651
1 files changed, 651 insertions, 0 deletions
diff --git a/fs/quota/quota_tree.c b/fs/quota/quota_tree.c
new file mode 100644
index 0000000..f81f4bc
--- /dev/null
+++ b/fs/quota/quota_tree.c
@@ -0,0 +1,651 @@
+/*
+ * 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.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.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);