[PATCH] [8/13] quota-8-format1

Implementation of old quota format. All the code for old format is now in
quota_v1.c. Code mostly remained the same as in older kernels (just minor
changes were needed to bind it with quota interface).

fs/Config.help

@@ -6,6 +6,11 @@ CONFIG_QUOTA
   <http://www.linuxdoc.org/docs.html#howto>. Probably the quota
   support is only useful for multi user systems. If unsure, say N.
 
+CONFIG_QFMT_V1
+  This quota format was (is) used by kernels earlier than 2.4.??. If
+  you have quota working and you don't want to convert to new quota
+  format say Y here.
+
 CONFIG_MINIX_FS
   Minix is a simple operating system used in many classes about OS's.
   The minix file system (method to organize files on a hard disk

fs/Config.in

@@ -5,6 +5,7 @@ mainmenu_option next_comment
 comment 'File systems'
 
 bool 'Quota support' CONFIG_QUOTA
+dep_tristate '  Old quota format support' CONFIG_QFMT_V1 $CONFIG_QUOTA
 tristate 'Kernel automounter support' CONFIG_AUTOFS_FS
 tristate 'Kernel automounter version 4 support (also supports v3)' CONFIG_AUTOFS4_FS
 

fs/Makefile

@@ -82,6 +82,7 @@ obj-y				+= binfmt_script.o
 obj-$(CONFIG_BINFMT_ELF)	+= binfmt_elf.o
 
 obj-$(CONFIG_QUOTA) += dquot.o
+obj-$(CONFIG_QFMT_V1) += quota_v1.o
 
 # persistent filesystems
 obj-y += $(join $(subdir-y),$(subdir-y:%=/%.o))

fs/dquot.c

@@ -792,7 +792,10 @@ static inline void flush_warnings(struct dquot **dquots, char *warntype)
 
 static inline char ignore_hardlimit(struct dquot *dquot)
 {
-	return capable(CAP_SYS_RESOURCE);
+	struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
+
+	return capable(CAP_SYS_RESOURCE) &&
+	    (info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
 }
 
 static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)

fs/quota_v1.c

+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/quota.h>
+#include <linux/dqblk_v1.h>
+#include <linux/quotaio_v1.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+#include <asm/uaccess.h>
+#include <asm/byteorder.h>
+
+static void v1_disk2mem_dqblk(struct mem_dqblk *m, struct v1_disk_dqblk *d)
+{
+	m->dqb_ihardlimit = d->dqb_ihardlimit;
+	m->dqb_isoftlimit = d->dqb_isoftlimit;
+	m->dqb_curinodes = d->dqb_curinodes;
+	m->dqb_bhardlimit = d->dqb_bhardlimit;
+	m->dqb_bsoftlimit = d->dqb_bsoftlimit;
+	m->dqb_curspace = d->dqb_curblocks << QUOTABLOCK_BITS;
+	m->dqb_itime = d->dqb_itime;
+	m->dqb_btime = d->dqb_btime;
+}
+
+static void v1_mem2disk_dqblk(struct v1_disk_dqblk *d, struct mem_dqblk *m)
+{
+	d->dqb_ihardlimit = m->dqb_ihardlimit;
+	d->dqb_isoftlimit = m->dqb_isoftlimit;
+	d->dqb_curinodes = m->dqb_curinodes;
+	d->dqb_bhardlimit = m->dqb_bhardlimit;
+	d->dqb_bsoftlimit = m->dqb_bsoftlimit;
+	d->dqb_curblocks = toqb(m->dqb_curspace);
+	d->dqb_itime = m->dqb_itime;
+	d->dqb_btime = m->dqb_btime;
+}
+
+static int v1_read_dqblk(struct dquot *dquot)
+{
+	int type = dquot->dq_type;
+	struct file *filp;
+	mm_segment_t fs;
+	loff_t offset;
+	struct v1_disk_dqblk dqblk;
+
+	filp = sb_dqopt(dquot->dq_sb)->files[type];
+	if (filp == (struct file *)NULL)
+		return -EINVAL;
+
+	/* Now we are sure filp is valid */
+	offset = v1_dqoff(dquot->dq_id);
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+	filp->f_op->read(filp, (char *)&dqblk, sizeof(struct v1_disk_dqblk), &offset);
+	set_fs(fs);
+
+	v1_disk2mem_dqblk(&dquot->dq_dqb, &dqblk);
+	if (dquot->dq_dqb.dqb_bhardlimit == 0 && dquot->dq_dqb.dqb_bsoftlimit == 0 &&
+	    dquot->dq_dqb.dqb_ihardlimit == 0 && dquot->dq_dqb.dqb_isoftlimit == 0)
+		dquot->dq_flags |= DQ_FAKE;
+	dqstats.reads++;
+	return 0;
+}
+
+static int v1_commit_dqblk(struct dquot *dquot)
+{
+	short type = dquot->dq_type;
+	struct file *filp;
+	mm_segment_t fs;
+	loff_t offset;
+	ssize_t ret;
+	struct v1_disk_dqblk dqblk;
+
+	filp = sb_dqopt(dquot->dq_sb)->files[type];
+	offset = v1_dqoff(dquot->dq_id);
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+
+	/*
+	 * Note: clear the DQ_MOD flag unconditionally,
+	 * so we don't loop forever on failure.
+	 */
+	v1_mem2disk_dqblk(&dqblk, &dquot->dq_dqb);
+	dquot->dq_flags &= ~DQ_MOD;
+	if (dquot->dq_id == 0) {
+		dqblk.dqb_btime = sb_dqopt(dquot->dq_sb)->info[type].dqi_bgrace;
+		dqblk.dqb_itime = sb_dqopt(dquot->dq_sb)->info[type].dqi_igrace;
+	}
+	ret = 0;
+	if (filp)
+		ret = filp->f_op->write(filp, (char *)&dqblk,
+					sizeof(struct v1_disk_dqblk), &offset);
+	if (ret != sizeof(struct v1_disk_dqblk)) {
+		printk(KERN_WARNING "VFS: dquota write failed on dev %s\n",
+			kdevname(dquot->dq_sb->s_dev));
+		if (ret >= 0)
+			ret = -EIO;
+		goto out;
+	}
+	ret = 0;
+
+out:
+	set_fs(fs);
+	dqstats.writes++;
+	return ret;
+}
+
+/* Magics of new quota format */
+#define V2_INITQMAGICS {\
+	0xd9c01f11,     /* USRQUOTA */\
+	0xd9c01927      /* GRPQUOTA */\
+}
+
+/* Header of new quota format */
+struct v2_disk_dqheader {
+	__u32 dqh_magic;        /* Magic number identifying file */
+	__u32 dqh_version;      /* File version */
+};
+
+static int v1_check_quota_file(struct super_block *sb, int type)
+{
+	struct file *f = sb_dqopt(sb)->files[type];
+	struct inode *inode = f->f_dentry->d_inode;
+	ulong blocks;
+	size_t off; 
+	struct v2_disk_dqheader dqhead;
+	mm_segment_t fs;
+	ssize_t size;
+	loff_t offset = 0;
+	static const uint quota_magics[] = V2_INITQMAGICS;
+
+	if (!inode->i_size)
+		return 0;
+	blocks = inode->i_size >> BLOCK_SIZE_BITS;
+	off = inode->i_size & (BLOCK_SIZE - 1);
+	if ((blocks % sizeof(struct v1_disk_dqblk) * BLOCK_SIZE + off) % sizeof(struct v1_disk_dqblk))
+		return 0;
+	/* Doublecheck whether we didn't get file with new format - with old quotactl() this could happen */
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+	size = f->f_op->read(f, (char *)&dqhead, sizeof(struct v2_disk_dqheader), &offset);
+	set_fs(fs);
+	if (size != sizeof(struct v2_disk_dqheader))
+		return 1;	/* Probably not new format */
+	if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type])
+		return 1;	/* Definitely not new format */
+	printk(KERN_INFO "VFS: %s: Refusing to turn on old quota format on given file. It probably contains newer quota format.\n", kdevname(sb->s_dev));
+        return 0;		/* Seems like a new format file -> refuse it */
+}
+
+static int v1_read_file_info(struct super_block *sb, int type)
+{
+	struct quota_info *dqopt = sb_dqopt(sb);
+	mm_segment_t fs;
+	loff_t offset;
+	struct file *filp = dqopt->files[type];
+	struct v1_disk_dqblk dqblk;
+	int ret;
+
+	down(&dqopt->dqio_sem);
+	offset = v1_dqoff(0);
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+	if ((ret = filp->f_op->read(filp, (char *)&dqblk, sizeof(struct v1_disk_dqblk), &offset)) != sizeof(struct v1_disk_dqblk)) {
+		if (ret >= 0)
+			ret = -EIO;
+		goto out;
+	}
+	ret = 0;
+	dqopt->info[type].dqi_igrace = dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
+	dqopt->info[type].dqi_bgrace = dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
+out:
+	up(&dqopt->dqio_sem);
+	set_fs(fs);
+	return ret;
+}
+
+static int v1_write_file_info(struct super_block *sb, int type)
+{
+	struct quota_info *dqopt = sb_dqopt(sb);
+	mm_segment_t fs;
+	struct file *filp = dqopt->files[type];
+	struct v1_disk_dqblk dqblk;
+	loff_t offset;
+	int ret;
+
+	down(&dqopt->dqio_sem);
+	dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
+	offset = v1_dqoff(0);
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+	if ((ret = filp->f_op->read(filp, (char *)&dqblk, sizeof(struct v1_disk_dqblk), &offset)) != sizeof(struct v1_disk_dqblk)) {
+		if (ret >= 0)
+			ret = -EIO;
+		goto out;
+	}
+	dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
+	dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
+	offset = v1_dqoff(0);
+	ret = filp->f_op->write(filp, (char *)&dqblk, sizeof(struct v1_disk_dqblk), &offset);
+	if (ret == sizeof(struct v1_disk_dqblk))
+		ret = 0;
+	else if (ret > 0)
+		ret = -EIO;
+out:
+	up(&dqopt->dqio_sem);
+	set_fs(fs);
+	return ret;
+}
+
+static struct quota_format_ops v1_format_ops = {
+	check_quota_file:	v1_check_quota_file,
+	read_file_info:		v1_read_file_info,
+	write_file_info:	v1_write_file_info,
+	free_file_info:		NULL,
+	read_dqblk:		v1_read_dqblk,
+	commit_dqblk:		v1_commit_dqblk,
+};
+
+static struct quota_format_type v1_quota_format = {
+	qf_fmt_id:	QFMT_VFS_OLD,
+	qf_ops:		&v1_format_ops,
+	qf_owner:	THIS_MODULE
+};
+
+static int __init init_v1_quota_format(void)
+{
+        return register_quota_format(&v1_quota_format);
+}
+
+static void __exit exit_v1_quota_format(void)
+{
+        unregister_quota_format(&v1_quota_format);
+}
+
+EXPORT_NO_SYMBOLS;
+
+module_init(init_v1_quota_format);
+module_exit(exit_v1_quota_format);
+

include/linux/dqblk_v1.h

+/*
+ *	File with in-memory structures of old quota format
+ */
+
+#ifndef _LINUX_DQBLK_V1_H
+#define _LINUX_DQBLK_V1_H
+
+/* Id of quota format */
+#define QFMT_VFS_OLD 1
+
+/* Root squash turned on */
+#define V1_DQF_RSQUASH 1
+
+/* Special information about quotafile */
+struct v1_mem_dqinfo {
+};
+
+#endif	/* _LINUX_DQBLK_V1_H */

include/linux/quota.h

@@ -135,6 +135,7 @@ struct if_dqinfo {
 #ifdef __KERNEL__
 
 #include <linux/xqm.h>
+#include <linux/dqblk_v1.h>
 
 /*
  * Data for one user/group kept in memory
@@ -161,6 +162,7 @@ struct mem_dqinfo {
 	unsigned int dqi_bgrace;
 	unsigned int dqi_igrace;
 	union {
+		struct v1_mem_dqinfo v1_i;
 	} u;
 };
 

include/linux/quotaio_v1.h

+#ifndef _LINUX_QUOTAIO_V1_H
+#define _LINUX_QUOTAIO_V1_H
+
+#include <linux/types.h>
+
+/*
+ * The following constants define the amount of time given a user
+ * before the soft limits are treated as hard limits (usually resulting
+ * in an allocation failure). The timer is started when the user crosses
+ * their soft limit, it is reset when they go below their soft limit.
+ */
+#define MAX_IQ_TIME  604800	/* (7*24*60*60) 1 week */
+#define MAX_DQ_TIME  604800	/* (7*24*60*60) 1 week */
+
+/*
+ * The following structure defines the format of the disk quota file
+ * (as it appears on disk) - the file is an array of these structures
+ * indexed by user or group number.
+ */
+struct v1_disk_dqblk {
+	__u32 dqb_bhardlimit;	/* absolute limit on disk blks alloc */
+	__u32 dqb_bsoftlimit;	/* preferred limit on disk blks */
+	__u32 dqb_curblocks;	/* current block count */
+	__u32 dqb_ihardlimit;	/* absolute limit on allocated inodes */
+	__u32 dqb_isoftlimit;	/* preferred inode limit */
+	__u32 dqb_curinodes;	/* current # allocated inodes */
+	time_t dqb_btime;	/* time limit for excessive disk use */
+	time_t dqb_itime;	/* time limit for excessive inode use */
+};
+
+#define v1_dqoff(UID)      ((loff_t)((UID) * sizeof (struct v1_disk_dqblk)))
+
+#endif	/* _LINUX_QUOTAIO_V1_H */