Re: [PATCH] disk quotas fail when /etc/mtab is symlinked to /proc/mounts
From: Mark Bellon
Date: Fri Jul 29 2005 - 10:49:47 EST
Jan Kara wrote:
Hello,
If /etc/mtab is a regular file all of the mount options (of a file
system) are written to /etc/mtab by the mount command. The quota tools
look there for the quota strings for their operation. If, however,
/etc/mtab is a symlink to /proc/mounts (a "good thing" in some
environments) the tools don't write anything - they assume the kernel
will take care of things.
While the quota options are sent down to the kernel via the mount system
call and the file system codes handle them properly unfortunately there
is no code to echo the quota strings into /proc/mounts and the quota
tools fail in the symlink case.
Yes, I agree that it's a good think to have quota options in
/proc/mounts. Doing it per filesystem is not nice but I don't know a
nice way of doing it a VFS level either...
I'll have a new patch which includes your comments and a few I thought
up soon. I'll repost the new patch.
mark
The attached patchs modify the EXT[2|3] and [X|J]FS codes to add the
necessary hooks. The show_options function of each file system in these
patches currently deal with only those things that seemed related to
quotas; especially in the EXT3 case more can be done (later?).
The EXT3 has added error checking and has two minor changes:
The "quota" option is considered part of the older style quotas
Journalled quotas and older style quotas are mutually exclusive.
- both discussable topics
Ack.
mark
Signed-off-by: Mark Bellon <mbellon@xxxxxxxxxx>
Thanks for the patch - I have some comments below...
<snip>
#ifdef CONFIG_QUOTA
+static int ext3_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+ struct ext3_sb_info *sbi = EXT3_SB(vfs->mnt_sb);
+
+ if (sbi->s_mount_opt & EXT3_MOUNT_JOURNAL_DATA)
+ seq_puts(seq, ",data=journal");
+
+ if (sbi->s_mount_opt & EXT3_MOUNT_ORDERED_DATA)
+ seq_puts(seq, ",data=ordered");
+
+ if (sbi->s_mount_opt & EXT3_MOUNT_WRITEBACK_DATA)
+ seq_puts(seq, ",data=writeback");
Showing 'data' option only when quota is compile is ugly... Please move
CONFIG_QUOTA inside only around quota specific stuff.
+
+ if (sbi->s_jquota_fmt)
+ seq_printf(seq, ",jqfmt=%s",
+ (sbi->s_jquota_fmt == QFMT_VFS_OLD) ? "vfsold": "vfsv0");
+
+ if (sbi->s_qf_names[USRQUOTA])
+ seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
+
+ if (sbi->s_qf_names[GRPQUOTA])
+ seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
+
+ if (sbi->s_mount_opt & EXT3_MOUNT_USRQUOTA)
+ seq_puts(seq, ",usrquota");
+
+ if (sbi->s_mount_opt & EXT3_MOUNT_GRPQUOTA)
+ seq_puts(seq, ",grpquota");
+
+ return 0;
+}
#define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
#define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
@@ -572,6 +604,7 @@
#ifdef CONFIG_QUOTA
.quota_read = ext3_quota_read,
.quota_write = ext3_quota_write,
+ .show_options = ext3_show_options,
Probably set this function everytime...
<snip>
+ case Opt_quota:
+ case Opt_usrquota:
+ case Opt_grpquota:
case Opt_usrjquota:
case Opt_grpjquota:
case Opt_offusrjquota:
@@ -924,7 +973,6 @@
"EXT3-fs: journalled quota options not "
"supported.\n");
break;
- case Opt_quota:
case Opt_noquota:
break;
I'm not sure with the above change.. Previously if you mounted a
filesystem with 'usrquota' option without a kernel quota support the mount
succeeded. With your patch it will fail. I agree that that makes more
sense but I'm not sure it's correct to change a behaviour so suddently.
Maybe just issue a warning but let the mount succeed.
#endif
@@ -962,11 +1010,36 @@
}
}
#ifdef CONFIG_QUOTA
- if (!sbi->s_jquota_fmt && (sbi->s_qf_names[USRQUOTA] ||
- sbi->s_qf_names[GRPQUOTA])) {
- printk(KERN_ERR
+ if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
+ if ((sbi->s_mount_opt & EXT3_MOUNT_USRQUOTA) ||
+ (sbi->s_mount_opt & EXT3_MOUNT_GRPQUOTA)) {
+ printk(KERN_ERR
+ "EXT3-fs: only one type of quotas allowed.\n");
+
+ return 0;
+ }
+
+ if (!sbi->s_jquota_fmt) {
+ printk(KERN_ERR
"EXT3-fs: journalled quota format not specified.\n");
- return 0;
+
+ return 0;
+ }
+
+ if ((sbi->s_mount_opt & EXT3_MOUNT_JOURNAL_DATA) == 0) {
This test does not make sense - journaled quota in recent kernels
works with arbitrary journaling data mode.
+ printk(KERN_ERR
+ "EXT3-fs: journalled quota specified when data journalling is not.\n");
+
+ return 0;
+ }
+ }
+ else {
+ if (sbi->s_jquota_fmt) {
+ printk(KERN_ERR
+"EXT3-fs: journalled quota format specified with no journalling enabled.\n");
+
+ return 0;
+ }
}
#endif
+#if defined(CONFIG_QUOTA)
+ case Opt_usrquota:
+ set_opt(sbi->s_mount_opt, USRQUOTA);
+ break;
+
+ case Opt_grpquota:
+ set_opt(sbi->s_mount_opt, GRPQUOTA);
+ break;
+
+ case Opt_quota:
+ set_opt(sbi->s_mount_opt, GRPQUOTA);
+ set_opt(sbi->s_mount_opt, USRQUOTA);
+ break;
The old 'quota' option means the same as 'usrquota' - at least tools
consider it like that.
+#else
+ case Opt_quota:
+ case Opt_usrquota:
+ case Opt_grpquota:
+ printk(KERN_ERR
+ "EXT2-fs: quota operations not supported.\n");
+
+ break;
+#endif
The same as with ext3 - I don't like this change...
<snip>
Honza
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/