[linux-lvm] Updated patch VFS-lock for 2.4.18+ XFS enabled kernels
Adrian Head
ahead at bigpond.net.au
Tue Apr 2 07:57:01 UTC 2002
Chris Mason,
I'm hoping that this linux-2.4.18+-xfs-VFS-lock.patch can be added to the
PATCHES directory in the LVM CVS for those people that use both LVM and SGI's
XFS filesystem.
When compiling an SGI XFS Kernel (both the official split patches and CVS)
with the standard linux-2.4.18-VFS-lock.patch the compile will fail because
of an undefined macro DQUOT_SYNC(). The XFS project is currently ahead of
Marcelo's mainline 2.4.x kernel with respect to the new Quota code from
Jan Kara. LVM uses DQUOT_SYNC() to flush Quota changes to disk before
locking the VFS for snapshot creation. This patch is the standard
linux-2.4.18-VFS-lock.patch with DQUOT_SYNC() changed to the new Quota code
DQUOT_SYNC_DEV().
For more information:
The SGI XFS project can be found here:
http://oss.sgi.com/projects/xfs/
The new 2.4.x Quota code by Jan Kara can be found here:
ftp://atrey.karlin.mff.cuni.cz/pub/local/jack/quota/v2.4/
The original email thread relating to this problem can be found here:
http://marc.theaimsgroup.com/?l=linux-lvm&m=101770214811117&w=2
This is against 2.4.18-xfs + lvm 1.0.4 or lvm 1.1rc1 and is _only_ relevent
for XFS enabled kernels above 2.4.18-xfs until Jan Kara's new Quota code is
accepted by Marcelo into the 2.4.x mainline kernel tree.
-Adrian
PS: I'm not officially associated with the SGI XFS project - just a happy
LVM & XFS user.
--
Adrian Head
(Public Key available on request.)
-------------- next part --------------
Hello everyone,
When compiling an SGI XFS Kernel (both the official split patches and CVS) with
the standard linux-2.4.18-VFS-lock.patch the compile will fail because of an
undefined macro DQUOT_SYNC(). The XFS project is currently ahead of Marcelo's
mainline 2.4.x kernel with respect to the new Quota code from Jan Kara.
LVM uses DQUOT_SYNC() to flush Quota changes to disk before locking the VFS for
snapshot creation. This patch is the standard linux-2.4.18-VFS-lock.patch with
DQUOT_SYNC() changed to the new Quota code DQUOT_SYNC_DEV().
For more information:
The SGI XFS project can be found here:
http://oss.sgi.com/projects/xfs/
The new 2.4.x Quota code by Jan Kara can be found here:
ftp://atrey.karlin.mff.cuni.cz/pub/local/jack/quota/v2.4/
The original email thread relating to this problem can be found here:
http://marc.theaimsgroup.com/?l=linux-lvm&m=101770214811117&w=2
This is against 2.4.18-xfs + lvm 1.0.4 or lvm 1.1rc1 and is _only_ relevent for
XFS enabled kernels above 2.4.18-xfs until Jan Kara's new Quota code is accepted by
Marcelo into the 2.4.x mainline kernel tree.
-Adrian
PS I'm not associated with SGI or the XFS project - just a happy LVM & XFS user.
Index: linus.21/fs/reiserfs/super.c
--- linus.21/fs/reiserfs/super.c Fri, 11 Jan 2002 10:14:59 -0500 root (linux/41_super.c 1.2.2.1.2.1.1.1 644)
+++ linus.21(w)/fs/reiserfs/super.c Mon, 28 Jan 2002 13:50:56 -0500 root (linux/41_super.c 1.2.2.1.2.1.1.1 644)
@@ -66,7 +66,7 @@
reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB (s));
reiserfs_block_writes(&th) ;
- journal_end(&th, s, 1) ;
+ journal_end_sync(&th, s, 1) ;
}
s->s_dirt = dirty;
unlock_kernel() ;
Index: linus.21/fs/super.c
--- linus.21/fs/super.c Mon, 28 Jan 2002 09:51:50 -0500 root (linux/d/45_super.c 1.6 644)
+++ linus.21(w)/fs/super.c Mon, 28 Jan 2002 17:19:58 -0500 root (linux/d/45_super.c 1.6 644)
@@ -54,6 +54,13 @@
LIST_HEAD(super_blocks);
spinlock_t sb_lock = SPIN_LOCK_UNLOCKED;
+/*
+ * lock/unlockfs grab a read lock on s_umount, but you need this lock to
+ * make sure no lockfs runs are in progress before inserting/removing
+ * supers from the list.
+ */
+static DECLARE_MUTEX(lockfs_sem);
+
/*
* Handling of filesystem drivers list.
* Rules:
@@ -453,6 +460,19 @@
put_super(sb);
}
+static void write_super_lockfs(struct super_block *sb)
+{
+ lock_super(sb);
+ if (sb->s_root && sb->s_op) {
+ if (sb->s_dirt && sb->s_op->write_super)
+ sb->s_op->write_super(sb);
+ if (sb->s_op->write_super_lockfs) {
+ sb->s_op->write_super_lockfs(sb);
+ }
+ }
+ unlock_super(sb);
+}
+
static inline void write_super(struct super_block *sb)
{
lock_super(sb);
@@ -496,6 +516,39 @@
spin_unlock(&sb_lock);
}
+/*
+ * Note: don't check the dirty flag before waiting, we want the lock
+ * to happen every time this is called. dev must be non-zero
+ */
+void sync_supers_lockfs(kdev_t dev)
+{
+ struct super_block * sb;
+
+ down(&lockfs_sem) ;
+ if (dev) {
+ sb = get_super(dev);
+ if (sb) {
+ write_super_lockfs(sb);
+ drop_super(sb);
+ }
+ }
+}
+
+void unlockfs(kdev_t dev)
+{
+ struct super_block * sb;
+
+ if (dev) {
+ sb = get_super(dev);
+ if (sb) {
+ if (sb->s_op && sb->s_op->unlockfs)
+ sb->s_op->unlockfs(sb) ;
+ drop_super(sb);
+ }
+ }
+ up(&lockfs_sem) ;
+}
+
/**
* get_super - get the superblock of a device
* @dev: device to get the superblock for
@@ -560,8 +613,10 @@
s->s_dev = dev;
s->s_bdev = bdev;
s->s_flags = flags;
+ down(&lockfs_sem);
spin_lock(&sb_lock);
insert_super(s, type);
+ up(&lockfs_sem);
lock_super(s);
if (!type->read_super(s, data, flags & MS_VERBOSE ? 1 : 0))
goto out_fail;
@@ -664,6 +719,7 @@
}
error = -EBUSY;
+ down(&lockfs_sem);
restart:
spin_lock(&sb_lock);
@@ -676,6 +732,7 @@
spin_unlock(&sb_lock);
destroy_super(s);
blkdev_put(bdev, BDEV_FS);
+ up(&lockfs_sem);
goto out;
}
if (!grab_super(old))
@@ -683,12 +740,15 @@
destroy_super(s);
blkdev_put(bdev, BDEV_FS);
path_release(&nd);
+ up(&lockfs_sem);
return old;
}
s->s_dev = dev;
s->s_bdev = bdev;
s->s_flags = flags;
+
insert_super(s, fs_type);
+ up(&lockfs_sem);
error = -EINVAL;
lock_super(s);
@@ -779,7 +839,10 @@
if (!deactivate_super(sb))
return;
+ down(&lockfs_sem);
down_write(&sb->s_umount);
+ up(&lockfs_sem);
+
lock_kernel();
sb->s_root = NULL;
/* Need to clean after the sucker */
Index: linus.21/fs/buffer.c
--- linus.21/fs/buffer.c Mon, 28 Jan 2002 09:51:50 -0500 root (linux/i/45_buffer.c 1.5.2.6 644)
+++ linus.21(w)/fs/buffer.c Mon, 28 Jan 2002 11:54:36 -0500 root (linux/i/45_buffer.c 1.5.2.6 644)
@@ -361,6 +361,34 @@
fsync_dev(dev);
}
+int fsync_dev_lockfs(kdev_t dev)
+{
+ /* you are not allowed to try locking all the filesystems
+ ** on the system, your chances of getting through without
+ ** total deadlock are slim to none.
+ */
+ if (!dev)
+ return fsync_dev(dev) ;
+
+ sync_buffers(dev, 0);
+
+ lock_kernel();
+ /* note, the FS might need to start transactions to
+ ** sync the inodes, or the quota, no locking until
+ ** after these are done
+ */
+ sync_inodes(dev);
+ DQUOT_SYNC_DEV(dev);
+ /* if inodes or quotas could be dirtied during the
+ ** sync_supers_lockfs call, the FS is responsible for getting
+ ** them on disk, without deadlocking against the lock
+ */
+ sync_supers_lockfs(dev) ;
+ unlock_kernel();
+
+ return sync_buffers(dev, 1) ;
+}
+
asmlinkage long sys_sync(void)
{
fsync_dev(0);
Index: linus.21/drivers/md/lvm.c
--- linus.21/drivers/md/lvm.c Mon, 28 Jan 2002 11:52:24 -0500 root (linux/h/c/34_lvm.c 1.5 644)
+++ linus.21(w)/drivers/md/lvm.c Mon, 28 Jan 2002 11:55:57 -0500 root (linux/h/c/34_lvm.c 1.5 644)
@@ -223,9 +223,6 @@
#define DEVICE_OFF(device)
#define LOCAL_END_REQUEST
-/* lvm_do_lv_create calls fsync_dev_lockfs()/unlockfs() */
-/* #define LVM_VFS_ENHANCEMENT */
-
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
@@ -2107,12 +2104,8 @@
if (lv_ptr->lv_access & LV_SNAPSHOT) {
lv_t *org = lv_ptr->lv_snapshot_org, *last;
- /* sync the original logical volume */
- fsync_dev(org->lv_dev);
-#ifdef LVM_VFS_ENHANCEMENT
/* VFS function call to sync and lock the filesystem */
fsync_dev_lockfs(org->lv_dev);
-#endif
down_write(&org->lv_lock);
org->lv_access |= LV_SNAPSHOT_ORG;
@@ -2137,11 +2130,9 @@
else
set_device_ro(lv_ptr->lv_dev, 1);
-#ifdef LVM_VFS_ENHANCEMENT
/* VFS function call to unlock the filesystem */
if (lv_ptr->lv_access & LV_SNAPSHOT)
unlockfs(lv_ptr->lv_snapshot_org->lv_dev);
-#endif
lvm_gendisk.part[MINOR(lv_ptr->lv_dev)].de =
lvm_fs_create_lv(vg_ptr, lv_ptr);
Index: linus.21/kernel/ksyms.c
--- linus.21/kernel/ksyms.c Mon, 28 Jan 2002 09:51:50 -0500 root (linux/m/c/25_ksyms.c 1.5.2.4 644)
+++ linus.21(w)/kernel/ksyms.c Mon, 28 Jan 2002 11:54:36 -0500 root (linux/m/c/25_ksyms.c 1.5.2.4 644)
@@ -178,6 +178,8 @@
EXPORT_SYMBOL(invalidate_inode_pages);
EXPORT_SYMBOL(truncate_inode_pages);
EXPORT_SYMBOL(fsync_dev);
+EXPORT_SYMBOL(fsync_dev_lockfs);
+EXPORT_SYMBOL(unlockfs);
EXPORT_SYMBOL(fsync_no_super);
EXPORT_SYMBOL(permission);
EXPORT_SYMBOL(vfs_permission);
Index: linus.21/include/linux/fs.h
--- linus.21/include/linux/fs.h Mon, 28 Jan 2002 09:51:50 -0500 root (linux/e/d/3_fs.h 1.2.1.1.1.3.3.1.1.2 644)
+++ linus.21(w)/include/linux/fs.h Mon, 28 Jan 2002 12:15:21 -0500 root (linux/e/d/3_fs.h 1.2.1.1.1.3.3.1.1.2 644)
@@ -1205,6 +1205,7 @@
extern int sync_buffers(kdev_t, int);
extern void sync_dev(kdev_t);
extern int fsync_dev(kdev_t);
+extern int fsync_dev_lockfs(kdev_t);
extern int fsync_super(struct super_block *);
extern int fsync_no_super(kdev_t);
extern void sync_inodes_sb(struct super_block *);
@@ -1216,6 +1217,8 @@
extern int filemap_fdatasync(struct address_space *);
extern int filemap_fdatawait(struct address_space *);
extern void sync_supers(kdev_t);
+extern void sync_supers_lockfs(kdev_t);
+extern void unlockfs(kdev_t);
extern int bmap(struct inode *, int);
extern int notify_change(struct dentry *, struct iattr *);
extern int permission(struct inode *, int);
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