[linux-lvm] VFS lock patch for 2.4.22 ???
Patrick Caulfield
caulfield at sistina.com
Tue Oct 7 07:34:05 UTC 2003
On Sun, Oct 05, 2003 at 01:21:25AM +0100, Damir Dezeljin wrote:
> Hi.
>
> I have to use kernel 2.4.22 on my box (due to new drivers and fixes),
> however I also have to use LVM10 snapshots (Debian Woody) on the same box
> (I already have an volume group and logical volumes configured).
>
> The problem is that I'm using ext3 on the logical volumes and when I try
> to mount an snapshot I got an error.
>
>
> Is there an VFS-lock patch for kernel 2.4.22?
> If not ... is there any other way to get work mounting of ext3 snapshots
> with kernel 2.4.22?
Try this one, It's merely a massaged version of the 2.4.21 one.
I haven't given it a whole lot of testing though.
patrick
-------------- next part --------------
diff -rwu linux-2.4.21.orig/drivers/md/lvm.c linux-2.4.21/drivers/md/lvm.c
--- linux-2.4.21.orig/drivers/md/lvm.c 2003-10-06 10:32:00.000000000 +0100
+++ linux-2.4.21/drivers/md/lvm.c 2003-10-06 10:33:22.000000000 +0100
@@ -236,9 +236,6 @@
#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>
@@ -2248,12 +2245,8 @@
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;
@@ -2279,11 +2272,9 @@
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);
diff -rwu linux-2.4.21.orig/fs/buffer.c linux-2.4.21/fs/buffer.c
--- linux-2.4.21.orig/fs/buffer.c 2003-10-06 10:26:47.000000000 +0100
+++ linux-2.4.21/fs/buffer.c 2003-10-06 10:33:22.000000000 +0100
@@ -376,6 +376,34 @@
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);
diff -rwu linux-2.4.21.orig/fs/reiserfs/super.c linux-2.4.21/fs/reiserfs/super.c
--- linux-2.4.21.orig/fs/reiserfs/super.c 2003-10-06 10:26:47.000000000 +0100
+++ linux-2.4.21/fs/reiserfs/super.c 2003-10-06 10:33:22.000000000 +0100
@@ -73,7 +73,7 @@
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() ;
diff -rwu linux-2.4.21.orig/fs/super.c linux-2.4.21/fs/super.c
--- linux-2.4.21.orig/fs/super.c 2003-10-06 10:26:47.000000000 +0100
+++ linux-2.4.21/fs/super.c 2003-10-06 10:33:22.000000000 +0100
@@ -39,6 +39,13 @@
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:
* Inclusion to/removals from/scanning of list are protected by spinlock.
@@ -436,6 +443,19 @@
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);
@@ -483,6 +503,39 @@
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
@@ -702,6 +755,7 @@
goto out1;
error = -EBUSY;
+ down(&lockfs_sem);
restart:
spin_lock(&sb_lock);
@@ -713,6 +767,7 @@
((flags ^ old->s_flags) & MS_RDONLY)) {
spin_unlock(&sb_lock);
destroy_super(s);
+ up(&lockfs_sem);
goto out1;
}
if (!grab_super(old))
@@ -720,12 +775,14 @@
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);
if (!fs_type->read_super(s, data, flags & MS_VERBOSE ? 1 : 0))
goto Einval;
s->s_flags |= MS_ACTIVE;
@@ -833,7 +890,10 @@
if (!deactivate_super(sb))
return;
+ down(&lockfs_sem);
down_write(&sb->s_umount);
+ up(&lockfs_sem);
+
sb->s_root = NULL;
/* Need to clean after the sucker */
if (fs->fs_flags & FS_LITTER)
diff -rwu linux-2.4.21.orig/include/linux/fs.h linux-2.4.21/include/linux/fs.h
--- linux-2.4.21.orig/include/linux/fs.h 2003-10-06 10:34:32.000000000 +0100
+++ linux-2.4.21/include/linux/fs.h 2003-10-06 10:33:22.000000000 +0100
@@ -1272,6 +1272,7 @@
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 *);
@@ -1289,6 +1290,8 @@
extern int filemap_fdatasync(struct address_space *);
extern int filemap_fdatawait(struct address_space *);
extern void sync_supers(kdev_t dev, int wait);
+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);
diff -rwu linux-2.4.21.orig/kernel/ksyms.c linux-2.4.21/kernel/ksyms.c
--- linux-2.4.21.orig/kernel/ksyms.c 2003-10-06 10:26:49.000000000 +0100
+++ linux-2.4.21/kernel/ksyms.c 2003-10-06 10:33:22.000000000 +0100
@@ -188,6 +188,8 @@
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);
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