[linux-lvm] [PATCH] updated lvm VFS locking patch 2.4.18-pre7
Chris Mason
mason at suse.com
Tue Jan 29 09:01:02 UTC 2002
Hello everyone,
2.4.18pre7 includes some super.c cleanups that trigger rejects on
the lvm VFS locking patch for journaled filesystems.
This is against 2.4.18pre7 + lvm 1.0.2, I'm forwarding it to Marcelo
later today.
-chris
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);
+ /* 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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