Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 15 Oct 2001 04:19:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 15 Oct 2001 04:18:55 -0400 Received: from roc-24-169-102-121.rochester.rr.com ([24.169.102.121]:19410 "EHLO roc-24-169-102-121.rochester.rr.com") by vger.kernel.org with ESMTP id ; Mon, 15 Oct 2001 04:18:39 -0400 Date: Mon, 15 Oct 2001 04:18:42 -0400 From: Chris Mason To: Alexander Viro cc: Ed Tomlinson , Matthew Dharm , linux-kernel@vger.kernel.org Subject: Re: mount hanging 2.4.12 Message-ID: <2314290000.1003133922@tiny> In-Reply-To: In-Reply-To: X-Mailer: Mulberry/2.1.0 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [ bad lvm<->reiserfs locking patch causes hangs ] Ok, here's an updated patch, one liner fix from the original. -chris Index: 0.41/fs/super.c --- 0.41/fs/super.c Thu, 11 Oct 2001 09:27:57 -0400 root (linux/d/45_super.c 1.1.2.1.4.1.2.1 644) +++ 0.42/fs/super.c Mon, 15 Oct 2001 03:42:49 -0400 root (linux/d/45_super.c 1.1.2.1.4.1.2.2 644) @@ -54,6 +54,8 @@ LIST_HEAD(super_blocks); spinlock_t sb_lock = SPIN_LOCK_UNLOCKED; +static DECLARE_MUTEX(lockfs_sem); + /* * Handling of filesystem drivers list. * Rules: @@ -322,6 +324,19 @@ sb->s_op->write_super(sb); unlock_super(sb); } + +static inline 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); +} /* * Note: check the dirty flag before waiting, so we don't @@ -357,6 +372,39 @@ 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 @@ -578,6 +626,7 @@ if (!s) goto out1; down_write(&s->s_umount); + down(&lockfs_sem) ; error = -EBUSY; restart: @@ -590,11 +639,13 @@ if (old->s_type != fs_type || ((flags ^ old->s_flags) & MS_RDONLY)) { spin_unlock(&sb_lock); + up(&lockfs_sem); put_super(s); goto out1; } if (!grab_super(old)) goto restart; + up(&lockfs_sem); put_super(s); blkdev_put(bdev, BDEV_FS); path_release(&nd); @@ -615,6 +666,9 @@ if (!fs_type->read_super(s, data, flags & MS_VERBOSE ? 1 : 0)) goto out_fail; unlock_super(s); + + up(&lockfs_sem); + get_filesystem(fs_type); path_release(&nd); return s; @@ -623,6 +677,7 @@ s->s_dev = 0; s->s_bdev = 0; s->s_type = NULL; + up(&lockfs_sem) ; unlock_super(s); spin_lock(&sb_lock); list_del(&s->s_list); @@ -728,6 +783,7 @@ sb->s_count -= S_BIAS; spin_unlock(&sb_lock); + down(&lockfs_sem); down_write(&sb->s_umount); lock_kernel(); sb->s_root = NULL; @@ -744,6 +800,7 @@ if (sop->put_super) sop->put_super(sb); } + up(&lockfs_sem); /* Forget any remaining inodes */ if (invalidate_inodes(sb)) { Index: 0.41/fs/buffer.c --- 0.41/fs/buffer.c Sun, 14 Oct 2001 10:34:39 -0400 root (linux/i/46_buffer.c 1.1.2.1.9.1.4.1 644) +++ 0.42/fs/buffer.c Mon, 15 Oct 2001 03:42:49 -0400 root (linux/i/46_buffer.c 1.1.2.1.9.1.4.2 644) @@ -359,6 +359,34 @@ 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: 0.41/drivers/md/lvm.c --- 0.41/drivers/md/lvm.c Sun, 23 Sep 2001 20:11:16 -0400 root (linux/i/c/30_lvm.c 1.1.2.1 644) +++ 0.42/drivers/md/lvm.c Mon, 15 Oct 2001 03:42:49 -0400 root (linux/i/c/30_lvm.c 1.1.2.1.9.1 644) @@ -161,9 +161,6 @@ #define MAJOR_NR LVM_BLK_MAJOR #define DEVICE_OFF(device) -/* lvm_do_lv_create calls fsync_dev_lockfs()/unlockfs() */ -/* #define LVM_VFS_ENHANCEMENT */ - #include #include #include @@ -2301,12 +2298,8 @@ 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(&org->lv_snapshot_sem); org->lv_access |= LV_SNAPSHOT_ORG; @@ -2326,12 +2319,10 @@ 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 lv_ptr->vg = vg_ptr; Index: 0.41/kernel/ksyms.c --- 0.41/kernel/ksyms.c Sun, 14 Oct 2001 10:34:39 -0400 root (linux/n/c/22_ksyms.c 1.1.2.1.9.1.4.1 644) +++ 0.42/kernel/ksyms.c Mon, 15 Oct 2001 03:42:49 -0400 root (linux/n/c/22_ksyms.c 1.1.2.1.9.1.4.2 644) @@ -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: 0.41/include/linux/fs.h --- 0.41/include/linux/fs.h Sun, 14 Oct 2001 10:34:39 -0400 root (linux/f/d/9_fs.h 1.1.2.1.10.1.2.2 644) +++ 0.42/include/linux/fs.h Mon, 15 Oct 2001 03:42:49 -0400 root (linux/f/d/9_fs.h 1.1.2.1.10.1.2.2.1.1 644) @@ -1185,6 +1185,7 @@ 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 *); @@ -1196,6 +1197,8 @@ extern void filemap_fdatasync(struct address_space *); extern void 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); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/