[PATCH 01/27] BKL: Push down BKL from do_new_mount() to the filesystems get_sb/fill_super operation

[PATCH 01/27] BKL: Push down BKL from do_new_mount() to the filesystems get_sb/fill_super operation

[Jan Blunck]

I've read through all the code formerly covered by the BKL inside
do_kern_mount() and have satisfied myself that it doesn't need the BKL
any more.

do_kern_mount() is already called without the BKL when mounting the rootfs
and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
afs_mntpt_follow_link(). Both later functions are actually the filesystems
follow_link inode operation. vfs_kern_mount() is calling the specified
get_sb function and lets the filesystem do its job by calling the given
fill_super function.

Therefore I think it is safe to push down the BKL from the VFS to the
low-level filesystems get_sb/fill_super operation.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Matthew Wilcox <matthew@wil.cx>
---
 fs/9p/vfs_super.c            |    9 ++++++++-
 fs/adfs/super.c              |    8 +++++++-
 fs/affs/super.c              |    9 ++++++++-
 fs/afs/super.c               |    5 +++++
 fs/autofs4/inode.c           |    4 ++++
 fs/befs/linuxvfs.c           |    4 ++++
 fs/bfs/inode.c               |    9 ++++++++-
 fs/binfmt_misc.c             |    6 +++++-
 fs/btrfs/super.c             |    8 +++++++-
 fs/cifs/cifsfs.c             |   12 ++++++++++--
 fs/coda/inode.c              |    8 +++++++-
 fs/configfs/mount.c          |    5 +++++
 fs/cramfs/inode.c            |    8 +++++++-
 fs/devpts/inode.c            |   13 +++++++++++--
 fs/ecryptfs/main.c           |    3 +++
 fs/efs/super.c               |   10 ++++++++--
 fs/exofs/super.c             |    7 ++++++-
 fs/ext2/super.c              |   10 ++++++++--
 fs/ext3/super.c              |    9 ++++++++-
 fs/ext4/super.c              |    9 ++++++---
 fs/fat/namei_msdos.c         |    6 +++++-
 fs/fat/namei_vfat.c          |    6 +++++-
 fs/freevxfs/vxfs_super.c     |    7 ++++++-
 fs/fuse/control.c            |    9 ++++++++-
 fs/fuse/inode.c              |    5 +++++
 fs/gfs2/ops_fstype.c         |    9 +++++++++
 fs/hfs/super.c               |    8 +++++++-
 fs/hfsplus/super.c           |    8 +++++++-
 fs/hostfs/hostfs_kern.c      |    4 ++++
 fs/hpfs/super.c              |    8 +++++++-
 fs/hppfs/hppfs.c             |    4 ++++
 fs/hugetlbfs/inode.c         |   12 ++++++++++--
 fs/isofs/inode.c             |    8 +++++++-
 fs/jffs2/super.c             |   11 +++++++++--
 fs/jfs/super.c               |   14 ++++++++++++--
 fs/libfs.c                   |   10 +++++++++-
 fs/minix/inode.c             |    8 +++++++-
 fs/namespace.c               |    2 --
 fs/ncpfs/inode.c             |    8 +++++++-
 fs/nfs/super.c               |   19 +++++++++++++++++++
 fs/nfsd/nfsctl.c             |    7 ++++++-
 fs/nilfs2/super.c            |    9 ++++++++-
 fs/ntfs/super.c              |    5 +++++
 fs/ocfs2/dlm/dlmfs.c         |    8 +++++++-
 fs/ocfs2/super.c             |    5 +++++
 fs/omfs/inode.c              |    7 ++++++-
 fs/openpromfs/inode.c        |    4 ++++
 fs/proc/root.c               |    9 ++++++++-
 fs/qnx4/inode.c              |    8 +++++++-
 fs/ramfs/inode.c             |    5 +++++
 fs/reiserfs/super.c          |    4 ++++
 fs/romfs/super.c             |    9 ++++++++-
 fs/smbfs/inode.c             |    5 +++++
 fs/squashfs/super.c          |    6 ++++++
 fs/sysfs/mount.c             |    6 ++++++
 fs/sysv/super.c              |   24 +++++++++++++++++++-----
 fs/ubifs/super.c             |    5 +++++
 fs/udf/super.c               |    8 +++++++-
 fs/ufs/super.c               |    5 +++++
 fs/xfs/linux-2.6/xfs_super.c |    4 ++++
 60 files changed, 412 insertions(+), 53 deletions(-)

diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index 14a8644..4156a0c 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -106,11 +106,15 @@ static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 	struct p9_fid *fid;
 	int retval = 0;
 
+	lock_kernel();
+
 	P9_DPRINTK(P9_DEBUG_VFS, " \n");
 
 	v9ses = kzalloc(sizeof(struct v9fs_session_info), GFP_KERNEL);
-	if (!v9ses)
+	if (!v9ses) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	fid = v9fs_session_init(v9ses, dev_name, data);
 	if (IS_ERR(fid)) {
@@ -155,6 +159,7 @@ static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
 
 P9_DPRINTK(P9_DEBUG_VFS, " simple set mount, return 0\n");
 	simple_set_mnt(mnt, sb);
+	unlock_kernel();
 	return 0;
 
 free_stat:
@@ -167,12 +172,14 @@ clunk_fid:
 close_session:
 	v9fs_session_close(v9ses);
 	kfree(v9ses);
+	unlock_kernel();
 	return retval;
 
 release_sb:
 	p9stat_free(st);
 	kfree(st);
 	deactivate_locked_super(sb);
+	unlock_kernel();
 	return retval;
 }
 
diff --git a/fs/adfs/super.c b/fs/adfs/super.c
index 6910a98..e94f111 100644
--- a/fs/adfs/super.c
+++ b/fs/adfs/super.c
@@ -351,11 +351,15 @@ static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 	struct adfs_sb_info *asb;
 	struct inode *root;
 
+	lock_kernel();
+
 	sb->s_flags |= MS_NODIRATIME;
 
 	asb = kzalloc(sizeof(*asb), GFP_KERNEL);
-	if (!asb)
+	if (!asb) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	sb->s_fs_info = asb;
 
 	/* set default options */
@@ -473,6 +477,7 @@ static int adfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto error;
 	} else
 		sb->s_root->d_op = &adfs_dentry_operations;
+	unlock_kernel();
 	return 0;
 
 error_free_bh:
@@ -480,6 +485,7 @@ error_free_bh:
 error:
 	sb->s_fs_info = NULL;
 	kfree(asb);
+	unlock_kernel();
 	return -EINVAL;
 }
 
diff --git a/fs/affs/super.c b/fs/affs/super.c
index 104fdcb..135f0d3 100644
--- a/fs/affs/super.c
+++ b/fs/affs/super.c
@@ -298,6 +298,8 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
 	u8			 sig[4];
 	int			 ret = -EINVAL;
 
+	lock_kernel();
+
 	save_mount_options(sb, data);
 
 	pr_debug("AFFS: read_super(%s)\n",data ? (const char *)data : "no options");
@@ -307,8 +309,10 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_flags |= MS_NODIRATIME;
 
 	sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	sb->s_fs_info = sbi;
 	mutex_init(&sbi->s_bmlock);
 
@@ -316,6 +320,7 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
 				&blocksize,&sbi->s_prefix,
 				sbi->s_volume, &mount_flags)) {
 		printk(KERN_ERR "AFFS: Error parsing options\n");
+		unlock_kernel();
 		return -EINVAL;
 	}
 	/* N.B. after this point s_prefix must be released */
@@ -486,6 +491,7 @@ got_root:
 	sb->s_root->d_op = &affs_dentry_operations;
 
 	pr_debug("AFFS: s_flags=%lX\n",sb->s_flags);
+	unlock_kernel();
 	return 0;
 
 	/*
@@ -500,6 +506,7 @@ out_error_noinode:
 	kfree(sbi->s_prefix);
 	kfree(sbi);
 	sb->s_fs_info = NULL;
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/afs/super.c b/fs/afs/super.c
index e1ea1c2..108fb3e 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -294,12 +294,15 @@ static int afs_fill_super(struct super_block *sb, void *data)
 	struct inode *inode = NULL;
 	int ret;
 
+	lock_kernel();
+
 	_enter("");
 
 	/* allocate a superblock info record */
 	as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
 	if (!as) {
 		_leave(" = -ENOMEM");
+		unlock_kernel();
 		return -ENOMEM;
 	}
 
@@ -329,6 +332,7 @@ static int afs_fill_super(struct super_block *sb, void *data)
 	sb->s_root = root;
 
 	_leave(" = 0");
+	unlock_kernel();
 	return 0;
 
 error_inode:
@@ -342,6 +346,7 @@ error:
 	sb->s_fs_info = NULL;
 
 	_leave(" = %d", ret);
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index 69c8142..3adaba9 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -323,6 +323,8 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
 	struct autofs_sb_info *sbi;
 	struct autofs_info *ino;
 
+	lock_kernel();
+
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
 		goto fail_unlock;
@@ -418,6 +420,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
 	 * Success! Install the root dentry now to indicate completion.
 	 */
 	s->s_root = root;
+	unlock_kernel();
 	return 0;
 	
 	/*
@@ -439,6 +442,7 @@ fail_free:
 	kfree(sbi);
 	s->s_fs_info = NULL;
 fail_unlock:
+	unlock_kernel();
 	return -EINVAL;
 }
 
diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
index 33baf27..f2aa193 100644
--- a/fs/befs/linuxvfs.c
+++ b/fs/befs/linuxvfs.c
@@ -759,6 +759,8 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
 	const unsigned long sb_block = 0;
 	const off_t x86_sb_off = 512;
 
+	lock_kernel();
+
 	save_mount_options(sb, data);
 
 	sb->s_fs_info = kmalloc(sizeof (*befs_sb), GFP_KERNEL);
@@ -867,6 +869,7 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
 		befs_sb->nls = load_nls_default();
 	}
 
+	unlock_kernel();
 	return 0;
 /*****************/
       unacquire_bh:
@@ -877,6 +880,7 @@ befs_fill_super(struct super_block *sb, void *data, int silent)
 
       unacquire_none:
 	sb->s_fs_info = NULL;
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index 6f60336..4bff506 100644
--- a/fs/bfs/inode.c
+++ b/fs/bfs/inode.c
@@ -356,9 +356,13 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 	long ret = -EINVAL;
 	unsigned long i_sblock, i_eblock, i_eoff, s_size;
 
+	lock_kernel();
+
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
-	if (!info)
+	if (!info) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	s->s_fs_info = info;
 
 	sb_set_blocksize(s, BFS_BSIZE);
@@ -463,6 +467,7 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 			kfree(info->si_imap);
 			kfree(info);
 			s->s_fs_info = NULL;
+			unlock_kernel();
 			return -EIO;
 		}
 
@@ -484,12 +489,14 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 	} 
 	dump_imap("read_super", s);
 	mutex_init(&info->bfs_lock);
+	unlock_kernel();
 	return 0;
 
 out:
 	brelse(bh);
 	kfree(info);
 	s->s_fs_info = NULL;
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index c4e8353..ca0e22d 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -695,9 +695,13 @@ static int bm_fill_super(struct super_block * sb, void * data, int silent)
 		[3] = {"register", &bm_register_operations, S_IWUSR},
 		/* last one */ {""}
 	};
-	int err = simple_fill_super(sb, 0x42494e4d, bm_files);
+	int err;
+
+	lock_kernel();
+	err = simple_fill_super(sb, 0x42494e4d, bm_files);
 	if (!err)
 		sb->s_op = &s_ops;
+	unlock_kernel();
 	return err;
 }
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 752a546..e5cd2cf 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -480,13 +480,17 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 	fmode_t mode = FMODE_READ;
 	int error = 0;
 
+	lock_kernel();
+
 	if (!(flags & MS_RDONLY))
 		mode |= FMODE_WRITE;
 
 	error = btrfs_parse_early_options(data, mode, fs_type,
 					  &subvol_name, &fs_devices);
-	if (error)
+	if (error) {
+		unlock_kernel();
 		return error;
+	}
 
 	error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
 	if (error)
@@ -555,6 +559,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 	mnt->mnt_root = root;
 
 	kfree(subvol_name);
+	unlock_kernel();
 	return 0;
 
 error_s:
@@ -563,6 +568,7 @@ error_close_devices:
 	btrfs_close_devices(fs_devices);
 error_free_subvol_name:
 	kfree(subvol_name);
+	unlock_kernel();
 	return error;
 }
 
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 9a5e4f5..09ccb9d 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -596,22 +596,30 @@ cifs_get_sb(struct file_system_type *fs_type,
 	    int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
 	int rc;
-	struct super_block *sb = sget(fs_type, NULL, set_anon_super, NULL);
+	struct super_block *sb;
+
+	lock_kernel();
+
+	sb = sget(fs_type, NULL, set_anon_super, NULL);
 
 	cFYI(1, ("Devname: %s flags: %d ", dev_name, flags));
 
-	if (IS_ERR(sb))
+	if (IS_ERR(sb)) {
+		unlock_kernel();
 		return PTR_ERR(sb);
+	}
 
 	sb->s_flags = flags;
 
 	rc = cifs_read_super(sb, data, dev_name, flags & MS_SILENT ? 1 : 0);
 	if (rc) {
 		deactivate_locked_super(sb);
+		unlock_kernel();
 		return rc;
 	}
 	sb->s_flags |= MS_ACTIVE;
 	simple_set_mnt(mnt, sb);
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/fs/coda/inode.c b/fs/coda/inode.c
index 830f51a..d081fc5 100644
--- a/fs/coda/inode.c
+++ b/fs/coda/inode.c
@@ -147,6 +147,8 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
 	int error;
 	int idx;
 
+	lock_kernel();
+
 	idx = get_device_index((struct coda_mount_data *) data);
 
 	/* Ignore errors in data, for backward compatibility */
@@ -158,11 +160,13 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
 	vc = &coda_comms[idx];
 	if (!vc->vc_inuse) {
 		printk("coda_read_super: No pseudo device\n");
+		unlock_kernel();
 		return -EINVAL;
 	}
 
         if ( vc->vc_sb ) {
 		printk("coda_read_super: Device already mounted\n");
+		unlock_kernel();
 		return -EBUSY;
 	}
 
@@ -196,7 +200,8 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_root = d_alloc_root(root);
 	if (!sb->s_root)
 		goto error;
-        return 0;
+	unlock_kernel();
+	return 0;
 
  error:
 	if (root)
@@ -204,6 +209,7 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
 	if (vc)
 		vc->vc_sb = NULL;
 
+	unlock_kernel();
 	return -EINVAL;
 }
 
diff --git a/fs/configfs/mount.c b/fs/configfs/mount.c
index 8421cea..5b2e06e 100644
--- a/fs/configfs/mount.c
+++ b/fs/configfs/mount.c
@@ -71,6 +71,8 @@ static int configfs_fill_super(struct super_block *sb, void *data, int silent)
 	struct inode *inode;
 	struct dentry *root;
 
+	lock_kernel();
+
 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = CONFIGFS_MAGIC;
@@ -87,6 +89,7 @@ static int configfs_fill_super(struct super_block *sb, void *data, int silent)
 		inc_nlink(inode);
 	} else {
 		pr_debug("configfs: could not get root inode\n");
+		unlock_kernel();
 		return -ENOMEM;
 	}
 
@@ -94,12 +97,14 @@ static int configfs_fill_super(struct super_block *sb, void *data, int silent)
 	if (!root) {
 		pr_debug("%s: could not get root dentry!\n",__func__);
 		iput(inode);
+		unlock_kernel();
 		return -ENOMEM;
 	}
 	config_group_init(&configfs_root_group);
 	configfs_root_group.cg_item.ci_dentry = root;
 	root->d_fsdata = &configfs_root;
 	sb->s_root = root;
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index dd3634e..13e696a 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -227,11 +227,15 @@ static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
 	struct cramfs_sb_info *sbi;
 	struct inode *root;
 
+	lock_kernel();
+
 	sb->s_flags |= MS_RDONLY;
 
 	sbi = kzalloc(sizeof(struct cramfs_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	sb->s_fs_info = sbi;
 
 	/* Invalidate the read buffers on mount: think disk change.. */
@@ -308,10 +312,12 @@ static int cramfs_fill_super(struct super_block *sb, void *data, int silent)
 		iput(root);
 		goto out;
 	}
+	unlock_kernel();
 	return 0;
 out:
 	kfree(sbi);
 	sb->s_fs_info = NULL;
+	unlock_kernel();
 	return -EINVAL;
 }
 
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index d5f8c96..e206eef 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -24,6 +24,7 @@
 #include <linux/parser.h>
 #include <linux/fsnotify.h>
 #include <linux/seq_file.h>
+#include <linux/smp_lock.h> /* just for lock_kernel() */
 
 #define DEVPTS_DEFAULT_MODE 0600
 /*
@@ -363,17 +364,23 @@ static int devpts_get_sb(struct file_system_type *fs_type,
 	struct pts_mount_opts opts;
 	struct super_block *s;
 
+	lock_kernel();
+
 	error = parse_mount_options(data, PARSE_MOUNT, &opts);
-	if (error)
+	if (error) {
+		unlock_kernel();
 		return error;
+	}
 
 	if (opts.newinstance)
 		s = sget(fs_type, NULL, set_anon_super, NULL);
 	else
 		s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL);
 
-	if (IS_ERR(s))
+	if (IS_ERR(s)) {
+		unlock_kernel();
 		return PTR_ERR(s);
+	}
 
 	if (!s->s_root) {
 		s->s_flags = flags;
@@ -391,6 +398,7 @@ static int devpts_get_sb(struct file_system_type *fs_type,
 	if (error)
 		goto out_dput;
 
+	unlock_kernel();
 	return 0;
 
 out_dput:
@@ -398,6 +406,7 @@ out_dput:
 
 out_undo_sget:
 	deactivate_locked_super(s);
+	unlock_kernel();
 	return error;
 }
 
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index c6ac85d..fdc7bda 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -600,6 +600,8 @@ static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
 	int rc;
 	struct super_block *sb;
 
+	lock_kernel();
+
 	rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
 	if (rc < 0) {
 		printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
@@ -621,6 +623,7 @@ out_abort:
 	dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */
 	deactivate_locked_super(sb);
 out:
+	unlock_kernel();
 	return rc;
 }
 
diff --git a/fs/efs/super.c b/fs/efs/super.c
index f049428..0981141 100644
--- a/fs/efs/super.c
+++ b/fs/efs/super.c
@@ -249,9 +249,13 @@ static int efs_fill_super(struct super_block *s, void *d, int silent)
 	struct inode *root;
 	int ret = -EINVAL;
 
- 	sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
-	if (!sb)
+	lock_kernel();
+
+	sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
+	if (!sb) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	s->s_fs_info = sb;
  
 	s->s_magic		= EFS_SUPER_MAGIC;
@@ -319,12 +323,14 @@ static int efs_fill_super(struct super_block *s, void *d, int silent)
 		goto out_no_fs;
 	}
 
+	unlock_kernel();
 	return 0;
 
 out_no_fs_ul:
 out_no_fs:
 	s->s_fs_info = NULL;
 	kfree(sb);
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 9f500de..ea045b8 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -297,9 +297,13 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 	struct osd_obj_id obj;
 	int ret;
 
+	lock_kernel();
+
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	sb->s_fs_info = sbi;
 
 	/* use mount options to fill superblock */
@@ -399,6 +403,7 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 out:
 	if (or)
 		osd_end_request(or);
+	unlock_kernel();
 	return ret;
 
 free_sbi:
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 1a9ffee..5af1775 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -745,15 +745,18 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	__le32 features;
 	int err;
 
+	lock_kernel();
+
+	err = -ENOMEM;
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
-		return -ENOMEM;
+		goto failed_unlock;
 
 	sbi->s_blockgroup_lock =
 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 	if (!sbi->s_blockgroup_lock) {
 		kfree(sbi);
-		return -ENOMEM;
+		goto failed_unlock;
 	}
 	sb->s_fs_info = sbi;
 	sbi->s_sb_block = sb_block;
@@ -1063,6 +1066,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 		ext2_warning(sb, __func__,
 			"mounting ext3 filesystem as ext2");
 	ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
+	unlock_kernel();
 	return 0;
 
 cantfind_ext2:
@@ -1086,6 +1090,8 @@ failed_sbi:
 	sb->s_fs_info = NULL;
 	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
+failed_unlock:
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 7a520a8..38261a5 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -1568,14 +1568,19 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 	__le32 features;
 	int err;
 
+	lock_kernel();
+
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	sbi->s_blockgroup_lock =
 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 	if (!sbi->s_blockgroup_lock) {
 		kfree(sbi);
+		unlock_kernel();
 		return -ENOMEM;
 	}
 	sb->s_fs_info = sbi;
@@ -1992,6 +1997,7 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 		"writeback");
 
 	lock_kernel();
+	unlock_kernel();
 	return 0;
 
 cantfind_ext3:
@@ -2022,6 +2028,7 @@ out_fail:
 	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
 	lock_kernel();
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 312211e..9db81d2 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2328,14 +2328,19 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	int err;
 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
 
+	lock_kernel();
+
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	sbi->s_blockgroup_lock =
 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 	if (!sbi->s_blockgroup_lock) {
 		kfree(sbi);
+		unlock_kernel();
 		return -ENOMEM;
 	}
 	sb->s_fs_info = sbi;
@@ -2913,7 +2918,6 @@ no_journal:
 
 	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s", descr);
 
-	lock_kernel();
 	return 0;
 
 cantfind_ext4:
@@ -2959,7 +2963,6 @@ out_fail:
 	sb->s_fs_info = NULL;
 	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
-	lock_kernel();
 	return ret;
 }
 
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index bbc94ae..31dd072 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -662,12 +662,16 @@ static int msdos_fill_super(struct super_block *sb, void *data, int silent)
 {
 	int res;
 
+	lock_kernel();
 	res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
-	if (res)
+	if (res) {
+		unlock_kernel();
 		return res;
+	}
 
 	sb->s_flags |= MS_NOATIME;
 	sb->s_root->d_op = &msdos_dentry_operations;
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index f565f24..12961b8 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -1044,15 +1044,19 @@ static int vfat_fill_super(struct super_block *sb, void *data, int silent)
 {
 	int res;
 
+	lock_kernel();
 	res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
-	if (res)
+	if (res) {
+		unlock_kernel();
 		return res;
+	}
 
 	if (MSDOS_SB(sb)->options.name_check != 's')
 		sb->s_root->d_op = &vfat_ci_dentry_ops;
 	else
 		sb->s_root->d_op = &vfat_dentry_ops;
 
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/fs/freevxfs/vxfs_super.c b/fs/freevxfs/vxfs_super.c
index 1e8af93..b8b7821 100644
--- a/fs/freevxfs/vxfs_super.c
+++ b/fs/freevxfs/vxfs_super.c
@@ -148,7 +148,7 @@ static int vxfs_remount(struct super_block *sb, int *flags, char *data)
  *   The superblock on success, else %NULL.
  *
  * Locking:
- *   We are under the bkl and @sbp->s_lock.
+ *   We are under @sbp->s_lock.
  */
 static int vxfs_fill_super(struct super_block *sbp, void *dp, int silent)
 {
@@ -159,11 +159,14 @@ static int vxfs_fill_super(struct super_block *sbp, void *dp, int silent)
 	struct inode *root;
 	int ret = -EINVAL;
 
+	lock_kernel();
+
 	sbp->s_flags |= MS_RDONLY;
 
 	infp = kzalloc(sizeof(*infp), GFP_KERNEL);
 	if (!infp) {
 		printk(KERN_WARNING "vxfs: unable to allocate incore superblock\n");
+		unlock_kernel();
 		return -ENOMEM;
 	}
 
@@ -236,6 +239,7 @@ static int vxfs_fill_super(struct super_block *sbp, void *dp, int silent)
 		goto out_free_ilist;
 	}
 
+	unlock_kernel();
 	return 0;
 	
 out_free_ilist:
@@ -245,6 +249,7 @@ out_free_ilist:
 out:
 	brelse(bp);
 	kfree(infp);
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/fuse/control.c b/fs/fuse/control.c
index 3773fd6..8d769f7 100644
--- a/fs/fuse/control.c
+++ b/fs/fuse/control.c
@@ -10,6 +10,7 @@
 
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/smp_lock.h> /* just for lock_kernel() */
 
 #define FUSE_CTL_SUPER_MAGIC 0x65735543
 
@@ -297,9 +298,13 @@ static int fuse_ctl_fill_super(struct super_block *sb, void *data, int silent)
 	struct fuse_conn *fc;
 	int err;
 
+	lock_kernel();
+
 	err = simple_fill_super(sb, FUSE_CTL_SUPER_MAGIC, &empty_descr);
-	if (err)
+	if (err) {
+		unlock_kernel();
 		return err;
+	}
 
 	mutex_lock(&fuse_mutex);
 	BUG_ON(fuse_control_sb);
@@ -309,10 +314,12 @@ static int fuse_ctl_fill_super(struct super_block *sb, void *data, int silent)
 		if (err) {
 			fuse_control_sb = NULL;
 			mutex_unlock(&fuse_mutex);
+			unlock_kernel();
 			return err;
 		}
 	}
 	mutex_unlock(&fuse_mutex);
+	unlock_kernel();
 
 	return 0;
 }
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 1a822ce..5690279 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -20,6 +20,7 @@
 #include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/exportfs.h>
+#include <linux/smp_lock.h> /* Only for lock_kernel() */
 
 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
 MODULE_DESCRIPTION("Filesystem in Userspace");
@@ -919,6 +920,8 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	int err;
 	int is_bdev = sb->s_bdev != NULL;
 
+	lock_kernel();
+
 	err = -EINVAL;
 	if (sb->s_flags & MS_MANDLOCK)
 		goto err;
@@ -1022,6 +1025,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 
 	fuse_send_init(fc, init_req);
 
+	unlock_kernel();
 	return 0;
 
  err_unlock:
@@ -1036,6 +1040,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
  err_fput:
 	fput(file);
  err:
+	unlock_kernel();
 	return err;
 }
 
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 52fb6c0..76415fe 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1120,9 +1120,12 @@ static int fill_super(struct super_block *sb, void *data, int silent)
 	struct gfs2_holder mount_gh;
 	int error;
 
+	lock_kernel();
+
 	sdp = init_sbd(sb);
 	if (!sdp) {
 		printk(KERN_WARNING "GFS2: can't alloc struct gfs2_sbd\n");
+		unlock_kernel();
 		return -ENOMEM;
 	}
 
@@ -1211,6 +1214,7 @@ static int fill_super(struct super_block *sb, void *data, int silent)
 
 	gfs2_glock_dq_uninit(&mount_gh);
 	gfs2_online_uevent(sdp);
+	unlock_kernel();
 	return 0;
 
 fail_threads:
@@ -1240,6 +1244,7 @@ fail:
 	gfs2_delete_debugfs_file(sdp);
 	kfree(sdp);
 	sb->s_fs_info = NULL;
+	unlock_kernel();
 	return error;
 }
 
@@ -1268,10 +1273,12 @@ static int gfs2_get_sb_meta(struct file_system_type *fs_type, int flags,
 	struct path path;
 	int error;
 
+	lock_kernel();
 	error = kern_path(dev_name, LOOKUP_FOLLOW, &path);
 	if (error) {
 		printk(KERN_WARNING "GFS2: path_lookup on %s returned error %d\n",
 		       dev_name, error);
+		unlock_kernel();
 		return error;
 	}
 	s = sget(&gfs2_fs_type, test_meta_super, set_meta_super,
@@ -1279,11 +1286,13 @@ static int gfs2_get_sb_meta(struct file_system_type *fs_type, int flags,
 	path_put(&path);
 	if (IS_ERR(s)) {
 		printk(KERN_WARNING "GFS2: gfs2 mount does not exist\n");
+		unlock_kernel();
 		return PTR_ERR(s);
 	}
 	sdp = s->s_fs_info;
 	mnt->mnt_sb = s;
 	mnt->mnt_root = dget(sdp->sd_master_dir);
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index f7fcbe4..a2e19ff 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -381,9 +381,13 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
 	struct inode *root_inode;
 	int res;
 
+	lock_kernel();
+
 	sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	sb->s_fs_info = sbi;
 	INIT_HLIST_HEAD(&sbi->rsrc_inodes);
 
@@ -429,6 +433,7 @@ static int hfs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_root->d_op = &hfs_dentry_operations;
 
 	/* everything's okay */
+	unlock_kernel();
 	return 0;
 
 bail_iput:
@@ -437,6 +442,7 @@ bail_no_root:
 	printk(KERN_ERR "hfs: get root inode failed.\n");
 bail:
 	hfs_mdb_put(sb);
+	unlock_kernel();
 	return res;
 }
 
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 43022f3..824f57a 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -312,9 +312,13 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 	struct nls_table *nls = NULL;
 	int err = -EINVAL;
 
+	lock_kernel();
+
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	sb->s_fs_info = sbi;
 	INIT_HLIST_HEAD(&sbi->rsrc_inodes);
@@ -459,11 +463,13 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 out:
 	unload_nls(sbi->nls);
 	sbi->nls = nls;
+	unlock_kernel();
 	return 0;
 
 cleanup:
 	hfsplus_put_super(sb);
 	unload_nls(nls);
+	unlock_kernel();
 	return err;
 }
 
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index 032604e..5eb2c26 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -968,6 +968,8 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 	char *host_root_path, *req_root = d;
 	int err;
 
+	lock_kernel();
+
 	sb->s_blocksize = 1024;
 	sb->s_blocksize_bits = 10;
 	sb->s_magic = HOSTFS_SUPER_MAGIC;
@@ -1016,6 +1018,7 @@ static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
 		goto out;
 	}
 
+	unlock_kernel();
 	return 0;
 
 out_put:
@@ -1023,6 +1026,7 @@ out_put:
 out_free:
 	kfree(host_root_path);
 out:
+	unlock_kernel();
 	return err;
 }
 
diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c
index f2feaa0..a7b348a 100644
--- a/fs/hpfs/super.c
+++ b/fs/hpfs/super.c
@@ -477,11 +477,15 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
 
 	int o;
 
+	lock_kernel();
+
 	save_mount_options(s, options);
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	s->s_fs_info = sbi;
 
 	sbi->sb_bmp_dir = NULL;
@@ -666,6 +670,7 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
 			root->i_blocks = 5;
 		hpfs_brelse4(&qbh);
 	}
+	unlock_kernel();
 	return 0;
 
 bail4:	brelse(bh2);
@@ -677,6 +682,7 @@ bail0:
 	kfree(sbi->sb_cp_table);
 	s->s_fs_info = NULL;
 	kfree(sbi);
+	unlock_kernel();
 	return -EINVAL;
 }
 
diff --git a/fs/hppfs/hppfs.c b/fs/hppfs/hppfs.c
index a5089a6..6263973 100644
--- a/fs/hppfs/hppfs.c
+++ b/fs/hppfs/hppfs.c
@@ -712,6 +712,8 @@ static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 	struct vfsmount *proc_mnt;
 	int err = -ENOENT;
 
+	lock_kernel();
+
 	proc_mnt = do_kern_mount("proc", 0, "proc", NULL);
 	if (IS_ERR(proc_mnt))
 		goto out;
@@ -731,6 +733,7 @@ static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 	if (!sb->s_root)
 		goto out_iput;
 
+	unlock_kernel();
 	return 0;
 
  out_iput:
@@ -738,6 +741,7 @@ static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
  out_mntput:
 	mntput(proc_mnt);
  out:
+	unlock_kernel();
 	return(err);
 }
 
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 87a1258..53be2b9 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -32,6 +32,7 @@
 #include <linux/security.h>
 #include <linux/ima.h>
 #include <linux/magic.h>
+#include <linux/smp_lock.h> /* Only for lock_kernel() */
 
 #include <asm/uaccess.h>
 
@@ -824,6 +825,7 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 	struct hugetlbfs_config config;
 	struct hugetlbfs_sb_info *sbinfo;
 
+	lock_kernel();
 	save_mount_options(sb, data);
 
 	config.nr_blocks = -1; /* No limit on size by default */
@@ -833,12 +835,16 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 	config.mode = 0755;
 	config.hstate = &default_hstate;
 	ret = hugetlbfs_parse_options(data, &config);
-	if (ret)
+	if (ret) {
+		unlock_kernel();
 		return ret;
+	}
 
 	sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
-	if (!sbinfo)
+	if (!sbinfo) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	sb->s_fs_info = sbinfo;
 	sbinfo->hstate = config.hstate;
 	spin_lock_init(&sbinfo->stat_lock);
@@ -863,9 +869,11 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto out_free;
 	}
 	sb->s_root = root;
+	unlock_kernel();
 	return 0;
 out_free:
 	kfree(sbinfo);
+	unlock_kernel();
 	return -ENOMEM;
 }
 
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 6b4dcd4..7c501d5 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -571,11 +571,15 @@ static int isofs_fill_super(struct super_block *s, void *data, int silent)
 	int table, error = -EINVAL;
 	unsigned int vol_desc_start;
 
+	lock_kernel();
+
 	save_mount_options(s, data);
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	s->s_fs_info = sbi;
 
 	if (!parse_options((char *)data, &opt))
@@ -895,6 +899,7 @@ root_found:
 
 	kfree(opt.iocharset);
 
+	unlock_kernel();
 	return 0;
 
 	/*
@@ -934,6 +939,7 @@ out_freesbi:
 	kfree(opt.iocharset);
 	kfree(sbi);
 	s->s_fs_info = NULL;
+	unlock_kernel();
 	return error;
 }
 
diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index 9a80e8e..622bd51 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -148,14 +148,19 @@ static const struct super_operations jffs2_super_operations =
 static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct jffs2_sb_info *c;
+	int ret;
+
+	lock_kernel();
 
 	D1(printk(KERN_DEBUG "jffs2_get_sb_mtd():"
 		  " New superblock for device %d (\"%s\")\n",
 		  sb->s_mtd->index, sb->s_mtd->name));
 
 	c = kzalloc(sizeof(*c), GFP_KERNEL);
-	if (!c)
+	if (!c) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	c->mtd = sb->s_mtd;
 	c->os_priv = sb;
@@ -177,7 +182,9 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
 	sb->s_flags |= MS_POSIXACL;
 #endif
-	return jffs2_do_fill_super(sb, data, silent);
+	ret = jffs2_do_fill_super(sb, data, silent);
+	unlock_kernel();
+	return ret;
 }
 
 static int jffs2_get_sb(struct file_system_type *fs_type,
diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index 2234c73..329d7b6 100644
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -425,14 +425,20 @@ static int jfs_fill_super(struct super_block *sb, void *data, int silent)
 	s64 newLVSize = 0;
 	int flag, ret = -EINVAL;
 
+	lock_kernel();
+
 	jfs_info("In jfs_read_super: s_flags=0x%lx", sb->s_flags);
 
-	if (!new_valid_dev(sb->s_bdev->bd_dev))
+	if (!new_valid_dev(sb->s_bdev->bd_dev)) {
+		unlock_kernel();
 		return -EOVERFLOW;
+	}
 
 	sbi = kzalloc(sizeof (struct jfs_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	sb->s_fs_info = sbi;
 	sbi->sb = sb;
 	sbi->uid = sbi->gid = sbi->umask = -1;
@@ -442,6 +448,7 @@ static int jfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	if (!parse_options((char *) data, sb, &newLVSize, &flag)) {
 		kfree(sbi);
+		unlock_kernel();
 		return -EINVAL;
 	}
 	sbi->flag = flag;
@@ -452,6 +459,7 @@ static int jfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	if (newLVSize) {
 		printk(KERN_ERR "resize option for remount only\n");
+		unlock_kernel();
 		return -EINVAL;
 	}
 
@@ -527,6 +535,7 @@ static int jfs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_maxbytes = min(((u64) PAGE_CACHE_SIZE << 32) - 1, sb->s_maxbytes);
 #endif
 	sb->s_time_gran = 1;
+	unlock_kernel();
 	return 0;
 
 out_no_root:
@@ -548,6 +557,7 @@ out_kfree:
 	if (sbi->nls_tab)
 		unload_nls(sbi->nls_tab);
 	kfree(sbi);
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/libfs.c b/fs/libfs.c
index 219576c..3484040 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -11,6 +11,7 @@
 #include <linux/exportfs.h>
 #include <linux/writeback.h>
 #include <linux/buffer_head.h>
+#include <linux/smp_lock.h> /* Only for lock_kernel() */
 
 #include <asm/uaccess.h>
 
@@ -422,6 +423,8 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files
 	struct dentry *dentry;
 	int i;
 
+	lock_kernel();
+
 	s->s_blocksize = PAGE_CACHE_SIZE;
 	s->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	s->s_magic = magic;
@@ -429,8 +432,10 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files
 	s->s_time_gran = 1;
 
 	inode = new_inode(s);
-	if (!inode)
+	if (!inode) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	/*
 	 * because the root inode is 1, the files array must not contain an
 	 * entry at index 1
@@ -444,6 +449,7 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files
 	root = d_alloc_root(inode);
 	if (!root) {
 		iput(inode);
+		unlock_kernel();
 		return -ENOMEM;
 	}
 	for (i = 0; !files->name || files->name[0]; i++, files++) {
@@ -469,10 +475,12 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files
 		d_add(dentry, inode);
 	}
 	s->s_root = root;
+	unlock_kernel();
 	return 0;
 out:
 	d_genocide(root);
 	dput(root);
+	unlock_kernel();
 	return -ENOMEM;
 }
 
diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index 74ea82d..b8aa0a6 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -147,9 +147,13 @@ static int minix_fill_super(struct super_block *s, void *data, int silent)
 	struct minix_sb_info *sbi;
 	int ret = -EINVAL;
 
+	lock_kernel();
+
 	sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	s->s_fs_info = sbi;
 
 	BUILD_BUG_ON(32 != sizeof (struct minix_inode));
@@ -265,6 +269,7 @@ static int minix_fill_super(struct super_block *s, void *data, int silent)
  	else if (sbi->s_mount_state & MINIX_ERROR_FS)
 		printk("MINIX-fs: mounting file system with errors, "
 			"running fsck is recommended\n");
+	unlock_kernel();
 	return 0;
 
 out_iput:
@@ -314,6 +319,7 @@ out_bad_sb:
 out:
 	s->s_fs_info = NULL;
 	kfree(sbi);
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/namespace.c b/fs/namespace.c
index bdc3cb4..3f95497 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1647,9 +1647,7 @@ static int do_new_mount(struct path *path, char *type, int flags,
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	lock_kernel();
 	mnt = do_kern_mount(type, flags, name, data);
-	unlock_kernel();
 	if (IS_ERR(mnt))
 		return PTR_ERR(mnt);
 
diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index cf98da1..a020d86 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -445,10 +445,14 @@ static int ncp_fill_super(struct super_block *sb, void *raw_data, int silent)
 #endif
 	struct ncp_entry_info finfo;
 
+	lock_kernel();
+
 	data.wdog_pid = NULL;
 	server = kzalloc(sizeof(struct ncp_server), GFP_KERNEL);
-	if (!server)
+	if (!server) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	sb->s_fs_info = server;
 
 	error = -EFAULT;
@@ -695,6 +699,7 @@ static int ncp_fill_super(struct super_block *sb, void *raw_data, int silent)
         if (!sb->s_root)
 		goto out_no_root;
 	sb->s_root->d_op = &ncp_root_dentry_operations;
+	unlock_kernel();
 	return 0;
 
 out_no_root:
@@ -729,6 +734,7 @@ out:
 	put_pid(data.wdog_pid);
 	sb->s_fs_info = NULL;
 	kfree(server);
+	unlock_kernel();
 	return error;
 }
 
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 90be551..1f97aad 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1877,6 +1877,8 @@ nfs_remount(struct super_block *sb, int *flags, char *raw_data)
 					   options->version <= 6))))
 		return 0;
 
+	lock_kernel();
+
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (data == NULL)
 		return -ENOMEM;
@@ -2184,6 +2186,7 @@ out:
 out_free_fh:
 	kfree(mntfh);
 	kfree(data);
+	unlock_kernel();
 	return error;
 
 out_err_nosb:
@@ -2227,6 +2230,8 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
 	};
 	int error;
 
+	lock_kernel();
+
 	dprintk("--> nfs_xdev_get_sb()\n");
 
 	/* create a new volume representation */
@@ -2281,17 +2286,20 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
 	security_sb_clone_mnt_opts(data->sb, s);
 
 	dprintk("<-- nfs_xdev_get_sb() = 0\n");
+	unlock_kernel();
 	return 0;
 
 out_err_nosb:
 	nfs_free_server(server);
 out_err_noserver:
 	dprintk("<-- nfs_xdev_get_sb() = %d [error]\n", error);
+	unlock_kernel();
 	return error;
 
 error_splat_super:
 	deactivate_locked_super(s);
 	dprintk("<-- nfs_xdev_get_sb() = %d [splat]\n", error);
+	unlock_kernel();
 	return error;
 }
 
@@ -2475,6 +2483,8 @@ static int nfs4_remote_get_sb(struct file_system_type *fs_type,
 	};
 	int error = -ENOMEM;
 
+	lock_kernel();
+
 	mntfh = kzalloc(sizeof(*mntfh), GFP_KERNEL);
 	if (data == NULL || mntfh == NULL)
 		goto out_free_fh;
@@ -2534,6 +2544,7 @@ out:
 	security_free_mnt_opts(&data->lsm_opts);
 out_free_fh:
 	kfree(mntfh);
+	unlock_kernel();
 	return error;
 
 out_free:
@@ -2794,6 +2805,8 @@ static int nfs4_remote_referral_get_sb(struct file_system_type *fs_type,
 	};
 	int error;
 
+	lock_kernel();
+
 	dprintk("--> nfs4_referral_get_sb()\n");
 
 	/* create a new volume representation */
@@ -2847,17 +2860,20 @@ static int nfs4_remote_referral_get_sb(struct file_system_type *fs_type,
 	security_sb_clone_mnt_opts(data->sb, s);
 
 	dprintk("<-- nfs4_referral_get_sb() = 0\n");
+	unlock_kernel();
 	return 0;
 
 out_err_nosb:
 	nfs_free_server(server);
 out_err_noserver:
 	dprintk("<-- nfs4_referral_get_sb() = %d [error]\n", error);
+	unlock_kernel();
 	return error;
 
 error_splat_super:
 	deactivate_locked_super(s);
 	dprintk("<-- nfs4_referral_get_sb() = %d [splat]\n", error);
+	unlock_kernel();
 	return error;
 }
 
@@ -2873,6 +2889,8 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type,
 	struct vfsmount *root_mnt;
 	int error;
 
+	lock_kernel();
+
 	dprintk("--> nfs4_referral_get_sb()\n");
 
 	export_path = data->mnt_path;
@@ -2890,6 +2908,7 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type,
 out:
 	dprintk("<-- nfs4_referral_get_sb() = %d%s\n", error,
 			error != 0 ? " [error]" : "");
+	unlock_kernel();
 	return error;
 }
 
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 5c01fc1..dcaef52 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1347,7 +1347,12 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
 #endif
 		/* last one */ {""}
 	};
-	return simple_fill_super(sb, 0x6e667364, nfsd_files);
+	int ret;
+
+	lock_kernel();
+	ret = simple_fill_super(sb, 0x6e667364, nfsd_files);
+	unlock_kernel();
+	return ret;
 }
 
 static int nfsd_get_sb(struct file_system_type *fs_type,
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 644e667..3448ec3 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -1059,9 +1059,13 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
 	struct the_nilfs *nilfs;
 	int err, need_to_close = 1;
 
+	lock_kernel();
+
 	sd.bdev = open_bdev_exclusive(dev_name, flags, fs_type);
-	if (IS_ERR(sd.bdev))
+	if (IS_ERR(sd.bdev)) {
+		unlock_kernel();
 		return PTR_ERR(sd.bdev);
+	}
 
 	/*
 	 * To get mount instance using sget() vfs-routine, NILFS needs
@@ -1142,6 +1146,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
 	if (need_to_close)
 		close_bdev_exclusive(sd.bdev, flags);
 	simple_set_mnt(mnt, s);
+	unlock_kernel();
 	return 0;
 
  failed_unlock:
@@ -1150,6 +1155,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
  failed:
 	close_bdev_exclusive(sd.bdev, flags);
 
+	unlock_kernel();
 	return err;
 
  cancel_new:
@@ -1163,6 +1169,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
 	 * We must finish all post-cleaning before this call;
 	 * put_nilfs() needs the block device.
 	 */
+	unlock_kernel();
 	return err;
 }
 
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 80b0477..ab09c02 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -2723,6 +2723,8 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
 	struct inode *tmp_ino;
 	int blocksize, result;
 
+	lock_kernel();
+
 	/*
 	 * We do a pretty difficult piece of bootstrap by reading the
 	 * MFT (and other metadata) from disk into memory. We'll only
@@ -2746,6 +2748,7 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
 			ntfs_error(sb, "Allocation of NTFS volume structure "
 					"failed. Aborting mount...");
 		lockdep_on();
+		unlock_kernel();
 		return -ENOMEM;
 	}
 	/* Initialize ntfs_volume structure. */
@@ -2933,6 +2936,7 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
 		sb->s_export_op = &ntfs_export_ops;
 		lock_kernel();
 		lockdep_on();
+		unlock_kernel();
 		return 0;
 	}
 	ntfs_error(sb, "Failed to allocate root directory.");
@@ -3053,6 +3057,7 @@ err_out_now:
 	kfree(vol);
 	ntfs_debug("Failed, returning -EINVAL.");
 	lockdep_on();
+	unlock_kernel();
 	return -EINVAL;
 }
 
diff --git a/fs/ocfs2/dlm/dlmfs.c b/fs/ocfs2/dlm/dlmfs.c
index 02bf178..58ce813 100644
--- a/fs/ocfs2/dlm/dlmfs.c
+++ b/fs/ocfs2/dlm/dlmfs.c
@@ -528,21 +528,27 @@ static int dlmfs_fill_super(struct super_block * sb,
 	struct inode * inode;
 	struct dentry * root;
 
+	lock_kernel();
+
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = DLMFS_MAGIC;
 	sb->s_op = &dlmfs_ops;
 	inode = dlmfs_get_root_inode(sb);
-	if (!inode)
+	if (!inode) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	root = d_alloc_root(inode);
 	if (!root) {
 		iput(inode);
+		unlock_kernel();
 		return -ENOMEM;
 	}
 	sb->s_root = root;
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index c0e48ae..fab815f 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -986,6 +986,8 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 	char nodestr[8];
 	struct ocfs2_blockcheck_stats stats;
 
+	lock_kernel();
+
 	mlog_entry("%p, %p, %i", sb, data, silent);
 
 	if (!ocfs2_parse_options(sb, data, &parsed_options, 0)) {
@@ -1172,6 +1174,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 			atomic_set(&osb->vol_state, VOLUME_DISABLED);
 			wake_up(&osb->osb_mount_event);
 			mlog_exit(status);
+			unlock_kernel();
 			return status;
 		}
 	}
@@ -1186,6 +1189,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 	ocfs2_orphan_scan_start(osb);
 
 	mlog_exit(status);
+	unlock_kernel();
 	return status;
 
 read_super_error:
@@ -1201,6 +1205,7 @@ read_super_error:
 	}
 
 	mlog_exit(status);
+	unlock_kernel();
 	return status;
 }
 
diff --git a/fs/omfs/inode.c b/fs/omfs/inode.c
index f3b7c15..ddfbb22 100644
--- a/fs/omfs/inode.c
+++ b/fs/omfs/inode.c
@@ -416,11 +416,15 @@ static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 	sector_t start;
 	int ret = -EINVAL;
 
+	lock_kernel();
+
 	save_mount_options(sb, (char *) data);
 
 	sbi = kzalloc(sizeof(struct omfs_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	sb->s_fs_info = sbi;
 
@@ -525,6 +529,7 @@ out_brelse_bh2:
 out_brelse_bh:
 	brelse(bh);
 end:
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/openpromfs/inode.c b/fs/openpromfs/inode.c
index ffcd04f..50dc4be 100644
--- a/fs/openpromfs/inode.c
+++ b/fs/openpromfs/inode.c
@@ -386,6 +386,8 @@ static int openprom_fill_super(struct super_block *s, void *data, int silent)
 	struct op_inode_info *oi;
 	int ret;
 
+	lock_kernel();
+
 	s->s_flags |= MS_NOATIME;
 	s->s_blocksize = 1024;
 	s->s_blocksize_bits = 10;
@@ -405,6 +407,7 @@ static int openprom_fill_super(struct super_block *s, void *data, int silent)
 	s->s_root = d_alloc_root(root_inode);
 	if (!s->s_root)
 		goto out_no_root_dentry;
+	unlock_kernel();
 	return 0;
 
 out_no_root_dentry:
@@ -412,6 +415,7 @@ out_no_root_dentry:
 	ret = -ENOMEM;
 out_no_root:
 	printk("openprom_fill_super: get root inode failed\n");
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/proc/root.c b/fs/proc/root.c
index b080b79..6384680 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -18,6 +18,7 @@
 #include <linux/bitops.h>
 #include <linux/mount.h>
 #include <linux/pid_namespace.h>
+#include <linux/smp_lock.h> /* For lock_kernel() only */
 
 #include "internal.h"
 
@@ -43,6 +44,8 @@ static int proc_get_sb(struct file_system_type *fs_type,
 	struct pid_namespace *ns;
 	struct proc_inode *ei;
 
+	lock_kernel();
+
 	if (proc_mnt) {
 		/* Seed the root directory with a pid so it doesn't need
 		 * to be special in base.c.  I would do this earlier but
@@ -60,14 +63,17 @@ static int proc_get_sb(struct file_system_type *fs_type,
 		ns = current->nsproxy->pid_ns;
 
 	sb = sget(fs_type, proc_test_super, proc_set_super, ns);
-	if (IS_ERR(sb))
+	if (IS_ERR(sb)) {
+		unlock_kernel();
 		return PTR_ERR(sb);
+	}
 
 	if (!sb->s_root) {
 		sb->s_flags = flags;
 		err = proc_fill_super(sb);
 		if (err) {
 			deactivate_locked_super(sb);
+			unlock_kernel();
 			return err;
 		}
 
@@ -83,6 +89,7 @@ static int proc_get_sb(struct file_system_type *fs_type,
 	}
 
 	simple_set_mnt(mnt, sb);
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/fs/qnx4/inode.c b/fs/qnx4/inode.c
index d2cd179..18640ce 100644
--- a/fs/qnx4/inode.c
+++ b/fs/qnx4/inode.c
@@ -253,9 +253,13 @@ static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 	struct qnx4_sb_info *qs;
 	int ret = -EINVAL;
 
+	lock_kernel();
+
 	qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
-	if (!qs)
+	if (!qs) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 	s->s_fs_info = qs;
 
 	sb_set_blocksize(s, QNX4_BLOCK_SIZE);
@@ -303,6 +307,7 @@ static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 
 	brelse(bh);
 
+	unlock_kernel();
 	return 0;
 
       outi:
@@ -312,6 +317,7 @@ static int qnx4_fill_super(struct super_block *s, void *data, int silent)
       outnobh:
 	kfree(qs);
 	s->s_fs_info = NULL;
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index a6090aa..9b3983f 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -35,6 +35,7 @@
 #include <linux/sched.h>
 #include <linux/parser.h>
 #include <linux/magic.h>
+#include <linux/smp_lock.h> /* Only for lock_kernel() */
 #include <asm/uaccess.h>
 #include "internal.h"
 
@@ -220,6 +221,8 @@ static int ramfs_fill_super(struct super_block * sb, void * data, int silent)
 	struct dentry *root;
 	int err;
 
+	lock_kernel();
+
 	save_mount_options(sb, data);
 
 	fsi = kzalloc(sizeof(struct ramfs_fs_info), GFP_KERNEL);
@@ -253,11 +256,13 @@ static int ramfs_fill_super(struct super_block * sb, void * data, int silent)
 		goto fail;
 	}
 
+	unlock_kernel();
 	return 0;
 fail:
 	kfree(fsi);
 	sb->s_fs_info = NULL;
 	iput(inode);
+	unlock_kernel();
 	return err;
 }
 
diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index f0ad05f..f32bf62 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -1608,6 +1608,8 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 	char *qf_names[MAXQUOTAS] = {};
 	unsigned int qfmt = 0;
 
+	lock_kernel();
+
 	save_mount_options(s, data);
 
 	sbi = kzalloc(sizeof(struct reiserfs_sb_info), GFP_KERNEL);
@@ -1852,6 +1854,7 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 	init_waitqueue_head(&(sbi->s_wait));
 	spin_lock_init(&sbi->bitmap_lock);
 
+	unlock_kernel();
 	return (0);
 
 error:
@@ -1872,6 +1875,7 @@ error:
 	kfree(sbi);
 
 	s->s_fs_info = NULL;
+	unlock_kernel();
 	return errval;
 }
 
diff --git a/fs/romfs/super.c b/fs/romfs/super.c
index c117fa8..7342617 100644
--- a/fs/romfs/super.c
+++ b/fs/romfs/super.c
@@ -468,6 +468,8 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 	size_t len;
 	int ret;
 
+	lock_kernel();
+
 #ifdef CONFIG_BLOCK
 	if (!sb->s_mtd) {
 		sb_set_blocksize(sb, ROMBSIZE);
@@ -484,8 +486,10 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	/* read the image superblock and check it */
 	rsb = kmalloc(512, GFP_KERNEL);
-	if (!rsb)
+	if (!rsb) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	sb->s_fs_info = (void *) 512;
 	ret = romfs_dev_read(sb, 0, rsb, 512);
@@ -535,15 +539,18 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 	if (!sb->s_root)
 		goto error_i;
 
+	unlock_kernel();
 	return 0;
 
 error_i:
 	iput(root);
 error:
+	unlock_kernel();
 	return -EINVAL;
 error_rsb_inval:
 	ret = -EINVAL;
 error_rsb:
+	unlock_kernel();
 	return ret;
 }
 
diff --git a/fs/smbfs/inode.c b/fs/smbfs/inode.c
index 1c4c8f0..c3c9044 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -500,6 +500,8 @@ static int smb_fill_super(struct super_block *sb, void *raw_data, int silent)
 	void *mem;
 	static int warn_count;
 
+	lock_kernel();
+
 	if (warn_count < 5) {
 		warn_count++;
 		printk(KERN_EMERG "smbfs is deprecated and will be removed"
@@ -615,6 +617,7 @@ static int smb_fill_super(struct super_block *sb, void *raw_data, int silent)
 
 	smb_new_dentry(sb->s_root);
 
+	unlock_kernel();
 	return 0;
 
 out_no_root:
@@ -635,9 +638,11 @@ out_wrong_data:
 out_no_data:
 	printk(KERN_ERR "smb_fill_super: missing data argument\n");
 out_fail:
+	unlock_kernel();
 	return -EINVAL;
 out_no_server:
 	printk(KERN_ERR "smb_fill_super: cannot allocate struct smb_sb_info\n");
+	unlock_kernel();
 	return -ENOMEM;
 }
 
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 6c197ef..23cea83 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -78,11 +78,14 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 	u64 lookup_table_start;
 	int err;
 
+	lock_kernel();
+
 	TRACE("Entered squashfs_fill_superblock\n");
 
 	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
 	if (sb->s_fs_info == NULL) {
 		ERROR("Failed to allocate squashfs_sb_info\n");
+		unlock_kernel();
 		return -ENOMEM;
 	}
 	msblk = sb->s_fs_info;
@@ -286,6 +289,7 @@ allocate_root:
 
 	TRACE("Leaving squashfs_fill_super\n");
 	kfree(sblk);
+	unlock_kernel();
 	return 0;
 
 failed_mount:
@@ -299,12 +303,14 @@ failed_mount:
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
 	kfree(sblk);
+	unlock_kernel();
 	return err;
 
 failure:
 	kfree(msblk->stream.workspace);
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
+	unlock_kernel();
 	return -ENOMEM;
 }
 
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 4974995..2e5a870 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -18,6 +18,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/magic.h>
+#include <linux/smp_lock.h> /* Only for lock_kernel() */
 
 #include "sysfs.h"
 
@@ -45,6 +46,8 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
 	struct inode *inode;
 	struct dentry *root;
 
+	lock_kernel();
+
 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = SYSFS_MAGIC;
@@ -58,6 +61,7 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
 	mutex_unlock(&sysfs_mutex);
 	if (!inode) {
 		pr_debug("sysfs: could not get root inode\n");
+		unlock_kernel();
 		return -ENOMEM;
 	}
 
@@ -66,10 +70,12 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
 	if (!root) {
 		pr_debug("%s: could not get root dentry!\n",__func__);
 		iput(inode);
+		unlock_kernel();
 		return -ENOMEM;
 	}
 	root->d_fsdata = &sysfs_root;
 	sb->s_root = root;
+	unlock_kernel();
 	return 0;
 }
 
diff --git a/fs/sysv/super.c b/fs/sysv/super.c
index 5a903da..145d949 100644
--- a/fs/sysv/super.c
+++ b/fs/sysv/super.c
@@ -357,7 +357,9 @@ static int sysv_fill_super(struct super_block *sb, void *data, int silent)
 	struct sysv_sb_info *sbi;
 	unsigned long blocknr;
 	int size = 0, i;
-	
+
+	lock_kernel();
+
 	BUILD_BUG_ON(1024 != sizeof (struct xenix_super_block));
 	BUILD_BUG_ON(512 != sizeof (struct sysv4_super_block));
 	BUILD_BUG_ON(512 != sizeof (struct sysv2_super_block));
@@ -365,8 +367,10 @@ static int sysv_fill_super(struct super_block *sb, void *data, int silent)
 	BUILD_BUG_ON(64 != sizeof (struct sysv_inode));
 
 	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	sbi->s_sb = sb;
 	sbi->s_block_base = 0;
@@ -409,8 +413,10 @@ static int sysv_fill_super(struct super_block *sb, void *data, int silent)
 	if (bh && bh1) {
 		sbi->s_bh1 = bh1;
 		sbi->s_bh2 = bh;
-		if (complete_read_super(sb, silent, size))
+		if (complete_read_super(sb, silent, size)) {
+			unlock_kernel();
 			return 0;
+		}
 	}
 
 	brelse(bh1);
@@ -419,6 +425,7 @@ static int sysv_fill_super(struct super_block *sb, void *data, int silent)
 	printk("oldfs: cannot read superblock\n");
 failed:
 	kfree(sbi);
+	unlock_kernel();
 	return -EINVAL;
 
 Eunknown:
@@ -442,14 +449,18 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
 	struct v7_super_block *v7sb;
 	struct sysv_inode *v7i;
 
+	lock_kernel();
+
 	if (440 != sizeof (struct v7_super_block))
 		panic("V7 FS: bad super-block size");
 	if (64 != sizeof (struct sysv_inode))
 		panic("sysv fs: bad i-node size");
 
 	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	sbi->s_sb = sb;
 	sbi->s_block_base = 0;
@@ -487,13 +498,16 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
 
 	sbi->s_bh1 = bh;
 	sbi->s_bh2 = bh;
-	if (complete_read_super(sb, silent, 1))
+	if (complete_read_super(sb, silent, 1)) {
+		unlock_kernel();
 		return 0;
+	}
 
 failed:
 	brelse(bh2);
 	brelse(bh);
 	kfree(sbi);
+	unlock_kernel();
 	return -EINVAL;
 }
 
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 333e181..04a0fc9 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2029,6 +2029,8 @@ static int ubifs_get_sb(struct file_system_type *fs_type, int flags,
 	struct super_block *sb;
 	int err;
 
+	lock_kernel();
+
 	dbg_gen("name %s, flags %#x", name, flags);
 
 	/*
@@ -2040,6 +2042,7 @@ static int ubifs_get_sb(struct file_system_type *fs_type, int flags,
 	if (IS_ERR(ubi)) {
 		ubifs_err("cannot open \"%s\", error %d",
 			  name, (int)PTR_ERR(ubi));
+		unlock_kernel();
 		return PTR_ERR(ubi);
 	}
 	ubi_get_volume_info(ubi, &vi);
@@ -2077,12 +2080,14 @@ static int ubifs_get_sb(struct file_system_type *fs_type, int flags,
 	ubi_close_volume(ubi);
 
 	simple_set_mnt(mnt, sb);
+	unlock_kernel();
 	return 0;
 
 out_deact:
 	deactivate_locked_super(sb);
 out_close:
 	ubi_close_volume(ubi);
+	unlock_kernel();
 	return err;
 }
 
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 9d1b8c2..fa6f8db 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1866,6 +1866,8 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
 	struct kernel_lb_addr rootdir, fileset;
 	struct udf_sb_info *sbi;
 
+	lock_kernel();
+
 	uopt.flags = (1 << UDF_FLAG_USE_AD_IN_ICB) | (1 << UDF_FLAG_STRICT);
 	uopt.uid = -1;
 	uopt.gid = -1;
@@ -1874,8 +1876,10 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
 	uopt.dmode = UDF_INVALID_MODE;
 
 	sbi = kzalloc(sizeof(struct udf_sb_info), GFP_KERNEL);
-	if (!sbi)
+	if (!sbi) {
+		unlock_kernel();
 		return -ENOMEM;
+	}
 
 	sb->s_fs_info = sbi;
 
@@ -2021,6 +2025,7 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
 		goto error_out;
 	}
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	unlock_kernel();
 	return 0;
 
 error_out:
@@ -2041,6 +2046,7 @@ error_out:
 	kfree(sbi);
 	sb->s_fs_info = NULL;
 
+	unlock_kernel();
 	return -EINVAL;
 }
 
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 5faed79..31ad198 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -646,6 +646,8 @@ static int ufs_fill_super(struct super_block *sb, void *data, int silent)
 	unsigned maxsymlen;
 	int ret = -EINVAL;
 
+	lock_kernel();
+
 	uspi = NULL;
 	ubh = NULL;
 	flags = 0;
@@ -1107,6 +1109,7 @@ magic_found:
 			goto failed;
 
 	UFSD("EXIT\n");
+	unlock_kernel();
 	return 0;
 
 dalloc_failed:
@@ -1118,10 +1121,12 @@ failed:
 	kfree(sbi);
 	sb->s_fs_info = NULL;
 	UFSD("EXIT (FAILED)\n");
+	unlock_kernel();
 	return ret;
 
 failed_nomem:
 	UFSD("EXIT (NOMEM)\n");
+	unlock_kernel();
 	return -ENOMEM;
 }
 
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 18a4b8e..7426166 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1412,6 +1412,8 @@ xfs_fs_fill_super(
 	int			flags = 0, error = ENOMEM;
 	char			*mtpt = NULL;
 
+	lock_kernel();
+
 	mp = kzalloc(sizeof(struct xfs_mount), GFP_KERNEL);
 	if (!mp)
 		goto out;
@@ -1506,6 +1508,7 @@ xfs_fs_fill_super(
 	kfree(mtpt);
 
 	xfs_itrace_exit(XFS_I(sb->s_root->d_inode));
+	unlock_kernel();
 	return 0;
 
  out_filestream_unmount:
@@ -1522,6 +1525,7 @@ xfs_fs_fill_super(
 	kfree(mtpt);
 	kfree(mp);
  out:
+	unlock_kernel();
 	return -error;
 
  fail_vnrele:
-- 
1.6.4.2


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

[PATCH 04/27] ext2: Add ext2_sb_info mutex

[Jan Blunck]

Add a mutex that protects the ext2_sb_info from concurrent modifications.
This is a preparation for removing the BKL later.

Signed-off-by: Jan Blunck <jblunck@suse.de>
---
 fs/ext2/inode.c            |    2 ++
 fs/ext2/super.c            |   30 +++++++++++++++++++++++++++---
 include/linux/ext2_fs_sb.h |    2 ++
 3 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index ade6340..057074e 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1401,9 +1401,11 @@ int ext2_write_inode(struct inode *inode, int do_sync)
 				* created, add a flag to the superblock.
 				*/
 				lock_kernel();
+				mutex_lock(&EXT2_SB(sb)->s_mutex);
 				ext2_update_dynamic_rev(sb);
 				EXT2_SET_RO_COMPAT_FEATURE(sb,
 					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
+				mutex_unlock(&EXT2_SB(sb)->s_mutex);
 				unlock_kernel();
 				ext2_write_super(sb);
 			}
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 5af1775..d610eb9 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -84,6 +84,9 @@ void ext2_warning (struct super_block * sb, const char * function,
 	va_end(args);
 }
 
+/*
+ * This must be called with sbi->s_mutex held.
+ */
 void ext2_update_dynamic_rev(struct super_block *sb)
 {
 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
@@ -117,8 +120,8 @@ static void ext2_put_super (struct super_block * sb)
 
 	lock_kernel();
 
-	if (sb->s_dirt)
-		ext2_write_super(sb);
+	if (sb->s_dirt && !(sb->s_flags & MS_RDONLY))
+		ext2_sync_fs(sb, 1);
 
 	ext2_xattr_put_super(sb);
 	if (!(sb->s_flags & MS_RDONLY)) {
@@ -207,6 +210,7 @@ static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 	struct ext2_super_block *es = sbi->s_es;
 	unsigned long def_mount_opts;
 
+	mutex_lock(&sbi->s_mutex);
 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 
 	if (sbi->s_sb_block != 1)
@@ -279,6 +283,7 @@ static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 	if (!test_opt(sb, RESERVATION))
 		seq_puts(seq, ",noreservation");
 
+	mutex_unlock(&sbi->s_mutex);
 	return 0;
 }
 
@@ -762,6 +767,12 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->s_sb_block = sb_block;
 
 	/*
+	 * mutex for protection of modifications of the superblock while being
+	 * write out by ext2_write_super() or ext2_sync_fs().
+	 */
+	mutex_init(&sbi->s_mutex);
+
+	/*
 	 * See what the current blocksize for the device is, and
 	 * use that as the blocksize.  Otherwise (or if the blocksize
 	 * is smaller than the default) use the default.
@@ -1122,8 +1133,9 @@ static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
  * flags to 0.  We need to set this flag to 0 since the fs
  * may have been checked while mounted and e2fsck may have
  * set s_state to EXT2_VALID_FS after some corrections.
+ *
+ * This must be called with sbi->s_mutex held.
  */
-
 static int ext2_sync_fs(struct super_block *sb, int wait)
 {
 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
@@ -1150,10 +1162,14 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
 
 void ext2_write_super(struct super_block *sb)
 {
+	struct ext2_sb_info * sbi = EXT2_SB(sb);
+
+	mutex_lock(&sbi->s_mutex);
 	if (!(sb->s_flags & MS_RDONLY))
 		ext2_sync_fs(sb, 1);
 	else
 		sb->s_dirt = 0;
+	mutex_unlock(&sbi->s_mutex);
 }
 
 static int ext2_remount (struct super_block * sb, int * flags, char * data)
@@ -1166,6 +1182,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 	int err;
 
 	lock_kernel();
+	mutex_lock(&sbi->s_mutex);
 
 	/* Store the old options */
 	old_sb_flags = sb->s_flags;
@@ -1203,12 +1220,14 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 		sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
 	}
 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
+		mutex_unlock(&sbi->s_mutex);
 		unlock_kernel();
 		return 0;
 	}
 	if (*flags & MS_RDONLY) {
 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 		    !(sbi->s_mount_state & EXT2_VALID_FS)) {
+			mutex_unlock(&sbi->s_mutex);
 			unlock_kernel();
 			return 0;
 		}
@@ -1238,6 +1257,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 			sb->s_flags &= ~MS_RDONLY;
 	}
 	ext2_sync_super(sb, es);
+	mutex_unlock(&sbi->s_mutex);
 	unlock_kernel();
 	return 0;
 restore_opts:
@@ -1245,6 +1265,7 @@ restore_opts:
 	sbi->s_resuid = old_opts.s_resuid;
 	sbi->s_resgid = old_opts.s_resgid;
 	sb->s_flags = old_sb_flags;
+	mutex_unlock(&sbi->s_mutex);
 	unlock_kernel();
 	return err;
 }
@@ -1256,6 +1277,8 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
 	struct ext2_super_block *es = sbi->s_es;
 	u64 fsid;
 
+	mutex_lock(&sbi->s_mutex);
+
 	if (test_opt (sb, MINIX_DF))
 		sbi->s_overhead_last = 0;
 	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
@@ -1310,6 +1333,7 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
+	mutex_unlock(&sbi->s_mutex);
 	return 0;
 }
 
diff --git a/include/linux/ext2_fs_sb.h b/include/linux/ext2_fs_sb.h
index 1cdb663..8518361 100644
--- a/include/linux/ext2_fs_sb.h
+++ b/include/linux/ext2_fs_sb.h
@@ -106,6 +106,8 @@ struct ext2_sb_info {
 	spinlock_t s_rsv_window_lock;
 	struct rb_root s_rsv_window_root;
 	struct ext2_reserve_window_node s_rsv_window_head;
+	/* protect against concurrent modifications of this structure */
+	struct mutex s_mutex;
 };
 
 static inline spinlock_t *
-- 
1.6.4.2

Re: [PATCH 04/27] ext2: Add ext2_sb_info mutex

[Andi Kleen]

> @@ -762,6 +767,12 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
>  	sbi->s_sb_block = sb_block;
>  
>  	/*
> +	 * mutex for protection of modifications of the superblock while being
> +	 * write out by ext2_write_super() or ext2_sync_fs().
> +	 */
> +	mutex_init(&sbi->s_mutex);

I didn't go over all the code paths in detail, but if you replace
the BKL with a mutex that is hold over a longer write-out sleep
period you potentially limit IO parallelism a lot.

In this case since the BKL didn't protect over the sleep anyways it might
be reasonable to drop it during the IO operation (and possibly if
you're sure nothing else sleeps use a spin lock)

-Andi

Re: [PATCH 04/27] ext2: Add ext2_sb_info mutex

[Jan Blunck]

[-- Attachment #1: Type: text/plain, Size: 672 bytes --]

On Mon, Nov 02, Andi Kleen wrote:

> > @@ -762,6 +767,12 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
> >  	sbi->s_sb_block = sb_block;
> >  
> >  	/*
> > +	 * mutex for protection of modifications of the superblock while being
> > +	 * write out by ext2_write_super() or ext2_sync_fs().
> > +	 */
> > +	mutex_init(&sbi->s_mutex);
> 
> I didn't go over all the code paths in detail, but if you replace
> the BKL with a mutex that is hold over a longer write-out sleep
> period you potentially limit IO parallelism a lot.

Right. I converted it to be a spinlock and unlock before calling
ext2_sync_super().

What do you think?

Thanks,
Jan

[-- Attachment #2: 0005-ext2-Add-ext2_sb_info-spinlock.patch --]
[-- Type: text/x-patch, Size: 7270 bytes --]

>From d70afd90149d0318c0fe51d05aaebe24c7def96a Mon Sep 17 00:00:00 2001
From: Jan Blunck <jblunck@suse.de>
Date: Mon, 2 Nov 2009 17:20:28 +0100
Subject: [PATCH 05/28] ext2: Add ext2_sb_info spinlock

Add a spinlock that protects the ext2_sb_info from concurrent modifications.
This is a preparation for removing the BKL later.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
---
 fs/ext2/inode.c            |    2 ++
 fs/ext2/super.c            |   41 ++++++++++++++++++++++++++++++++++++-----
 include/linux/ext2_fs_sb.h |    2 ++
 3 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index ade6340..65a0d4b 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1401,9 +1401,11 @@ int ext2_write_inode(struct inode *inode, int do_sync)
 				* created, add a flag to the superblock.
 				*/
 				lock_kernel();
+				spin_lock(&EXT2_SB(sb)->s_lock);
 				ext2_update_dynamic_rev(sb);
 				EXT2_SET_RO_COMPAT_FEATURE(sb,
 					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
+				spin_unlock(&EXT2_SB(sb)->s_lock);
 				unlock_kernel();
 				ext2_write_super(sb);
 			}
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 5af1775..70c326c 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -52,8 +52,10 @@ void ext2_error (struct super_block * sb, const char * function,
 	struct ext2_super_block *es = sbi->s_es;
 
 	if (!(sb->s_flags & MS_RDONLY)) {
+		spin_lock(&sbi->s_lock);
 		sbi->s_mount_state |= EXT2_ERROR_FS;
 		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
+		/* drops sbi->s_lock */
 		ext2_sync_super(sb, es);
 	}
 
@@ -84,6 +86,9 @@ void ext2_warning (struct super_block * sb, const char * function,
 	va_end(args);
 }
 
+/*
+ * This must be called with sbi->s_lock held.
+ */
 void ext2_update_dynamic_rev(struct super_block *sb)
 {
 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
@@ -117,14 +122,16 @@ static void ext2_put_super (struct super_block * sb)
 
 	lock_kernel();
 
-	if (sb->s_dirt)
-		ext2_write_super(sb);
+	if (sb->s_dirt && !(sb->s_flags & MS_RDONLY))
+		ext2_sync_fs(sb, 1);
 
 	ext2_xattr_put_super(sb);
 	if (!(sb->s_flags & MS_RDONLY)) {
 		struct ext2_super_block *es = sbi->s_es;
 
+		spin_lock(&sbi->s_lock);
 		es->s_state = cpu_to_le16(sbi->s_mount_state);
+		/* drops sbi->s_lock */
 		ext2_sync_super(sb, es);
 	}
 	db_count = sbi->s_gdb_count;
@@ -207,6 +214,7 @@ static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 	struct ext2_super_block *es = sbi->s_es;
 	unsigned long def_mount_opts;
 
+	spin_lock(&sbi->s_lock);
 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 
 	if (sbi->s_sb_block != 1)
@@ -279,6 +287,7 @@ static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 	if (!test_opt(sb, RESERVATION))
 		seq_puts(seq, ",noreservation");
 
+	spin_unlock(&sbi->s_lock);
 	return 0;
 }
 
@@ -762,6 +771,12 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->s_sb_block = sb_block;
 
 	/*
+	 * mutex for protection of modifications of the superblock while being
+	 * write out by ext2_write_super() or ext2_sync_fs().
+	 */
+	spin_lock_init(&sbi->s_lock);
+
+	/*
 	 * See what the current blocksize for the device is, and
 	 * use that as the blocksize.  Otherwise (or if the blocksize
 	 * is smaller than the default) use the default.
@@ -1103,11 +1118,14 @@ static void ext2_commit_super (struct super_block * sb,
 	sb->s_dirt = 0;
 }
 
-static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
+static void ext2_sync_super(struct super_block *sb,
+			    struct ext2_super_block *es)
 {
 	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 	es->s_wtime = cpu_to_le32(get_seconds());
+	/* unlock before we do IO */
+	spin_unlock(&EXT2_SB(sb)->s_lock);
 	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 	sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 	sb->s_dirt = 0;
@@ -1122,13 +1140,16 @@ static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
  * flags to 0.  We need to set this flag to 0 since the fs
  * may have been checked while mounted and e2fsck may have
  * set s_state to EXT2_VALID_FS after some corrections.
+ *
+ * This must be called with sbi->s_lock held.
  */
-
 static int ext2_sync_fs(struct super_block *sb, int wait)
 {
-	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = sbi->s_es;
 
 	lock_kernel();
+	spin_lock(&sbi->s_lock);
 	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
 		ext2_debug("setting valid to 0\n");
 		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
@@ -1137,9 +1158,11 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
 		es->s_free_inodes_count =
 			cpu_to_le32(ext2_count_free_inodes(sb));
 		es->s_mtime = cpu_to_le32(get_seconds());
+		/* drops sbi->s_lock */
 		ext2_sync_super(sb, es);
 	} else {
 		ext2_commit_super(sb, es);
+		spin_unlock(&sbi->s_lock);
 	}
 	sb->s_dirt = 0;
 	unlock_kernel();
@@ -1166,6 +1189,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 	int err;
 
 	lock_kernel();
+	spin_lock(&sbi->s_lock);
 
 	/* Store the old options */
 	old_sb_flags = sb->s_flags;
@@ -1203,12 +1227,14 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 		sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
 	}
 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
+		spin_unlock(&sbi->s_lock);
 		unlock_kernel();
 		return 0;
 	}
 	if (*flags & MS_RDONLY) {
 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 		    !(sbi->s_mount_state & EXT2_VALID_FS)) {
+			spin_unlock(&sbi->s_lock);
 			unlock_kernel();
 			return 0;
 		}
@@ -1237,6 +1263,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 		if (!ext2_setup_super (sb, es, 0))
 			sb->s_flags &= ~MS_RDONLY;
 	}
+	/* drops sbi->s_lock */
 	ext2_sync_super(sb, es);
 	unlock_kernel();
 	return 0;
@@ -1245,6 +1272,7 @@ restore_opts:
 	sbi->s_resuid = old_opts.s_resuid;
 	sbi->s_resgid = old_opts.s_resgid;
 	sb->s_flags = old_sb_flags;
+	spin_unlock(&sbi->s_lock);
 	unlock_kernel();
 	return err;
 }
@@ -1256,6 +1284,8 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
 	struct ext2_super_block *es = sbi->s_es;
 	u64 fsid;
 
+	spin_lock(&sbi->s_lock);
+
 	if (test_opt (sb, MINIX_DF))
 		sbi->s_overhead_last = 0;
 	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
@@ -1310,6 +1340,7 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
 	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
 	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
 	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
+	spin_unlock(&sbi->s_lock);
 	return 0;
 }
 
diff --git a/include/linux/ext2_fs_sb.h b/include/linux/ext2_fs_sb.h
index 1cdb663..0d20278 100644
--- a/include/linux/ext2_fs_sb.h
+++ b/include/linux/ext2_fs_sb.h
@@ -106,6 +106,8 @@ struct ext2_sb_info {
 	spinlock_t s_rsv_window_lock;
 	struct rb_root s_rsv_window_root;
 	struct ext2_reserve_window_node s_rsv_window_head;
+	/* protect against concurrent modifications of this structure */
+	spinlock_t s_lock;
 };
 
 static inline spinlock_t *
-- 
1.6.4.2

Re: [PATCH 04/27] ext2: Add ext2_sb_info mutex

[Andi Kleen]

> Right. I converted it to be a spinlock and unlock before calling
> ext2_sync_super().
> 
> What do you think?

Again didn't go through all the code paths, but it seems like a good
approach.

-Andi

Re: [PATCH 04/27] ext2: Add ext2_sb_info mutex

[Jan Kara]

On Mon 02-11-09 17:57:52, Jan Blunck wrote:
> On Mon, Nov 02, Andi Kleen wrote:
> 
> > > @@ -762,6 +767,12 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
> > >  	sbi->s_sb_block = sb_block;
> > >  
> > >  	/*
> > > +	 * mutex for protection of modifications of the superblock while being
> > > +	 * write out by ext2_write_super() or ext2_sync_fs().
> > > +	 */
> > > +	mutex_init(&sbi->s_mutex);
> > 
> > I didn't go over all the code paths in detail, but if you replace
> > the BKL with a mutex that is hold over a longer write-out sleep
> > period you potentially limit IO parallelism a lot.
> 
> Right. I converted it to be a spinlock and unlock before calling
> ext2_sync_super().
> 
> What do you think?
  The patch is generally fine. I have just a few minor comments below:

> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> index 5af1775..70c326c 100644
> --- a/fs/ext2/super.c
> +++ b/fs/ext2/super.c
> @@ -52,8 +52,10 @@ void ext2_error (struct super_block * sb, const char * function,
>  	struct ext2_super_block *es = sbi->s_es;
>  
>  	if (!(sb->s_flags & MS_RDONLY)) {
> +		spin_lock(&sbi->s_lock);
>  		sbi->s_mount_state |= EXT2_ERROR_FS;
>  		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
> +		/* drops sbi->s_lock */
>  		ext2_sync_super(sb, es);
   I don't like this dropping of spinlock inside ext2_sync_super. Can we
just drop it here and retake it in ext2_sync_super? It's by far not a
performance critical path so it should not really matter.

> diff --git a/include/linux/ext2_fs_sb.h b/include/linux/ext2_fs_sb.h
> index 1cdb663..0d20278 100644
> --- a/include/linux/ext2_fs_sb.h
> +++ b/include/linux/ext2_fs_sb.h
> @@ -106,6 +106,8 @@ struct ext2_sb_info {
>  	spinlock_t s_rsv_window_lock;
>  	struct rb_root s_rsv_window_root;
>  	struct ext2_reserve_window_node s_rsv_window_head;
> +	/* protect against concurrent modifications of this structure */
> +	spinlock_t s_lock;
>  };
  As I'm reading the code s_lock protects some of the fieds but definitely
not all. I'd say it protects s_mount_state, s_blocks_last, s_overhead_last,
and a content of superblock's buffer pointed to by sbi->s_es. The rest just
either does not change during lifetime of the filesystem or has different
locks (either s_umount semaphore or other spinlocks).

								Honza

-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

[PATCH 05/27] BKL: Remove BKL from ext2 filesystem

[Jan Blunck]

The BKL is still used in ext2_put_super(), ext2_fill_super(), ext2_sync_fs()
ext2_remount() and ext2_write_inode(). From these calls ext2_put_super(),
ext2_fill_super() and ext2_remount() are protected against each other by
the struct super_block s_umount rw semaphore. The call in ext2_write_inode()
could only protect the modification of the ext2_sb_info through
ext2_update_dynamic_rev() against concurrent ext2_sync_fs() or ext2_remount().
ext2_fill_super() and ext2_put_super() can be left out because you need a
valid filesystem reference in all three cases, which you do not have when
you are one of these functions.

If the BKL is only protecting the modification of the ext2_sb_info it can
safely be removed since this is protected by the struct ext2_sb_info s_mutex.

Signed-off-by: Jan Blunck <jblunck@suse.de>
---
 fs/ext2/inode.c |    3 ---
 fs/ext2/super.c |   16 ----------------
 2 files changed, 0 insertions(+), 19 deletions(-)

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 057074e..8b51416 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -22,7 +22,6 @@
  *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
  */
 
-#include <linux/smp_lock.h>
 #include <linux/time.h>
 #include <linux/highuid.h>
 #include <linux/pagemap.h>
@@ -1400,13 +1399,11 @@ int ext2_write_inode(struct inode *inode, int do_sync)
 			       /* If this is the first large file
 				* created, add a flag to the superblock.
 				*/
-				lock_kernel();
 				mutex_lock(&EXT2_SB(sb)->s_mutex);
 				ext2_update_dynamic_rev(sb);
 				EXT2_SET_RO_COMPAT_FEATURE(sb,
 					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
 				mutex_unlock(&EXT2_SB(sb)->s_mutex);
-				unlock_kernel();
 				ext2_write_super(sb);
 			}
 		}
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index d610eb9..7e819ac 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -26,7 +26,6 @@
 #include <linux/random.h>
 #include <linux/buffer_head.h>
 #include <linux/exportfs.h>
-#include <linux/smp_lock.h>
 #include <linux/vfs.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
@@ -118,8 +117,6 @@ static void ext2_put_super (struct super_block * sb)
 	int i;
 	struct ext2_sb_info *sbi = EXT2_SB(sb);
 
-	lock_kernel();
-
 	if (sb->s_dirt && !(sb->s_flags & MS_RDONLY))
 		ext2_sync_fs(sb, 1);
 
@@ -143,8 +140,6 @@ static void ext2_put_super (struct super_block * sb)
 	sb->s_fs_info = NULL;
 	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
-
-	unlock_kernel();
 }
 
 static struct kmem_cache * ext2_inode_cachep;
@@ -750,8 +745,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 	__le32 features;
 	int err;
 
-	lock_kernel();
-
 	err = -ENOMEM;
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
@@ -1077,7 +1070,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 		ext2_warning(sb, __func__,
 			"mounting ext3 filesystem as ext2");
 	ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
-	unlock_kernel();
 	return 0;
 
 cantfind_ext2:
@@ -1102,7 +1094,6 @@ failed_sbi:
 	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
 failed_unlock:
-	unlock_kernel();
 	return ret;
 }
 
@@ -1140,7 +1131,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
 {
 	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
 
-	lock_kernel();
 	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
 		ext2_debug("setting valid to 0\n");
 		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
@@ -1154,7 +1144,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
 		ext2_commit_super(sb, es);
 	}
 	sb->s_dirt = 0;
-	unlock_kernel();
 
 	return 0;
 }
@@ -1181,7 +1170,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 	unsigned long old_sb_flags;
 	int err;
 
-	lock_kernel();
 	mutex_lock(&sbi->s_mutex);
 
 	/* Store the old options */
@@ -1221,14 +1209,12 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 	}
 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
 		mutex_unlock(&sbi->s_mutex);
-		unlock_kernel();
 		return 0;
 	}
 	if (*flags & MS_RDONLY) {
 		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
 		    !(sbi->s_mount_state & EXT2_VALID_FS)) {
 			mutex_unlock(&sbi->s_mutex);
-			unlock_kernel();
 			return 0;
 		}
 		/*
@@ -1258,7 +1244,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
 	}
 	ext2_sync_super(sb, es);
 	mutex_unlock(&sbi->s_mutex);
-	unlock_kernel();
 	return 0;
 restore_opts:
 	sbi->s_mount_opt = old_opts.s_mount_opt;
@@ -1266,7 +1251,6 @@ restore_opts:
 	sbi->s_resgid = old_opts.s_resgid;
 	sb->s_flags = old_sb_flags;
 	mutex_unlock(&sbi->s_mutex);
-	unlock_kernel();
 	return err;
 }
 
-- 
1.6.4.2

Re: [PATCH 05/27] BKL: Remove BKL from ext2 filesystem

[Jan Kara]

On Mon 02-11-09 11:04:45, Jan Blunck wrote:
> The BKL is still used in ext2_put_super(), ext2_fill_super(), ext2_sync_fs()
> ext2_remount() and ext2_write_inode(). From these calls ext2_put_super(),
> ext2_fill_super() and ext2_remount() are protected against each other by
> the struct super_block s_umount rw semaphore. The call in ext2_write_inode()
> could only protect the modification of the ext2_sb_info through
> ext2_update_dynamic_rev() against concurrent ext2_sync_fs() or ext2_remount().
> ext2_fill_super() and ext2_put_super() can be left out because you need a
> valid filesystem reference in all three cases, which you do not have when
> you are one of these functions.
  This is not quite true. Actually, ext2_sync_fs() is called also with
s_umount held (for reading) so it cannot race with any of the mounting /
umounting functions. But it should probably be guarded against running two
instances of ext2_sync_fs() in parallel.
  Looking into the code, we probably have a race in ext2_write_inode that
two threads can write one inode in parallel. But that's a separe issue from
BKL removal.

								Honza 

> diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
> index 057074e..8b51416 100644
> --- a/fs/ext2/inode.c
> +++ b/fs/ext2/inode.c
> @@ -22,7 +22,6 @@
>   *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
>   */
>  
> -#include <linux/smp_lock.h>
>  #include <linux/time.h>
>  #include <linux/highuid.h>
>  #include <linux/pagemap.h>
> @@ -1400,13 +1399,11 @@ int ext2_write_inode(struct inode *inode, int do_sync)
>  			       /* If this is the first large file
>  				* created, add a flag to the superblock.
>  				*/
> -				lock_kernel();
>  				mutex_lock(&EXT2_SB(sb)->s_mutex);
>  				ext2_update_dynamic_rev(sb);
>  				EXT2_SET_RO_COMPAT_FEATURE(sb,
>  					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
>  				mutex_unlock(&EXT2_SB(sb)->s_mutex);
> -				unlock_kernel();
>  				ext2_write_super(sb);
>  			}
>  		}
> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> index d610eb9..7e819ac 100644
> --- a/fs/ext2/super.c
> +++ b/fs/ext2/super.c
> @@ -26,7 +26,6 @@
>  #include <linux/random.h>
>  #include <linux/buffer_head.h>
>  #include <linux/exportfs.h>
> -#include <linux/smp_lock.h>
>  #include <linux/vfs.h>
>  #include <linux/seq_file.h>
>  #include <linux/mount.h>
> @@ -118,8 +117,6 @@ static void ext2_put_super (struct super_block * sb)
>  	int i;
>  	struct ext2_sb_info *sbi = EXT2_SB(sb);
>  
> -	lock_kernel();
> -
>  	if (sb->s_dirt && !(sb->s_flags & MS_RDONLY))
>  		ext2_sync_fs(sb, 1);
>  
> @@ -143,8 +140,6 @@ static void ext2_put_super (struct super_block * sb)
>  	sb->s_fs_info = NULL;
>  	kfree(sbi->s_blockgroup_lock);
>  	kfree(sbi);
> -
> -	unlock_kernel();
>  }
>  
>  static struct kmem_cache * ext2_inode_cachep;
> @@ -750,8 +745,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
>  	__le32 features;
>  	int err;
>  
> -	lock_kernel();
> -
>  	err = -ENOMEM;
>  	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
>  	if (!sbi)
> @@ -1077,7 +1070,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
>  		ext2_warning(sb, __func__,
>  			"mounting ext3 filesystem as ext2");
>  	ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
> -	unlock_kernel();
>  	return 0;
>  
>  cantfind_ext2:
> @@ -1102,7 +1094,6 @@ failed_sbi:
>  	kfree(sbi->s_blockgroup_lock);
>  	kfree(sbi);
>  failed_unlock:
> -	unlock_kernel();
>  	return ret;
>  }
>  
> @@ -1140,7 +1131,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
>  {
>  	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
>  
> -	lock_kernel();
>  	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
>  		ext2_debug("setting valid to 0\n");
>  		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
> @@ -1154,7 +1144,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
>  		ext2_commit_super(sb, es);
>  	}
>  	sb->s_dirt = 0;
> -	unlock_kernel();
>  
>  	return 0;
>  }
> @@ -1181,7 +1170,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
>  	unsigned long old_sb_flags;
>  	int err;
>  
> -	lock_kernel();
>  	mutex_lock(&sbi->s_mutex);
>  
>  	/* Store the old options */
> @@ -1221,14 +1209,12 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
>  	}
>  	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
>  		mutex_unlock(&sbi->s_mutex);
> -		unlock_kernel();
>  		return 0;
>  	}
>  	if (*flags & MS_RDONLY) {
>  		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
>  		    !(sbi->s_mount_state & EXT2_VALID_FS)) {
>  			mutex_unlock(&sbi->s_mutex);
> -			unlock_kernel();
>  			return 0;
>  		}
>  		/*
> @@ -1258,7 +1244,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
>  	}
>  	ext2_sync_super(sb, es);
>  	mutex_unlock(&sbi->s_mutex);
> -	unlock_kernel();
>  	return 0;
>  restore_opts:
>  	sbi->s_mount_opt = old_opts.s_mount_opt;
> @@ -1266,7 +1251,6 @@ restore_opts:
>  	sbi->s_resgid = old_opts.s_resgid;
>  	sb->s_flags = old_sb_flags;
>  	mutex_unlock(&sbi->s_mutex);
> -	unlock_kernel();
>  	return err;
>  }
>  
> -- 
> 1.6.4.2
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

Re: [PATCH 05/27] BKL: Remove BKL from ext2 filesystem

[Jan Blunck]

On Thu, Nov 05, Jan Kara wrote:

> On Mon 02-11-09 11:04:45, Jan Blunck wrote:
> > The BKL is still used in ext2_put_super(), ext2_fill_super(), ext2_sync_fs()
> > ext2_remount() and ext2_write_inode(). From these calls ext2_put_super(),
> > ext2_fill_super() and ext2_remount() are protected against each other by
> > the struct super_block s_umount rw semaphore. The call in ext2_write_inode()
> > could only protect the modification of the ext2_sb_info through
> > ext2_update_dynamic_rev() against concurrent ext2_sync_fs() or ext2_remount().
> > ext2_fill_super() and ext2_put_super() can be left out because you need a
> > valid filesystem reference in all three cases, which you do not have when
> > you are one of these functions.
>   This is not quite true. Actually, ext2_sync_fs() is called also with
> s_umount held (for reading) so it cannot race with any of the mounting /
> umounting functions. But it should probably be guarded against running two
> instances of ext2_sync_fs() in parallel.
>   Looking into the code, we probably have a race in ext2_write_inode that
> two threads can write one inode in parallel. But that's a separe issue from
> BKL removal.

Have you actually seen that the previous patch introduces s_mutex? Meanwhile
that mutex has been replaced by a spinlock due to Andy's feedback.

Anyway, thanks for the review.

Cheers,
	Jan


> 								Honza 
> 
> > diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
> > index 057074e..8b51416 100644
> > --- a/fs/ext2/inode.c
> > +++ b/fs/ext2/inode.c
> > @@ -22,7 +22,6 @@
> >   *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
> >   */
> >  
> > -#include <linux/smp_lock.h>
> >  #include <linux/time.h>
> >  #include <linux/highuid.h>
> >  #include <linux/pagemap.h>
> > @@ -1400,13 +1399,11 @@ int ext2_write_inode(struct inode *inode, int do_sync)
> >  			       /* If this is the first large file
> >  				* created, add a flag to the superblock.
> >  				*/
> > -				lock_kernel();
> >  				mutex_lock(&EXT2_SB(sb)->s_mutex);
> >  				ext2_update_dynamic_rev(sb);
> >  				EXT2_SET_RO_COMPAT_FEATURE(sb,
> >  					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
> >  				mutex_unlock(&EXT2_SB(sb)->s_mutex);
> > -				unlock_kernel();
> >  				ext2_write_super(sb);
> >  			}
> >  		}
> > diff --git a/fs/ext2/super.c b/fs/ext2/super.c
> > index d610eb9..7e819ac 100644
> > --- a/fs/ext2/super.c
> > +++ b/fs/ext2/super.c
> > @@ -26,7 +26,6 @@
> >  #include <linux/random.h>
> >  #include <linux/buffer_head.h>
> >  #include <linux/exportfs.h>
> > -#include <linux/smp_lock.h>
> >  #include <linux/vfs.h>
> >  #include <linux/seq_file.h>
> >  #include <linux/mount.h>
> > @@ -118,8 +117,6 @@ static void ext2_put_super (struct super_block * sb)
> >  	int i;
> >  	struct ext2_sb_info *sbi = EXT2_SB(sb);
> >  
> > -	lock_kernel();
> > -
> >  	if (sb->s_dirt && !(sb->s_flags & MS_RDONLY))
> >  		ext2_sync_fs(sb, 1);
> >  
> > @@ -143,8 +140,6 @@ static void ext2_put_super (struct super_block * sb)
> >  	sb->s_fs_info = NULL;
> >  	kfree(sbi->s_blockgroup_lock);
> >  	kfree(sbi);
> > -
> > -	unlock_kernel();
> >  }
> >  
> >  static struct kmem_cache * ext2_inode_cachep;
> > @@ -750,8 +745,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
> >  	__le32 features;
> >  	int err;
> >  
> > -	lock_kernel();
> > -
> >  	err = -ENOMEM;
> >  	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
> >  	if (!sbi)
> > @@ -1077,7 +1070,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
> >  		ext2_warning(sb, __func__,
> >  			"mounting ext3 filesystem as ext2");
> >  	ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
> > -	unlock_kernel();
> >  	return 0;
> >  
> >  cantfind_ext2:
> > @@ -1102,7 +1094,6 @@ failed_sbi:
> >  	kfree(sbi->s_blockgroup_lock);
> >  	kfree(sbi);
> >  failed_unlock:
> > -	unlock_kernel();
> >  	return ret;
> >  }
> >  
> > @@ -1140,7 +1131,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
> >  {
> >  	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
> >  
> > -	lock_kernel();
> >  	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
> >  		ext2_debug("setting valid to 0\n");
> >  		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
> > @@ -1154,7 +1144,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
> >  		ext2_commit_super(sb, es);
> >  	}
> >  	sb->s_dirt = 0;
> > -	unlock_kernel();
> >  
> >  	return 0;
> >  }
> > @@ -1181,7 +1170,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
> >  	unsigned long old_sb_flags;
> >  	int err;
> >  
> > -	lock_kernel();
> >  	mutex_lock(&sbi->s_mutex);
> >  
> >  	/* Store the old options */
> > @@ -1221,14 +1209,12 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
> >  	}
> >  	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
> >  		mutex_unlock(&sbi->s_mutex);
> > -		unlock_kernel();
> >  		return 0;
> >  	}
> >  	if (*flags & MS_RDONLY) {
> >  		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
> >  		    !(sbi->s_mount_state & EXT2_VALID_FS)) {
> >  			mutex_unlock(&sbi->s_mutex);
> > -			unlock_kernel();
> >  			return 0;
> >  		}
> >  		/*
> > @@ -1258,7 +1244,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
> >  	}
> >  	ext2_sync_super(sb, es);
> >  	mutex_unlock(&sbi->s_mutex);
> > -	unlock_kernel();
> >  	return 0;
> >  restore_opts:
> >  	sbi->s_mount_opt = old_opts.s_mount_opt;
> > @@ -1266,7 +1251,6 @@ restore_opts:
> >  	sbi->s_resgid = old_opts.s_resgid;
> >  	sb->s_flags = old_sb_flags;
> >  	mutex_unlock(&sbi->s_mutex);
> > -	unlock_kernel();
> >  	return err;
> >  }
> >  
> > -- 
> > 1.6.4.2
> > 
> -- 
> Jan Kara <jack@suse.cz>
> SUSE Labs, CR

Re: [PATCH 05/27] BKL: Remove BKL from ext2 filesystem

[Jan Kara]

On Thu 05-11-09 14:06:35, Jan Blunck wrote:
> On Thu, Nov 05, Jan Kara wrote:
> 
> > On Mon 02-11-09 11:04:45, Jan Blunck wrote:
> > > The BKL is still used in ext2_put_super(), ext2_fill_super(), ext2_sync_fs()
> > > ext2_remount() and ext2_write_inode(). From these calls ext2_put_super(),
> > > ext2_fill_super() and ext2_remount() are protected against each other by
> > > the struct super_block s_umount rw semaphore. The call in ext2_write_inode()
> > > could only protect the modification of the ext2_sb_info through
> > > ext2_update_dynamic_rev() against concurrent ext2_sync_fs() or ext2_remount().
> > > ext2_fill_super() and ext2_put_super() can be left out because you need a
> > > valid filesystem reference in all three cases, which you do not have when
> > > you are one of these functions.
> >   This is not quite true. Actually, ext2_sync_fs() is called also with
> > s_umount held (for reading) so it cannot race with any of the mounting /
> > umounting functions. But it should probably be guarded against running two
> > instances of ext2_sync_fs() in parallel.
> >   Looking into the code, we probably have a race in ext2_write_inode that
> > two threads can write one inode in parallel. But that's a separe issue from
> > BKL removal.
> 
> Have you actually seen that the previous patch introduces s_mutex? Meanwhile
> that mutex has been replaced by a spinlock due to Andy's feedback.
  Ops, I wanted to comment on that patch as well but then decided it might
be better to write my version and didn't get to it yet... Thinking more
about it, probably go ahead with these two patches (modulo some changes
I've now suggested in a reply to your second ext2 patch) and I can cleanup
ext2 code after that.

									Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

[PATCH 06/27] BKL: Remove BKL from ext3 fill_super()

[Jan Blunck]

The BKL is protecting nothing than two memory allocations here.

Signed-off-by: Jan Blunck <jblunck@suse.de>
---
 fs/ext3/super.c |   13 +------------
 1 files changed, 1 insertions(+), 12 deletions(-)

diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 38261a5..4b635b7 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -1568,19 +1568,14 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 	__le32 features;
 	int err;
 
-	lock_kernel();
-
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi) {
-		unlock_kernel();
+	if (!sbi)
 		return -ENOMEM;
-	}
 
 	sbi->s_blockgroup_lock =
 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 	if (!sbi->s_blockgroup_lock) {
 		kfree(sbi);
-		unlock_kernel();
 		return -ENOMEM;
 	}
 	sb->s_fs_info = sbi;
@@ -1589,8 +1584,6 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 	sbi->s_resgid = EXT3_DEF_RESGID;
 	sbi->s_sb_block = sb_block;
 
-	unlock_kernel();

Re: [PATCH 06/27] BKL: Remove BKL from ext3 fill_super()

[Jan Kara]

On Mon 02-11-09 11:04:46, Jan Blunck wrote:
> The BKL is protecting nothing than two memory allocations here.
  The patch looks good.
Acked-by: Jan Kara <jack@suse.cz>
  Should I merge it or will you do it with other patches?

									Honza
> 
> Signed-off-by: Jan Blunck <jblunck@suse.de>
> ---
>  fs/ext3/super.c |   13 +------------
>  1 files changed, 1 insertions(+), 12 deletions(-)
> 
> diff --git a/fs/ext3/super.c b/fs/ext3/super.c
> index 38261a5..4b635b7 100644
> --- a/fs/ext3/super.c
> +++ b/fs/ext3/super.c
> @@ -1568,19 +1568,14 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
>  	__le32 features;
>  	int err;
>  
> -	lock_kernel();
> -
>  	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
> -	if (!sbi) {
> -		unlock_kernel();
> +	if (!sbi)
>  		return -ENOMEM;
> -	}
>  
>  	sbi->s_blockgroup_lock =
>  		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
>  	if (!sbi->s_blockgroup_lock) {
>  		kfree(sbi);
> -		unlock_kernel();
>  		return -ENOMEM;
>  	}
>  	sb->s_fs_info = sbi;
> @@ -1589,8 +1584,6 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
>  	sbi->s_resgid = EXT3_DEF_RESGID;
>  	sbi->s_sb_block = sb_block;
>  
> -	unlock_kernel();
> -
>  	blocksize = sb_min_blocksize(sb, EXT3_MIN_BLOCK_SIZE);
>  	if (!blocksize) {
>  		printk(KERN_ERR "EXT3-fs: unable to set blocksize\n");
> @@ -1996,8 +1989,6 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
>  		test_opt(sb,DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA ? "ordered":
>  		"writeback");
>  
> -	lock_kernel();
> -	unlock_kernel();
>  	return 0;
>  
>  cantfind_ext3:
> @@ -2027,8 +2018,6 @@ out_fail:
>  	sb->s_fs_info = NULL;
>  	kfree(sbi->s_blockgroup_lock);
>  	kfree(sbi);
> -	lock_kernel();
> -	unlock_kernel();
>  	return ret;
>  }
>  
> -- 
> 1.6.4.2
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

[PATCH 07/27] BKL: Remove BKL from ext3_put_super() and ext3_remount()

[Jan Blunck]

The BKL lock is protecting the remounting against a potential call to
ext3_put_super(). This could not happen, since this is protected by the
s_umount rw semaphore of struct super_block.

Therefore I think the BKL is protecting nothing here.

Signed-off-by: Jan Blunck <jblunck@suse.de>
---
 fs/ext3/super.c |    8 --------
 1 files changed, 0 insertions(+), 8 deletions(-)

diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 4b635b7..3ddce03 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -398,8 +398,6 @@ static void ext3_put_super (struct super_block * sb)
 	struct ext3_super_block *es = sbi->s_es;
 	int i, err;
 
-	lock_kernel();
-
 	ext3_xattr_put_super(sb);
 	err = journal_destroy(sbi->s_journal);
 	sbi->s_journal = NULL;
@@ -448,8 +446,6 @@ static void ext3_put_super (struct super_block * sb)
 	sb->s_fs_info = NULL;
 	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
-
-	unlock_kernel();
 }
 
 static struct kmem_cache *ext3_inode_cachep;
@@ -2495,8 +2491,6 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
 	int i;
 #endif
 
-	lock_kernel();

Re: [PATCH 07/27] BKL: Remove BKL from ext3_put_super() and ext3_remount()

[Jan Kara]

On Mon 02-11-09 11:04:47, Jan Blunck wrote:
> The BKL lock is protecting the remounting against a potential call to
> ext3_put_super(). This could not happen, since this is protected by the
> s_umount rw semaphore of struct super_block.
> 
> Therefore I think the BKL is protecting nothing here.
  Yes, I'm also not aware of anything BKL would really protect. So I'm fine
with removing it here.
  Acked-by: Jan Kara <jack@suse.cz>
I can merge this patch as well if you want.

									Honza
> 
> Signed-off-by: Jan Blunck <jblunck@suse.de>
> ---
>  fs/ext3/super.c |    8 --------
>  1 files changed, 0 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/ext3/super.c b/fs/ext3/super.c
> index 4b635b7..3ddce03 100644
> --- a/fs/ext3/super.c
> +++ b/fs/ext3/super.c
> @@ -398,8 +398,6 @@ static void ext3_put_super (struct super_block * sb)
>  	struct ext3_super_block *es = sbi->s_es;
>  	int i, err;
>  
> -	lock_kernel();
> -
>  	ext3_xattr_put_super(sb);
>  	err = journal_destroy(sbi->s_journal);
>  	sbi->s_journal = NULL;
> @@ -448,8 +446,6 @@ static void ext3_put_super (struct super_block * sb)
>  	sb->s_fs_info = NULL;
>  	kfree(sbi->s_blockgroup_lock);
>  	kfree(sbi);
> -
> -	unlock_kernel();
>  }
>  
>  static struct kmem_cache *ext3_inode_cachep;
> @@ -2495,8 +2491,6 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
>  	int i;
>  #endif
>  
> -	lock_kernel();
> -
>  	/* Store the original options */
>  	lock_super(sb);
>  	old_sb_flags = sb->s_flags;
> @@ -2607,7 +2601,6 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
>  			kfree(old_opts.s_qf_names[i]);
>  #endif
>  	unlock_super(sb);
> -	unlock_kernel();
>  	return 0;
>  restore_opts:
>  	sb->s_flags = old_sb_flags;
> @@ -2625,7 +2618,6 @@ restore_opts:
>  	}
>  #endif
>  	unlock_super(sb);
> -	unlock_kernel();
>  	return err;
>  }
>  
> -- 
> 1.6.4.2
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

[PATCH 08/27] BKL: Remove BKL from ext4 filesystem

[Jan Blunck]

The BKL is still used in ext4_put_super(), ext4_fill_super() and
ext4_remount(). All three calles are protected against concurrent calls by
the s_umount rw semaphore of struct super_block.

Therefore the BKL is protecting nothing in this case.

Signed-off-by: Jan Blunck <jblunck@suse.de>
---
 fs/ext4/super.c |   16 +---------------
 1 files changed, 1 insertions(+), 15 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9db81d2..328e9dc 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -26,7 +26,6 @@
 #include <linux/init.h>
 #include <linux/blkdev.h>
 #include <linux/parser.h>
-#include <linux/smp_lock.h>
 #include <linux/buffer_head.h>
 #include <linux/exportfs.h>
 #include <linux/vfs.h>
@@ -599,7 +598,6 @@ static void ext4_put_super(struct super_block *sb)
 	destroy_workqueue(sbi->dio_unwritten_wq);
 
 	lock_super(sb);
-	lock_kernel();
 	if (sb->s_dirt)
 		ext4_commit_super(sb, 1);
 
@@ -665,7 +663,6 @@ static void ext4_put_super(struct super_block *sb)
 	 * Now that we are completely done shutting down the
 	 * superblock, we need to actually destroy the kobject.
 	 */
-	unlock_kernel();
 	unlock_super(sb);
 	kobject_put(&sbi->s_kobj);
 	wait_for_completion(&sbi->s_kobj_unregister);
@@ -2328,19 +2325,14 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	int err;
 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
 
-	lock_kernel();
-
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi) {
-		unlock_kernel();
+	if (!sbi)
 		return -ENOMEM;
-	}
 
 	sbi->s_blockgroup_lock =
 		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 	if (!sbi->s_blockgroup_lock) {
 		kfree(sbi);
-		unlock_kernel();
 		return -ENOMEM;
 	}
 	sb->s_fs_info = sbi;
@@ -2352,8 +2344,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->s_sectors_written_start = part_stat_read(sb->s_bdev->bd_part,
 						      sectors[1]);
 
-	unlock_kernel();
-
 	/* Cleanup superblock name */
 	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
 		*cp = '!';
@@ -3456,8 +3446,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 	int i;
 #endif
 
-	lock_kernel();
-
 	/* Store the original options */
 	lock_super(sb);
 	old_sb_flags = sb->s_flags;
@@ -3587,7 +3575,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 			kfree(old_opts.s_qf_names[i]);
 #endif
 	unlock_super(sb);
-	unlock_kernel();
 	return 0;
 
 restore_opts:
@@ -3608,7 +3595,6 @@ restore_opts:
 	}
 #endif
 	unlock_super(sb);
-	unlock_kernel();
 	return err;
 }
 
-- 
1.6.4.2

Re: [PATCH 08/27] BKL: Remove BKL from ext4 filesystem

[Theodore Tso]

On Mon, Nov 02, 2009 at 11:04:48AM +0100, Jan Blunck wrote:
> The BKL is still used in ext4_put_super(), ext4_fill_super() and
> ext4_remount(). All three calles are protected against concurrent calls by
> the s_umount rw semaphore of struct super_block.
> 
> Therefore the BKL is protecting nothing in this case.
> 
> Signed-off-by: Jan Blunck <jblunck@suse.de>

Acked-by: "Theodore Ts'o" <tytso@mit.edu>

						- Ted