[PATCH] Shift BKL into ->statfs()

[PATCH] Shift BKL into ->statfs()

[Paul Menage]

This patch removes BKL protection from the invocation of the
super_operations ->statfs() method, and shifts it into the filesystems
where necessary. Any out-of-tree filesystems may need to take the BKL in
their statfs() methods if they were relying on it for synchronisation.

All ->statfs() implementations have been modified to take the BKL,
except for the following, which don't reference any external mutable
data:

simple_statfs
isofs_statfs
ncp_statfs
cramfs_statfs
romfs_statfs

Additionally, capifs is changed to use simple_statfs rather than its 
own home-grown version.


All modified filesystems have been compiled except for the disabled
umsdos; only ext2 and shmfs have actually been tested.

Paul


diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/Documentation/filesystems/Locking linux-2.5.24-statfs/Documentation/filesystems/Locking
--- linux-2.5.24/Documentation/filesystems/Locking	Tue Jun 18 19:11:52 2002
+++ linux-2.5.24-statfs/Documentation/filesystems/Locking	Wed Jun 26 01:41:08 2002
@@ -108,7 +108,7 @@
 clear_inode:	no	
 put_super:	yes	yes	maybe		(see below)
 write_super:	no	yes	maybe		(see below)
-statfs:		yes	no	no
+statfs:		no	no	no
 remount_fs:	yes	yes	maybe		(see below)
 umount_begin:	yes	no	maybe		(see below)
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/Documentation/filesystems/porting linux-2.5.24-statfs/Documentation/filesystems/porting
--- linux-2.5.24/Documentation/filesystems/porting	Tue Jun 18 19:11:51 2002
+++ linux-2.5.24-statfs/Documentation/filesystems/porting	Wed Jun 26 01:41:08 2002
@@ -91,9 +91,10 @@
 ---
 [mandatory]
 
-BKL is also moved from around sb operations.  ->write_super() Is now called 
-without BKL held.  BKL should have been shifted into individual fs sb_op
-functions.  If you don't need it, remove it.  
+BKL is also moved from around sb operations.  ->write_super() and
+->statfs() are now called without BKL held.  BKL should have been
+shifted into individual fs sb_op functions.  If you don't need it,
+remove it.
 
 ---
 [informational]
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/drivers/isdn/capi/capifs.c linux-2.5.24-statfs/drivers/isdn/capi/capifs.c
--- linux-2.5.24/drivers/isdn/capi/capifs.c	Tue Jun 18 19:11:50 2002
+++ linux-2.5.24-statfs/drivers/isdn/capi/capifs.c	Wed Jun 26 01:41:08 2002
@@ -221,11 +221,9 @@
 	kfree(sbi);
 }
 
-static int capifs_statfs(struct super_block *sb, struct statfs *buf);
-
 static struct super_operations capifs_sops = {
 	put_super:	capifs_put_super,
-	statfs:		capifs_statfs,
+	statfs:		simple_statfs,
 };
 
 static int capifs_parse_options(char *options, struct capifs_sb_info *sbi)
@@ -354,19 +352,6 @@
 	return -EINVAL;
 }
 
-static int capifs_statfs(struct super_block *sb, struct statfs *buf)
-{
-	buf->f_type = CAPIFS_SUPER_MAGIC;
-	buf->f_bsize = 1024;
-	buf->f_blocks = 0;
-	buf->f_bfree = 0;
-	buf->f_bavail = 0;
-	buf->f_files = 0;
-	buf->f_ffree = 0;
-	buf->f_namelen = NAME_MAX;
-	return 0;
-}
-
 static struct inode *capifs_new_inode(struct super_block *sb)
 {
 	struct inode *inode = new_inode(sb);
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/adfs/super.c linux-2.5.24-statfs/fs/adfs/super.c
--- linux-2.5.24/fs/adfs/super.c	Tue Jun 18 19:11:45 2002
+++ linux-2.5.24-statfs/fs/adfs/super.c	Wed Jun 26 01:41:08 2002
@@ -18,6 +18,7 @@
 #include <linux/string.h>
 #include <linux/init.h>
 #include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
 
 #include <asm/bitops.h>
 #include <asm/uaccess.h>
@@ -192,6 +193,8 @@
 {
 	struct adfs_sb_info *asb = ADFS_SB(sb);
 
+	lock_kernel();
+
 	buf->f_type    = ADFS_SUPER_MAGIC;
 	buf->f_namelen = asb->s_namelen;
 	buf->f_bsize   = sb->s_blocksize;
@@ -201,6 +204,8 @@
 	buf->f_bfree   = adfs_map_free(sb);
 	buf->f_ffree   = buf->f_bfree * buf->f_files / buf->f_blocks;
 
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/affs/super.c linux-2.5.24-statfs/fs/affs/super.c
--- linux-2.5.24/fs/affs/super.c	Tue Jun 18 19:11:57 2002
+++ linux-2.5.24-statfs/fs/affs/super.c	Wed Jun 26 01:41:08 2002
@@ -531,6 +531,8 @@
 {
 	int		 free;
 
+	lock_kernel();
+
 	pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
 	     AFFS_SB(sb)->s_reserved);
 
@@ -540,6 +542,9 @@
 	buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
 	buf->f_bfree   = free;
 	buf->f_bavail  = free;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/bfs/inode.c linux-2.5.24-statfs/fs/bfs/inode.c
--- linux-2.5.24/fs/bfs/inode.c	Tue Jun 18 19:11:53 2002
+++ linux-2.5.24-statfs/fs/bfs/inode.c	Wed Jun 26 01:41:08 2002
@@ -190,6 +190,9 @@
 static int bfs_statfs(struct super_block *s, struct statfs *buf)
 {
 	struct bfs_sb_info *info = BFS_SB(s);
+
+	lock_kernel();
+
 	buf->f_type = BFS_MAGIC;
 	buf->f_bsize = s->s_blocksize;
 	buf->f_blocks = info->si_blocks;
@@ -198,6 +201,9 @@
 	buf->f_ffree = info->si_freei;
 	buf->f_fsid.val[0] = s->s_dev;
 	buf->f_namelen = BFS_NAMELEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/coda/inode.c linux-2.5.24-statfs/fs/coda/inode.c
--- linux-2.5.24/fs/coda/inode.c	Tue Jun 18 19:11:55 2002
+++ linux-2.5.24-statfs/fs/coda/inode.c	Wed Jun 26 01:41:08 2002
@@ -281,9 +281,13 @@
 static int coda_statfs(struct super_block *sb, struct statfs *buf)
 {
 	int error;
+	
+	lock_kernel();
 
 	error = venus_statfs(sb, buf);
 
+	unlock_kernel();
+
 	if (error) {
 		/* fake something like AFS does */
 		buf->f_blocks = 9000000;
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/efs/super.c linux-2.5.24-statfs/fs/efs/super.c
--- linux-2.5.24/fs/efs/super.c	Tue Jun 18 19:11:50 2002
+++ linux-2.5.24-statfs/fs/efs/super.c	Wed Jun 26 01:41:08 2002
@@ -13,6 +13,7 @@
 #include <linux/efs_fs_sb.h>
 #include <linux/slab.h>
 #include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
 
 static struct super_block *efs_get_sb(struct file_system_type *fs_type,
 	int flags, char *dev_name, void *data)
@@ -280,6 +281,8 @@
 int efs_statfs(struct super_block *s, struct statfs *buf) {
 	struct efs_sb_info *sb = SUPER_INFO(s);
 
+	lock_kernel();
+
 	buf->f_type    = EFS_SUPER_MAGIC;	/* efs magic number */
 	buf->f_bsize   = EFS_BLOCKSIZE;		/* blocksize */
 	buf->f_blocks  = sb->total_groups *	/* total data blocks */
@@ -294,6 +297,8 @@
 	buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
 	buf->f_namelen = EFS_MAXNAMELEN;	/* max filename length */
 
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/ext2/super.c linux-2.5.24-statfs/fs/ext2/super.c
--- linux-2.5.24/fs/ext2/super.c	Wed Jun 26 01:07:20 2002
+++ linux-2.5.24-statfs/fs/ext2/super.c	Wed Jun 26 01:41:08 2002
@@ -835,6 +835,8 @@
 	unsigned long overhead;
 	int i;
 
+	lock_kernel();
+
 	if (test_opt (sb, MINIX_DF))
 		overhead = 0;
 	else {
@@ -875,6 +877,9 @@
 	buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
 	buf->f_ffree = ext2_count_free_inodes (sb);
 	buf->f_namelen = EXT2_NAME_LEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/ext3/super.c linux-2.5.24-statfs/fs/ext3/super.c
--- linux-2.5.24/fs/ext3/super.c	Tue Jun 18 19:11:58 2002
+++ linux-2.5.24-statfs/fs/ext3/super.c	Wed Jun 26 01:41:08 2002
@@ -504,7 +504,7 @@
 	write_super:	ext3_write_super,	/* BKL not held. We take it. Needed? */
 	write_super_lockfs: ext3_write_super_lockfs, /* BKL not held. Take it */
 	unlockfs:	ext3_unlockfs,		/* BKL not held.  We take it */
-	statfs:		ext3_statfs,		/* BKL held */
+	statfs:		ext3_statfs,		/* BKL not held.  We take it. Needed? */
 	remount_fs:	ext3_remount,		/* BKL held */
 };
 
@@ -1732,6 +1732,8 @@
 	unsigned long overhead;
 	int i;
 
+	lock_kernel();
+
 	if (test_opt (sb, MINIX_DF))
 		overhead = 0;
 	else {
@@ -1772,6 +1774,8 @@
 	buf->f_files = le32_to_cpu(es->s_inodes_count);
 	buf->f_ffree = ext3_count_free_inodes (sb);
 	buf->f_namelen = EXT3_NAME_LEN;
+
+	unlock_kernel();
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/fat/inode.c linux-2.5.24-statfs/fs/fat/inode.c
--- linux-2.5.24/fs/fat/inode.c	Tue Jun 18 19:11:54 2002
+++ linux-2.5.24-statfs/fs/fat/inode.c	Wed Jun 26 01:41:08 2002
@@ -934,11 +934,15 @@
 int fat_statfs(struct super_block *sb,struct statfs *buf)
 {
 	int free,nr;
-       
+	int ret = 0;
+        
+	lock_kernel();
 	if (MSDOS_SB(sb)->cvf_format &&
-	    MSDOS_SB(sb)->cvf_format->cvf_statfs)
-		return MSDOS_SB(sb)->cvf_format->cvf_statfs(sb,buf,
+	    MSDOS_SB(sb)->cvf_format->cvf_statfs) {
+		ret = MSDOS_SB(sb)->cvf_format->cvf_statfs(sb,buf,
 						sizeof(struct statfs));
+		goto out;
+	}
 	  
 	lock_fat(sb);
 	if (MSDOS_SB(sb)->free_clusters != -1)
@@ -959,7 +963,9 @@
 	buf->f_bavail = free;
 	buf->f_namelen = MSDOS_SB(sb)->options.isvfat ? 260 : 12;
 
-	return 0;
+ out:
+	unlock_kernel();
+	return ret;
 }
 
 static int is_exec(char *extension)
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/freevxfs/vxfs_super.c linux-2.5.24-statfs/fs/freevxfs/vxfs_super.c
--- linux-2.5.24/fs/freevxfs/vxfs_super.c	Tue Jun 18 19:11:51 2002
+++ linux-2.5.24-statfs/fs/freevxfs/vxfs_super.c	Wed Jun 26 01:41:08 2002
@@ -41,6 +41,7 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/stat.h>
+#include <linux/smp_lock.h>
 
 #include "vxfs.h"
 #include "vxfs_extern.h"
@@ -98,7 +99,7 @@
  *   Zero.
  *
  * Locking:
- *   We are under bkl and @sbp->s_lock.
+ *   We are under @sbp->s_lock.
  *
  * Notes:
  *   This is everything but complete...
@@ -108,6 +109,8 @@
 {
 	struct vxfs_sb_info		*infp = VXFS_SBI(sbp);
 
+	lock_kernel();
+
 	bufp->f_type = VXFS_SUPER_MAGIC;
 	bufp->f_bsize = sbp->s_blocksize;
 	bufp->f_blocks = infp->vsi_raw->vs_dsize;
@@ -117,6 +120,8 @@
 	bufp->f_ffree = infp->vsi_raw->vs_ifree;
 	bufp->f_namelen = VXFS_NAMELEN;
 
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/hfs/super.c linux-2.5.24-statfs/fs/hfs/super.c
--- linux-2.5.24/fs/hfs/super.c	Tue Jun 18 19:11:52 2002
+++ linux-2.5.24-statfs/fs/hfs/super.c	Wed Jun 26 01:41:08 2002
@@ -198,6 +198,8 @@
 {
 	struct hfs_mdb *mdb = HFS_SB(sb)->s_mdb;
 
+	lock_kernel();
+
 	buf->f_type = HFS_SUPER_MAGIC;
 	buf->f_bsize = HFS_SECTOR_SIZE;
 	buf->f_blocks = mdb->alloc_blksz * mdb->fs_ablocks;
@@ -207,6 +209,8 @@
 	buf->f_ffree = mdb->free_ablocks;
 	buf->f_namelen = HFS_NAMELEN;
 
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/hpfs/super.c linux-2.5.24-statfs/fs/hpfs/super.c
--- linux-2.5.24/fs/hpfs/super.c	Tue Jun 18 19:11:56 2002
+++ linux-2.5.24-statfs/fs/hpfs/super.c	Tue Jul  2 16:51:50 2002
@@ -134,6 +134,8 @@
 
 int hpfs_statfs(struct super_block *s, struct statfs *buf)
 {
+	lock_kernel();
+
 	/*if (s->s_hpfs_n_free == -1) {*/
 		s->s_hpfs_n_free = count_bitmaps(s);
 		s->s_hpfs_n_free_dnodes = hpfs_count_one_bitmap(s, s->s_hpfs_dmap);
@@ -146,6 +148,8 @@
 	buf->f_files = s->s_hpfs_dirband_size / 4;
 	buf->f_ffree = s->s_hpfs_n_free_dnodes;
 	buf->f_namelen = 254;
+
+	unlock_kernel();
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/jffs/inode-v23.c linux-2.5.24-statfs/fs/jffs/inode-v23.c
--- linux-2.5.24/fs/jffs/inode-v23.c	Tue Jun 18 19:11:56 2002
+++ linux-2.5.24-statfs/fs/jffs/inode-v23.c	Wed Jun 26 01:41:08 2002
@@ -383,7 +383,11 @@
 jffs_statfs(struct super_block *sb, struct statfs *buf)
 {
 	struct jffs_control *c = (struct jffs_control *) sb->u.generic_sbp;
-	struct jffs_fmcontrol *fmc = c->fmc;
+	struct jffs_fmcontrol *fmc;
+
+	lock_kernel();
+
+	fmc = c->fmc;
 
 	D2(printk("jffs_statfs()\n"));
 
@@ -401,6 +405,9 @@
 	buf->f_ffree = buf->f_bfree;
 	/* buf->f_fsid = 0; */
 	buf->f_namelen = JFFS_MAX_NAME_LEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/jffs2/fs.c linux-2.5.24-statfs/fs/jffs2/fs.c
--- linux-2.5.24/fs/jffs2/fs.c	Tue Jun 18 19:11:53 2002
+++ linux-2.5.24-statfs/fs/jffs2/fs.c	Wed Jun 26 01:41:08 2002
@@ -52,6 +52,8 @@
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 	unsigned long avail;
 
+	lock_kernel();
+
 	buf->f_type = JFFS2_SUPER_MAGIC;
 	buf->f_bsize = 1 << PAGE_SHIFT;
 	buf->f_blocks = c->flash_size >> PAGE_SHIFT;
@@ -184,6 +186,7 @@
 
 	spin_unlock_bh(&c->erase_completion_lock);
 
+	unlock_kernel();
 
 	return 0;
 }
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/jfs/super.c linux-2.5.24-statfs/fs/jfs/super.c
--- linux-2.5.24/fs/jfs/super.c	Wed Jun 26 01:07:20 2002
+++ linux-2.5.24-statfs/fs/jfs/super.c	Wed Jun 26 01:41:08 2002
@@ -21,6 +21,7 @@
 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/completion.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include "jfs_incore.h"
 #include "jfs_filsys.h"
@@ -96,7 +97,11 @@
 {
 	struct jfs_sb_info *sbi = JFS_SBI(sb);
 	s64 maxinodes;
-	imap_t *imap = JFS_IP(sbi->ipimap)->i_imap;
+	imap_t *imap;
+
+	lock_kernel();
+
+	imap = JFS_IP(sbi->ipimap)->i_imap;
 
 	jFYI(1, ("In jfs_statfs\n"));
 	buf->f_type = JFS_SUPER_MAGIC;
@@ -121,6 +126,9 @@
 				    atomic_read(&imap->im_numfree));
 
 	buf->f_namelen = JFS_NAME_MAX;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/minix/inode.c linux-2.5.24-statfs/fs/minix/inode.c
--- linux-2.5.24/fs/minix/inode.c	Tue Jun 18 19:11:55 2002
+++ linux-2.5.24-statfs/fs/minix/inode.c	Wed Jun 26 01:41:08 2002
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/highuid.h>
+#include <linux/smp_lock.h>
 
 static void minix_read_inode(struct inode * inode);
 static void minix_write_inode(struct inode * inode, int wait);
@@ -296,6 +297,9 @@
 static int minix_statfs(struct super_block *sb, struct statfs *buf)
 {
 	struct minix_sb_info *sbi = minix_sb(sb);
+
+	lock_kernel();
+
 	buf->f_type = sb->s_magic;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
@@ -304,6 +308,9 @@
 	buf->f_files = sbi->s_ninodes;
 	buf->f_ffree = minix_count_free_inodes(sbi);
 	buf->f_namelen = sbi->s_namelen;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/nfs/inode.c linux-2.5.24-statfs/fs/nfs/inode.c
--- linux-2.5.24/fs/nfs/inode.c	Tue Jun 18 19:11:57 2002
+++ linux-2.5.24-statfs/fs/nfs/inode.c	Wed Jun 26 01:41:08 2002
@@ -474,6 +474,8 @@
 	struct nfs_fsinfo res;
 	int error;
 
+	lock_kernel();
+
 	error = server->rpc_ops->statfs(server, NFS_FH(sb->s_root->d_inode), &res);
 	buf->f_type = NFS_SUPER_MAGIC;
 	if (error < 0)
@@ -491,11 +493,16 @@
 	if (res.namelen == 0 || res.namelen > server->namelen)
 		res.namelen = server->namelen;
 	buf->f_namelen = res.namelen;
+
+ out:
+	unlock_kernel();
 	return 0;
+
  out_err:
-	printk("nfs_statfs: statfs error = %d\n", -error);
+	printk(KERN_WARNING "nfs_statfs: statfs error = %d\n", -error);
 	buf->f_bsize = buf->f_blocks = buf->f_bfree = buf->f_bavail = -1;
-	return 0;
+	goto out;
+
 }
 
 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/ntfs/super.c linux-2.5.24-statfs/fs/ntfs/super.c
--- linux-2.5.24/fs/ntfs/super.c	Wed Jun 26 01:07:20 2002
+++ linux-2.5.24-statfs/fs/ntfs/super.c	Tue Jul  2 16:52:35 2002
@@ -27,6 +27,7 @@
 #include <linux/blkdev.h>	/* For bdev_hardsect_size(). */
 #include <linux/backing-dev.h>
 #include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
 
 #include "ntfs.h"
 #include "sysctl.h"
@@ -1334,6 +1335,8 @@
 {
 	ntfs_volume *vol = NTFS_SB(sb);
 	s64 size;
+	
+	lock_kernel();
 
 	ntfs_debug("Entering.");
 	/* Type of filesystem. */
@@ -1372,6 +1375,9 @@
 	sfs->f_fsid.val[1] = (vol->serial_no >> 32) & 0xffffffff;
 	/* Maximum length of filenames. */
 	sfs->f_namelen	   = NTFS_MAX_NAME_LEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/open.c linux-2.5.24-statfs/fs/open.c
--- linux-2.5.24/fs/open.c	Tue Jun 18 19:11:46 2002
+++ linux-2.5.24-statfs/fs/open.c	Wed Jun 26 01:41:08 2002
@@ -30,9 +30,7 @@
 		retval = -ENOSYS;
 		if (sb->s_op && sb->s_op->statfs) {
 			memset(buf, 0, sizeof(struct statfs));
-			lock_kernel();
 			retval = sb->s_op->statfs(sb, buf);
-			unlock_kernel();
 		}
 	}
 	return retval;
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/qnx4/inode.c linux-2.5.24-statfs/fs/qnx4/inode.c
--- linux-2.5.24/fs/qnx4/inode.c	Tue Jun 18 19:11:52 2002
+++ linux-2.5.24-statfs/fs/qnx4/inode.c	Wed Jun 26 01:41:08 2002
@@ -281,6 +281,8 @@
 
 static int qnx4_statfs(struct super_block *sb, struct statfs *buf)
 {
+	lock_kernel();
+
 	buf->f_type    = sb->s_magic;
 	buf->f_bsize   = sb->s_blocksize;
 	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
@@ -288,6 +290,7 @@
 	buf->f_bavail  = buf->f_bfree;
 	buf->f_namelen = QNX4_NAME_MAX;
 
+	unlock_kernel();
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/reiserfs/super.c linux-2.5.24-statfs/fs/reiserfs/super.c
--- linux-2.5.24/fs/reiserfs/super.c	Tue Jun 18 19:11:54 2002
+++ linux-2.5.24-statfs/fs/reiserfs/super.c	Wed Jun 26 01:41:08 2002
@@ -1257,6 +1257,8 @@
 {
   struct reiserfs_super_block * rs = SB_DISK_SUPER_BLOCK (s);
   
+  lock_kernel();
+
   buf->f_namelen = (REISERFS_MAX_NAME (s->s_blocksize));
   buf->f_ffree   = -1;
   buf->f_files   = -1;
@@ -1266,6 +1268,9 @@
   buf->f_bsize   = s->s_blocksize;
   /* changed to accomodate gcc folks.*/
   buf->f_type    =  REISERFS_SUPER_MAGIC;
+
+  unlock_kernel();
+
   return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/smbfs/inode.c linux-2.5.24-statfs/fs/smbfs/inode.c
--- linux-2.5.24/fs/smbfs/inode.c	Tue Jun 18 19:11:48 2002
+++ linux-2.5.24-statfs/fs/smbfs/inode.c	Tue Jul  2 17:18:29 2002
@@ -604,7 +604,13 @@
 static int
 smb_statfs(struct super_block *sb, struct statfs *buf)
 {
-	int result = smb_proc_dskattr(sb, buf);
+	int result;
+	
+	lock_kernel();
+
+	result = smb_proc_dskattr(sb, buf);
+
+	unlock_kernel();
 
 	buf->f_type = SMB_SUPER_MAGIC;
 	buf->f_namelen = SMB_MAXPATHLEN;
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/sysv/inode.c linux-2.5.24-statfs/fs/sysv/inode.c
--- linux-2.5.24/fs/sysv/inode.c	Tue Jun 18 19:11:45 2002
+++ linux-2.5.24-statfs/fs/sysv/inode.c	Wed Jun 26 01:41:08 2002
@@ -78,6 +78,8 @@
 {
 	struct sysv_sb_info *sbi = SYSV_SB(sb);
 
+	lock_kernel();
+
 	buf->f_type = sb->s_magic;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = sbi->s_ndatazones;
@@ -85,6 +87,8 @@
 	buf->f_files = sbi->s_ninodes;
 	buf->f_ffree = sysv_count_free_inodes(sb);
 	buf->f_namelen = SYSV_NAMELEN;
+
+	unlock_kernel();
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/udf/super.c linux-2.5.24-statfs/fs/udf/super.c
--- linux-2.5.24/fs/udf/super.c	Tue Jun 18 19:11:56 2002
+++ linux-2.5.24-statfs/fs/udf/super.c	Wed Jun 26 01:41:08 2002
@@ -1726,6 +1726,7 @@
 static int
 udf_statfs(struct super_block *sb, struct statfs *buf)
 {
+	lock_kernel();
 	buf->f_type = UDF_SUPER_MAGIC;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = UDF_SB_PARTLEN(sb, UDF_SB_PARTITION(sb));
@@ -1737,7 +1738,7 @@
 	buf->f_ffree = buf->f_bfree;
 	/* __kernel_fsid_t f_fsid */
 	buf->f_namelen = UDF_NAME_LEN;
-
+	unlock_kernel();
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/ufs/super.c linux-2.5.24-statfs/fs/ufs/super.c
--- linux-2.5.24/fs/ufs/super.c	Tue Jun 18 19:11:44 2002
+++ linux-2.5.24-statfs/fs/ufs/super.c	Wed Jun 26 01:41:08 2002
@@ -959,6 +959,8 @@
 	struct ufs_sb_private_info * uspi;
 	struct ufs_super_block_first * usb1;
 
+	lock_kernel();
+
 	uspi = sb->u.ufs_sb.s_uspi;
 	usb1 = ubh_get_usb_first (USPI_UBH);
 	
@@ -972,6 +974,9 @@
 	buf->f_files = uspi->s_ncg * uspi->s_ipg;
 	buf->f_ffree = fs32_to_cpu(sb, usb1->fs_cstotal.cs_nifree);
 	buf->f_namelen = UFS_MAXNAMLEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/umsdos/inode.c linux-2.5.24-statfs/fs/umsdos/inode.c
--- linux-2.5.24/fs/umsdos/inode.c	Tue Jun 18 19:11:48 2002
+++ linux-2.5.24-statfs/fs/umsdos/inode.c	Tue Jul  2 17:19:28 2002
@@ -19,6 +19,7 @@
 #include <linux/umsdos_fs.h>
 #include <linux/list.h>
 #include <linux/pagemap.h>
+#include <linux/smp_lock.h>
 
 extern struct dentry_operations umsdos_dentry_operations;
 
@@ -346,9 +347,12 @@
 int UMSDOS_statfs(struct super_block *sb,struct statfs *buf)
 {
 	int ret;
+
+	lock_kernel();
 	ret = fat_statfs (sb, buf);
 	if (!ret)	
 		buf->f_namelen = UMSDOS_MAXNAME;
+	unlock_kernel();
 	return ret;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/mm/shmem.c linux-2.5.24-statfs/mm/shmem.c
--- linux-2.5.24/mm/shmem.c	Tue Jun 18 19:11:53 2002
+++ linux-2.5.24-statfs/mm/shmem.c	Wed Jun 26 01:41:08 2002
@@ -1035,6 +1035,8 @@
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
 
+	lock_kernel();
+
 	buf->f_type = TMPFS_MAGIC;
 	buf->f_bsize = PAGE_CACHE_SIZE;
 	spin_lock (&sbinfo->stat_lock);
@@ -1044,6 +1046,9 @@
 	buf->f_ffree = sbinfo->free_inodes;
 	spin_unlock (&sbinfo->stat_lock);
 	buf->f_namelen = 255;
+
+	unlock_kernel();
+
 	return 0;
 }
 

Re: [PATCH] Shift BKL into ->statfs()

[Matthew Wilcox]

On Tue, Jul 02, 2002 at 06:25:47PM -0700, Paul Menage wrote:
> This patch removes BKL protection from the invocation of the
> super_operations ->statfs() method, and shifts it into the filesystems
> where necessary. Any out-of-tree filesystems may need to take the BKL in
> their statfs() methods if they were relying on it for synchronisation.

Sure, makes sense to do.  For real credit though, let's see how much we
need the BKL.  In ext2's statfs, we reference:

sbi->s_groups_count (not modified)
sbi->s_itb_per_group (not modified)
sbi->s_es->s_first_data_block (not modified)
sbi->s_es->s_blocks_count (not modified)
sbi->s_es->s_free_blocks_count (lock_super)
sbi->s_es->s_r_blocks_count (not modified)
sbi->s_es->s_inodes_count (not modified)
sbi->s_es->s_free_inodes_count (lock_super)
sb->s_blocksize (modified many places ... but we all know you don't do it
	to a mounted fs).
sb->s_mount_opt (NOT LOCKED)

s_mount_opt doesn't actually need to be locked due to how it is
modified & used.  So it _looks_ like we only need to lock_super(sb); /
unlock_super(sb); in ext2.  Anyone more familiar with ext2 locking care
to comment?

I bet most other filesystems can handle lock_super / unlock_super
for themselves.  See if some kerneljanitors are willing to help audit,
perhaps?

-- 
Revolutions do not require corporate support.

Re: [PATCH] Shift BKL into ->statfs()

[Paul Menage]

>On Tue, Jul 02, 2002 at 06:25:47PM -0700, Paul Menage wrote:
>> This patch removes BKL protection from the invocation of the
>> super_operations ->statfs() method, and shifts it into the filesystems
>> where necessary. Any out-of-tree filesystems may need to take the BKL in
>> their statfs() methods if they were relying on it for synchronisation.
>
>Sure, makes sense to do.  For real credit though, let's see how much we
>need the BKL.  In ext2's statfs, we reference:
>

I'm sure the BKL can be ripped out further, but I preferred not to risk
breakage in this patch due to unfamiliarity with the locking rules for
particular filesystems - I just left the BKL out of those that were 
clearly not touching mutable data. Patches that shrink the BKL usage for 
individual filesystems can be sent (hopefully with copious 
justifications) once this or something like it is applied.

Paul

Re: [PATCH] Shift BKL into ->statfs()

[Alexander Viro]

On Wed, 3 Jul 2002, Matthew Wilcox wrote:

> On Tue, Jul 02, 2002 at 06:25:47PM -0700, Paul Menage wrote:
> > This patch removes BKL protection from the invocation of the
> > super_operations ->statfs() method, and shifts it into the filesystems
> > where necessary. Any out-of-tree filesystems may need to take the BKL in
> > their statfs() methods if they were relying on it for synchronisation.
> 
> Sure, makes sense to do.  For real credit though, let's see how much we
> need the BKL.  In ext2's statfs, we reference:

[snip]

> s_mount_opt doesn't actually need to be locked due to how it is
> modified & used.  So it _looks_ like we only need to lock_super(sb); /
> unlock_super(sb); in ext2.  Anyone more familiar with ext2 locking care
> to comment?

We actually don't need even that - the only places that might need
lock_super() (ext2_count_free_blocks()/ext2_count_free_inodes()) are
already taking it.

So BKL can be dropped in ext2_statfs() and no extra locks are needed.

> I bet most other filesystems can handle lock_super / unlock_super
> for themselves.  See if some kerneljanitors are willing to help audit,
> perhaps?

Depending on filesystem, lock_super() might be a bad idea.  Keep in
mind that these days ->s_lock is a private filesystem lock...

Re: [PATCH] Shift BKL into ->statfs()

[Alexander Viro]

On Tue, 2 Jul 2002, Paul Menage wrote:

> 
> This patch removes BKL protection from the invocation of the
> super_operations ->statfs() method, and shifts it into the filesystems
> where necessary. Any out-of-tree filesystems may need to take the BKL in
> their statfs() methods if they were relying on it for synchronisation.
> 
> All ->statfs() implementations have been modified to take the BKL,
> except for the following, which don't reference any external mutable
> data:
> 
> simple_statfs
> isofs_statfs
> ncp_statfs
> cramfs_statfs
> romfs_statfs
> 
> Additionally, capifs is changed to use simple_statfs rather than its 
> own home-grown version.

Patch makes sense.  However

	1) please, let's keep Documentation/filesystems/porting more or less
in chronological order.  I.e. somebody who wants to check what's new should
be able to check the end of the list, not hunt through the middle for changes.
IOW, I'd rather see duplicate sections (or even "->statfs() had lost BKL; see
section on ->write_super()")

	2) ext2, shmem, FAT, minix and sysv ->statfs() don't need BKL.

	3) efs and vxfs are read-only.

Re: [PATCH] Shift BKL into ->statfs()

[Paul Menage]

This patch removes BKL protection from the invocation of the
super_operations ->statfs() method, and shifts it into the filesystems
where necessary. Any out-of-tree filesystems may need to take the BKL in
their statfs() methods if they were relying on it for synchronisation.

All ->statfs() implementations have been modified to take the BKL,
except for the following:

- those that don't reference any external mutable data:

simple_statfs
isofs_statfs
ncp_statfs
cramfs_statfs
romfs_statfs
efs_statfs
vxfs_statfs

- those that already have their own locking:

ext2_statfs
shmem_statfs
fat_statfs
UMSDOS_statfs
minix_statfs
sysv_statfs

Additionally, capifs is changed to use simple_statfs rather than its 
own home-grown version.

The BKL change has been flagged at the end of 
Documentation/filesystems/porting, along with the recent change to 
->permission BKL usage.

The vertical whitespace around the lock/unlock_kernel() calls has been 
made a little more consistent at the suggestion of Joe Perches.

Paul

diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/Documentation/filesystems/Locking linux-2.5.24-statfs2/Documentation/filesystems/Locking
--- linux-2.5.24/Documentation/filesystems/Locking	Tue Jun 18 19:11:52 2002
+++ linux-2.5.24-statfs2/Documentation/filesystems/Locking	Wed Jul  3 00:22:36 2002
@@ -108,7 +108,7 @@
 clear_inode:	no	
 put_super:	yes	yes	maybe		(see below)
 write_super:	no	yes	maybe		(see below)
-statfs:		yes	no	no
+statfs:		no	no	no
 remount_fs:	yes	yes	maybe		(see below)
 umount_begin:	yes	no	maybe		(see below)
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/Documentation/filesystems/porting linux-2.5.24-statfs2/Documentation/filesystems/porting
--- linux-2.5.24/Documentation/filesystems/porting	Tue Jun 18 19:11:51 2002
+++ linux-2.5.24-statfs2/Documentation/filesystems/porting	Wed Jul  3 00:26:49 2002
@@ -81,7 +81,7 @@
 [mandatory]
 
 ->lookup(), ->truncate(), ->create(), ->unlink(), ->mknod(), ->mkdir(),
-->rmdir(), ->link(), ->lseek(), ->symlink(), ->rename(), ->permission()
+->rmdir(), ->link(), ->lseek(), ->symlink(), ->rename()
 and ->readdir() are called without BKL now.  Grab it on entry, drop upon return
 - that will guarantee the same locking you used to have.  If your method or its
 parts do not need BKL - better yet, now you can shift lock_kernel() and
@@ -228,3 +228,19 @@
 	Use bdev_read_only(bdev) instead of is_read_only(kdev).  The latter
 is still alive, but only because of the mess in drivers/s390/block/dasd.c.
 As soon as it gets fixed is_read_only() will die.
+
+---
+[mandatory]
+
+->permission() is called without BKL now. Grab it on entry, drop upon
+return - that will guarantee the same locking you used to have.  If
+your method or its parts do not need BKL - better yet, now you can
+shift lock_kernel() and unlock_kernel() so that they would protect
+exactly what needs to be protected.
+
+---
+[mandatory]
+
+->statfs() is now called without BKL held.  BKL should have been
+shifted into individual fs sb_op functions where it's not clear that
+it's safe to remove it.  If you don't need it, remove it.
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/drivers/isdn/capi/capifs.c linux-2.5.24-statfs2/drivers/isdn/capi/capifs.c
--- linux-2.5.24/drivers/isdn/capi/capifs.c	Tue Jun 18 19:11:50 2002
+++ linux-2.5.24-statfs2/drivers/isdn/capi/capifs.c	Wed Jul  3 00:22:36 2002
@@ -221,11 +221,9 @@
 	kfree(sbi);
 }
 
-static int capifs_statfs(struct super_block *sb, struct statfs *buf);
-
 static struct super_operations capifs_sops = {
 	put_super:	capifs_put_super,
-	statfs:		capifs_statfs,
+	statfs:		simple_statfs,
 };
 
 static int capifs_parse_options(char *options, struct capifs_sb_info *sbi)
@@ -354,19 +352,6 @@
 	return -EINVAL;
 }
 
-static int capifs_statfs(struct super_block *sb, struct statfs *buf)
-{
-	buf->f_type = CAPIFS_SUPER_MAGIC;
-	buf->f_bsize = 1024;
-	buf->f_blocks = 0;
-	buf->f_bfree = 0;
-	buf->f_bavail = 0;
-	buf->f_files = 0;
-	buf->f_ffree = 0;
-	buf->f_namelen = NAME_MAX;
-	return 0;
-}
-
 static struct inode *capifs_new_inode(struct super_block *sb)
 {
 	struct inode *inode = new_inode(sb);
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/adfs/super.c linux-2.5.24-statfs2/fs/adfs/super.c
--- linux-2.5.24/fs/adfs/super.c	Tue Jun 18 19:11:45 2002
+++ linux-2.5.24-statfs2/fs/adfs/super.c	Wed Jul  3 00:22:36 2002
@@ -18,6 +18,7 @@
 #include <linux/string.h>
 #include <linux/init.h>
 #include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
 
 #include <asm/bitops.h>
 #include <asm/uaccess.h>
@@ -192,6 +193,8 @@
 {
 	struct adfs_sb_info *asb = ADFS_SB(sb);
 
+	lock_kernel();
+
 	buf->f_type    = ADFS_SUPER_MAGIC;
 	buf->f_namelen = asb->s_namelen;
 	buf->f_bsize   = sb->s_blocksize;
@@ -201,6 +204,8 @@
 	buf->f_bfree   = adfs_map_free(sb);
 	buf->f_ffree   = buf->f_bfree * buf->f_files / buf->f_blocks;
 
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/affs/super.c linux-2.5.24-statfs2/fs/affs/super.c
--- linux-2.5.24/fs/affs/super.c	Tue Jun 18 19:11:57 2002
+++ linux-2.5.24-statfs2/fs/affs/super.c	Wed Jul  3 00:22:36 2002
@@ -531,6 +531,8 @@
 {
 	int		 free;
 
+	lock_kernel();
+
 	pr_debug("AFFS: statfs() partsize=%d, reserved=%d\n",AFFS_SB(sb)->s_partition_size,
 	     AFFS_SB(sb)->s_reserved);
 
@@ -540,6 +542,9 @@
 	buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
 	buf->f_bfree   = free;
 	buf->f_bavail  = free;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/bfs/inode.c linux-2.5.24-statfs2/fs/bfs/inode.c
--- linux-2.5.24/fs/bfs/inode.c	Tue Jun 18 19:11:53 2002
+++ linux-2.5.24-statfs2/fs/bfs/inode.c	Wed Jul  3 00:22:36 2002
@@ -190,6 +190,9 @@
 static int bfs_statfs(struct super_block *s, struct statfs *buf)
 {
 	struct bfs_sb_info *info = BFS_SB(s);
+
+	lock_kernel();
+
 	buf->f_type = BFS_MAGIC;
 	buf->f_bsize = s->s_blocksize;
 	buf->f_blocks = info->si_blocks;
@@ -198,6 +201,9 @@
 	buf->f_ffree = info->si_freei;
 	buf->f_fsid.val[0] = s->s_dev;
 	buf->f_namelen = BFS_NAMELEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/coda/inode.c linux-2.5.24-statfs2/fs/coda/inode.c
--- linux-2.5.24/fs/coda/inode.c	Tue Jun 18 19:11:55 2002
+++ linux-2.5.24-statfs2/fs/coda/inode.c	Wed Jul  3 00:22:36 2002
@@ -281,9 +281,13 @@
 static int coda_statfs(struct super_block *sb, struct statfs *buf)
 {
 	int error;
+	
+	lock_kernel();
 
 	error = venus_statfs(sb, buf);
 
+	unlock_kernel();
+
 	if (error) {
 		/* fake something like AFS does */
 		buf->f_blocks = 9000000;
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/ext3/super.c linux-2.5.24-statfs2/fs/ext3/super.c
--- linux-2.5.24/fs/ext3/super.c	Tue Jun 18 19:11:58 2002
+++ linux-2.5.24-statfs2/fs/ext3/super.c	Wed Jul  3 00:28:00 2002
@@ -504,7 +504,7 @@
 	write_super:	ext3_write_super,	/* BKL not held. We take it. Needed? */
 	write_super_lockfs: ext3_write_super_lockfs, /* BKL not held. Take it */
 	unlockfs:	ext3_unlockfs,		/* BKL not held.  We take it */
-	statfs:		ext3_statfs,		/* BKL held */
+	statfs:		ext3_statfs,		/* BKL not held.  We take it. Needed? */
 	remount_fs:	ext3_remount,		/* BKL held */
 };
 
@@ -1732,6 +1732,8 @@
 	unsigned long overhead;
 	int i;
 
+	lock_kernel();
+
 	if (test_opt (sb, MINIX_DF))
 		overhead = 0;
 	else {
@@ -1772,6 +1774,9 @@
 	buf->f_files = le32_to_cpu(es->s_inodes_count);
 	buf->f_ffree = ext3_count_free_inodes (sb);
 	buf->f_namelen = EXT3_NAME_LEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/freevxfs/vxfs_super.c linux-2.5.24-statfs2/fs/freevxfs/vxfs_super.c
--- linux-2.5.24/fs/freevxfs/vxfs_super.c	Tue Jun 18 19:11:51 2002
+++ linux-2.5.24-statfs2/fs/freevxfs/vxfs_super.c	Wed Jul  3 00:22:36 2002
@@ -98,7 +98,7 @@
  *   Zero.
  *
  * Locking:
- *   We are under bkl and @sbp->s_lock.
+ *   No locks held.
  *
  * Notes:
  *   This is everything but complete...
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/hfs/super.c linux-2.5.24-statfs2/fs/hfs/super.c
--- linux-2.5.24/fs/hfs/super.c	Tue Jun 18 19:11:52 2002
+++ linux-2.5.24-statfs2/fs/hfs/super.c	Wed Jul  3 00:22:36 2002
@@ -198,6 +198,8 @@
 {
 	struct hfs_mdb *mdb = HFS_SB(sb)->s_mdb;
 
+	lock_kernel();
+
 	buf->f_type = HFS_SUPER_MAGIC;
 	buf->f_bsize = HFS_SECTOR_SIZE;
 	buf->f_blocks = mdb->alloc_blksz * mdb->fs_ablocks;
@@ -207,6 +209,8 @@
 	buf->f_ffree = mdb->free_ablocks;
 	buf->f_namelen = HFS_NAMELEN;
 
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/hpfs/super.c linux-2.5.24-statfs2/fs/hpfs/super.c
--- linux-2.5.24/fs/hpfs/super.c	Tue Jun 18 19:11:56 2002
+++ linux-2.5.24-statfs2/fs/hpfs/super.c	Wed Jul  3 00:28:21 2002
@@ -134,6 +134,8 @@
 
 int hpfs_statfs(struct super_block *s, struct statfs *buf)
 {
+	lock_kernel();
+
 	/*if (s->s_hpfs_n_free == -1) {*/
 		s->s_hpfs_n_free = count_bitmaps(s);
 		s->s_hpfs_n_free_dnodes = hpfs_count_one_bitmap(s, s->s_hpfs_dmap);
@@ -146,6 +148,9 @@
 	buf->f_files = s->s_hpfs_dirband_size / 4;
 	buf->f_ffree = s->s_hpfs_n_free_dnodes;
 	buf->f_namelen = 254;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/jffs/inode-v23.c linux-2.5.24-statfs2/fs/jffs/inode-v23.c
--- linux-2.5.24/fs/jffs/inode-v23.c	Tue Jun 18 19:11:56 2002
+++ linux-2.5.24-statfs2/fs/jffs/inode-v23.c	Wed Jul  3 00:22:36 2002
@@ -383,7 +383,11 @@
 jffs_statfs(struct super_block *sb, struct statfs *buf)
 {
 	struct jffs_control *c = (struct jffs_control *) sb->u.generic_sbp;
-	struct jffs_fmcontrol *fmc = c->fmc;
+	struct jffs_fmcontrol *fmc;
+
+	lock_kernel();
+
+	fmc = c->fmc;
 
 	D2(printk("jffs_statfs()\n"));
 
@@ -401,6 +405,9 @@
 	buf->f_ffree = buf->f_bfree;
 	/* buf->f_fsid = 0; */
 	buf->f_namelen = JFFS_MAX_NAME_LEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/jffs2/fs.c linux-2.5.24-statfs2/fs/jffs2/fs.c
--- linux-2.5.24/fs/jffs2/fs.c	Tue Jun 18 19:11:53 2002
+++ linux-2.5.24-statfs2/fs/jffs2/fs.c	Wed Jul  3 00:22:36 2002
@@ -52,6 +52,8 @@
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
 	unsigned long avail;
 
+	lock_kernel();
+
 	buf->f_type = JFFS2_SUPER_MAGIC;
 	buf->f_bsize = 1 << PAGE_SHIFT;
 	buf->f_blocks = c->flash_size >> PAGE_SHIFT;
@@ -184,6 +186,7 @@
 
 	spin_unlock_bh(&c->erase_completion_lock);
 
+	unlock_kernel();
 
 	return 0;
 }
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/jfs/super.c linux-2.5.24-statfs2/fs/jfs/super.c
--- linux-2.5.24/fs/jfs/super.c	Wed Jun 26 01:07:20 2002
+++ linux-2.5.24-statfs2/fs/jfs/super.c	Wed Jul  3 00:22:36 2002
@@ -21,6 +21,7 @@
 #include <linux/config.h>
 #include <linux/module.h>
 #include <linux/completion.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include "jfs_incore.h"
 #include "jfs_filsys.h"
@@ -96,7 +97,11 @@
 {
 	struct jfs_sb_info *sbi = JFS_SBI(sb);
 	s64 maxinodes;
-	imap_t *imap = JFS_IP(sbi->ipimap)->i_imap;
+	imap_t *imap;
+
+	lock_kernel();
+
+	imap = JFS_IP(sbi->ipimap)->i_imap;
 
 	jFYI(1, ("In jfs_statfs\n"));
 	buf->f_type = JFS_SUPER_MAGIC;
@@ -121,6 +126,9 @@
 				    atomic_read(&imap->im_numfree));
 
 	buf->f_namelen = JFS_NAME_MAX;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/nfs/inode.c linux-2.5.24-statfs2/fs/nfs/inode.c
--- linux-2.5.24/fs/nfs/inode.c	Tue Jun 18 19:11:57 2002
+++ linux-2.5.24-statfs2/fs/nfs/inode.c	Wed Jul  3 00:28:52 2002
@@ -474,6 +474,8 @@
 	struct nfs_fsinfo res;
 	int error;
 
+	lock_kernel();
+
 	error = server->rpc_ops->statfs(server, NFS_FH(sb->s_root->d_inode), &res);
 	buf->f_type = NFS_SUPER_MAGIC;
 	if (error < 0)
@@ -491,11 +493,17 @@
 	if (res.namelen == 0 || res.namelen > server->namelen)
 		res.namelen = server->namelen;
 	buf->f_namelen = res.namelen;
+
+ out:
+	unlock_kernel();
+
 	return 0;
+
  out_err:
-	printk("nfs_statfs: statfs error = %d\n", -error);
+	printk(KERN_WARNING "nfs_statfs: statfs error = %d\n", -error);
 	buf->f_bsize = buf->f_blocks = buf->f_bfree = buf->f_bavail = -1;
-	return 0;
+	goto out;
+
 }
 
 static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt)
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/ntfs/super.c linux-2.5.24-statfs2/fs/ntfs/super.c
--- linux-2.5.24/fs/ntfs/super.c	Wed Jun 26 01:07:20 2002
+++ linux-2.5.24-statfs2/fs/ntfs/super.c	Wed Jul  3 00:22:36 2002
@@ -27,6 +27,7 @@
 #include <linux/blkdev.h>	/* For bdev_hardsect_size(). */
 #include <linux/backing-dev.h>
 #include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
 
 #include "ntfs.h"
 #include "sysctl.h"
@@ -1334,6 +1335,8 @@
 {
 	ntfs_volume *vol = NTFS_SB(sb);
 	s64 size;
+	
+	lock_kernel();
 
 	ntfs_debug("Entering.");
 	/* Type of filesystem. */
@@ -1372,6 +1375,9 @@
 	sfs->f_fsid.val[1] = (vol->serial_no >> 32) & 0xffffffff;
 	/* Maximum length of filenames. */
 	sfs->f_namelen	   = NTFS_MAX_NAME_LEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/open.c linux-2.5.24-statfs2/fs/open.c
--- linux-2.5.24/fs/open.c	Tue Jun 18 19:11:46 2002
+++ linux-2.5.24-statfs2/fs/open.c	Wed Jul  3 00:22:36 2002
@@ -30,9 +30,7 @@
 		retval = -ENOSYS;
 		if (sb->s_op && sb->s_op->statfs) {
 			memset(buf, 0, sizeof(struct statfs));
-			lock_kernel();
 			retval = sb->s_op->statfs(sb, buf);
-			unlock_kernel();
 		}
 	}
 	return retval;
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/qnx4/inode.c linux-2.5.24-statfs2/fs/qnx4/inode.c
--- linux-2.5.24/fs/qnx4/inode.c	Tue Jun 18 19:11:52 2002
+++ linux-2.5.24-statfs2/fs/qnx4/inode.c	Wed Jul  3 00:29:20 2002
@@ -281,6 +281,8 @@
 
 static int qnx4_statfs(struct super_block *sb, struct statfs *buf)
 {
+	lock_kernel();
+
 	buf->f_type    = sb->s_magic;
 	buf->f_bsize   = sb->s_blocksize;
 	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
@@ -288,6 +290,8 @@
 	buf->f_bavail  = buf->f_bfree;
 	buf->f_namelen = QNX4_NAME_MAX;
 
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/reiserfs/super.c linux-2.5.24-statfs2/fs/reiserfs/super.c
--- linux-2.5.24/fs/reiserfs/super.c	Tue Jun 18 19:11:54 2002
+++ linux-2.5.24-statfs2/fs/reiserfs/super.c	Wed Jul  3 00:22:36 2002
@@ -1257,6 +1257,8 @@
 {
   struct reiserfs_super_block * rs = SB_DISK_SUPER_BLOCK (s);
   
+  lock_kernel();
+
   buf->f_namelen = (REISERFS_MAX_NAME (s->s_blocksize));
   buf->f_ffree   = -1;
   buf->f_files   = -1;
@@ -1266,6 +1268,9 @@
   buf->f_bsize   = s->s_blocksize;
   /* changed to accomodate gcc folks.*/
   buf->f_type    =  REISERFS_SUPER_MAGIC;
+
+  unlock_kernel();
+
   return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/smbfs/inode.c linux-2.5.24-statfs2/fs/smbfs/inode.c
--- linux-2.5.24/fs/smbfs/inode.c	Tue Jun 18 19:11:48 2002
+++ linux-2.5.24-statfs2/fs/smbfs/inode.c	Wed Jul  3 00:22:36 2002
@@ -604,7 +604,13 @@
 static int
 smb_statfs(struct super_block *sb, struct statfs *buf)
 {
-	int result = smb_proc_dskattr(sb, buf);
+	int result;
+	
+	lock_kernel();
+
+	result = smb_proc_dskattr(sb, buf);
+
+	unlock_kernel();
 
 	buf->f_type = SMB_SUPER_MAGIC;
 	buf->f_namelen = SMB_MAXPATHLEN;
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/udf/super.c linux-2.5.24-statfs2/fs/udf/super.c
--- linux-2.5.24/fs/udf/super.c	Tue Jun 18 19:11:56 2002
+++ linux-2.5.24-statfs2/fs/udf/super.c	Wed Jul  3 00:29:44 2002
@@ -1726,6 +1726,8 @@
 static int
 udf_statfs(struct super_block *sb, struct statfs *buf)
 {
+	lock_kernel();
+
 	buf->f_type = UDF_SUPER_MAGIC;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = UDF_SB_PARTLEN(sb, UDF_SB_PARTITION(sb));
@@ -1738,6 +1740,8 @@
 	/* __kernel_fsid_t f_fsid */
 	buf->f_namelen = UDF_NAME_LEN;
 
+	unlock_kernel();
+
 	return 0;
 }
 
diff -Naur -X /mnt/elbrus/home/pmenage/dontdiff linux-2.5.24/fs/ufs/super.c linux-2.5.24-statfs2/fs/ufs/super.c
--- linux-2.5.24/fs/ufs/super.c	Tue Jun 18 19:11:44 2002
+++ linux-2.5.24-statfs2/fs/ufs/super.c	Wed Jul  3 00:22:36 2002
@@ -959,6 +959,8 @@
 	struct ufs_sb_private_info * uspi;
 	struct ufs_super_block_first * usb1;
 
+	lock_kernel();
+
 	uspi = sb->u.ufs_sb.s_uspi;
 	usb1 = ubh_get_usb_first (USPI_UBH);
 	
@@ -972,6 +974,9 @@
 	buf->f_files = uspi->s_ncg * uspi->s_ipg;
 	buf->f_ffree = fs32_to_cpu(sb, usb1->fs_cstotal.cs_nifree);
 	buf->f_namelen = UFS_MAXNAMLEN;
+
+	unlock_kernel();
+
 	return 0;
 }
 

Re: [PATCH] Shift BKL into ->statfs()

[Oleg Drokin]

Hello!

On Wed, Jul 03, 2002 at 02:25:02AM -0400, Alexander Viro wrote:

> 	2) ext2, shmem, FAT, minix and sysv ->statfs() don't need BKL.

reiserfs does not need BKL in ->statfs() too.

Bye,
    Oleg

Re: [PATCH] Shift BKL into ->statfs()

[Anton Altaparmakov]

At 07:25 03/07/02, Alexander Viro wrote:
>         2) ext2, shmem, FAT, minix and sysv ->statfs() don't need BKL.
>
>         3) efs and vxfs are read-only.

Just to chime in: NTFS doesn't need BKL either as it is read-only.

Also it uses its own locking, so once read-write is enabled only a minor 
modification will be needed (read mft_ino->i_size under protection of 
mftbmp_lock semaphore) to make it race free without the BKL, too. But no 
need to worry about that change, I will take care of that later...

Best regards,

         Anton


-- 
   "I've not lost my mind. It's backed up on tape somewhere." - Unknown
-- 
Anton Altaparmakov <aia21 at cantab.net> (replace at with @)
Linux NTFS Maintainer / IRC: #ntfs on irc.openprojects.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/

Re: [PATCH] Shift BKL into ->statfs()

[Matthew Wilcox]

On Wed, Jul 03, 2002 at 12:57:56AM -0700, Paul Menage wrote:
> All ->statfs() implementations have been modified to take the BKL,
> except for the following:
> 
> - those that don't reference any external mutable data:

... also adfs_statfs, 

> - those that already have their own locking:

... also affs_statfs, bfs_statfs, ext3_statfs, hfs_statfs, jffs2_statfs,
jfs_statfs

I think ufs_statfs needs lock_super() due to its handling of fragments.

qnx4 looks terribly broken for read-write anyway... probably just keep the
lock_kernel / unlock_kernel around the call to qnx4_count_free_blocks().

I haven't audited coda, hpfs, jffs, nfs, smbfs & udf.

-- 
Revolutions do not require corporate support.

Re: [PATCH] Shift BKL into ->statfs()

[Matthew Wilcox]

On Wed, Jul 03, 2002 at 12:57:56AM -0700, Paul Menage wrote:
> All ->statfs() implementations have been modified to take the BKL,
> except for the following:
> 
> - those that don't reference any external mutable data:

... also adfs_statfs, 

> - those that already have their own locking:

... also affs_statfs, bfs_statfs, ext3_statfs, hfs_statfs, jffs2_statfs,
jfs_statfs

I think ufs_statfs needs lock_super() due to its handling of fragments.

qnx4 looks terribly broken for read-write anyway... probably just keep the
lock_kernel / unlock_kernel around the call to qnx4_count_free_blocks().

I haven't audited coda, hpfs, jffs, nfs, smbfs & udf.

-- 
Revolutions do not require corporate support.