[PATCH] BKL shifted into ->lookup()

	OK, here comes: ->lookup() had lost BKL, all in-tree instances of
->lookup() converted.

	I'm adding Documentation/filesystems/porting - with the list of
API changes since 2.4.  Are you OK with that format?

(and yes, this sucker is *post*-compile ;-)

Documentation/filesystems/Locking

@@ -49,7 +49,7 @@ prototypes:
 locking rules:
 	all may block
 		BKL	i_sem(inode)
-lookup:		yes	yes
+lookup:		no	yes
 create:		yes	yes
 link:		yes	yes
 mknod:		yes	yes

Documentation/filesystems/porting

+Changes since 2.5.0:
+
+--- 
+[recommeneded]
+
+New helpers: sb_bread(), sb_getblk(), sb_get_hash_table(), set_bh(),
+	sb_set_blocksize() and sb_min_blocksize().
+
+Use them.
+
+--- 
+[recommeneded]
+
+New methods: ->alloc_inode() and ->destroy_inode().
+
+Remove inode->u.foo_inode_i
+Declare
+	struct foo_inode_info {
+		/* fs-private stuff */
+		struct inode vfs_inode;
+	};
+	static inline FOO_I(struct inode *inode)
+	{
+		return list_entry(inode, struct foo_inode_info, vfs_inode);
+	}
+
+Use FOO_I(inode) instead of &inode->u.foo_inode_i;
+
+Add foo_alloc_inode() and foo_destory_inode() - the former should allocate
+foo_inode_info and return the address of ->vfs_inode, the latter should free
+FOO_I(inode) (see in-tree filesystems for examples).
+
+Make them ->alloc_inode and ->destroy_inode in your super_operations.
+
+Keep in mind that now you need explicit initialization of private data -
+typically in ->read_inode() and after getting an inode from new_inode().
+
+At some point that will become mandatory.
+
+---
+[mandatory]
+
+Change of file_system_type method (->read_super to ->get_sb)
+
+->read_super() is no more.  Ditto for DECLARE_FSTYPE and DECLARE_FSTYPE_DEV.
+
+Turn your foo_read_super() into a function that would return 0 in case of
+success and negative number in case of error (-EINVAL unless you have more
+informative error value to report).  Call it foo_fill_super().  Now declare
+
+struct super_block foo_get_sb(struct file_system_type *fs_type,
+	int flags, char *dev_name, void *data)
+{
+	return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
+}
+
+(or similar with s/bdev/nodev/ or s/bdev/single/, depending on the kind of
+filesystem).
+
+Replace DECLARE_FSTYPE... with explicit initializer and have ->get_sb set as
+foo_get_sb.
+
+---
+[mandatory]
+
+Locking change: ->s_vfs_rename_sem is taken only by cross-directory renames.
+Most likely there is no need to change anything, but if you relied on
+global exclusion between renames for some internal purpose - you need to
+change your internal locking.  Otherwise exclusion warranties remain the
+same (i.e. parents are victim are locked, etc.).
+
+---
+[informational]
+
+Now we have the exclusion between ->lookup() and directory removal (by
+->rmdir() and ->rename()).  If you used to need that exclusion and do
+it by internal locking (most of filesystems couldn't care less) - you
+can relax your locking.
+
+---
+[mandatory]
+
+->lookup() is called without BKL now.  Grab it on the entry, drop upon return
+- that will guarantee the same locking you used to have.  If your ->lookup()
+or its parts do not need BKL - better yet, now you can shift lock_kernel()/
+unlock_kernel() so that they would protect exactly what needs to be protected.

drivers/hotplug/pci_hotplug_core.c

@@ -94,6 +94,7 @@ static int pcihpfs_statfs (struct super_block *sb, struct statfs *buf)
 	return 0;
 }
 
+/* SMP-safe */
 static struct dentry *pcihpfs_lookup (struct inode *dir, struct dentry *dentry)
 {
 	d_add(dentry, NULL);

drivers/isdn/avmb1/capifs.c

@@ -25,6 +25,7 @@
 #include <linux/major.h>
 #include <linux/slab.h>
 #include <linux/ctype.h>
+#include <linux/smp_lock.h>
 #include <asm/bitops.h>
 #include <asm/uaccess.h>
 
@@ -170,10 +171,12 @@ static struct dentry *capifs_root_lookup(struct inode * dir, struct dentry * den
 	if (tmp == p || *tmp)
 		return NULL;
 
+	lock_kernel();
 	for (i = 0, np = sbi->nccis ; i < sbi->max_ncci; i++, np++) {
 		if (np->used && np->num == num && np->type == type)
 			break;
 	}
+	unlock_kernel();
 
 	if ( i >= sbi->max_ncci )
 		return NULL;

drivers/net/wan/comx.c

@@ -64,6 +64,7 @@
 #include <asm/uaccess.h>
 #include <linux/ctype.h>
 #include <linux/init.h>
+#include <linux/smp_lock.h>
 
 #ifdef CONFIG_KMOD
 #include <linux/kmod.h>
@@ -928,6 +929,7 @@ static struct dentry *comx_lookup(struct inode *dir, struct dentry *dentry)
 	struct proc_dir_entry *de;
 	struct inode *inode = NULL;
 
+	lock_kernel();
 	if ((de = PDE(dir)) != NULL) {
 		for (de = de->subdir ; de ; de = de->next) {
 			if ((de && de->low_ino) && 
@@ -937,12 +939,14 @@ static struct dentry *comx_lookup(struct inode *dir, struct dentry *dentry)
 			 	if ((inode = proc_get_inode(dir->i_sb, 
 			 	    de->low_ino, de)) == NULL) { 
 			 		printk(KERN_ERR "COMX: lookup error\n"); 
+					unlock_kernel();
 			 		return ERR_PTR(-EINVAL); 
 			 	}
 				break;
 			}
 		}
 	}
+	unlock_kernel();
 	dentry->d_op = &comx_dentry_operations;
 	d_add(dentry, inode);
 	return NULL;

drivers/usb/inode.c

@@ -142,6 +142,7 @@ static int parse_options(struct super_block *s, char *data)
 
 /* --------------------------------------------------------------------- */
 
+/* SMP-safe */
 static struct dentry *usbfs_lookup (struct inode *dir, struct dentry *dentry)
 {
 	d_add(dentry, NULL);

fs/adfs/dir.c

@@ -17,6 +17,7 @@
 #include <linux/time.h>
 #include <linux/stat.h>
 #include <linux/spinlock.h>
+#include <linux/smp_lock.h>
 
 #include "adfs.h"
 
@@ -271,6 +272,7 @@ struct dentry *adfs_lookup(struct inode *dir, struct dentry *dentry)
 	int error;
 
 	dentry->d_op = &adfs_dentry_operations;	
+	lock_kernel();
 	error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
 	if (error == 0) {
 		error = -EACCES;
@@ -282,6 +284,7 @@ struct dentry *adfs_lookup(struct inode *dir, struct dentry *dentry)
 		if (inode)
 			error = 0;
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return ERR_PTR(error);
 }

fs/affs/namei.c

@@ -16,6 +16,7 @@
 #include <linux/fcntl.h>
 #include <linux/locks.h>
 #include <linux/amigaffs.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 
 #include <linux/errno.h>
@@ -217,11 +218,14 @@ affs_lookup(struct inode *dir, struct dentry *dentry)
 
 	pr_debug("AFFS: lookup(\"%.*s\")\n",(int)dentry->d_name.len,dentry->d_name.name);
 
+	lock_kernel();
 	affs_lock_dir(dir);
 	bh = affs_find_entry(dir, dentry);
 	affs_unlock_dir(dir);
-	if (IS_ERR(bh))
+	if (IS_ERR(bh)) {
+		unlock_kernel();
 		return ERR_PTR(PTR_ERR(bh));
+	}
 	if (bh) {
 		u32 ino = bh->b_blocknr;
 
@@ -235,10 +239,13 @@ affs_lookup(struct inode *dir, struct dentry *dentry)
 		}
 		affs_brelse(bh);
 		inode = iget(sb, ino);
-		if (!inode)
+		if (!inode) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
 	dentry->d_op = AFFS_SB->s_flags & SF_INTL ? &affs_intl_dentry_operations : &affs_dentry_operations;
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/autofs/dir.c

@@ -17,6 +17,7 @@
  * layer. So all children are negative and dcache-based versions of operations
  * are OK.
  */
+/* SMP-safe */
 static struct dentry *autofs_dir_lookup(struct inode *dir,struct dentry *dentry)
 {
 	d_add(dentry, NULL);

fs/autofs/root.c

@@ -197,10 +197,13 @@ static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentr
 	int oz_mode;
 
 	DPRINTK(("autofs_root_lookup: name = "));
+	lock_kernel();
 	autofs_say(dentry->d_name.name,dentry->d_name.len);
 
-	if (dentry->d_name.len > NAME_MAX)
+	if (dentry->d_name.len > NAME_MAX) {
+		unlock_kernel();
 		return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
+	}
 
 	sbi = autofs_sbi(dir->i_sb);
 
@@ -231,9 +234,12 @@ static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentr
 	 * a signal. If so we can force a restart..
 	 */
 	if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
-		if (signal_pending(current))
+		if (signal_pending(current)) {
+			unlock_kernel();
 			return ERR_PTR(-ERESTARTNOINTR);
+		}
 	}
+	unlock_kernel();
 
 	/*
 	 * If this dentry is unhashed, then we shouldn't honour this

fs/autofs4/root.c

@@ -229,6 +229,7 @@ static struct dentry_operations autofs4_dentry_operations = {
 
 /* Lookups in non-root dirs never find anything - if it's there, it's
    already in the dcache */
+/* SMP-safe */
 static struct dentry *autofs4_dir_lookup(struct inode *dir, struct dentry *dentry)
 {
 #if 0
@@ -256,6 +257,7 @@ static struct dentry *autofs4_root_lookup(struct inode *dir, struct dentry *dent
 
 	sbi = autofs4_sbi(dir->i_sb);
 
+	lock_kernel();
 	oz_mode = autofs4_oz_mode(sbi);
 	DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
 		 current->pid, current->pgrp, sbi->catatonic, oz_mode));
@@ -288,9 +290,12 @@ static struct dentry *autofs4_root_lookup(struct inode *dir, struct dentry *dent
 	 * a signal. If so we can force a restart..
 	 */
 	if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
-		if (signal_pending(current))
+		if (signal_pending(current)) {
+			unlock_kernel();
 			return ERR_PTR(-ERESTARTNOINTR);
+		}
 	}
+	unlock_kernel();
 
 	/*
 	 * If this dentry is unhashed, then we shouldn't honour this

fs/bfs/dir.c

@@ -8,6 +8,7 @@
 #include <linux/string.h>
 #include <linux/bfs_fs.h>
 #include <linux/locks.h>
+#include <linux/smp_lock.h>
 
 #include "bfs_defs.h"
 
@@ -125,14 +126,18 @@ static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry)
 	if (dentry->d_name.len > BFS_NAMELEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
+	lock_kernel();
 	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
 	if (bh) {
 		unsigned long ino = le32_to_cpu(de->ino);
 		brelse(bh);
 		inode = iget(dir->i_sb, ino);
-		if (!inode)
+		if (!inode) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/binfmt_misc.c

@@ -618,6 +618,7 @@ static struct file_operations bm_status_operations = {
 
 /* / */
 
+/* SMP-safe */
 static struct dentry * bm_lookup(struct inode *dir, struct dentry *dentry)
 {
 	d_add(dentry, NULL);

fs/coda/dir.c

@@ -112,6 +112,7 @@ static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry)
         CDEBUG(D_INODE, "name %s, len %ld in ino %ld, fid %s\n", 
 	       name, (long)length, dir->i_ino, coda_i2s(dir));
 
+	lock_kernel();
         /* control object, create inode on the fly */
         if (coda_isroot(dir) && coda_iscontrol(name, length)) {
 	        error = coda_cnode_makectl(&res_inode, dir->i_sb);
@@ -135,10 +136,14 @@ static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry)
 		}
 
 	    	error = coda_cnode_make(&res_inode, &resfid, dir->i_sb);
-		if (error) return ERR_PTR(error);
+		if (error) {
+			unlock_kernel();
+			return ERR_PTR(error);
+		}
 	} else if (error != -ENOENT) {
 	        CDEBUG(D_INODE, "error for %s(%*s)%d\n",
 		       coda_i2s(dir), (int)length, name, error);
+		unlock_kernel();
 		return ERR_PTR(error);
 	}
 	CDEBUG(D_INODE, "lookup: %s is (%s), type %d result %d, dropme %d\n",
@@ -152,6 +157,7 @@ static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry)
 		d_drop(entry);
 		coda_flag_inode(res_inode, C_VATTR);
 	}
+	unlock_kernel();
         return NULL;
 }
 

fs/cramfs/inode.c

@@ -19,6 +19,7 @@
 #include <linux/locks.h>
 #include <linux/blkdev.h>
 #include <linux/cramfs_fs.h>
+#include <linux/smp_lock.h>
 #include <asm/semaphore.h>
 
 #include <asm/uaccess.h>
@@ -330,8 +331,10 @@ static int cramfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 static struct dentry * cramfs_lookup(struct inode *dir, struct dentry *dentry)
 {
 	unsigned int offset = 0;
-	int sorted = dir->i_sb->CRAMFS_SB_FLAGS & CRAMFS_FLAG_SORTED_DIRS;
+	int sorted;
 
+	lock_kernel();
+	sorted = dir->i_sb->CRAMFS_SB_FLAGS & CRAMFS_FLAG_SORTED_DIRS;
 	while (offset < dir->i_size) {
 		struct cramfs_inode *de;
 		char *name;
@@ -354,8 +357,10 @@ static struct dentry * cramfs_lookup(struct inode *dir, struct dentry *dentry)
 			continue;
 
 		for (;;) {
-			if (!namelen)
+			if (!namelen) {
+				unlock_kernel();
 				return ERR_PTR(-EIO);
+			}
 			if (name[namelen-1])
 				break;
 			namelen--;
@@ -367,12 +372,14 @@ static struct dentry * cramfs_lookup(struct inode *dir, struct dentry *dentry)
 			continue;
 		if (!retval) {
 			d_add(dentry, get_cramfs_inode(dir->i_sb, de));
+			unlock_kernel();
 			return NULL;
 		}
 		/* else (retval < 0) */
 		if (sorted)
 			break;
 	}
+	unlock_kernel();
 	d_add(dentry, NULL);
 	return NULL;
 }

fs/devfs/base.c

@@ -2944,10 +2944,14 @@ static struct dentry *devfs_lookup (struct inode *dir, struct dentry *dentry)
 	up on any error  */
     dentry->d_op = &devfs_dops;
     /*  First try to get the devfs entry for this directory  */
+    lock_kernel();
     parent = get_devfs_entry_from_vfs_inode (dir);
     DPRINTK (DEBUG_I_LOOKUP, "(%s): dentry: %p parent: %p by: \"%s\"\n",
 	     dentry->d_name.name, dentry, parent, current->comm);
-    if (parent == NULL) return ERR_PTR (-ENOENT);
+    if (parent == NULL) {
+	unlock_kernel();
+	return ERR_PTR (-ENOENT);
+    }
     read_lock (&parent->u.dir.lock);
     de = _devfs_search_dir (parent, dentry->d_name.name, dentry->d_name.len);
     read_unlock (&parent->u.dir.lock);
@@ -2972,6 +2976,7 @@ static struct dentry *devfs_lookup (struct inode *dir, struct dentry *dentry)
 	if (try_modload (parent, fs_info,
 			 dentry->d_name.name, dentry->d_name.len, &tmp) < 0)
 	{   /*  Lookup event was not queued to devfsd  */
+	    unlock_kernel();
 	    d_add (dentry, NULL);
 	    return NULL;
 	}
@@ -3014,6 +3019,7 @@ static struct dentry *devfs_lookup (struct inode *dir, struct dentry *dentry)
     wake_up (&lookup_info.wait_queue);
     write_unlock (&parent->u.dir.lock);
     devfs_put (de);
+    unlock_kernel();
     return retval;
 }   /*  End Function devfs_lookup  */
 

fs/devpts/root.c

@@ -14,6 +14,7 @@
 #include <linux/stat.h>
 #include <linux/param.h>
 #include <linux/string.h>
+#include <linux/smp_lock.h>
 #include "devpts_i.h"
 
 static int devpts_root_readdir(struct file *,void *,filldir_t);
@@ -126,10 +127,12 @@ static struct dentry *devpts_root_lookup(struct inode * dir, struct dentry * den
 	if ( entry >= sbi->max_ptys )
 		return NULL;
 
+	lock_kernel();
 	if ( sbi->inodes[entry] )
 		atomic_inc(&sbi->inodes[entry]->i_count);
 	
 	d_add(dentry, sbi->inodes[entry]);
+	unlock_kernel();
 
 	return NULL;
 }

fs/driverfs/inode.c

@@ -68,6 +68,7 @@ static int driverfs_statfs(struct super_block *sb, struct statfs *buf)
 	return 0;
 }
 
+/* SMP-safe */
 static struct dentry *driverfs_lookup(struct inode *dir, struct dentry *dentry)
 {
 	d_add(dentry, NULL);

fs/efs/namei.c

@@ -8,6 +8,7 @@
 
 #include <linux/string.h>
 #include <linux/efs_fs.h>
+#include <linux/smp_lock.h>
 
 static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len) {
 	struct buffer_head *bh;
@@ -57,18 +58,17 @@ static efs_ino_t efs_find_entry(struct inode *inode, const char *name, int len)
 
 struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry) {
 	efs_ino_t inodenum;
-	struct inode * inode;
-
-	if (!dir || !S_ISDIR(dir->i_mode))
-		return ERR_PTR(-ENOENT);
-
-	inode = NULL;
+	struct inode * inode = NULL;
 
+	lock_kernel();
 	inodenum = efs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
 	if (inodenum) {
-		if (!(inode = iget(dir->i_sb, inodenum)))
+		if (!(inode = iget(dir->i_sb, inodenum))) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 
 	d_add(dentry, inode);
 	return NULL;

fs/ext2/namei.c

@@ -31,6 +31,7 @@
 
 #include "ext2.h"
 #include <linux/pagemap.h>
+#include <linux/smp_lock.h>
 
 /*
  * Couple of helper functions - make the code slightly cleaner.
@@ -72,13 +73,17 @@ static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry)
 	if (dentry->d_name.len > EXT2_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
+	lock_kernel();
 	ino = ext2_inode_by_name(dir, dentry);
 	inode = NULL;
 	if (ino) {
 		inode = iget(dir->i_sb, ino);
-		if (!inode) 
+		if (!inode)  {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/ext3/namei.c

@@ -28,6 +28,7 @@
 #include <linux/string.h>
 #include <linux/locks.h>
 #include <linux/quotaops.h>
+#include <linux/smp_lock.h>
 
 
 /*
@@ -205,6 +206,7 @@ static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry)
 	if (dentry->d_name.len > EXT3_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
+	lock_kernel();
 	bh = ext3_find_entry(dentry, &de);
 	inode = NULL;
 	if (bh) {
@@ -212,9 +214,12 @@ static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry)
 		brelse (bh);
 		inode = iget(dir->i_sb, ino);
 
-		if (!inode)
+		if (!inode) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/freevxfs/vxfs_lookup.c

@@ -38,6 +38,7 @@
 #include <linux/highmem.h>
 #include <linux/kernel.h>
 #include <linux/pagemap.h>
+#include <linux/smp_lock.h>
 
 #include "vxfs.h"
 #include "vxfs_dir.h"
@@ -210,13 +211,16 @@ vxfs_lookup(struct inode *dip, struct dentry *dp)
 	if (dp->d_name.len > VXFS_NAMELEN)
 		return ERR_PTR(-ENAMETOOLONG);
 				 
+	lock_kernel();
 	ino = vxfs_inode_by_name(dip, dp);
-	if (ino == 0)
-		return NULL;
-
-	ip = iget(dip->i_sb, ino);
-	if (!ip)
-		return ERR_PTR(-EACCES);
+	if (ino) {
+		ip = iget(dip->i_sb, ino);
+		if (!ip) {
+			unlock_kernel();
+			return ERR_PTR(-EACCES);
+		}
+	}
+	unlock_kernel();
 	d_add(dp, ip);
 	return NULL;
 }

fs/hfs/dir_cap.c

@@ -24,6 +24,7 @@
 #include <linux/hfs_fs_sb.h>
 #include <linux/hfs_fs_i.h>
 #include <linux/hfs_fs.h>
+#include <linux/smp_lock.h>
 
 /*================ Forward declarations ================*/
 
@@ -102,6 +103,8 @@ static struct dentry *cap_lookup(struct inode * dir, struct dentry *dentry)
 	struct hfs_cat_key key;
 	struct inode *inode = NULL;
 
+	lock_kernel();
+
 	dentry->d_op = &hfs_dentry_operations;
 	entry = HFS_I(dir)->entry;
 	dtype = HFS_ITYPE(dir->i_ino);
@@ -112,7 +115,7 @@ static struct dentry *cap_lookup(struct inode * dir, struct dentry *dentry)
 
 	/* no need to check for "."  or ".." */
 
-	/* Check for special directories if in a normal directory.
+	/* Check for epecial directories if in a normal directory.
 	   Note that cap_dupdir() does an iput(dir). */
 	if (dtype==HFS_CAP_NDIR) {
 		/* Check for ".resource", ".finderinfo" and ".rootinfo" */
@@ -149,6 +152,7 @@ static struct dentry *cap_lookup(struct inode * dir, struct dentry *dentry)
 	}
 
 done:
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/hfs/dir_dbl.c

@@ -20,6 +20,7 @@
 #include <linux/hfs_fs_sb.h>
 #include <linux/hfs_fs_i.h>
 #include <linux/hfs_fs.h>
+#include <linux/smp_lock.h>
 
 /*================ Forward declarations ================*/
 
@@ -114,6 +115,7 @@ static struct dentry *dbl_lookup(struct inode * dir, struct dentry *dentry)
 	struct hfs_cat_key key;
 	struct inode *inode = NULL;
 
+	lock_kernel();
 	dentry->d_op = &hfs_dentry_operations;
 	entry = HFS_I(dir)->entry;
 	
@@ -145,6 +147,7 @@ static struct dentry *dbl_lookup(struct inode * dir, struct dentry *dentry)
 	}
 	
 done:
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/hfs/dir_nat.c

@@ -26,6 +26,7 @@
 #include <linux/hfs_fs_sb.h>
 #include <linux/hfs_fs_i.h>
 #include <linux/hfs_fs.h>
+#include <linux/smp_lock.h>
 
 /*================ Forward declarations ================*/
 
@@ -104,6 +105,7 @@ static struct dentry *nat_lookup(struct inode * dir, struct dentry *dentry)
 	struct hfs_cat_key key;
 	struct inode *inode = NULL;
 
+	lock_kernel();
 	dentry->d_op = &hfs_dentry_operations;
 	entry = HFS_I(dir)->entry;
 	dtype = HFS_ITYPE(dir->i_ino);
@@ -154,6 +156,7 @@ static struct dentry *nat_lookup(struct inode * dir, struct dentry *dentry)
 	}
 
 done:
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/hpfs/dir.c

@@ -189,6 +189,7 @@ struct dentry *hpfs_lookup(struct inode *dir, struct dentry *dentry)
 	struct inode *result = NULL;
 	struct hpfs_inode_info *hpfs_result;
 
+	lock_kernel();
 	if ((err = hpfs_chk_name((char *)name, &len))) {
 		if (err == -ENAMETOOLONG) return ERR_PTR(-ENAMETOOLONG);
 		goto end_add;
@@ -273,6 +274,7 @@ struct dentry *hpfs_lookup(struct inode *dir, struct dentry *dentry)
 	hpfs_unlock_inode(dir);
 	end_add:
 	hpfs_set_dentry_operations(dentry);
+	unlock_kernel();
 	d_add(dentry, result);
 	return NULL;
 
@@ -286,5 +288,6 @@ struct dentry *hpfs_lookup(struct inode *dir, struct dentry *dentry)
 	/*bail:*/
 
 	hpfs_unlock_inode(dir);
+	unlock_kernel();
 	return ERR_PTR(-ENOENT);
 }

fs/isofs/namei.c

@@ -15,6 +15,7 @@
 #include <linux/mm.h>
 #include <linux/errno.h>
 #include <linux/config.h>	/* Joliet? */
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 
@@ -167,6 +168,7 @@ struct dentry *isofs_lookup(struct inode * dir, struct dentry * dentry)
 	if (!page)
 		return ERR_PTR(-ENOMEM);
 
+	lock_kernel();
 	ino = isofs_find_entry(dir, dentry, page_address(page),
 			       1024 + page_address(page));
 	__free_page(page);
@@ -174,9 +176,12 @@ struct dentry *isofs_lookup(struct inode * dir, struct dentry * dentry)
 	inode = NULL;
 	if (ino) {
 		inode = iget(dir->i_sb, ino);
-		if (!inode)
+		if (!inode) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/jffs/inode-v23.c

@@ -631,6 +631,8 @@ jffs_lookup(struct inode *dir, struct dentry *dentry)
 	len = dentry->d_name.len;
 	name = dentry->d_name.name;
 
+	lock_kernel();
+
 	D3({
 		char *s = (char *)kmalloc(len + 1, GFP_KERNEL);
 		memcpy(s, name, len);
@@ -698,6 +700,7 @@ jffs_lookup(struct inode *dir, struct dentry *dentry)
 	d_add(dentry, inode);
 	D3(printk (KERN_NOTICE "lookup(): up biglock\n"));
 	up(&c->fmc->biglock);
+	unlock_kernel();
 	return NULL;
 
 jffs_lookup_end:
@@ -705,6 +708,7 @@ jffs_lookup(struct inode *dir, struct dentry *dentry)
 	up(&c->fmc->biglock);
 
 jffs_lookup_end_no_biglock:
+	unlock_kernel();
 	return ERR_PTR(r);
 } /* jffs_lookup()  */
 

fs/jffs2/dir.c

@@ -43,6 +43,7 @@
 #include <linux/jffs2_fs_i.h>
 #include <linux/jffs2_fs_sb.h>
 #include <linux/time.h>
+#include <linux/smp_lock.h>
 #include "nodelist.h"
 
 static int jffs2_readdir (struct file *, void *, filldir_t);
@@ -98,6 +99,7 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target)
 
 	D1(printk(KERN_DEBUG "jffs2_lookup()\n"));
 
+	lock_kernel();
 	dir_f = JFFS2_INODE_INFO(dir_i);
 	c = JFFS2_SB_INFO(dir_i->i_sb);
 
@@ -118,10 +120,12 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target)
 	if (ino) {
 		inode = iget(dir_i->i_sb, ino);
 		if (!inode) {
+			unlock_kernel();
 			printk(KERN_WARNING "iget() failed for ino #%u\n", ino);
 			return (ERR_PTR(-EIO));
 		}
 	}
+	unlock_kernel();
 
 	d_add(target, inode);
 

fs/minix/namei.c

@@ -6,6 +6,7 @@
 
 #include <linux/fs.h>
 #include <linux/minix_fs.h>
+#include <linux/smp_lock.h>
 #include <linux/pagemap.h>
 
 static inline void inc_count(struct inode *inode)
@@ -66,13 +67,17 @@ static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry)
 	if (dentry->d_name.len > dir->i_sb->u.minix_sb.s_namelen)
 		return ERR_PTR(-ENAMETOOLONG);
 
+	lock_kernel();
 	ino = minix_inode_by_name(dentry);
 	if (ino) {
 		inode = iget(dir->i_sb, ino);
  
-		if (!inode)
+		if (!inode) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/msdos/namei.c

@@ -12,6 +12,7 @@
 
 #include <linux/time.h>
 #include <linux/msdos_fs.h>
+#include <linux/smp_lock.h>
 
 #define MSDOS_DEBUG 0
 #define PRINTK(x)
@@ -215,6 +216,7 @@ struct dentry *msdos_lookup(struct inode *dir,struct dentry *dentry)
 
 	dentry->d_op = &msdos_dentry_operations;
 
+	lock_kernel();
 	res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &bh,
 			&de, &ino);
 
@@ -231,6 +233,7 @@ struct dentry *msdos_lookup(struct inode *dir,struct dentry *dentry)
 out:
 	if (bh)
 		fat_brelse(sb, bh);
+	unlock_kernel();
 	return ERR_PTR(res);
 }
 

fs/namei.c

@@ -304,9 +304,7 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, i
 		struct dentry * dentry = d_alloc(parent, name);
 		result = ERR_PTR(-ENOMEM);
 		if (dentry) {
-			lock_kernel();
 			result = dir->i_op->lookup(dir, dentry);
-			unlock_kernel();
 			if (result)
 				dput(dentry);
 			else
@@ -778,9 +776,7 @@ struct dentry * lookup_hash(struct qstr *name, struct dentry * base)
 		dentry = ERR_PTR(-ENOMEM);
 		if (!new)
 			goto out;
-		lock_kernel();
 		dentry = inode->i_op->lookup(inode, new);
-		unlock_kernel();
 		if (!dentry)
 			dentry = new;
 		else

fs/ncpfs/dir.c

@@ -741,6 +741,7 @@ static struct dentry *ncp_lookup(struct inode *dir, struct dentry *dentry)
 	int error, res, len = dentry->d_name.len + 1;
 	__u8 __name[len];
 
+	lock_kernel();
 	error = -EIO;
 	if (!ncp_conn_valid(server))
 		goto finished;
@@ -785,6 +786,7 @@ static struct dentry *ncp_lookup(struct inode *dir, struct dentry *dentry)
 
 finished:
 	PPRINTK("ncp_lookup: result=%d\n", error);
+	unlock_kernel();
 	return ERR_PTR(error);
 }
 

fs/nfs/dir.c

@@ -579,6 +579,7 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry)
 	error = -ENOMEM;
 	dentry->d_op = &nfs_dentry_operations;
 
+	lock_kernel();
 	error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
 	inode = NULL;
 	if (error == -ENOENT)
@@ -593,6 +594,7 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry)
 		}
 		nfs_renew_times(dentry);
 	}
+	unlock_kernel();
 out:
 	return ERR_PTR(error);
 }

fs/ntfs/fs.c

@@ -529,6 +529,7 @@ static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *d)
 	walk.name = NULL;
 	walk.namelen = 0;
 	/* Convert to wide string. */
+	lock_kernel();
 	err = ntfs_decodeuni(NTFS_INO2VOL(dir), (char*)d->d_name.name,
 			       d->d_name.len, &walk.name, &walk.namelen);
 	if (err)
@@ -548,10 +549,12 @@ static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *d)
 	d_add(d, res);
 	ntfs_free(item);
 	ntfs_free(walk.name);
+	unlock_kernel();
 	/* Always return success, the dcache will handle negative entries. */
 	return NULL;
 err_ret:
 	ntfs_free(walk.name);
+	unlock_kernel();
 	return ERR_PTR(err);
 }
 

fs/openpromfs/inode.c

@@ -633,6 +633,7 @@ static struct dentry *openpromfs_lookup(struct inode * dir, struct dentry *dentr
 	inode = NULL;
 	name = dentry->d_name.name;
 	len = dentry->d_name.len;
+	lock_kernel();
 	if (name [0] == '.' && len == 5 && !strncmp (name + 1, "node", 4)) {
 		ino = NODEP2INO(NODE(dir->i_ino).first_prop);
 		type = OPFSL_NODENUM;
@@ -692,10 +693,13 @@ static struct dentry *openpromfs_lookup(struct inode * dir, struct dentry *dentr
 		ino = lookup_children (NODE(dir->i_ino).child, name, len);
 		if (ino)
 			type = OPFSL_DIR;
-		else
+		else {
+			unlock_kernel();
 			return ERR_PTR(-ENOENT);
+		}
 	}
 	inode = iget (dir->i_sb, ino);
+	unlock_kernel();
 	if (!inode)
 		return ERR_PTR(-EINVAL);
 	switch (type) {

fs/proc/base.c

@@ -777,6 +777,7 @@ static struct dentry_operations pid_base_dentry_operations =
 /* Lookups */
 #define MAX_MULBY10	((~0U-9)/10)
 
+/* SMP-safe */
 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry)
 {
 	unsigned int fd, c;
@@ -855,6 +856,7 @@ static struct inode_operations proc_fd_inode_operations = {
 	permission:	proc_permission,
 };
 
+/* SMP-safe */
 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
 {
 	struct inode *inode;
@@ -984,6 +986,7 @@ static struct inode_operations proc_self_inode_operations = {
 	follow_link:	proc_self_follow_link,
 };
 
+/* SMP-safe */
 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry)
 {
 	unsigned int pid, c;

fs/proc/generic.c

@@ -258,12 +258,11 @@ static struct dentry_operations proc_dentry_operations =
  */
 struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry)
 {
-	struct inode *inode;
+	struct inode *inode = NULL;
 	struct proc_dir_entry * de;
-	int error;
+	int error = -ENOENT;
 
-	error = -ENOENT;
-	inode = NULL;
+	lock_kernel();
 	de = PDE(dir);
 	if (de) {
 		for (de = de->subdir; de ; de = de->next) {
@@ -279,6 +278,7 @@ struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry)
 			}
 		}
 	}
+	unlock_kernel();
 
 	if (inode) {
 		dentry->d_op = &proc_dentry_operations;

fs/proc/root.c

@@ -16,6 +16,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <asm/bitops.h>
+#include <linux/smp_lock.h>
 
 struct proc_dir_entry *proc_net, *proc_bus, *proc_root_fs, *proc_root_driver;
 
@@ -80,15 +81,14 @@ void __init proc_root_init(void)
 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry)
 {
 	if (dir->i_ino == PROC_ROOT_INO) { /* check for safety... */
-		int nlink = proc_root.nlink;
-
-		nlink += nr_threads;
-
-		dir->i_nlink = nlink;
+		lock_kernel();
+		dir->i_nlink = proc_root.nlink + nr_threads;
+		unlock_kernel();
 	}
 
-	if (!proc_lookup(dir, dentry))
+	if (!proc_lookup(dir, dentry)) {
 		return NULL;
+	}
 	
 	return proc_pid_lookup(dir, dentry);
 }

fs/qnx4/namei.c

@@ -21,6 +21,7 @@
 #include <linux/stat.h>
 #include <linux/fcntl.h>
 #include <linux/errno.h>
+#include <linux/smp_lock.h>
 
 
 /*
@@ -115,6 +116,7 @@ struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry)
 	int len = dentry->d_name.len;
 	struct inode *foundinode = NULL;
 
+	lock_kernel();
 	if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
 		goto out;
 	/* The entry is linked, let's get the real info */
@@ -127,10 +129,12 @@ struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry)
 	brelse(bh);
 
 	if ((foundinode = iget(dir->i_sb, ino)) == NULL) {
+		unlock_kernel();
 		QNX4DEBUG(("qnx4: lookup->iget -> NULL\n"));
 		return ERR_PTR(-EACCES);
 	}
 out:
+	unlock_kernel();
 	d_add(dentry, foundinode);
 
 	return NULL;

fs/ramfs/inode.c

@@ -53,6 +53,7 @@ static int ramfs_statfs(struct super_block *sb, struct statfs *buf)
  * Lookup the data. This is trivial - if the dentry didn't already
  * exist, we know it is negative.
  */
+/* SMP-safe */
 static struct dentry * ramfs_lookup(struct inode *dir, struct dentry *dentry)
 {
 	d_add(dentry, NULL);

fs/reiserfs/namei.c

@@ -349,15 +349,18 @@ static struct dentry * reiserfs_lookup (struct inode * dir, struct dentry * dent
     if (dentry->d_name.len > REISERFS_MAX_NAME_LEN (dir->i_sb->s_blocksize))
 	return ERR_PTR(-ENAMETOOLONG);
 
+    lock_kernel();
     de.de_gen_number_bit_string = 0;
     retval = reiserfs_find_entry (dir, dentry->d_name.name, dentry->d_name.len, &path_to_entry, &de);
     pathrelse (&path_to_entry);
     if (retval == NAME_FOUND) {
 	inode = reiserfs_iget (dir->i_sb, (struct cpu_key *)&(de.de_dir_id));
 	if (!inode || IS_ERR(inode)) {
+	    unlock_kernel();
 	    return ERR_PTR(-EACCES);
         }
     }
+    unlock_kernel();
 
     d_add(dentry, inode);
     return NULL;

fs/romfs/inode.c

@@ -318,6 +318,7 @@ romfs_lookup(struct inode *dir, struct dentry *dentry)
 
 	res = -EACCES;			/* placeholder for "no data here" */
 	offset = dir->i_ino & ROMFH_MASK;
+	lock_kernel();
 	if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0)
 		goto out;
 
@@ -378,7 +379,8 @@ out0:	inode = NULL;
 outi:	res = 0;
 	d_add (dentry, inode);
 
-out:	return ERR_PTR(res);
+out:	unlock_kernel();
+	return ERR_PTR(res);
 }
 
 /*

fs/smbfs/dir.c

@@ -399,6 +399,7 @@ smb_lookup(struct inode *dir, struct dentry *dentry)
 	if (dentry->d_name.len > SMB_MAXNAMELEN)
 		goto out;
 
+	lock_kernel();
 	error = smb_proc_getattr(dentry, &finfo);
 #ifdef SMBFS_PARANOIA
 	if (error && error != -ENOENT)
@@ -426,6 +427,7 @@ smb_lookup(struct inode *dir, struct dentry *dentry)
 			error = 0;
 		}
 	}
+	unlock_kernel();
 out:
 	return ERR_PTR(error);
 }

fs/sysv/namei.c

@@ -15,6 +15,7 @@
 #include <linux/fs.h>
 #include <linux/sysv_fs.h>
 #include <linux/pagemap.h>
+#include <linux/smp_lock.h>
 
 static inline void inc_count(struct inode *inode)
 {
@@ -72,13 +73,17 @@ static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry)
 	dentry->d_op = dir->i_sb->s_root->d_op;
 	if (dentry->d_name.len > SYSV_NAMELEN)
 		return ERR_PTR(-ENAMETOOLONG);
+	lock_kernel();
 	ino = sysv_inode_by_name(dentry);
 
 	if (ino) {
 		inode = iget(dir->i_sb, ino);
-		if (!inode) 
+		if (!inode) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/udf/namei.c

@@ -298,14 +298,17 @@ udf_lookup(struct inode *dir, struct dentry *dentry)
 	if (dentry->d_name.len > UDF_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
+	lock_kernel();
 #ifdef UDF_RECOVERY
 	/* temporary shorthand for specifying files by inode number */
 	if (!strncmp(dentry->d_name.name, ".B=", 3) )
 	{
 		lb_addr lb = { 0, simple_strtoul(dentry->d_name.name+3, NULL, 0) };
 		inode = udf_iget(dir->i_sb, lb);
-		if (!inode)
+		if (!inode) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
 	else
 #endif /* UDF_RECOVERY */
@@ -317,9 +320,12 @@ udf_lookup(struct inode *dir, struct dentry *dentry)
 		udf_release_data(fibh.sbh);
 
 		inode = udf_iget(dir->i_sb, lelb_to_cpu(cfi.icb.extLocation));
-		if ( !inode )
+		if ( !inode ) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/ufs/namei.c

@@ -27,6 +27,7 @@
 #include <linux/time.h>
 #include <linux/fs.h>
 #include <linux/ufs_fs.h>
+#include <linux/smp_lock.h>
 
 #undef UFS_NAMEI_DEBUG
 
@@ -68,12 +69,16 @@ static struct dentry *ufs_lookup(struct inode * dir, struct dentry *dentry)
 	if (dentry->d_name.len > UFS_MAXNAMLEN)
 		return ERR_PTR(-ENAMETOOLONG);
 
+	lock_kernel();
 	ino = ufs_inode_by_name(dir, dentry);
 	if (ino) {
 		inode = iget(dir->i_sb, ino);
-		if (!inode) 
+		if (!inode) {
+			unlock_kernel();
 			return ERR_PTR(-EACCES);
+		}
 	}
+	unlock_kernel();
 	d_add(dentry, inode);
 	return NULL;
 }

fs/vfat/namei.c

@@ -21,6 +21,7 @@
 #include <linux/msdos_fs.h>
 #include <linux/ctype.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 
 #define DEBUG_LEVEL 0
 #if (DEBUG_LEVEL >= 1)
@@ -986,6 +987,7 @@ struct dentry *vfat_lookup(struct inode *dir,struct dentry *dentry)
 	PRINTK2(("vfat_lookup: name=%s, len=%d\n", 
 		 dentry->d_name.name, dentry->d_name.len));
 
+	lock_kernel();
 	table = (MSDOS_SB(dir->i_sb)->options.name_check == 's') ? 2 : 0;
 	dentry->d_op = &vfat_dentry_ops[table];
 
@@ -997,19 +999,23 @@ struct dentry *vfat_lookup(struct inode *dir,struct dentry *dentry)
 	}
 	inode = fat_build_inode(dir->i_sb, de, sinfo.ino, &res);
 	fat_brelse(dir->i_sb, bh);
-	if (res)
+	if (res) {
+		unlock_kernel();
 		return ERR_PTR(res);
+	}
 	alias = d_find_alias(inode);
 	if (alias) {
 		if (d_invalidate(alias)==0)
 			dput(alias);
 		else {
 			iput(inode);
+			unlock_kernel();
 			return alias;
 		}
 		
 	}
 error:
+	unlock_kernel();
 	dentry->d_op = &vfat_dentry_ops[table];
 	dentry->d_time = dentry->d_parent->d_inode->i_version;
 	d_add(dentry,inode);

mm/shmem.c

@@ -973,6 +973,7 @@ static int shmem_statfs(struct super_block *sb, struct statfs *buf)
  * Lookup the data. This is trivial - if the dentry didn't already
  * exist, we know it is negative.
  */
+/* SMP-safe */
 static struct dentry * shmem_lookup(struct inode *dir, struct dentry *dentry)
 {
 	d_add(dentry, NULL);