[PATCH] (3/5) more BKL shifting

BKL shifted into ->link(), check for S_ISDIR moved into vfs_link().

Documentation/filesystems/Locking

@@ -55,7 +55,7 @@ locking rules:
 		BKL	i_sem(inode)
 lookup:		no	yes
 create:		no	yes
-link:		yes	yes
+link:		no	yes
 mknod:		no	yes
 mkdir:		no	yes
 unlink:		no	yes (both)

Documentation/filesystems/porting

@@ -80,9 +80,15 @@ can relax your locking.
 ---
 [mandatory]
 
-->lookup(), ->truncate(), ->create(), ->unlink(), ->mknod(), ->mkdir() and
-->rmdir() are called without BKL now.  Grab it on the 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
+->lookup(), ->truncate(), ->create(), ->unlink(), ->mknod(), ->mkdir(),
+->rmdir() and ->link() are called without BKL now.  Grab it on the 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() / unlock_kernel() so that they would protect exactly what
 needs to be protected.
+
+---
+[informational]
+
+check for ->link() target not being a directory is done by callers.  Feel
+free to drop it...

drivers/hotplug/pci_hotplug_core.c

@@ -159,10 +159,9 @@ static int pcihpfs_link (struct dentry *old_dentry, struct inode *dir,
 {
 	struct inode *inode = old_dentry->d_inode;
 
-	if(S_ISDIR(inode->i_mode))
-		return -EPERM;
-
+	lock_kernel();
 	inode->i_nlink++;
+	unlock_kernel();
 	atomic_inc(&inode->i_count);
  	dget(dentry);
 	d_instantiate(dentry, inode);

drivers/usb/inode.c

@@ -216,10 +216,9 @@ static int usbfs_link (struct dentry *old_dentry, struct inode *dir,
 {
 	struct inode *inode = old_dentry->d_inode;
 
-	if(S_ISDIR(inode->i_mode))
-		return -EPERM;
-
+	lock_kernel();
 	inode->i_nlink++;
+	unlock_kernel();
 	atomic_inc(&inode->i_count);
  	dget(dentry);
 	d_instantiate(dentry, inode);

fs/affs/namei.c

@@ -435,16 +435,17 @@ affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
 	pr_debug("AFFS: link(%u, %u, \"%.*s\")\n", (u32)inode->i_ino, (u32)dir->i_ino,
 		 (int)dentry->d_name.len,dentry->d_name.name);
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
-	error = affs_add_entry(dir, inode, dentry, S_ISDIR(inode->i_mode) ? ST_LINKDIR : ST_LINKFILE);
+	lock_kernel();
+	error = affs_add_entry(dir, inode, dentry, ST_LINKFILE);
 	if (error) {
+		/* WTF??? */
 		inode->i_nlink = 0;
 		mark_inode_dirty(inode);
 		iput(inode);
+		unlock_kernel();
 		return error;
 	}
+	unlock_kernel();
 	return 0;
 }
 

fs/bfs/dir.c

@@ -151,17 +151,18 @@ static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new
 	struct inode * inode = old->d_inode;
 	int err;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
+	lock_kernel();
 	err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino);
-	if (err)
+	if (err) {
+		unlock_kernel();
 		return err;
+	}
 	inode->i_nlink++;
 	inode->i_ctime = CURRENT_TIME;
 	mark_inode_dirty(inode);
 	atomic_inc(&inode->i_count);
 	d_instantiate(new, inode);
+	unlock_kernel();
 	return 0;
 }
 

fs/coda/dir.c

@@ -362,10 +362,13 @@ static int coda_link(struct dentry *source_de, struct inode *dir_inode,
 	int len = de->d_name.len;
 	int error;
 
+	lock_kernel();
 	coda_vfs_stat.link++;
 
-	if (coda_isroot(dir_inode) && coda_iscontrol(name, len))
+	if (coda_isroot(dir_inode) && coda_iscontrol(name, len)) {
+		unlock_kernel();
 		return -EPERM;
+	}
 
 	CDEBUG(D_INODE, "old: fid: %s\n", coda_i2s(inode));
 	CDEBUG(D_INODE, "directory: %s\n", coda_i2s(dir_inode));
@@ -385,6 +388,7 @@ static int coda_link(struct dentry *source_de, struct inode *dir_inode,
         
 out:
 	CDEBUG(D_INODE, "link result %d\n",error);
+	unlock_kernel();
 	return(error);
 }
 

fs/ext2/namei.c

@@ -168,14 +168,15 @@ static int ext2_link (struct dentry * old_dentry, struct inode * dir,
 {
 	struct inode *inode = old_dentry->d_inode;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
-	if (inode->i_nlink >= EXT2_LINK_MAX)
+	lock_kernel();
+	if (inode->i_nlink >= EXT2_LINK_MAX) {
+		unlock_kernel();
 		return -EMLINK;
+	}
 
 	inode->i_ctime = CURRENT_TIME;
 	ext2_inc_count(inode);
+	unlock_kernel();
 	atomic_inc(&inode->i_count);
 
 	return ext2_add_nondir(dentry, inode);

fs/ext3/namei.c

@@ -978,15 +978,17 @@ static int ext3_link (struct dentry * old_dentry,
 	struct inode *inode = old_dentry->d_inode;
 	int err;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
-	if (inode->i_nlink >= EXT3_LINK_MAX)
+	lock_kernel();
+	if (inode->i_nlink >= EXT3_LINK_MAX) {
+		unlock_kernel();
 		return -EMLINK;
+	}
 
 	handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS);
-	if (IS_ERR(handle))
+	if (IS_ERR(handle)) {
+		unlock_kernel();
 		return PTR_ERR(handle);
+	}
 
 	if (IS_SYNC(dir))
 		handle->h_sync = 1;
@@ -998,6 +1000,7 @@ static int ext3_link (struct dentry * old_dentry,
 	ext3_mark_inode_dirty(handle, inode);
 	err = ext3_add_nondir(handle, dentry, inode);
 	ext3_journal_stop(handle, dir);
+	unlock_kernel();
 	return err;
 }
 

fs/jffs2/dir.c

@@ -501,11 +501,15 @@ static int jffs2_do_link (struct dentry *old_dentry, struct inode *dir_i, struct
 
 static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct dentry *dentry)
 {
-	int ret = jffs2_do_link(old_dentry, dir_i, dentry, 0);
+	int ret;
+
+	lock_kernel();
+	ret = jffs2_do_link(old_dentry, dir_i, dentry, 0);
 	if (!ret) {
 		d_instantiate(dentry, old_dentry->d_inode);
 		atomic_inc(&old_dentry->d_inode->i_count);
 	}
+	unlock_kernel();
 	return ret;
 }
 

fs/minix/namei.c

@@ -136,14 +136,15 @@ static int minix_link(struct dentry * old_dentry, struct inode * dir,
 {
 	struct inode *inode = old_dentry->d_inode;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
-	if (inode->i_nlink >= inode->i_sb->u.minix_sb.s_link_max)
+	lock_kernel();
+	if (inode->i_nlink >= inode->i_sb->u.minix_sb.s_link_max) {
+		unlock_kernel();
 		return -EMLINK;
+	}
 
 	inode->i_ctime = CURRENT_TIME;
 	inc_count(inode);
+	unlock_kernel();
 	atomic_inc(&inode->i_count);
 	return add_nondir(dentry, inode);
 }

fs/namei.c

@@ -1613,11 +1613,11 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
 		return -EPERM;
 	if (!dir->i_op || !dir->i_op->link)
 		return -EPERM;
+	if (S_ISDIR(old_dentry->d_inode->i_mode))
+		return -EPERM;
 
 	DQUOT_INIT(dir);
-	lock_kernel();
 	error = dir->i_op->link(old_dentry, dir, new_dentry);
-	unlock_kernel();
 	if (!error)
 		inode_dir_notify(dir, DN_CREATE);
 	return error;

fs/nfs/dir.c

@@ -951,10 +951,12 @@ nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
 	 * Since nfs_proc_link doesn't return a file handle,
 	 * we can't use the existing dentry.
 	 */
+	lock_kernel();
 	d_drop(dentry);
 	nfs_zap_caches(dir);
 	NFS_CACHEINV(inode);
 	error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
+	unlock_kernel();
 	return error;
 }
 

fs/ramfs/inode.c

@@ -166,10 +166,9 @@ static int ramfs_link(struct dentry *old_dentry, struct inode * dir, struct dent
 {
 	struct inode *inode = old_dentry->d_inode;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
+	lock_kernel();
 	inode->i_nlink++;
+	unlock_kernel();
 	atomic_inc(&inode->i_count);	/* New dentry reference */
 	dget(dentry);		/* Extra pinning count for the created dentry */
 	d_instantiate(dentry, inode);

fs/reiserfs/namei.c

@@ -978,12 +978,10 @@ static int reiserfs_link (struct dentry * old_dentry, struct inode * dir, struct
     struct reiserfs_transaction_handle th ;
     int jbegin_count = JOURNAL_PER_BALANCE_CNT * 3; 
 
-
-    if (S_ISDIR(inode->i_mode))
-	return -EPERM;
-  
+    lock_kernel();
     if (inode->i_nlink >= REISERFS_LINK_MAX) {
 	//FIXME: sd_nlink is 32 bit for new files
+	unlock_kernel();
 	return -EMLINK;
     }
 
@@ -1000,6 +998,7 @@ static int reiserfs_link (struct dentry * old_dentry, struct inode * dir, struct
     if (retval) {
 	pop_journal_writer(windex) ;
 	journal_end(&th, dir->i_sb, jbegin_count) ;
+	unlock_kernel();
 	return retval;
     }
 
@@ -1011,6 +1010,7 @@ static int reiserfs_link (struct dentry * old_dentry, struct inode * dir, struct
     d_instantiate(dentry, inode);
     pop_journal_writer(windex) ;
     journal_end(&th, dir->i_sb, jbegin_count) ;
+    unlock_kernel();
     return 0;
 }
 

fs/sysv/namei.c

@@ -142,14 +142,15 @@ static int sysv_link(struct dentry * old_dentry, struct inode * dir,
 {
 	struct inode *inode = old_dentry->d_inode;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
-	if (inode->i_nlink >= inode->i_sb->sv_link_max)
+	lock_kernel();
+	if (inode->i_nlink >= inode->i_sb->sv_link_max) {
+		unlock_kernel();
 		return -EMLINK;
+	}
 
 	inode->i_ctime = CURRENT_TIME;
 	inc_count(inode);
+	unlock_kernel();
 	atomic_inc(&inode->i_count);
 
 	return add_nondir(dentry, inode);

fs/udf/namei.c

@@ -1109,14 +1109,16 @@ static int udf_link(struct dentry * old_dentry, struct inode * dir,
 	int err;
 	struct FileIdentDesc cfi, *fi;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
-	if (inode->i_nlink >= (256<<sizeof(inode->i_nlink))-1)
+	lock_kernel();
+	if (inode->i_nlink >= (256<<sizeof(inode->i_nlink))-1) {
+		unlock_kernel();
 		return -EMLINK;
+	}
 
-	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
+	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err))) {
+		unlock_kernel();
 		return err;
+	}
 	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
 	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
 	if (UDF_SB_LVIDBH(inode->i_sb))
@@ -1146,6 +1148,7 @@ static int udf_link(struct dentry * old_dentry, struct inode * dir,
 	mark_inode_dirty(inode);
 	atomic_inc(&inode->i_count);
 	d_instantiate(dentry, inode);
+	unlock_kernel();
 	return 0;
 }
 

fs/ufs/namei.c

@@ -166,18 +166,21 @@ static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 	struct dentry *dentry)
 {
 	struct inode *inode = old_dentry->d_inode;
+	int error;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
-	if (inode->i_nlink >= UFS_LINK_MAX)
+	lock_kernel();
+	if (inode->i_nlink >= UFS_LINK_MAX) {
+		unlock_kernel();
 		return -EMLINK;
+	}
 
 	inode->i_ctime = CURRENT_TIME;
 	ufs_inc_count(inode);
 	atomic_inc(&inode->i_count);
 
-	return ufs_add_nondir(dentry, inode);
+	error = ufs_add_nondir(dentry, inode);
+	unlock_kernel();
+	return error;
 }
 
 static int ufs_mkdir(struct inode * dir, struct dentry * dentry, int mode)

mm/shmem.c

@@ -1021,11 +1021,10 @@ static int shmem_link(struct dentry *old_dentry, struct inode * dir, struct dent
 {
 	struct inode *inode = old_dentry->d_inode;
 
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
-
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+	lock_kernel();
 	inode->i_nlink++;
+	unlock_kernel();
 	atomic_inc(&inode->i_count);	/* New dentry reference */
 	dget(dentry);		/* Extra pinning count for the created dentry */
 	d_instantiate(dentry, inode);