Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  truncate: use new helpers
  truncate: new helpers
  fs: fix overflow in sys_mount() for in-kernel calls
  fs: Make unload_nls() NULL pointer safe
  freeze_bdev: grab active reference to frozen superblocks
  freeze_bdev: kill bd_mount_sem
  exofs: remove BKL from super operations
  fs/romfs: correct error-handling code
  vfs: seq_file: add helpers for data filling
  vfs: remove redundant position check in do_sendfile
  vfs: change sb->s_maxbytes to a loff_t
  vfs: explicitly cast s_maxbytes in fiemap_check_ranges
  libfs: return error code on failed attr set
  seq_file: return a negative error code when seq_path_root() fails.
  vfs: optimize touch_time() too
  vfs: optimization for touch_atime()
  vfs: split generic_forget_inode() so that hugetlbfs does not have to copy it
  fs/inode.c: add dev-id and inode number for debugging in init_special_inode()
  libfs: make simple_read_from_buffer conventional

Documentation/vm/locking

@@ -80,7 +80,7 @@ Note: PTL can also be used to guarantee that no new clones using the
 mm start up ... this is a loose form of stability on mm_users. For
 example, it is used in copy_mm to protect against a racing tlb_gather_mmu
 single address space optimization, so that the zap_page_range (from
-vmtruncate) does not lose sending ipi's to cloned threads that might 
+truncate) does not lose sending ipi's to cloned threads that might
 be spawned underneath it and go to user mode to drag in pte's into tlbs.
 
 swap_lock

fs/attr.c

@@ -18,7 +18,7 @@
 /* Taken over from the old code... */
 
 /* POSIX UID/GID verification for setting inode attributes. */
-int inode_change_ok(struct inode *inode, struct iattr *attr)
+int inode_change_ok(const struct inode *inode, struct iattr *attr)
 {
 	int retval = -EPERM;
 	unsigned int ia_valid = attr->ia_valid;
@@ -60,9 +60,51 @@ int inode_change_ok(struct inode *inode, struct iattr *attr)
 error:
 	return retval;
 }
-
 EXPORT_SYMBOL(inode_change_ok);
 
+/**
+ * inode_newsize_ok - may this inode be truncated to a given size
+ * @inode:	the inode to be truncated
+ * @offset:	the new size to assign to the inode
+ * @Returns:	0 on success, -ve errno on failure
+ *
+ * inode_newsize_ok will check filesystem limits and ulimits to check that the
+ * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
+ * when necessary. Caller must not proceed with inode size change if failure is
+ * returned. @inode must be a file (not directory), with appropriate
+ * permissions to allow truncate (inode_newsize_ok does NOT check these
+ * conditions).
+ *
+ * inode_newsize_ok must be called with i_mutex held.
+ */
+int inode_newsize_ok(const struct inode *inode, loff_t offset)
+{
+	if (inode->i_size < offset) {
+		unsigned long limit;
+
+		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+		if (limit != RLIM_INFINITY && offset > limit)
+			goto out_sig;
+		if (offset > inode->i_sb->s_maxbytes)
+			goto out_big;
+	} else {
+		/*
+		 * truncation of in-use swapfiles is disallowed - it would
+		 * cause subsequent swapout to scribble on the now-freed
+		 * blocks.
+		 */
+		if (IS_SWAPFILE(inode))
+			return -ETXTBSY;
+	}
+
+	return 0;
+out_sig:
+	send_sig(SIGXFSZ, current, 0);
+out_big:
+	return -EFBIG;
+}
+EXPORT_SYMBOL(inode_newsize_ok);
+
 int inode_setattr(struct inode * inode, struct iattr * attr)
 {
 	unsigned int ia_valid = attr->ia_valid;

fs/befs/linuxvfs.c

@@ -737,12 +737,7 @@ befs_put_super(struct super_block *sb)
 {
 	kfree(BEFS_SB(sb)->mount_opts.iocharset);
 	BEFS_SB(sb)->mount_opts.iocharset = NULL;
-
-	if (BEFS_SB(sb)->nls) {
-		unload_nls(BEFS_SB(sb)->nls);
-		BEFS_SB(sb)->nls = NULL;
-	}
-
+	unload_nls(BEFS_SB(sb)->nls);
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
 }

fs/block_dev.c

@@ -216,8 +216,6 @@ EXPORT_SYMBOL(fsync_bdev);
  * freeze_bdev  --  lock a filesystem and force it into a consistent state
  * @bdev:	blockdevice to lock
  *
- * This takes the block device bd_mount_sem to make sure no new mounts
- * happen on bdev until thaw_bdev() is called.
  * If a superblock is found on this device, we take the s_umount semaphore
  * on it to make sure nobody unmounts until the snapshot creation is done.
  * The reference counter (bd_fsfreeze_count) guarantees that only the last
@@ -232,46 +230,55 @@ struct super_block *freeze_bdev(struct block_device *bdev)
 	int error = 0;
 
 	mutex_lock(&bdev->bd_fsfreeze_mutex);
-	if (bdev->bd_fsfreeze_count > 0) {
-		bdev->bd_fsfreeze_count++;
+	if (++bdev->bd_fsfreeze_count > 1) {
+		/*
+		 * We don't even need to grab a reference - the first call
+		 * to freeze_bdev grab an active reference and only the last
+		 * thaw_bdev drops it.
+		 */
 		sb = get_super(bdev);
+		drop_super(sb);
 		mutex_unlock(&bdev->bd_fsfreeze_mutex);
 		return sb;
 	}
-	bdev->bd_fsfreeze_count++;
-
-	down(&bdev->bd_mount_sem);
-	sb = get_super(bdev);
-	if (sb && !(sb->s_flags & MS_RDONLY)) {
-		sb->s_frozen = SB_FREEZE_WRITE;
-		smp_wmb();
-
-		sync_filesystem(sb);
-
-		sb->s_frozen = SB_FREEZE_TRANS;
-		smp_wmb();
-
-		sync_blockdev(sb->s_bdev);
-
-		if (sb->s_op->freeze_fs) {
-			error = sb->s_op->freeze_fs(sb);
-			if (error) {
-				printk(KERN_ERR
-					"VFS:Filesystem freeze failed\n");
-				sb->s_frozen = SB_UNFROZEN;
-				drop_super(sb);
-				up(&bdev->bd_mount_sem);
-				bdev->bd_fsfreeze_count--;
-				mutex_unlock(&bdev->bd_fsfreeze_mutex);
-				return ERR_PTR(error);
-			}
+
+	sb = get_active_super(bdev);
+	if (!sb)
+		goto out;
+	if (sb->s_flags & MS_RDONLY) {
+		deactivate_locked_super(sb);
+		mutex_unlock(&bdev->bd_fsfreeze_mutex);
+		return sb;
+	}
+
+	sb->s_frozen = SB_FREEZE_WRITE;
+	smp_wmb();
+
+	sync_filesystem(sb);
+
+	sb->s_frozen = SB_FREEZE_TRANS;
+	smp_wmb();
+
+	sync_blockdev(sb->s_bdev);
+
+	if (sb->s_op->freeze_fs) {
+		error = sb->s_op->freeze_fs(sb);
+		if (error) {
+			printk(KERN_ERR
+				"VFS:Filesystem freeze failed\n");
+			sb->s_frozen = SB_UNFROZEN;
+			deactivate_locked_super(sb);
+			bdev->bd_fsfreeze_count--;
+			mutex_unlock(&bdev->bd_fsfreeze_mutex);
+			return ERR_PTR(error);
 		}
 	}
+	up_write(&sb->s_umount);
 
+ out:
 	sync_blockdev(bdev);
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
-
-	return sb;	/* thaw_bdev releases s->s_umount and bd_mount_sem */
+	return sb;	/* thaw_bdev releases s->s_umount */
 }
 EXPORT_SYMBOL(freeze_bdev);
 
@@ -284,44 +291,44 @@ EXPORT_SYMBOL(freeze_bdev);
  */
 int thaw_bdev(struct block_device *bdev, struct super_block *sb)
 {
-	int error = 0;
+	int error = -EINVAL;
 
 	mutex_lock(&bdev->bd_fsfreeze_mutex);
-	if (!bdev->bd_fsfreeze_count) {
-		mutex_unlock(&bdev->bd_fsfreeze_mutex);
-		return -EINVAL;
-	}
-
-	bdev->bd_fsfreeze_count--;
-	if (bdev->bd_fsfreeze_count > 0) {
-		if (sb)
-			drop_super(sb);
-		mutex_unlock(&bdev->bd_fsfreeze_mutex);
-		return 0;
-	}
-
-	if (sb) {
-		BUG_ON(sb->s_bdev != bdev);
-		if (!(sb->s_flags & MS_RDONLY)) {
-			if (sb->s_op->unfreeze_fs) {
-				error = sb->s_op->unfreeze_fs(sb);
-				if (error) {
-					printk(KERN_ERR
-						"VFS:Filesystem thaw failed\n");
-					sb->s_frozen = SB_FREEZE_TRANS;
-					bdev->bd_fsfreeze_count++;
-					mutex_unlock(&bdev->bd_fsfreeze_mutex);
-					return error;
-				}
-			}
-			sb->s_frozen = SB_UNFROZEN;
-			smp_wmb();
-			wake_up(&sb->s_wait_unfrozen);
+	if (!bdev->bd_fsfreeze_count)
+		goto out_unlock;
+
+	error = 0;
+	if (--bdev->bd_fsfreeze_count > 0)
+		goto out_unlock;
+
+	if (!sb)
+		goto out_unlock;
+
+	BUG_ON(sb->s_bdev != bdev);
+	down_write(&sb->s_umount);
+	if (sb->s_flags & MS_RDONLY)
+		goto out_deactivate;
+
+	if (sb->s_op->unfreeze_fs) {
+		error = sb->s_op->unfreeze_fs(sb);
+		if (error) {
+			printk(KERN_ERR
+				"VFS:Filesystem thaw failed\n");
+			sb->s_frozen = SB_FREEZE_TRANS;
+			bdev->bd_fsfreeze_count++;
+			mutex_unlock(&bdev->bd_fsfreeze_mutex);
+			return error;
 		}
-		drop_super(sb);
 	}
 
-	up(&bdev->bd_mount_sem);
+	sb->s_frozen = SB_UNFROZEN;
+	smp_wmb();
+	wake_up(&sb->s_wait_unfrozen);
+
+out_deactivate:
+	if (sb)
+		deactivate_locked_super(sb);
+out_unlock:
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
 	return 0;
 }
@@ -430,7 +437,6 @@ static void init_once(void *foo)
 
 	memset(bdev, 0, sizeof(*bdev));
 	mutex_init(&bdev->bd_mutex);
-	sema_init(&bdev->bd_mount_sem, 1);
 	INIT_LIST_HEAD(&bdev->bd_inodes);
 	INIT_LIST_HEAD(&bdev->bd_list);
 #ifdef CONFIG_SYSFS

fs/buffer.c

@@ -2239,16 +2239,10 @@ int generic_cont_expand_simple(struct inode *inode, loff_t size)
 	struct address_space *mapping = inode->i_mapping;
 	struct page *page;
 	void *fsdata;
-	unsigned long limit;
 	int err;
 
-	err = -EFBIG;
-        limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-	if (limit != RLIM_INFINITY && size > (loff_t)limit) {
-		send_sig(SIGXFSZ, current, 0);
-		goto out;
-	}
-	if (size > inode->i_sb->s_maxbytes)
+	err = inode_newsize_ok(inode, size);
+	if (err)
 		goto out;
 
 	err = pagecache_write_begin(NULL, mapping, size, 0,

fs/cifs/cifsfs.c

@@ -185,8 +185,7 @@ cifs_read_super(struct super_block *sb, void *data,
 			cifs_sb->mountdata = NULL;
 		}
 #endif
-		if (cifs_sb->local_nls)
-			unload_nls(cifs_sb->local_nls);
+		unload_nls(cifs_sb->local_nls);
 		kfree(cifs_sb);
 	}
 	return rc;

fs/cifs/inode.c

@@ -1557,57 +1557,24 @@ static int cifs_truncate_page(struct address_space *mapping, loff_t from)
 
 static int cifs_vmtruncate(struct inode *inode, loff_t offset)
 {
-	struct address_space *mapping = inode->i_mapping;
-	unsigned long limit;
+	loff_t oldsize;
+	int err;
 
 	spin_lock(&inode->i_lock);
-	if (inode->i_size < offset)
-		goto do_expand;
-	/*
-	 * truncation of in-use swapfiles is disallowed - it would cause
-	 * subsequent swapout to scribble on the now-freed blocks.
-	 */
-	if (IS_SWAPFILE(inode)) {
-		spin_unlock(&inode->i_lock);
-		goto out_busy;
-	}
-	i_size_write(inode, offset);
-	spin_unlock(&inode->i_lock);
-	/*
-	 * unmap_mapping_range is called twice, first simply for efficiency
-	 * so that truncate_inode_pages does fewer single-page unmaps. However
-	 * after this first call, and before truncate_inode_pages finishes,
-	 * it is possible for private pages to be COWed, which remain after
-	 * truncate_inode_pages finishes, hence the second unmap_mapping_range
-	 * call must be made for correctness.
-	 */
-	unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-	truncate_inode_pages(mapping, offset);
-	unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-	goto out_truncate;
-
-do_expand:
-	limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-	if (limit != RLIM_INFINITY && offset > limit) {
+	err = inode_newsize_ok(inode, offset);
+	if (err) {
 		spin_unlock(&inode->i_lock);
-		goto out_sig;
-	}
-	if (offset > inode->i_sb->s_maxbytes) {
-		spin_unlock(&inode->i_lock);
-		goto out_big;
+		goto out;
 	}
+
+	oldsize = inode->i_size;
 	i_size_write(inode, offset);
 	spin_unlock(&inode->i_lock);
-out_truncate:
+	truncate_pagecache(inode, oldsize, offset);
 	if (inode->i_op->truncate)
 		inode->i_op->truncate(inode);
-	return 0;
-out_sig:
-	send_sig(SIGXFSZ, current, 0);
-out_big:
-	return -EFBIG;
-out_busy:
-	return -ETXTBSY;
+out:
+	return err;
 }
 
 static int

fs/compat.c

@@ -768,13 +768,13 @@ asmlinkage long compat_sys_mount(char __user * dev_name, char __user * dir_name,
 				 char __user * type, unsigned long flags,
 				 void __user * data)
 {
-	unsigned long type_page;
+	char *kernel_type;
 	unsigned long data_page;
-	unsigned long dev_page;
+	char *kernel_dev;
 	char *dir_page;
 	int retval;
 
-	retval = copy_mount_options (type, &type_page);
+	retval = copy_mount_string(type, &kernel_type);
 	if (retval < 0)
 		goto out;
 
@@ -783,38 +783,38 @@ asmlinkage long compat_sys_mount(char __user * dev_name, char __user * dir_name,
 	if (IS_ERR(dir_page))
 		goto out1;
 
-	retval = copy_mount_options (dev_name, &dev_page);
+	retval = copy_mount_string(dev_name, &kernel_dev);
 	if (retval < 0)
 		goto out2;
 
-	retval = copy_mount_options (data, &data_page);
+	retval = copy_mount_options(data, &data_page);
 	if (retval < 0)
 		goto out3;
 
 	retval = -EINVAL;
 
-	if (type_page && data_page) {
-		if (!strcmp((char *)type_page, SMBFS_NAME)) {
+	if (kernel_type && data_page) {
+		if (!strcmp(kernel_type, SMBFS_NAME)) {
 			do_smb_super_data_conv((void *)data_page);
-		} else if (!strcmp((char *)type_page, NCPFS_NAME)) {
+		} else if (!strcmp(kernel_type, NCPFS_NAME)) {
 			do_ncp_super_data_conv((void *)data_page);
-		} else if (!strcmp((char *)type_page, NFS4_NAME)) {
+		} else if (!strcmp(kernel_type, NFS4_NAME)) {
 			if (do_nfs4_super_data_conv((void *) data_page))
 				goto out4;
 		}
 	}
 
-	retval = do_mount((char*)dev_page, dir_page, (char*)type_page,
+	retval = do_mount(kernel_dev, dir_page, kernel_type,
 			flags, (void*)data_page);
 
  out4:
 	free_page(data_page);
  out3:
-	free_page(dev_page);
+	kfree(kernel_dev);
  out2:
 	putname(dir_page);
  out1:
-	free_page(type_page);
+	kfree(kernel_type);
  out:
 	return retval;
 }

fs/exofs/super.c

@@ -214,7 +214,6 @@ int exofs_sync_fs(struct super_block *sb, int wait)
 	}
 
 	lock_super(sb);
-	lock_kernel();
 	sbi = sb->s_fs_info;
 	fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
 	fscb->s_numfiles = cpu_to_le32(sbi->s_numfiles);
@@ -245,7 +244,6 @@ int exofs_sync_fs(struct super_block *sb, int wait)
 out:
 	if (or)
 		osd_end_request(or);
-	unlock_kernel();
 	unlock_super(sb);
 	kfree(fscb);
 	return ret;
@@ -268,8 +266,6 @@ static void exofs_put_super(struct super_block *sb)
 	int num_pend;
 	struct exofs_sb_info *sbi = sb->s_fs_info;
 
-	lock_kernel();
-
 	if (sb->s_dirt)
 		exofs_write_super(sb);
 
@@ -286,8 +282,6 @@ static void exofs_put_super(struct super_block *sb)
 	osduld_put_device(sbi->s_dev);
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
-
-	unlock_kernel();
 }
 
 /*

fs/fat/inode.c

@@ -470,19 +470,11 @@ static void fat_put_super(struct super_block *sb)
 
 	iput(sbi->fat_inode);
 
-	if (sbi->nls_disk) {
-		unload_nls(sbi->nls_disk);
-		sbi->nls_disk = NULL;
-		sbi->options.codepage = fat_default_codepage;
-	}
-	if (sbi->nls_io) {
-		unload_nls(sbi->nls_io);
-		sbi->nls_io = NULL;
-	}
-	if (sbi->options.iocharset != fat_default_iocharset) {
+	unload_nls(sbi->nls_disk);
+	unload_nls(sbi->nls_io);
+
+	if (sbi->options.iocharset != fat_default_iocharset)
 		kfree(sbi->options.iocharset);
-		sbi->options.iocharset = fat_default_iocharset;
-	}
 
 	sb->s_fs_info = NULL;
 	kfree(sbi);

fs/fuse/dir.c

@@ -1276,14 +1276,9 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
 		return 0;
 
 	if (attr->ia_valid & ATTR_SIZE) {
-		unsigned long limit;
-		if (IS_SWAPFILE(inode))
-			return -ETXTBSY;
-		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-		if (limit != RLIM_INFINITY && attr->ia_size > (loff_t) limit) {
-			send_sig(SIGXFSZ, current, 0);
-			return -EFBIG;
-		}
+		err = inode_newsize_ok(inode, attr->ia_size);
+		if (err)
+			return err;
 		is_truncate = true;
 	}
 
@@ -1350,8 +1345,7 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
 	 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
 	 */
 	if (S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
-		if (outarg.attr.size < oldsize)
-			fuse_truncate(inode->i_mapping, outarg.attr.size);
+		truncate_pagecache(inode, oldsize, outarg.attr.size);
 		invalidate_inode_pages2(inode->i_mapping);
 	}
 

fs/fuse/fuse_i.h

@@ -606,8 +606,6 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 				   u64 attr_valid);
 
-void fuse_truncate(struct address_space *mapping, loff_t offset);
-
 /**
  * Initialize the client device
  */

fs/fuse/inode.c

@@ -140,14 +140,6 @@ static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 	return 0;
 }
 
-void fuse_truncate(struct address_space *mapping, loff_t offset)
-{
-	/* See vmtruncate() */
-	unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-	truncate_inode_pages(mapping, offset);
-	unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-}
-
 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 				   u64 attr_valid)
 {
@@ -205,8 +197,7 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 	spin_unlock(&fc->lock);
 
 	if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
-		if (attr->size < oldsize)
-			fuse_truncate(inode->i_mapping, attr->size);
+		truncate_pagecache(inode, oldsize, attr->size);
 		invalidate_inode_pages2(inode->i_mapping);
 	}
 }

fs/hfs/mdb.c

@@ -344,10 +344,8 @@ void hfs_mdb_put(struct super_block *sb)
 	brelse(HFS_SB(sb)->mdb_bh);
 	brelse(HFS_SB(sb)->alt_mdb_bh);
 
-	if (HFS_SB(sb)->nls_io)
-		unload_nls(HFS_SB(sb)->nls_io);
-	if (HFS_SB(sb)->nls_disk)
-		unload_nls(HFS_SB(sb)->nls_disk);
+	unload_nls(HFS_SB(sb)->nls_io);
+	unload_nls(HFS_SB(sb)->nls_disk);
 
 	free_pages((unsigned long)HFS_SB(sb)->bitmap, PAGE_SIZE < 8192 ? 1 : 0);
 	kfree(HFS_SB(sb));

fs/hfsplus/super.c

@@ -229,8 +229,7 @@ static void hfsplus_put_super(struct super_block *sb)
 	iput(HFSPLUS_SB(sb).alloc_file);
 	iput(HFSPLUS_SB(sb).hidden_dir);
 	brelse(HFSPLUS_SB(sb).s_vhbh);
-	if (HFSPLUS_SB(sb).nls)
-		unload_nls(HFSPLUS_SB(sb).nls);
+	unload_nls(HFSPLUS_SB(sb).nls);
 	kfree(sb->s_fs_info);
 	sb->s_fs_info = NULL;
 
@@ -464,8 +463,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 
 cleanup:
 	hfsplus_put_super(sb);
-	if (nls)
-		unload_nls(nls);
+	unload_nls(nls);
 	return err;
 }
 

fs/hugetlbfs/inode.c

@@ -380,36 +380,11 @@ static void hugetlbfs_delete_inode(struct inode *inode)
 
 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
 {
-	struct super_block *sb = inode->i_sb;
-
-	if (!hlist_unhashed(&inode->i_hash)) {
-		if (!(inode->i_state & (I_DIRTY|I_SYNC)))
-			list_move(&inode->i_list, &inode_unused);
-		inodes_stat.nr_unused++;
-		if (!sb || (sb->s_flags & MS_ACTIVE)) {
-			spin_unlock(&inode_lock);
-			return;
-		}
-		inode->i_state |= I_WILL_FREE;
-		spin_unlock(&inode_lock);
-		/*
-		 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
-		 * in our backing_dev_info.
-		 */
-		write_inode_now(inode, 1);
-		spin_lock(&inode_lock);
-		inode->i_state &= ~I_WILL_FREE;
-		inodes_stat.nr_unused--;
-		hlist_del_init(&inode->i_hash);
+	if (generic_detach_inode(inode)) {
+		truncate_hugepages(inode, 0);
+		clear_inode(inode);
+		destroy_inode(inode);
 	}
-	list_del_init(&inode->i_list);
-	list_del_init(&inode->i_sb_list);
-	inode->i_state |= I_FREEING;
-	inodes_stat.nr_inodes--;
-	spin_unlock(&inode_lock);
-	truncate_hugepages(inode, 0);
-	clear_inode(inode);
-	destroy_inode(inode);
 }
 
 static void hugetlbfs_drop_inode(struct inode *inode)

fs/inode.c

@@ -1241,7 +1241,16 @@ void generic_delete_inode(struct inode *inode)
 }
 EXPORT_SYMBOL(generic_delete_inode);
 
-static void generic_forget_inode(struct inode *inode)
+/**
+ *	generic_detach_inode - remove inode from inode lists
+ *	@inode: inode to remove
+ *
+ *	Remove inode from inode lists, write it if it's dirty. This is just an
+ *	internal VFS helper exported for hugetlbfs. Do not use!
+ *
+ *	Returns 1 if inode should be completely destroyed.
+ */
+int generic_detach_inode(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
 
@@ -1251,7 +1260,7 @@ static void generic_forget_inode(struct inode *inode)
 		inodes_stat.nr_unused++;
 		if (sb->s_flags & MS_ACTIVE) {
 			spin_unlock(&inode_lock);
-			return;
+			return 0;
 		}
 		WARN_ON(inode->i_state & I_NEW);
 		inode->i_state |= I_WILL_FREE;
@@ -1269,6 +1278,14 @@ static void generic_forget_inode(struct inode *inode)
 	inode->i_state |= I_FREEING;
 	inodes_stat.nr_inodes--;
 	spin_unlock(&inode_lock);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(generic_detach_inode);
+
+static void generic_forget_inode(struct inode *inode)
+{
+	if (!generic_detach_inode(inode))
+		return;
 	if (inode->i_data.nrpages)
 		truncate_inode_pages(&inode->i_data, 0);
 	clear_inode(inode);
@@ -1399,31 +1416,31 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
 	struct inode *inode = dentry->d_inode;
 	struct timespec now;
 
-	if (mnt_want_write(mnt))
-		return;
 	if (inode->i_flags & S_NOATIME)
-		goto out;
+		return;
 	if (IS_NOATIME(inode))
-		goto out;
+		return;
 	if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
-		goto out;
+		return;
 
 	if (mnt->mnt_flags & MNT_NOATIME)
-		goto out;
+		return;
 	if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
-		goto out;
+		return;
 
 	now = current_fs_time(inode->i_sb);
 
 	if (!relatime_need_update(mnt, inode, now))
-		goto out;
+		return;
 
 	if (timespec_equal(&inode->i_atime, &now))
-		goto out;
+		return;
+
+	if (mnt_want_write(mnt))
+		return;
 
 	inode->i_atime = now;
 	mark_inode_dirty_sync(inode);
-out:
 	mnt_drop_write(mnt);
 }
 EXPORT_SYMBOL(touch_atime);
@@ -1444,34 +1461,37 @@ void file_update_time(struct file *file)
 {
 	struct inode *inode = file->f_path.dentry->d_inode;
 	struct timespec now;
-	int sync_it = 0;
-	int err;
+	enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;
 
+	/* First try to exhaust all avenues to not sync */
 	if (IS_NOCMTIME(inode))
 		return;
 
-	err = mnt_want_write_file(file);
-	if (err)
-		return;
-
 	now = current_fs_time(inode->i_sb);
-	if (!timespec_equal(&inode->i_mtime, &now)) {
-		inode->i_mtime = now;
-		sync_it = 1;
-	}
+	if (!timespec_equal(&inode->i_mtime, &now))
+		sync_it = S_MTIME;
 
-	if (!timespec_equal(&inode->i_ctime, &now)) {
-		inode->i_ctime = now;
-		sync_it = 1;
-	}
+	if (!timespec_equal(&inode->i_ctime, &now))
+		sync_it |= S_CTIME;
 
-	if (IS_I_VERSION(inode)) {
-		inode_inc_iversion(inode);
-		sync_it = 1;
-	}
+	if (IS_I_VERSION(inode))
+		sync_it |= S_VERSION;
+
+	if (!sync_it)
+		return;
 
-	if (sync_it)
-		mark_inode_dirty_sync(inode);
+	/* Finally allowed to write? Takes lock. */
+	if (mnt_want_write_file(file))
+		return;
+
+	/* Only change inode inside the lock region */
+	if (sync_it & S_VERSION)
+		inode_inc_iversion(inode);
+	if (sync_it & S_CTIME)
+		inode->i_ctime = now;
+	if (sync_it & S_MTIME)
+		inode->i_mtime = now;
+	mark_inode_dirty_sync(inode);
 	mnt_drop_write(file->f_path.mnt);
 }
 EXPORT_SYMBOL(file_update_time);
@@ -1599,7 +1619,8 @@ void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
 	else if (S_ISSOCK(mode))
 		inode->i_fop = &bad_sock_fops;
 	else
-		printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n",
-		       mode);
+		printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
+				  " inode %s:%lu\n", mode, inode->i_sb->s_id,
+				  inode->i_ino);
 }
 EXPORT_SYMBOL(init_special_inode);

fs/internal.h

@@ -57,6 +57,7 @@ extern int check_unsafe_exec(struct linux_binprm *);
  * namespace.c
  */
 extern int copy_mount_options(const void __user *, unsigned long *);
+extern int copy_mount_string(const void __user *, char **);
 
 extern void free_vfsmnt(struct vfsmount *);
 extern struct vfsmount *alloc_vfsmnt(const char *);

fs/ioctl.c

@@ -162,20 +162,21 @@ EXPORT_SYMBOL(fiemap_check_flags);
 static int fiemap_check_ranges(struct super_block *sb,
 			       u64 start, u64 len, u64 *new_len)
 {
+	u64 maxbytes = (u64) sb->s_maxbytes;
+
 	*new_len = len;
 
 	if (len == 0)
 		return -EINVAL;
 
-	if (start > sb->s_maxbytes)
+	if (start > maxbytes)
 		return -EFBIG;
 
 	/*
 	 * Shrink request scope to what the fs can actually handle.
 	 */
-	if ((len > sb->s_maxbytes) ||
-	    (sb->s_maxbytes - len) < start)
-		*new_len = sb->s_maxbytes - start;
+	if (len > maxbytes || (maxbytes - len) < start)
+		*new_len = maxbytes - start;
 
 	return 0;
 }

fs/isofs/inode.c

@@ -46,10 +46,7 @@ static void isofs_put_super(struct super_block *sb)
 #ifdef CONFIG_JOLIET
 	lock_kernel();
 
-	if (sbi->s_nls_iocharset) {
-		unload_nls(sbi->s_nls_iocharset);
-		sbi->s_nls_iocharset = NULL;
-	}
+	unload_nls(sbi->s_nls_iocharset);
 
 	unlock_kernel();
 #endif
@@ -912,8 +909,7 @@ static int isofs_fill_super(struct super_block *s, void *data, int silent)
 		printk(KERN_WARNING "%s: get root inode failed\n", __func__);
 out_no_inode:
 #ifdef CONFIG_JOLIET
-	if (sbi->s_nls_iocharset)
-		unload_nls(sbi->s_nls_iocharset);
+	unload_nls(sbi->s_nls_iocharset);
 #endif
 	goto out_freesbi;
 out_no_read:

fs/jfs/super.c

@@ -178,13 +178,11 @@ static void jfs_put_super(struct super_block *sb)
 	rc = jfs_umount(sb);
 	if (rc)
 		jfs_err("jfs_umount failed with return code %d", rc);
-	if (sbi->nls_tab)
-		unload_nls(sbi->nls_tab);
-	sbi->nls_tab = NULL;
+
+	unload_nls(sbi->nls_tab);
 
 	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
 	iput(sbi->direct_inode);
-	sbi->direct_inode = NULL;
 
 	kfree(sbi);
 
@@ -347,8 +345,7 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
 
 	if (nls_map != (void *) -1) {
 		/* Discard old (if remount) */
-		if (sbi->nls_tab)
-			unload_nls(sbi->nls_tab);
+		unload_nls(sbi->nls_tab);
 		sbi->nls_tab = nls_map;
 	}
 	return 1;

fs/libfs.c

@@ -527,14 +527,18 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
 				const void *from, size_t available)
 {
 	loff_t pos = *ppos;
+	size_t ret;
+
 	if (pos < 0)
 		return -EINVAL;
-	if (pos >= available)
+	if (pos >= available || !count)
 		return 0;
 	if (count > available - pos)
 		count = available - pos;
-	if (copy_to_user(to, from + pos, count))
+	ret = copy_to_user(to, from + pos, count);
+	if (ret == count)
 		return -EFAULT;
+	count -= ret;
 	*ppos = pos + count;
 	return count;
 }
@@ -735,10 +739,11 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
 	if (copy_from_user(attr->set_buf, buf, size))
 		goto out;
 
-	ret = len; /* claim we got the whole input */
 	attr->set_buf[size] = '\0';
 	val = simple_strtol(attr->set_buf, NULL, 0);
-	attr->set(attr->data, val);
+	ret = attr->set(attr->data, val);
+	if (ret == 0)
+		ret = len; /* on success, claim we got the whole input */
 out:
 	mutex_unlock(&attr->mutex);
 	return ret;

fs/namespace.c

@@ -1640,7 +1640,7 @@ static int do_new_mount(struct path *path, char *type, int flags,
 {
 	struct vfsmount *mnt;
 
-	if (!type || !memchr(type, 0, PAGE_SIZE))
+	if (!type)
 		return -EINVAL;
 
 	/* we need capabilities... */
@@ -1871,6 +1871,23 @@ int copy_mount_options(const void __user * data, unsigned long *where)
 	return 0;
 }
 
+int copy_mount_string(const void __user *data, char **where)
+{
+	char *tmp;
+
+	if (!data) {
+		*where = NULL;
+		return 0;
+	}
+
+	tmp = strndup_user(data, PAGE_SIZE);
+	if (IS_ERR(tmp))
+		return PTR_ERR(tmp);
+
+	*where = tmp;
+	return 0;
+}
+
 /*
  * Flags is a 32-bit value that allows up to 31 non-fs dependent flags to
  * be given to the mount() call (ie: read-only, no-dev, no-suid etc).
@@ -1900,8 +1917,6 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
 
 	if (!dir_name || !*dir_name || !memchr(dir_name, 0, PAGE_SIZE))
 		return -EINVAL;
-	if (dev_name && !memchr(dev_name, 0, PAGE_SIZE))
-		return -EINVAL;
 
 	if (data_page)
 		((char *)data_page)[PAGE_SIZE - 1] = 0;
@@ -2070,40 +2085,42 @@ EXPORT_SYMBOL(create_mnt_ns);
 SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
 		char __user *, type, unsigned long, flags, void __user *, data)
 {
-	int retval;
+	int ret;
+	char *kernel_type;
+	char *kernel_dir;
+	char *kernel_dev;
 	unsigned long data_page;
-	unsigned long type_page;
-	unsigned long dev_page;
-	char *dir_page;
 
-	retval = copy_mount_options(type, &type_page);
-	if (retval < 0)
-		return retval;
+	ret = copy_mount_string(type, &kernel_type);
+	if (ret < 0)
+		goto out_type;
 
-	dir_page = getname(dir_name);
-	retval = PTR_ERR(dir_page);
-	if (IS_ERR(dir_page))
-		goto out1;
+	kernel_dir = getname(dir_name);
+	if (IS_ERR(kernel_dir)) {
+		ret = PTR_ERR(kernel_dir);
+		goto out_dir;
+	}
 
-	retval = copy_mount_options(dev_name, &dev_page);
-	if (retval < 0)
-		goto out2;
+	ret = copy_mount_string(dev_name, &kernel_dev);
+	if (ret < 0)
+		goto out_dev;
 
-	retval = copy_mount_options(data, &data_page);
-	if (retval < 0)
-		goto out3;
+	ret = copy_mount_options(data, &data_page);
+	if (ret < 0)
+		goto out_data;
 
-	retval = do_mount((char *)dev_page, dir_page, (char *)type_page,
-			  flags, (void *)data_page);
-	free_page(data_page);
+	ret = do_mount(kernel_dev, kernel_dir, kernel_type, flags,
+		(void *) data_page);
 
-out3:
-	free_page(dev_page);
-out2:
-	putname(dir_page);
-out1:
-	free_page(type_page);
-	return retval;
+	free_page(data_page);
+out_data:
+	kfree(kernel_dev);
+out_dev:
+	putname(kernel_dir);
+out_dir:
+	kfree(kernel_type);
+out_type:
+	return ret;
 }
 
 /*

fs/ncpfs/inode.c

@@ -746,16 +746,8 @@ static void ncp_put_super(struct super_block *sb)
 
 #ifdef CONFIG_NCPFS_NLS
 	/* unload the NLS charsets */
-	if (server->nls_vol)
-	{
-		unload_nls(server->nls_vol);
-		server->nls_vol = NULL;
-	}
-	if (server->nls_io)
-	{
-		unload_nls(server->nls_io);
-		server->nls_io = NULL;
-	}
+	unload_nls(server->nls_vol);
+	unload_nls(server->nls_io);
 #endif /* CONFIG_NCPFS_NLS */
 
 	if (server->info_filp)

fs/ncpfs/ioctl.c

@@ -223,10 +223,8 @@ ncp_set_charsets(struct ncp_server* server, struct ncp_nls_ioctl __user *arg)
 	oldset_io = server->nls_io;
 	server->nls_io = iocharset;
 
-	if (oldset_cp)
-		unload_nls(oldset_cp);
-	if (oldset_io)
-		unload_nls(oldset_io);
+	unload_nls(oldset_cp);
+	unload_nls(oldset_io);
 
 	return 0;
 }

fs/nfs/inode.c

@@ -458,49 +458,21 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr)
  */
 static int nfs_vmtruncate(struct inode * inode, loff_t offset)
 {
-	if (i_size_read(inode) < offset) {
-		unsigned long limit;
-
-		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-		if (limit != RLIM_INFINITY && offset > limit)
-			goto out_sig;
-		if (offset > inode->i_sb->s_maxbytes)
-			goto out_big;
-		spin_lock(&inode->i_lock);
-		i_size_write(inode, offset);
-		spin_unlock(&inode->i_lock);
-	} else {
-		struct address_space *mapping = inode->i_mapping;
+	loff_t oldsize;
+	int err;
 
-		/*
-		 * truncation of in-use swapfiles is disallowed - it would
-		 * cause subsequent swapout to scribble on the now-freed
-		 * blocks.
-		 */
-		if (IS_SWAPFILE(inode))
-			return -ETXTBSY;
-		spin_lock(&inode->i_lock);
-		i_size_write(inode, offset);
-		spin_unlock(&inode->i_lock);
+	err = inode_newsize_ok(inode, offset);
+	if (err)
+		goto out;
 
-		/*
-		 * unmap_mapping_range is called twice, first simply for
-		 * efficiency so that truncate_inode_pages does fewer
-		 * single-page unmaps.  However after this first call, and
-		 * before truncate_inode_pages finishes, it is possible for
-		 * private pages to be COWed, which remain after
-		 * truncate_inode_pages finishes, hence the second
-		 * unmap_mapping_range call must be made for correctness.
-		 */
-		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-		truncate_inode_pages(mapping, offset);
-		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-	}
-	return 0;
-out_sig:
-	send_sig(SIGXFSZ, current, 0);
-out_big:
-	return -EFBIG;
+	spin_lock(&inode->i_lock);
+	oldsize = inode->i_size;
+	i_size_write(inode, offset);
+	spin_unlock(&inode->i_lock);
+
+	truncate_pagecache(inode, oldsize, offset);
+out:
+	return err;
 }
 
 /**

fs/nls/nls_base.c

@@ -270,7 +270,8 @@ struct nls_table *load_nls(char *charset)
 
 void unload_nls(struct nls_table *nls)
 {
-	module_put(nls->owner);
+	if (nls)
+		module_put(nls->owner);
 }
 
 static const wchar_t charset2uni[256] = {

fs/ntfs/super.c

@@ -201,8 +201,7 @@ static bool parse_options(ntfs_volume *vol, char *opt)
 						v, old_nls->charset);
 				nls_map = old_nls;
 			} else /* nls_map */ {
-				if (old_nls)
-					unload_nls(old_nls);
+				unload_nls(old_nls);
 			}
 		} else if (!strcmp(p, "utf8")) {
 			bool val = false;
@@ -2427,10 +2426,9 @@ static void ntfs_put_super(struct super_block *sb)
 		ntfs_free(vol->upcase);
 		vol->upcase = NULL;
 	}
-	if (vol->nls_map) {
-		unload_nls(vol->nls_map);
-		vol->nls_map = NULL;
-	}
+
+	unload_nls(vol->nls_map);
+
 	sb->s_fs_info = NULL;
 	kfree(vol);
 

fs/ramfs/file-nommu.c

@@ -69,14 +69,11 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
 	/* make various checks */
 	order = get_order(newsize);
 	if (unlikely(order >= MAX_ORDER))
-		goto too_big;
+		return -EFBIG;
 
-	limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-	if (limit != RLIM_INFINITY && newsize > limit)
-		goto fsize_exceeded;
-
-	if (newsize > inode->i_sb->s_maxbytes)
-		goto too_big;
+	ret = inode_newsize_ok(inode, newsize);
+	if (ret)
+		return ret;
 
 	i_size_write(inode, newsize);
 
@@ -118,12 +115,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
 
 	return 0;
 
- fsize_exceeded:
-	send_sig(SIGXFSZ, current, 0);
- too_big:
-	return -EFBIG;
-
- add_error:
+add_error:
 	while (loop < npages)
 		__free_page(pages + loop++);
 	return ret;

fs/read_write.c

@@ -839,9 +839,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 		max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
 
 	pos = *ppos;
-	retval = -EINVAL;
-	if (unlikely(pos < 0))
-		goto fput_out;
 	if (unlikely(pos + count > max)) {
 		retval = -EOVERFLOW;
 		if (pos >= max)

fs/seq_file.c

@@ -429,20 +429,21 @@ EXPORT_SYMBOL(mangle_path);
  */
 int seq_path(struct seq_file *m, struct path *path, char *esc)
 {
-	if (m->count < m->size) {
-		char *s = m->buf + m->count;
-		char *p = d_path(path, s, m->size - m->count);
+	char *buf;
+	size_t size = seq_get_buf(m, &buf);
+	int res = -1;
+
+	if (size) {
+		char *p = d_path(path, buf, size);
 		if (!IS_ERR(p)) {
-			s = mangle_path(s, p, esc);
-			if (s) {
-				p = m->buf + m->count;
-				m->count = s - m->buf;
-				return s - p;
-			}
+			char *end = mangle_path(buf, p, esc);
+			if (end)
+				res = end - buf;
 		}
 	}
-	m->count = m->size;
-	return -1;
+	seq_commit(m, res);
+
+	return res;
 }
 EXPORT_SYMBOL(seq_path);
 
@@ -454,26 +455,28 @@ EXPORT_SYMBOL(seq_path);
 int seq_path_root(struct seq_file *m, struct path *path, struct path *root,
 		  char *esc)
 {
-	int err = -ENAMETOOLONG;
-	if (m->count < m->size) {
-		char *s = m->buf + m->count;
+	char *buf;
+	size_t size = seq_get_buf(m, &buf);
+	int res = -ENAMETOOLONG;
+
+	if (size) {
 		char *p;
 
 		spin_lock(&dcache_lock);
-		p = __d_path(path, root, s, m->size - m->count);
+		p = __d_path(path, root, buf, size);
 		spin_unlock(&dcache_lock);
-		err = PTR_ERR(p);
+		res = PTR_ERR(p);
 		if (!IS_ERR(p)) {
-			s = mangle_path(s, p, esc);
-			if (s) {
-				p = m->buf + m->count;
-				m->count = s - m->buf;
-				return 0;
-			}
+			char *end = mangle_path(buf, p, esc);
+			if (end)
+				res = end - buf;
+			else
+				res = -ENAMETOOLONG;
 		}
 	}
-	m->count = m->size;
-	return err;
+	seq_commit(m, res);
+
+	return res < 0 ? res : 0;
 }
 
 /*
@@ -481,20 +484,21 @@ int seq_path_root(struct seq_file *m, struct path *path, struct path *root,
  */
 int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc)
 {
-	if (m->count < m->size) {
-		char *s = m->buf + m->count;
-		char *p = dentry_path(dentry, s, m->size - m->count);
+	char *buf;
+	size_t size = seq_get_buf(m, &buf);
+	int res = -1;
+
+	if (size) {
+		char *p = dentry_path(dentry, buf, size);
 		if (!IS_ERR(p)) {
-			s = mangle_path(s, p, esc);
-			if (s) {
-				p = m->buf + m->count;
-				m->count = s - m->buf;
-				return s - p;
-			}
+			char *end = mangle_path(buf, p, esc);
+			if (end)
+				res = end - buf;
 		}
 	}
-	m->count = m->size;
-	return -1;
+	seq_commit(m, res);
+
+	return res;
 }
 
 int seq_bitmap(struct seq_file *m, const unsigned long *bits,

fs/smbfs/inode.c

@@ -459,14 +459,8 @@ smb_show_options(struct seq_file *s, struct vfsmount *m)
 static void
 smb_unload_nls(struct smb_sb_info *server)
 {
-	if (server->remote_nls) {
-		unload_nls(server->remote_nls);
-		server->remote_nls = NULL;
-	}
-	if (server->local_nls) {
-		unload_nls(server->local_nls);
-		server->local_nls = NULL;
-	}
+	unload_nls(server->remote_nls);
+	unload_nls(server->local_nls);
 }
 
 static void

fs/super.c

@@ -465,6 +465,48 @@ struct super_block * get_super(struct block_device *bdev)
 }
 
 EXPORT_SYMBOL(get_super);
+
+/**
+ * get_active_super - get an active reference to the superblock of a device
+ * @bdev: device to get the superblock for
+ *
+ * Scans the superblock list and finds the superblock of the file system
+ * mounted on the device given.  Returns the superblock with an active
+ * reference and s_umount held exclusively or %NULL if none was found.
+ */
+struct super_block *get_active_super(struct block_device *bdev)
+{
+	struct super_block *sb;
+
+	if (!bdev)
+		return NULL;
+
+	spin_lock(&sb_lock);
+	list_for_each_entry(sb, &super_blocks, s_list) {
+		if (sb->s_bdev != bdev)
+			continue;
+
+		sb->s_count++;
+		spin_unlock(&sb_lock);
+		down_write(&sb->s_umount);
+		if (sb->s_root) {
+			spin_lock(&sb_lock);
+			if (sb->s_count > S_BIAS) {
+				atomic_inc(&sb->s_active);
+				sb->s_count--;
+				spin_unlock(&sb_lock);
+				return sb;
+			}
+			spin_unlock(&sb_lock);
+		}
+		up_write(&sb->s_umount);
+		put_super(sb);
+		yield();
+		spin_lock(&sb_lock);
+	}
+	spin_unlock(&sb_lock);
+	return NULL;
+}
  
 struct super_block * user_get_super(dev_t dev)
 {
@@ -527,11 +569,15 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
 {
 	int retval;
 	int remount_rw;
-	
+
+	if (sb->s_frozen != SB_UNFROZEN)
+		return -EBUSY;
+
 #ifdef CONFIG_BLOCK
 	if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
 		return -EACCES;
 #endif
+
 	if (flags & MS_RDONLY)
 		acct_auto_close(sb);
 	shrink_dcache_sb(sb);
@@ -743,9 +789,14 @@ int get_sb_bdev(struct file_system_type *fs_type,
 	 * will protect the lockfs code from trying to start a snapshot
 	 * while we are mounting
 	 */
-	down(&bdev->bd_mount_sem);
+	mutex_lock(&bdev->bd_fsfreeze_mutex);
+	if (bdev->bd_fsfreeze_count > 0) {
+		mutex_unlock(&bdev->bd_fsfreeze_mutex);
+		error = -EBUSY;
+		goto error_bdev;
+	}
 	s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
-	up(&bdev->bd_mount_sem);
+	mutex_unlock(&bdev->bd_fsfreeze_mutex);
 	if (IS_ERR(s))
 		goto error_s;
 
@@ -892,6 +943,16 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
  	if (error)
  		goto out_sb;
 
+	/*
+	 * filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE
+	 * but s_maxbytes was an unsigned long long for many releases. Throw
+	 * this warning for a little while to try and catch filesystems that
+	 * violate this rule. This warning should be either removed or
+	 * converted to a BUG() in 2.6.34.
+	 */
+	WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
+		"negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes);
+
 	mnt->mnt_mountpoint = mnt->mnt_root;
 	mnt->mnt_parent = mnt;
 	up_write(&mnt->mnt_sb->s_umount);

include/linux/fs.h

@@ -641,7 +641,6 @@ struct block_device {
 	struct super_block *	bd_super;
 	int			bd_openers;
 	struct mutex		bd_mutex;	/* open/close mutex */
-	struct semaphore	bd_mount_sem;
 	struct list_head	bd_inodes;
 	void *			bd_holder;
 	int			bd_holders;
@@ -1316,7 +1315,7 @@ struct super_block {
 	unsigned long		s_blocksize;
 	unsigned char		s_blocksize_bits;
 	unsigned char		s_dirt;
-	unsigned long long	s_maxbytes;	/* Max file size */
+	loff_t			s_maxbytes;	/* Max file size */
 	struct file_system_type	*s_type;
 	const struct super_operations	*s_op;
 	const struct dquot_operations	*dq_op;
@@ -2157,6 +2156,7 @@ extern ino_t iunique(struct super_block *, ino_t);
 extern int inode_needs_sync(struct inode *inode);
 extern void generic_delete_inode(struct inode *inode);
 extern void generic_drop_inode(struct inode *inode);
+extern int generic_detach_inode(struct inode *inode);
 
 extern struct inode *ilookup5_nowait(struct super_block *sb,
 		unsigned long hashval, int (*test)(struct inode *, void *),
@@ -2335,6 +2335,7 @@ extern void get_filesystem(struct file_system_type *fs);
 extern void put_filesystem(struct file_system_type *fs);
 extern struct file_system_type *get_fs_type(const char *name);
 extern struct super_block *get_super(struct block_device *);
+extern struct super_block *get_active_super(struct block_device *bdev);
 extern struct super_block *user_get_super(dev_t);
 extern void drop_super(struct super_block *sb);
 
@@ -2382,7 +2383,8 @@ extern int buffer_migrate_page(struct address_space *,
 #define buffer_migrate_page NULL
 #endif
 
-extern int inode_change_ok(struct inode *, struct iattr *);
+extern int inode_change_ok(const struct inode *, struct iattr *);
+extern int inode_newsize_ok(const struct inode *, loff_t offset);
 extern int __must_check inode_setattr(struct inode *, struct iattr *);
 
 extern void file_update_time(struct file *file);

include/linux/mm.h

@@ -792,8 +792,9 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
 	unmap_mapping_range(mapping, holebegin, holelen, 0);
 }
 
-extern int vmtruncate(struct inode * inode, loff_t offset);
-extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
+extern void truncate_pagecache(struct inode *inode, loff_t old, loff_t new);
+extern int vmtruncate(struct inode *inode, loff_t offset);
+extern int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end);
 
 int truncate_inode_page(struct address_space *mapping, struct page *page);
 int generic_error_remove_page(struct address_space *mapping, struct page *page);

include/linux/seq_file.h

@@ -35,6 +35,44 @@ struct seq_operations {
 
 #define SEQ_SKIP 1
 
+/**
+ * seq_get_buf - get buffer to write arbitrary data to
+ * @m: the seq_file handle
+ * @bufp: the beginning of the buffer is stored here
+ *
+ * Return the number of bytes available in the buffer, or zero if
+ * there's no space.
+ */
+static inline size_t seq_get_buf(struct seq_file *m, char **bufp)
+{
+	BUG_ON(m->count > m->size);
+	if (m->count < m->size)
+		*bufp = m->buf + m->count;
+	else
+		*bufp = NULL;
+
+	return m->size - m->count;
+}
+
+/**
+ * seq_commit - commit data to the buffer
+ * @m: the seq_file handle
+ * @num: the number of bytes to commit
+ *
+ * Commit @num bytes of data written to a buffer previously acquired
+ * by seq_buf_get.  To signal an error condition, or that the data
+ * didn't fit in the available space, pass a negative @num value.
+ */
+static inline void seq_commit(struct seq_file *m, int num)
+{
+	if (num < 0) {
+		m->count = m->size;
+	} else {
+		BUG_ON(m->count + num > m->size);
+		m->count += num;
+	}
+}
+
 char *mangle_path(char *s, char *p, char *esc);
 int seq_open(struct file *, const struct seq_operations *);
 ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);

mm/filemap.c

@@ -58,7 +58,7 @@
 /*
  * Lock ordering:
  *
- *  ->i_mmap_lock		(vmtruncate)
+ *  ->i_mmap_lock		(truncate_pagecache)
  *    ->private_lock		(__free_pte->__set_page_dirty_buffers)
  *      ->swap_lock		(exclusive_swap_page, others)
  *        ->mapping->tree_lock

mm/memory.c

@@ -297,7 +297,8 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		unsigned long addr = vma->vm_start;
 
 		/*
-		 * Hide vma from rmap and vmtruncate before freeing pgtables
+		 * Hide vma from rmap and truncate_pagecache before freeing
+		 * pgtables
 		 */
 		anon_vma_unlink(vma);
 		unlink_file_vma(vma);
@@ -2408,7 +2409,7 @@ static inline void unmap_mapping_range_list(struct list_head *head,
  * @mapping: the address space containing mmaps to be unmapped.
  * @holebegin: byte in first page to unmap, relative to the start of
  * the underlying file.  This will be rounded down to a PAGE_SIZE
- * boundary.  Note that this is different from vmtruncate(), which
+ * boundary.  Note that this is different from truncate_pagecache(), which
  * must keep the partial page.  In contrast, we must get rid of
  * partial pages.
  * @holelen: size of prospective hole in bytes.  This will be rounded
@@ -2459,63 +2460,6 @@ void unmap_mapping_range(struct address_space *mapping,
 }
 EXPORT_SYMBOL(unmap_mapping_range);
 
-/**
- * vmtruncate - unmap mappings "freed" by truncate() syscall
- * @inode: inode of the file used
- * @offset: file offset to start truncating
- *
- * NOTE! We have to be ready to update the memory sharing
- * between the file and the memory map for a potential last
- * incomplete page.  Ugly, but necessary.
- */
-int vmtruncate(struct inode * inode, loff_t offset)
-{
-	if (inode->i_size < offset) {
-		unsigned long limit;
-
-		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-		if (limit != RLIM_INFINITY && offset > limit)
-			goto out_sig;
-		if (offset > inode->i_sb->s_maxbytes)
-			goto out_big;
-		i_size_write(inode, offset);
-	} else {
-		struct address_space *mapping = inode->i_mapping;
-
-		/*
-		 * truncation of in-use swapfiles is disallowed - it would
-		 * cause subsequent swapout to scribble on the now-freed
-		 * blocks.
-		 */
-		if (IS_SWAPFILE(inode))
-			return -ETXTBSY;
-		i_size_write(inode, offset);
-
-		/*
-		 * unmap_mapping_range is called twice, first simply for
-		 * efficiency so that truncate_inode_pages does fewer
-		 * single-page unmaps.  However after this first call, and
-		 * before truncate_inode_pages finishes, it is possible for
-		 * private pages to be COWed, which remain after
-		 * truncate_inode_pages finishes, hence the second
-		 * unmap_mapping_range call must be made for correctness.
-		 */
-		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-		truncate_inode_pages(mapping, offset);
-		unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
-	}
-
-	if (inode->i_op->truncate)
-		inode->i_op->truncate(inode);
-	return 0;
-
-out_sig:
-	send_sig(SIGXFSZ, current, 0);
-out_big:
-	return -EFBIG;
-}
-EXPORT_SYMBOL(vmtruncate);
-
 int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
 {
 	struct address_space *mapping = inode->i_mapping;

mm/mremap.c

@@ -86,8 +86,8 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
 	if (vma->vm_file) {
 		/*
 		 * Subtle point from Rajesh Venkatasubramanian: before
-		 * moving file-based ptes, we must lock vmtruncate out,
-		 * since it might clean the dst vma before the src vma,
+		 * moving file-based ptes, we must lock truncate_pagecache
+		 * out, since it might clean the dst vma before the src vma,
 		 * and we propagate stale pages into the dst afterward.
 		 */
 		mapping = vma->vm_file->f_mapping;

mm/nommu.c

@@ -82,46 +82,6 @@ DECLARE_RWSEM(nommu_region_sem);
 struct vm_operations_struct generic_file_vm_ops = {
 };
 
-/*
- * Handle all mappings that got truncated by a "truncate()"
- * system call.
- *
- * NOTE! We have to be ready to update the memory sharing
- * between the file and the memory map for a potential last
- * incomplete page.  Ugly, but necessary.
- */
-int vmtruncate(struct inode *inode, loff_t offset)
-{
-	struct address_space *mapping = inode->i_mapping;
-	unsigned long limit;
-
-	if (inode->i_size < offset)
-		goto do_expand;
-	i_size_write(inode, offset);
-
-	truncate_inode_pages(mapping, offset);
-	goto out_truncate;
-
-do_expand:
-	limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
-	if (limit != RLIM_INFINITY && offset > limit)
-		goto out_sig;
-	if (offset > inode->i_sb->s_maxbytes)
-		goto out;
-	i_size_write(inode, offset);
-
-out_truncate:
-	if (inode->i_op->truncate)
-		inode->i_op->truncate(inode);
-	return 0;
-out_sig:
-	send_sig(SIGXFSZ, current, 0);
-out:
-	return -EFBIG;
-}
-
-EXPORT_SYMBOL(vmtruncate);
-
 /*
  * Return the total memory allocated for this pointer, not
  * just what the caller asked for.

mm/truncate.c

@@ -497,3 +497,67 @@ int invalidate_inode_pages2(struct address_space *mapping)
 	return invalidate_inode_pages2_range(mapping, 0, -1);
 }
 EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
+
+/**
+ * truncate_pagecache - unmap and remove pagecache that has been truncated
+ * @inode: inode
+ * @old: old file offset
+ * @new: new file offset
+ *
+ * inode's new i_size must already be written before truncate_pagecache
+ * is called.
+ *
+ * This function should typically be called before the filesystem
+ * releases resources associated with the freed range (eg. deallocates
+ * blocks). This way, pagecache will always stay logically coherent
+ * with on-disk format, and the filesystem would not have to deal with
+ * situations such as writepage being called for a page that has already
+ * had its underlying blocks deallocated.
+ */
+void truncate_pagecache(struct inode *inode, loff_t old, loff_t new)
+{
+	if (new < old) {
+		struct address_space *mapping = inode->i_mapping;
+
+		/*
+		 * unmap_mapping_range is called twice, first simply for
+		 * efficiency so that truncate_inode_pages does fewer
+		 * single-page unmaps.  However after this first call, and
+		 * before truncate_inode_pages finishes, it is possible for
+		 * private pages to be COWed, which remain after
+		 * truncate_inode_pages finishes, hence the second
+		 * unmap_mapping_range call must be made for correctness.
+		 */
+		unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
+		truncate_inode_pages(mapping, new);
+		unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
+	}
+}
+EXPORT_SYMBOL(truncate_pagecache);
+
+/**
+ * vmtruncate - unmap mappings "freed" by truncate() syscall
+ * @inode: inode of the file used
+ * @offset: file offset to start truncating
+ *
+ * NOTE! We have to be ready to update the memory sharing
+ * between the file and the memory map for a potential last
+ * incomplete page.  Ugly, but necessary.
+ */
+int vmtruncate(struct inode *inode, loff_t offset)
+{
+	loff_t oldsize;
+	int error;
+
+	error = inode_newsize_ok(inode, offset);
+	if (error)
+		return error;
+	oldsize = inode->i_size;
+	i_size_write(inode, offset);
+	truncate_pagecache(inode, oldsize, offset);
+	if (inode->i_op->truncate)
+		inode->i_op->truncate(inode);
+
+	return error;
+}
+EXPORT_SYMBOL(vmtruncate);