Commit 21fc61c7 authored by Al Viro's avatar Al Viro
Browse files

don't put symlink bodies in pagecache into highmem 



kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.

new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases.  page_follow_link_light()
instrumented to yell about anything missed.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent aa80deab

Documentation/filesystems/porting

+5 −0
Original line number Diff line number Diff line
@@ -504,3 +504,8 @@ in your dentry operations instead. 
[mandatory]

	__fd_install() & fd_install() can now sleep. Callers should not

	hold a spinlock	or other resources that do not allow a schedule.

--

[mandatory]

	any symlink that might use page_follow_link_light/page_put_link() must

	have inode_nohighmem(inode) called before anything might start playing with

	its pagecache.

fs/affs/inode.c

+1 −0
Original line number Diff line number Diff line
@@ -140,6 +140,7 @@ struct inode *affs_iget(struct super_block *sb, unsigned long ino) 
		break;

	case ST_SOFTLINK:

		inode->i_mode |= S_IFLNK;

		inode_nohighmem(inode);

		inode->i_op = &affs_symlink_inode_operations;

		inode->i_data.a_ops = &affs_symlink_aops;

		break;

fs/affs/namei.c

+1 −0
Original line number Diff line number Diff line
@@ -344,6 +344,7 @@ affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) 
		return -ENOSPC;



	inode->i_op = &affs_symlink_inode_operations;

	inode_nohighmem(inode);

	inode->i_data.a_ops = &affs_symlink_aops;

	inode->i_mode = S_IFLNK | 0777;

	mode_to_prot(inode);

fs/affs/symlink.c

+1 −3
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page) 
{

	struct buffer_head *bh;

	struct inode *inode = page->mapping->host;

	char *link = kmap(page);

	char *link = page_address(page);

	struct slink_front *lf;

	int			 i, j;

	char			 c;
@@ -57,12 +57,10 @@ static int affs_symlink_readpage(struct file *file, struct page *page) 
	link[i] = '\0';

	affs_brelse(bh);

	SetPageUptodate(page);

	kunmap(page);

	unlock_page(page);

	return 0;

fail:

	SetPageError(page);

	kunmap(page);

	unlock_page(page);

	return -EIO;

}

fs/afs/inode.c

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key) 
	case AFS_FTYPE_SYMLINK:

		inode->i_mode	= S_IFLNK | vnode->status.mode;

		inode->i_op	= &page_symlink_inode_operations;

		inode_nohighmem(inode);

		break;

	default:

		printk("kAFS: AFS vnode with undefined type\n");

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