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: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 2 insertions, 0 deletions

diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index 737160a7b819..d897e169ab9c 100644
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -533,6 +533,7 @@ static void ufs_set_inode_ops(struct inode *inode)
                 } else {
                         inode->i_mapping->a_ops = &ufs_aops;
                         inode->i_op = &page_symlink_inode_operations;
+                        inode_nohighmem(inode);
                 }
         } else
                 init_special_inode(inode, inode->i_mode,
diff --git a/fs/ufs/namei.c b/fs/ufs/namei.c
index 24b0cbd2d917..acf4a3b61b81 100644
--- a/fs/ufs/namei.c
+++ b/fs/ufs/namei.c
@@ -124,6 +124,7 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,
         if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
                 /* slow symlink */
                 inode->i_op = &page_symlink_inode_operations;
+                inode_nohighmem(inode);
                 inode->i_mapping->a_ops = &ufs_aops;
                 err = page_symlink(inode, symname, l);
                 if (err)