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 <[email protected]>
This commit is contained in:
Al Viro 2015-11-17 01:07:57 -05:00
commit 21fc61c73c
57 changed files with 81 additions and 46 deletions

View file

@ -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;

View file

@ -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);

View file

@ -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;
}