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don't put symlink bodies in pagecache into highmem

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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>
This commit is contained in:
Al Viro
2015-11-17 01:07:57 -05:00
parent aa80deab33
commit 21fc61c73c
57 changed files with 81 additions and 46 deletions
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1
fs/hpfs/inode.c
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@@ -77,6 +77,7 @@ void hpfs_read_inode(struct inode *i)
kfree(ea);
i->i_mode = S_IFLNK | 0777;
i->i_op = &page_symlink_inode_operations;
inode_nohighmem(i);
i->i_data.a_ops = &hpfs_symlink_aops;
set_nlink(i, 1);
i->i_size = ea_size;

5
fs/hpfs/namei.c
View File

@@ -332,6 +332,7 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy
result->i_blocks = 1;
set_nlink(result, 1);
result->i_size = strlen(symlink);
inode_nohighmem(result);
result->i_op = &page_symlink_inode_operations;
result->i_data.a_ops = &hpfs_symlink_aops;
@@ -500,7 +501,7 @@ out:
static int hpfs_symlink_readpage(struct file *file, struct page *page)
{
char *link = kmap(page);
char *link = page_address(page);
struct inode *i = page->mapping->host;
struct fnode *fnode;
struct buffer_head *bh;
@@ -516,14 +517,12 @@ static int hpfs_symlink_readpage(struct file *file, struct page *page)
goto fail;
hpfs_unlock(i->i_sb);
SetPageUptodate(page);
kunmap(page);
unlock_page(page);
return 0;
fail:
hpfs_unlock(i->i_sb);
SetPageError(page);
kunmap(page);
unlock_page(page);
return err;
}