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>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ea433a7..b3bd912 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4283,6 +4283,7 @@
inode->i_op = &ext4_symlink_inode_operations;
ext4_set_aops(inode);
}
+ inode_nohighmem(inode);
} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
inode->i_op = &ext4_special_inode_operations;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index a969ab3..f27e0c2 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3132,6 +3132,7 @@
if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
if (!encryption_required)
inode->i_op = &ext4_symlink_inode_operations;
+ inode_nohighmem(inode);
ext4_set_aops(inode);
/*
* We cannot call page_symlink() with transaction started
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index abe2401..0e6dc44 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -45,7 +45,7 @@
cpage = read_mapping_page(inode->i_mapping, 0, NULL);
if (IS_ERR(cpage))
return ERR_CAST(cpage);
- caddr = kmap(cpage);
+ caddr = page_address(cpage);
caddr[size] = 0;
}
@@ -75,16 +75,12 @@
/* Null-terminate the name */
if (res <= plen)
paddr[res] = '\0';
- if (cpage) {
- kunmap(cpage);
+ if (cpage)
page_cache_release(cpage);
- }
return *cookie = paddr;
errout:
- if (cpage) {
- kunmap(cpage);
+ if (cpage)
page_cache_release(cpage);
- }
kfree(paddr);
return ERR_PTR(res);
}