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mcoverlayfs 4.18: re-define ovl_readlink

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Apparently /proc needs it; it's normally implemented using get_link if
readlink isn't implemented but proc's get_link crashes the kernel in
this case (because nameidata is only defined for open* paths)

Change-Id: I1864d6c948db879d33ea29b1b281bf84ff8eeec6
This commit is contained in:
Dominique Martinet
2019-01-15 14:28:06 +09:00
parent 351fdead3b
commit 0fbdcc44b9
1 changed files with 17 additions and 0 deletions
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17
executer/kernel/mcoverlayfs/linux-4.18.14/inode.c
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@@ -250,6 +250,22 @@ int ovl_permission(struct inode *inode, int mask)
return err; return err;
} }
static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
{
struct path realpath;
struct inode *realinode;
ovl_path_real(dentry, &realpath);
realinode = realpath.dentry->d_inode;
if (!realinode->i_op->readlink)
return -EINVAL;
touch_atime(&realpath);
return realinode->i_op->readlink(realpath.dentry, buf, bufsiz);
}
static const char *ovl_get_link(struct dentry *dentry, static const char *ovl_get_link(struct dentry *dentry,
struct inode *inode, struct inode *inode,
struct delayed_call *done) struct delayed_call *done)
@@ -454,6 +470,7 @@ static const struct inode_operations ovl_file_inode_operations = {
static const struct inode_operations ovl_symlink_inode_operations = { static const struct inode_operations ovl_symlink_inode_operations = {
.setattr = ovl_setattr, .setattr = ovl_setattr,
.get_link = ovl_get_link, .get_link = ovl_get_link,
.readlink = ovl_readlink,
.getattr = ovl_getattr, .getattr = ovl_getattr,
.listxattr = ovl_listxattr, .listxattr = ovl_listxattr,
.update_time = ovl_update_time, .update_time = ovl_update_time,