eCryptfs: Add getattr function
The i_blocks field of an eCryptfs inode cannot be trusted, but
generic_fillattr() uses it to instantiate the blocks field of a stat()
syscall when a filesystem doesn't implement its own getattr(). Users
have noticed that the output of du is incorrect on newly created files.
This patch creates ecryptfs_getattr() which calls into the lower
filesystem's getattr() so that eCryptfs can use its kstat.blocks value
after calling generic_fillattr(). It is important to note that the
block count includes the eCryptfs metadata stored in the beginning of
the lower file plus any padding used to fill an extent before
encryption.
https://bugs.launchpad.net/ecryptfs/+bug/390833
Reported-by: Dominic Sacré <dominic.sacre@gmx.de>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 2b449d7..5726d7a 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -1006,6 +1006,21 @@
return rc;
}
+int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+{
+ struct kstat lower_stat;
+ int rc;
+
+ rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
+ ecryptfs_dentry_to_lower(dentry), &lower_stat);
+ if (!rc) {
+ generic_fillattr(dentry->d_inode, stat);
+ stat->blocks = lower_stat.blocks;
+ }
+ return rc;
+}
+
int
ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags)
@@ -1135,6 +1150,7 @@
const struct inode_operations ecryptfs_main_iops = {
.permission = ecryptfs_permission,
.setattr = ecryptfs_setattr,
+ .getattr = ecryptfs_getattr,
.setxattr = ecryptfs_setxattr,
.getxattr = ecryptfs_getxattr,
.listxattr = ecryptfs_listxattr,
