Commit f8f484d1 authored Nov 04, 2009 by Tyler Hicks

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>

parent 5f3ef64f

fs/ecryptfs/inode.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -1006,6 +1006,21 @@ out:
		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_dir_iops = {
		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,

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