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Commit caeeeecf authored by Michael Halcrow's avatar Michael Halcrow Committed by Linus Torvalds
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eCryptfs: fix dentry handling on create error, unlink, and inode destroy 



This patch corrects some erroneous dentry handling in eCryptfs.

If there is a problem creating the lower file, then there is nothing that
the persistent lower file can do to really help us.  This patch makes a
vfs_create() failure in the lower filesystem always lead to an
unconditional do_create failure in eCryptfs.

Under certain sequences of operations, the eCryptfs dentry can remain in
the dcache after an unlink.  This patch calls d_drop() on the eCryptfs
dentry to correct this.

eCryptfs has no business calling d_delete() directly on a lower
filesystem's dentry.  This patch removes the call to d_delete() on the
lower persistent file's dentry in ecryptfs_destroy_inode().

(Thanks to David Kleikamp, Eric Sandeen, and Jeff Moyer for helping
identify and resolve this issue)

Signed-off-by: default avatarMichael Halcrow <mhalcrow@us.ibm.com>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c51b1a16

fs/ecryptfs/inode.c

+4 −16
Original line number Diff line number Diff line
@@ -120,23 +120,10 @@ ecryptfs_do_create(struct inode *directory_inode, 
	rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,

					     ecryptfs_dentry, mode, nd);

	if (rc) {

		struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;

		struct ecryptfs_inode_info *inode_info =

			ecryptfs_inode_to_private(ecryptfs_inode);



		printk(KERN_WARNING "%s: Error creating underlying file; "

		       "rc = [%d]; checking for existing\n", __FUNCTION__, rc);

		if (inode_info) {

			mutex_lock(&inode_info->lower_file_mutex);

			if (!inode_info->lower_file) {

				mutex_unlock(&inode_info->lower_file_mutex);

				printk(KERN_ERR "%s: Failure to set underlying "

				       "file; rc = [%d]\n", __FUNCTION__, rc);

		printk(KERN_ERR "%s: Failure to create dentry in lower fs; "

		       "rc = [%d]\n", __FUNCTION__, rc);

		goto out_lock;

	}

			mutex_unlock(&inode_info->lower_file_mutex);

		}

	}

	rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,

				directory_inode->i_sb, 0);

	if (rc) {
@@ -451,6 +438,7 @@ static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) 
	dentry->d_inode->i_nlink =

		ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;

	dentry->d_inode->i_ctime = dir->i_ctime;

	d_drop(dentry);

out_unlock:

	unlock_parent(lower_dentry);

	return rc;

fs/ecryptfs/super.c

+0 −1
Original line number Diff line number Diff line
@@ -86,7 +86,6 @@ static void ecryptfs_destroy_inode(struct inode *inode) 
			fput(inode_info->lower_file);

			inode_info->lower_file = NULL;

			d_drop(lower_dentry);

			d_delete(lower_dentry);

		}

	}

	mutex_unlock(&inode_info->lower_file_mutex);