From 4981e081cfe2c3f4abcfa3924ebd999cdbed4914 Mon Sep 17 00:00:00 2001 From: Michael Halcrow Date: Tue, 16 Oct 2007 01:28:09 -0700 Subject: eCryptfs: set up and destroy persistent lower file This patch sets up and destroys the persistent lower file for each eCryptfs inode. Signed-off-by: Michael Halcrow Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ecryptfs/main.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) (limited to 'fs/ecryptfs/main.c') diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index 4954595..fb9d85b 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -99,6 +99,64 @@ void __ecryptfs_printk(const char *fmt, ...) } /** + * ecryptfs_init_persistent_file + * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with + * the lower dentry and the lower mount set + * + * eCryptfs only ever keeps a single open file for every lower + * inode. All I/O operations to the lower inode occur through that + * file. When the first eCryptfs dentry that interposes with the first + * lower dentry for that inode is created, this function creates the + * persistent file struct and associates it with the eCryptfs + * inode. When the eCryptfs inode is destroyed, the file is closed. + * + * The persistent file will be opened with read/write permissions, if + * possible. Otherwise, it is opened read-only. + * + * This function does nothing if a lower persistent file is already + * associated with the eCryptfs inode. + * + * Returns zero on success; non-zero otherwise + */ +int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry) +{ + struct ecryptfs_inode_info *inode_info = + ecryptfs_inode_to_private(ecryptfs_dentry->d_inode); + int rc = 0; + + mutex_lock(&inode_info->lower_file_mutex); + if (!inode_info->lower_file) { + struct dentry *lower_dentry; + struct vfsmount *lower_mnt = + ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry); + + lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); + /* Corresponding dput() and mntput() are done when the + * persistent file is fput() when the eCryptfs inode + * is destroyed. */ + dget(lower_dentry); + mntget(lower_mnt); + inode_info->lower_file = dentry_open(lower_dentry, + lower_mnt, + (O_RDWR | O_LARGEFILE)); + if (IS_ERR(inode_info->lower_file)) + inode_info->lower_file = dentry_open(lower_dentry, + lower_mnt, + (O_RDONLY + | O_LARGEFILE)); + if (IS_ERR(inode_info->lower_file)) { + printk(KERN_ERR "Error opening lower persistent file " + "for lower_dentry [0x%p] and lower_mnt [0x%p]\n", + lower_dentry, lower_mnt); + rc = PTR_ERR(inode_info->lower_file); + inode_info->lower_file = NULL; + } + } + mutex_unlock(&inode_info->lower_file_mutex); + return rc; +} + +/** * ecryptfs_interpose * @lower_dentry: Existing dentry in the lower filesystem * @dentry: ecryptfs' dentry @@ -155,6 +213,13 @@ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry, /* This size will be overwritten for real files w/ headers and * other metadata */ fsstack_copy_inode_size(inode, lower_inode); + rc = ecryptfs_init_persistent_file(dentry); + if (rc) { + printk(KERN_ERR "%s: Error attempting to initialize the " + "persistent file for the dentry with name [%s]; " + "rc = [%d]\n", __FUNCTION__, dentry->d_name.name, rc); + goto out; + } out: return rc; } -- cgit v1.1