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authorMichael Halcrow <mhalcrow@us.ibm.com>2007-10-16 01:28:09 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 09:43:12 -0700
commit4981e081cfe2c3f4abcfa3924ebd999cdbed4914 (patch)
tree066d56ba49195eb0e733236fef4bb98f2d5f0114 /fs/ecryptfs/main.c
parent0216f7f7921759211e48e8b940eae29f0fe43902 (diff)
downloadlinux-4981e081cfe2c3f4abcfa3924ebd999cdbed4914.tar.bz2
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 <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ecryptfs/main.c')
-rw-r--r--fs/ecryptfs/main.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 49545951912f..fb9d85b5c7b8 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;
}