diff options
author | Michael Halcrow <mhalcrow@us.ibm.com> | 2007-10-16 01:28:09 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-16 09:43:12 -0700 |
commit | 4981e081cfe2c3f4abcfa3924ebd999cdbed4914 (patch) | |
tree | 066d56ba49195eb0e733236fef4bb98f2d5f0114 /fs/ecryptfs/main.c | |
parent | 0216f7f7921759211e48e8b940eae29f0fe43902 (diff) | |
download | linux-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.c | 65 |
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; } |