6 files changed, 92 insertions, 59 deletions

diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index bd3cafd0949d..380bee1094c3 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -295,6 +295,8 @@ struct ecryptfs_crypt_stat {
 struct ecryptfs_inode_info {
         struct inode vfs_inode;
         struct inode *wii_inode;
+        struct mutex lower_file_mutex;
+        atomic_t lower_file_count;
         struct file *lower_file;
         struct ecryptfs_crypt_stat crypt_stat;
 };
@@ -757,7 +759,8 @@ int ecryptfs_privileged_open(struct file **lower_file,
                              struct dentry *lower_dentry,
                              struct vfsmount *lower_mnt,
                              const struct cred *cred);
-int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry);
+int ecryptfs_get_lower_file(struct dentry *ecryptfs_dentry);
+void ecryptfs_put_lower_file(struct inode *inode);
 int
 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
                              size_t *packet_size,
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index cedc913d11ba..146c4edff70c 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -191,10 +191,10 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
                                       | ECRYPTFS_ENCRYPTED);
         }
         mutex_unlock(&crypt_stat->cs_mutex);
-        rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
+        rc = ecryptfs_get_lower_file(ecryptfs_dentry);
         if (rc) {
                 printk(KERN_ERR "%s: Error attempting to initialize "
-                        "the persistent file for the dentry with name "
+                        "the lower file for the dentry with name "
                         "[%s]; rc = [%d]\n", __func__,
                         ecryptfs_dentry->d_name.name, rc);
                 goto out_free;
@@ -202,9 +202,9 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
         if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
             == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
                 rc = -EPERM;
-                printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
+                printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
                        "file must hence be opened RO\n", __func__);
-                goto out_free;
+                goto out_put;
         }
         ecryptfs_set_file_lower(
                 file, ecryptfs_inode_to_private(inode)->lower_file);
@@ -232,7 +232,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
                                        "Plaintext passthrough mode is not "
                                        "enabled; returning -EIO\n");
                                 mutex_unlock(&crypt_stat->cs_mutex);
-                                goto out_free;
+                                goto out_put;
                         }
                         rc = 0;
                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
@@ -245,6 +245,8 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
                         "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
                         (unsigned long long)i_size_read(inode));
         goto out;
+out_put:
+        ecryptfs_put_lower_file(inode);
 out_free:
         kmem_cache_free(ecryptfs_file_info_cache,
                         ecryptfs_file_to_private(file));
@@ -254,17 +256,13 @@ out:
 
 static int ecryptfs_flush(struct file *file, fl_owner_t td)
 {
-        int rc = 0;
-        struct file *lower_file = NULL;
-
-        lower_file = ecryptfs_file_to_lower(file);
-        if (lower_file->f_op && lower_file->f_op->flush)
-                rc = lower_file->f_op->flush(lower_file, td);
-        return rc;
+        return file->f_mode & FMODE_WRITE
+               ? filemap_write_and_wait(file->f_mapping) : 0;
 }
 
 static int ecryptfs_release(struct inode *inode, struct file *file)
 {
+        ecryptfs_put_lower_file(inode);
         kmem_cache_free(ecryptfs_file_info_cache,
                         ecryptfs_file_to_private(file));
         return 0;
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 72d357649599..f6b388638c3d 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -168,19 +168,18 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
                                 "context; rc = [%d]\n", rc);
                 goto out;
         }
-        rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
+        rc = ecryptfs_get_lower_file(ecryptfs_dentry);
         if (rc) {
                 printk(KERN_ERR "%s: Error attempting to initialize "
-                        "the persistent file for the dentry with name "
+                        "the lower file for the dentry with name "
                         "[%s]; rc = [%d]\n", __func__,
                         ecryptfs_dentry->d_name.name, rc);
                 goto out;
         }
         rc = ecryptfs_write_metadata(ecryptfs_dentry);
-        if (rc) {
+        if (rc)
                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
-                goto out;
-        }
+        ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
 out:
         return rc;
 }
@@ -230,7 +229,7 @@ int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
         struct ecryptfs_crypt_stat *crypt_stat;
         char *page_virt = NULL;
         u64 file_size;
-        int rc = 0;
+        int put_lower = 0, rc = 0;
 
         lower_dir_dentry = lower_dentry->d_parent;
         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
@@ -277,14 +276,15 @@ int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
                 rc = -ENOMEM;
                 goto out;
         }
-        rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
+        rc = ecryptfs_get_lower_file(ecryptfs_dentry);
         if (rc) {
                 printk(KERN_ERR "%s: Error attempting to initialize "
-                        "the persistent file for the dentry with name "
+                        "the lower file for the dentry with name "
                         "[%s]; rc = [%d]\n", __func__,
                         ecryptfs_dentry->d_name.name, rc);
                 goto out_free_kmem;
         }
+        put_lower = 1;
         crypt_stat = &ecryptfs_inode_to_private(
                                         ecryptfs_dentry->d_inode)->crypt_stat;
         /* TODO: lock for crypt_stat comparison */
@@ -322,6 +322,8 @@ out_put:
         mntput(lower_mnt);
         d_drop(ecryptfs_dentry);
 out:
+        if (put_lower)
+                ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
         return rc;
 }
 
@@ -757,8 +759,11 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 
         if (unlikely((ia->ia_size == i_size))) {
                 lower_ia->ia_valid &= ~ATTR_SIZE;
-                goto out;
+                return 0;
         }
+        rc = ecryptfs_get_lower_file(dentry);
+        if (rc)
+                return rc;
         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
         /* Switch on growing or shrinking file */
         if (ia->ia_size > i_size) {
@@ -836,6 +841,7 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia,
                         lower_ia->ia_valid &= ~ATTR_SIZE;
         }
 out:
+        ecryptfs_put_lower_file(inode);
         return rc;
 }
 
@@ -911,7 +917,13 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 
                 mount_crypt_stat = &ecryptfs_superblock_to_private(
                         dentry->d_sb)->mount_crypt_stat;
+                rc = ecryptfs_get_lower_file(dentry);
+                if (rc) {
+                        mutex_unlock(&crypt_stat->cs_mutex);
+                        goto out;
+                }
                 rc = ecryptfs_read_metadata(dentry);
+                ecryptfs_put_lower_file(inode);
                 if (rc) {
                         if (!(mount_crypt_stat->flags
                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
diff --git a/fs/ecryptfs/kthread.c b/fs/ecryptfs/kthread.c
index 0851ab6980f5..69f994a7d524 100644
--- a/fs/ecryptfs/kthread.c
+++ b/fs/ecryptfs/kthread.c
@@ -44,7 +44,7 @@ static struct task_struct *ecryptfs_kthread;
  * @ignored: ignored
  *
  * The eCryptfs kernel thread that has the responsibility of getting
- * the lower persistent file with RW permissions.
+ * the lower file with RW permissions.
  *
  * Returns zero on success; non-zero otherwise
  */
@@ -141,8 +141,8 @@ int ecryptfs_privileged_open(struct file **lower_file,
         int rc = 0;
 
         /* Corresponding dput() and mntput() are done when the
-         * persistent file is fput() when the eCryptfs inode is
-         * destroyed. */
+         * lower file is fput() when all eCryptfs files for the inode are
+         * released. */
         dget(lower_dentry);
         mntget(lower_mnt);
         flags |= IS_RDONLY(lower_dentry->d_inode) ? O_RDONLY : O_RDWR;
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index fdb2eb0ad09e..89b93389af8e 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -96,7 +96,7 @@ void __ecryptfs_printk(const char *fmt, ...)
 }
 
 /**
- * ecryptfs_init_persistent_file
+ * ecryptfs_init_lower_file
  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
  *                   the lower dentry and the lower mount set
  *
@@ -104,42 +104,70 @@ void __ecryptfs_printk(const char *fmt, ...)
  * 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.
+ * lower file struct and associates it with the eCryptfs
+ * inode. When all eCryptfs files associated with the inode are released, the
+ * file is closed.
  *
- * The persistent file will be opened with read/write permissions, if
+ * The lower 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
+ * This function does nothing if a lower file is already
  * associated with the eCryptfs inode.
  *
  * Returns zero on success; non-zero otherwise
  */
-int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
+static int ecryptfs_init_lower_file(struct dentry *dentry,
+                                    struct file **lower_file)
 {
         const struct cred *cred = current_cred();
-        struct ecryptfs_inode_info *inode_info =
-                ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
-        int rc = 0;
+        struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+        struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+        int rc;
 
-        if (!inode_info->lower_file) {
-                struct dentry *lower_dentry;
-                struct vfsmount *lower_mnt =
-                        ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
+        rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
+                                      cred);
+        if (rc) {
+                printk(KERN_ERR "Error opening lower file "
+                       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
+                       "rc = [%d]\n", lower_dentry, lower_mnt, rc);
+                (*lower_file) = NULL;
+        }
+        return rc;
+}
 
-                lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
-                rc = ecryptfs_privileged_open(&inode_info->lower_file,
-                                              lower_dentry, lower_mnt, cred);
-                if (rc) {
-                        printk(KERN_ERR "Error opening lower persistent file "
-                               "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
-                               "rc = [%d]\n", lower_dentry, lower_mnt, rc);
-                        inode_info->lower_file = NULL;
-                }
+int ecryptfs_get_lower_file(struct dentry *dentry)
+{
+        struct ecryptfs_inode_info *inode_info =
+                ecryptfs_inode_to_private(dentry->d_inode);
+        int count, rc = 0;
+
+        mutex_lock(&inode_info->lower_file_mutex);
+        count = atomic_inc_return(&inode_info->lower_file_count);
+        if (WARN_ON_ONCE(count < 1))
+                rc = -EINVAL;
+        else if (count == 1) {
+                rc = ecryptfs_init_lower_file(dentry,
+                                              &inode_info->lower_file);
+                if (rc)
+                        atomic_set(&inode_info->lower_file_count, 0);
         }
+        mutex_unlock(&inode_info->lower_file_mutex);
         return rc;
 }
 
+void ecryptfs_put_lower_file(struct inode *inode)
+{
+        struct ecryptfs_inode_info *inode_info;
+
+        inode_info = ecryptfs_inode_to_private(inode);
+        if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
+                                      &inode_info->lower_file_mutex)) {
+                fput(inode_info->lower_file);
+                inode_info->lower_file = NULL;
+                mutex_unlock(&inode_info->lower_file_mutex);
+        }
+}
+
 static struct inode *ecryptfs_get_inode(struct inode *lower_inode,
                        struct super_block *sb)
 {
diff --git a/fs/ecryptfs/super.c b/fs/ecryptfs/super.c
index bacc882e1ae4..245b517bf1b6 100644
--- a/fs/ecryptfs/super.c
+++ b/fs/ecryptfs/super.c
@@ -55,6 +55,8 @@ static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
         if (unlikely(!inode_info))
                 goto out;
         ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
+        mutex_init(&inode_info->lower_file_mutex);
+        atomic_set(&inode_info->lower_file_count, 0);
         inode_info->lower_file = NULL;
         inode = &inode_info->vfs_inode;
 out:
@@ -77,8 +79,7 @@ static void ecryptfs_i_callback(struct rcu_head *head)
  *
  * This is used during the final destruction of the inode.  All
  * allocation of memory related to the inode, including allocated
- * memory in the crypt_stat struct, will be released here. This
- * function also fput()'s the persistent file for the lower inode.
+ * memory in the crypt_stat struct, will be released here.
  * There should be no chance that this deallocation will be missed.
  */
 static void ecryptfs_destroy_inode(struct inode *inode)
@@ -86,16 +87,7 @@ static void ecryptfs_destroy_inode(struct inode *inode)
         struct ecryptfs_inode_info *inode_info;
 
         inode_info = ecryptfs_inode_to_private(inode);
-        if (inode_info->lower_file) {
-                struct dentry *lower_dentry =
-                        inode_info->lower_file->f_dentry;
-
-                BUG_ON(!lower_dentry);
-                if (lower_dentry->d_inode) {
-                        fput(inode_info->lower_file);
-                        inode_info->lower_file = NULL;
-                }
-        }
+        BUG_ON(inode_info->lower_file);
         ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
         call_rcu(&inode->i_rcu, ecryptfs_i_callback);
 }