From: Marco Stornelli <marco.stornelli@gmail.com>
To: Linux Kernel <linux-kernel@vger.kernel.org>,
Linux Embedded <linux-embedded@vger.kernel.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
Tim Bird <tim.bird@am.sony.com>
Subject: [PATCH 09/17] pramfs: dir operations
Date: Thu, 06 Jan 2011 13:03:04 +0100 [thread overview]
Message-ID: <4D25AF78.9020109@gmail.com> (raw)
From: Marco Stornelli <marco.stornelli@gmail.com>
File operations for directories.
Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
---
diff --git a/fs/pramfs/dir.c b/fs/pramfs/dir.c
new file mode 100644
index 0000000..cf0bcba
--- /dev/null
+++ b/fs/pramfs/dir.c
@@ -0,0 +1,208 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * File operations for directories.
+ *
+ * Copyright 2009-2010 Marco Stornelli <marco.stornelli@gmail.com>
+ * Copyright 2003 Sony Corporation
+ * Copyright 2003 Matsushita Electric Industrial Co., Ltd.
+ * 2003-2004 (c) MontaVista Software, Inc. , Steve Longerbeam
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include "pram.h"
+
+/*
+ * Parent is locked.
+ */
+int pram_add_link(struct dentry *dentry, struct inode *inode)
+{
+ struct inode *dir = dentry->d_parent->d_inode;
+ struct pram_inode *pidir, *pi, *pitail = NULL;
+ u64 tail_ino, prev_ino;
+
+ const char *name = dentry->d_name.name;
+
+ int namelen = min_t(unsigned int, dentry->d_name.len, PRAM_NAME_LEN);
+
+ pidir = pram_get_inode(dir->i_sb, dir->i_ino);
+ pi = pram_get_inode(dir->i_sb, inode->i_ino);
+
+ dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+
+ tail_ino = be64_to_cpu(pidir->i_type.dir.tail);
+ if (tail_ino != 0) {
+ pitail = pram_get_inode(dir->i_sb, tail_ino);
+ pram_memunlock_inode(dir->i_sb, pitail);
+ pitail->i_d.d_next = cpu_to_be64(inode->i_ino);
+ pram_memlock_inode(dir->i_sb, pitail);
+
+ prev_ino = tail_ino;
+
+ pram_memunlock_inode(dir->i_sb, pidir);
+ pidir->i_type.dir.tail = cpu_to_be64(inode->i_ino);
+ pidir->i_mtime = cpu_to_be32(dir->i_mtime.tv_sec);
+ pidir->i_ctime = cpu_to_be32(dir->i_ctime.tv_sec);
+ pram_memlock_inode(dir->i_sb, pidir);
+ } else {
+ /* the directory is empty */
+ prev_ino = 0;
+
+ pram_memunlock_inode(dir->i_sb, pidir);
+ pidir->i_type.dir.tail = cpu_to_be64(inode->i_ino);
+ pidir->i_type.dir.head = cpu_to_be64(inode->i_ino);
+ pidir->i_mtime = cpu_to_be32(dir->i_mtime.tv_sec);
+ pidir->i_ctime = cpu_to_be32(dir->i_ctime.tv_sec);
+ pram_memlock_inode(dir->i_sb, pidir);
+ }
+
+
+ pram_memunlock_inode(dir->i_sb, pi);
+ pi->i_d.d_prev = cpu_to_be64(prev_ino);
+ pi->i_d.d_parent = cpu_to_be64(dir->i_ino);
+ memcpy(pi->i_d.d_name, name, namelen);
+ pi->i_d.d_name[namelen] = '\0';
+ pram_memlock_inode(dir->i_sb, pi);
+ return 0;
+}
+
+int pram_remove_link(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+ struct pram_inode *prev = NULL;
+ struct pram_inode *next = NULL;
+ struct pram_inode *pidir, *pi;
+
+ pi = pram_get_inode(sb, inode->i_ino);
+ pidir = pram_get_inode(sb, be64_to_cpu(pi->i_d.d_parent));
+ if (!pidir)
+ return -EACCES;
+
+ if (inode->i_ino == be64_to_cpu(pidir->i_type.dir.head)) {
+ /* first inode in directory */
+ next = pram_get_inode(sb, be64_to_cpu(pi->i_d.d_next));
+
+ if (next) {
+ pram_memunlock_inode(sb, next);
+ next->i_d.d_prev = 0;
+ pram_memlock_inode(sb, next);
+
+ pram_memunlock_inode(sb, pidir);
+ pidir->i_type.dir.head = pi->i_d.d_next;
+ } else {
+ pram_memunlock_inode(sb, pidir);
+ pidir->i_type.dir.head = 0;
+ pidir->i_type.dir.tail = 0;
+ }
+ pram_memlock_inode(sb, pidir);
+ } else if (inode->i_ino == be64_to_cpu(pidir->i_type.dir.tail)) {
+ /* last inode in directory */
+ prev = pram_get_inode(sb, be64_to_cpu(pi->i_d.d_prev));
+
+ pram_memunlock_inode(sb, prev);
+ prev->i_d.d_next = 0;
+ pram_memlock_inode(sb, prev);
+
+ pram_memunlock_inode(sb, pidir);
+ pidir->i_type.dir.tail = pi->i_d.d_prev;
+ pram_memlock_inode(sb, pidir);
+ } else {
+ /* somewhere in the middle */
+ prev = pram_get_inode(sb, be64_to_cpu(pi->i_d.d_prev));
+ next = pram_get_inode(sb, be64_to_cpu(pi->i_d.d_next));
+
+ if (prev && next) {
+ pram_memunlock_inode(sb, prev);
+ prev->i_d.d_next = pi->i_d.d_next;
+ pram_memlock_inode(sb, prev);
+
+ pram_memunlock_inode(sb, next);
+ next->i_d.d_prev = pi->i_d.d_prev;
+ pram_memlock_inode(sb, next);
+ }
+ }
+
+ pram_memunlock_inode(sb, pi);
+ pi->i_d.d_next = 0;
+ pi->i_d.d_prev = 0;
+ pi->i_d.d_parent = 0;
+ pram_memlock_inode(sb, pi);
+
+ return 0;
+}
+
+#define DT2IF(dt) (((dt) << 12) & S_IFMT)
+#define IF2DT(sif) (((sif) & S_IFMT) >> 12)
+
+static int pram_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ struct super_block *sb = inode->i_sb;
+ struct pram_inode *pi;
+ int namelen, ret = 0;
+ char *name;
+ ino_t ino;
+
+ pi = pram_get_inode(sb, inode->i_ino);
+
+ switch ((unsigned long)filp->f_pos) {
+ case 0:
+ ret = filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR);
+ filp->f_pos++;
+ return ret;
+ case 1:
+ ret = filldir(dirent, "..", 2, 1, be64_to_cpu(pi->i_d.d_parent), DT_DIR);
+ ino = be64_to_cpu(pi->i_type.dir.head);
+ filp->f_pos = ino ? ino : 2;
+ return ret;
+ case 2:
+ ino = be64_to_cpu(pi->i_type.dir.head);
+ if (ino) {
+ filp->f_pos = ino;
+ pi = pram_get_inode(sb, ino);
+ break;
+ } else {
+ /* the directory is empty */
+ filp->f_pos = 2;
+ return 0;
+ }
+ case 3:
+ return 0;
+ default:
+ ino = filp->f_pos;
+ pi = pram_get_inode(sb, ino);
+ break;
+ }
+
+ while (pi && !be16_to_cpu(pi->i_links_count)) {
+ ino = filp->f_pos = be64_to_cpu(pi->i_d.d_next);
+ pi = pram_get_inode(sb, ino);
+ }
+
+ if (pi) {
+ name = pi->i_d.d_name;
+ namelen = strlen(name);
+
+ ret = filldir(dirent, name, namelen,
+ filp->f_pos, ino,
+ IF2DT(be16_to_cpu(pi->i_mode)));
+ filp->f_pos = pi->i_d.d_next ? be64_to_cpu(pi->i_d.d_next) : 3;
+ } else
+ filp->f_pos = 3;
+
+ return ret;
+}
+
+struct file_operations pram_dir_operations = {
+ .read = generic_read_dir,
+ .readdir = pram_readdir,
+ .fsync = noop_fsync,
+ .unlocked_ioctl = pram_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = pram_compat_ioctl,
+#endif
+};
reply other threads:[~2011-01-06 12:03 UTC|newest]
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