zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/fs/exportfs/expfs.c b/ap/os/linux/linux-3.4.x/fs/exportfs/expfs.c
new file mode 100644
index 0000000..3bbf5e7
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/exportfs/expfs.c
@@ -0,0 +1,497 @@
+/*
+ * Copyright (C) Neil Brown 2002
+ * Copyright (C) Christoph Hellwig 2007
+ *
+ * This file contains the code mapping from inodes to NFS file handles,
+ * and for mapping back from file handles to dentries.
+ *
+ * For details on why we do all the strange and hairy things in here
+ * take a look at Documentation/filesystems/nfs/Exporting.
+ */
+#include <linux/exportfs.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/sched.h>
+
+#define dprintk(fmt, args...) do{}while(0)
+
+
+static int get_name(struct vfsmount *mnt, struct dentry *dentry, char *name,
+ struct dentry *child);
+
+
+static int exportfs_get_name(struct vfsmount *mnt, struct dentry *dir,
+ char *name, struct dentry *child)
+{
+ const struct export_operations *nop = dir->d_sb->s_export_op;
+
+ if (nop->get_name)
+ return nop->get_name(dir, name, child);
+ else
+ return get_name(mnt, dir, name, child);
+}
+
+/*
+ * Check if the dentry or any of it's aliases is acceptable.
+ */
+static struct dentry *
+find_acceptable_alias(struct dentry *result,
+ int (*acceptable)(void *context, struct dentry *dentry),
+ void *context)
+{
+ struct dentry *dentry, *toput = NULL;
+ struct inode *inode;
+
+ if (acceptable(context, result))
+ return result;
+
+ inode = result->d_inode;
+ spin_lock(&inode->i_lock);
+ list_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
+ dget(dentry);
+ spin_unlock(&inode->i_lock);
+ if (toput)
+ dput(toput);
+ if (dentry != result && acceptable(context, dentry)) {
+ dput(result);
+ return dentry;
+ }
+ spin_lock(&inode->i_lock);
+ toput = dentry;
+ }
+ spin_unlock(&inode->i_lock);
+
+ if (toput)
+ dput(toput);
+ return NULL;
+}
+
+/*
+ * Find root of a disconnected subtree and return a reference to it.
+ */
+static struct dentry *
+find_disconnected_root(struct dentry *dentry)
+{
+ dget(dentry);
+ while (!IS_ROOT(dentry)) {
+ struct dentry *parent = dget_parent(dentry);
+
+ if (!(parent->d_flags & DCACHE_DISCONNECTED)) {
+ dput(parent);
+ break;
+ }
+
+ dput(dentry);
+ dentry = parent;
+ }
+ return dentry;
+}
+
+/*
+ * Make sure target_dir is fully connected to the dentry tree.
+ *
+ * It may already be, as the flag isn't always updated when connection happens.
+ */
+static int
+reconnect_path(struct vfsmount *mnt, struct dentry *target_dir, char *nbuf)
+{
+ int noprogress = 0;
+ int err = -ESTALE;
+
+ /*
+ * It is possible that a confused file system might not let us complete
+ * the path to the root. For example, if get_parent returns a directory
+ * in which we cannot find a name for the child. While this implies a
+ * very sick filesystem we don't want it to cause knfsd to spin. Hence
+ * the noprogress counter. If we go through the loop 10 times (2 is
+ * probably enough) without getting anywhere, we just give up
+ */
+ while (target_dir->d_flags & DCACHE_DISCONNECTED && noprogress++ < 10) {
+ struct dentry *pd = find_disconnected_root(target_dir);
+
+ if (!IS_ROOT(pd)) {
+ /* must have found a connected parent - great */
+ spin_lock(&pd->d_lock);
+ pd->d_flags &= ~DCACHE_DISCONNECTED;
+ spin_unlock(&pd->d_lock);
+ noprogress = 0;
+ } else if (pd == mnt->mnt_sb->s_root) {
+ printk(KERN_ERR "export: Eeek filesystem root is not connected, impossible\n");
+ spin_lock(&pd->d_lock);
+ pd->d_flags &= ~DCACHE_DISCONNECTED;
+ spin_unlock(&pd->d_lock);
+ noprogress = 0;
+ } else {
+ /*
+ * We have hit the top of a disconnected path, try to
+ * find parent and connect.
+ *
+ * Racing with some other process renaming a directory
+ * isn't much of a problem here. If someone renames
+ * the directory, it will end up properly connected,
+ * which is what we want
+ *
+ * Getting the parent can't be supported generically,
+ * the locking is too icky.
+ *
+ * Instead we just return EACCES. If server reboots
+ * or inodes get flushed, you lose
+ */
+ struct dentry *ppd = ERR_PTR(-EACCES);
+ struct dentry *npd;
+
+ mutex_lock(&pd->d_inode->i_mutex);
+ if (mnt->mnt_sb->s_export_op->get_parent)
+ ppd = mnt->mnt_sb->s_export_op->get_parent(pd);
+ mutex_unlock(&pd->d_inode->i_mutex);
+
+ if (IS_ERR(ppd)) {
+ err = PTR_ERR(ppd);
+ dprintk("%s: get_parent of %ld failed, err %d\n",
+ __func__, pd->d_inode->i_ino, err);
+ dput(pd);
+ break;
+ }
+
+ dprintk("%s: find name of %lu in %lu\n", __func__,
+ pd->d_inode->i_ino, ppd->d_inode->i_ino);
+ err = exportfs_get_name(mnt, ppd, nbuf, pd);
+ if (err) {
+ dput(ppd);
+ dput(pd);
+ if (err == -ENOENT)
+ /* some race between get_parent and
+ * get_name? just try again
+ */
+ continue;
+ break;
+ }
+ dprintk("%s: found name: %s\n", __func__, nbuf);
+ mutex_lock(&ppd->d_inode->i_mutex);
+ npd = lookup_one_len(nbuf, ppd, strlen(nbuf));
+ mutex_unlock(&ppd->d_inode->i_mutex);
+ if (IS_ERR(npd)) {
+ err = PTR_ERR(npd);
+ dprintk("%s: lookup failed: %d\n",
+ __func__, err);
+ dput(ppd);
+ dput(pd);
+ break;
+ }
+ /* we didn't really want npd, we really wanted
+ * a side-effect of the lookup.
+ * hopefully, npd == pd, though it isn't really
+ * a problem if it isn't
+ */
+ if (npd == pd)
+ noprogress = 0;
+ else
+ printk("%s: npd != pd\n", __func__);
+ dput(npd);
+ dput(ppd);
+ if (IS_ROOT(pd)) {
+ /* something went wrong, we have to give up */
+ dput(pd);
+ break;
+ }
+ }
+ dput(pd);
+ }
+
+ if (target_dir->d_flags & DCACHE_DISCONNECTED) {
+ /* something went wrong - oh-well */
+ if (!err)
+ err = -ESTALE;
+ return err;
+ }
+
+ return 0;
+}
+
+struct getdents_callback {
+ char *name; /* name that was found. It already points to a
+ buffer NAME_MAX+1 is size */
+ unsigned long ino; /* the inum we are looking for */
+ int found; /* inode matched? */
+ int sequence; /* sequence counter */
+};
+
+/*
+ * A rather strange filldir function to capture
+ * the name matching the specified inode number.
+ */
+static int filldir_one(void * __buf, const char * name, int len,
+ loff_t pos, u64 ino, unsigned int d_type)
+{
+ struct getdents_callback *buf = __buf;
+ int result = 0;
+
+ buf->sequence++;
+ if (buf->ino == ino) {
+ memcpy(buf->name, name, len);
+ buf->name[len] = '\0';
+ buf->found = 1;
+ result = -1;
+ }
+ return result;
+}
+
+/**
+ * get_name - default export_operations->get_name function
+ * @dentry: the directory in which to find a name
+ * @name: a pointer to a %NAME_MAX+1 char buffer to store the name
+ * @child: the dentry for the child directory.
+ *
+ * calls readdir on the parent until it finds an entry with
+ * the same inode number as the child, and returns that.
+ */
+static int get_name(struct vfsmount *mnt, struct dentry *dentry,
+ char *name, struct dentry *child)
+{
+ const struct cred *cred = current_cred();
+ struct inode *dir = dentry->d_inode;
+ int error;
+ struct file *file;
+ struct getdents_callback buffer;
+
+ error = -ENOTDIR;
+ if (!dir || !S_ISDIR(dir->i_mode))
+ goto out;
+ error = -EINVAL;
+ if (!dir->i_fop)
+ goto out;
+ /*
+ * Open the directory ...
+ */
+ file = dentry_open(dget(dentry), mntget(mnt), O_RDONLY, cred);
+ error = PTR_ERR(file);
+ if (IS_ERR(file))
+ goto out;
+
+ error = -EINVAL;
+ if (!file->f_op->readdir)
+ goto out_close;
+
+ buffer.name = name;
+ buffer.ino = child->d_inode->i_ino;
+ buffer.found = 0;
+ buffer.sequence = 0;
+ while (1) {
+ int old_seq = buffer.sequence;
+
+ error = vfs_readdir(file, filldir_one, &buffer);
+ if (buffer.found) {
+ error = 0;
+ break;
+ }
+
+ if (error < 0)
+ break;
+
+ error = -ENOENT;
+ if (old_seq == buffer.sequence)
+ break;
+ }
+
+out_close:
+ fput(file);
+out:
+ return error;
+}
+
+/**
+ * export_encode_fh - default export_operations->encode_fh function
+ * @dentry: the dentry to encode
+ * @fh: where to store the file handle fragment
+ * @max_len: maximum length to store there
+ * @connectable: whether to store parent information
+ *
+ * This default encode_fh function assumes that the 32 inode number
+ * is suitable for locating an inode, and that the generation number
+ * can be used to check that it is still valid. It places them in the
+ * filehandle fragment where export_decode_fh expects to find them.
+ */
+static int export_encode_fh(struct dentry *dentry, struct fid *fid,
+ int *max_len, int connectable)
+{
+ struct inode * inode = dentry->d_inode;
+ int len = *max_len;
+ int type = FILEID_INO32_GEN;
+
+ if (connectable && (len < 4)) {
+ *max_len = 4;
+ return 255;
+ } else if (len < 2) {
+ *max_len = 2;
+ return 255;
+ }
+
+ len = 2;
+ fid->i32.ino = inode->i_ino;
+ fid->i32.gen = inode->i_generation;
+ if (connectable && !S_ISDIR(inode->i_mode)) {
+ struct inode *parent;
+
+ spin_lock(&dentry->d_lock);
+ parent = dentry->d_parent->d_inode;
+ fid->i32.parent_ino = parent->i_ino;
+ fid->i32.parent_gen = parent->i_generation;
+ spin_unlock(&dentry->d_lock);
+ len = 4;
+ type = FILEID_INO32_GEN_PARENT;
+ }
+ *max_len = len;
+ return type;
+}
+
+int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len,
+ int connectable)
+{
+ const struct export_operations *nop = dentry->d_sb->s_export_op;
+ int error;
+
+ if (nop->encode_fh)
+ error = nop->encode_fh(dentry, fid->raw, max_len, connectable);
+ else
+ error = export_encode_fh(dentry, fid, max_len, connectable);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(exportfs_encode_fh);
+
+struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
+ int fh_len, int fileid_type,
+ int (*acceptable)(void *, struct dentry *), void *context)
+{
+ const struct export_operations *nop = mnt->mnt_sb->s_export_op;
+ struct dentry *result, *alias;
+ char nbuf[NAME_MAX+1];
+ int err;
+
+ /*
+ * Try to get any dentry for the given file handle from the filesystem.
+ */
+ if (!nop || !nop->fh_to_dentry)
+ return ERR_PTR(-ESTALE);
+ result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type);
+ if (!result)
+ result = ERR_PTR(-ESTALE);
+ if (IS_ERR(result))
+ return result;
+
+ if (S_ISDIR(result->d_inode->i_mode)) {
+ /*
+ * This request is for a directory.
+ *
+ * On the positive side there is only one dentry for each
+ * directory inode. On the negative side this implies that we
+ * to ensure our dentry is connected all the way up to the
+ * filesystem root.
+ */
+ if (result->d_flags & DCACHE_DISCONNECTED) {
+ err = reconnect_path(mnt, result, nbuf);
+ if (err)
+ goto err_result;
+ }
+
+ if (!acceptable(context, result)) {
+ err = -EACCES;
+ goto err_result;
+ }
+
+ return result;
+ } else {
+ /*
+ * It's not a directory. Life is a little more complicated.
+ */
+ struct dentry *target_dir, *nresult;
+
+ /*
+ * See if either the dentry we just got from the filesystem
+ * or any alias for it is acceptable. This is always true
+ * if this filesystem is exported without the subtreecheck
+ * option. If the filesystem is exported with the subtree
+ * check option there's a fair chance we need to look at
+ * the parent directory in the file handle and make sure
+ * it's connected to the filesystem root.
+ */
+ alias = find_acceptable_alias(result, acceptable, context);
+ if (alias)
+ return alias;
+
+ /*
+ * Try to extract a dentry for the parent directory from the
+ * file handle. If this fails we'll have to give up.
+ */
+ err = -ESTALE;
+ if (!nop->fh_to_parent)
+ goto err_result;
+
+ target_dir = nop->fh_to_parent(mnt->mnt_sb, fid,
+ fh_len, fileid_type);
+ if (!target_dir)
+ goto err_result;
+ err = PTR_ERR(target_dir);
+ if (IS_ERR(target_dir))
+ goto err_result;
+
+ /*
+ * And as usual we need to make sure the parent directory is
+ * connected to the filesystem root. The VFS really doesn't
+ * like disconnected directories..
+ */
+ err = reconnect_path(mnt, target_dir, nbuf);
+ if (err) {
+ dput(target_dir);
+ goto err_result;
+ }
+
+ /*
+ * Now that we've got both a well-connected parent and a
+ * dentry for the inode we're after, make sure that our
+ * inode is actually connected to the parent.
+ */
+ err = exportfs_get_name(mnt, target_dir, nbuf, result);
+ if (!err) {
+ mutex_lock(&target_dir->d_inode->i_mutex);
+ nresult = lookup_one_len(nbuf, target_dir,
+ strlen(nbuf));
+ mutex_unlock(&target_dir->d_inode->i_mutex);
+ if (!IS_ERR(nresult)) {
+ if (nresult->d_inode) {
+ dput(result);
+ result = nresult;
+ } else
+ dput(nresult);
+ }
+ }
+
+ /*
+ * At this point we are done with the parent, but it's pinned
+ * by the child dentry anyway.
+ */
+ dput(target_dir);
+
+ /*
+ * And finally make sure the dentry is actually acceptable
+ * to NFSD.
+ */
+ alias = find_acceptable_alias(result, acceptable, context);
+ if (!alias) {
+ err = -EACCES;
+ goto err_result;
+ }
+
+ return alias;
+ }
+
+ err_result:
+ dput(result);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(exportfs_decode_fh);
+
+MODULE_LICENSE("GPL");