Initial import

1 files changed, 405 insertions, 0 deletions

diff --git a/fs/ntfs/namei.c b/fs/ntfs/namei.c
new file mode 100644
index 000000000..0f35b80d1
--- /dev/null
+++ b/fs/ntfs/namei.c
@@ -0,0 +1,405 @@
+/*
+ * namei.c - NTFS kernel directory inode operations. Part of the Linux-NTFS
+ *	     project.
+ *
+ * Copyright (c) 2001-2006 Anton Altaparmakov
+ *
+ * This program/include file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program/include file is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (in the main directory of the Linux-NTFS
+ * distribution in the file COPYING); if not, write to the Free Software
+ * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/dcache.h>
+#include <linux/exportfs.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+
+#include "attrib.h"
+#include "debug.h"
+#include "dir.h"
+#include "mft.h"
+#include "ntfs.h"
+
+/**
+ * ntfs_lookup - find the inode represented by a dentry in a directory inode
+ * @dir_ino:	directory inode in which to look for the inode
+ * @dent:	dentry representing the inode to look for
+ * @nd:		lookup nameidata
+ *
+ * In short, ntfs_lookup() looks for the inode represented by the dentry @dent
+ * in the directory inode @dir_ino and if found attaches the inode to the
+ * dentry @dent.
+ *
+ * In more detail, the dentry @dent specifies which inode to look for by
+ * supplying the name of the inode in @dent->d_name.name. ntfs_lookup()
+ * converts the name to Unicode and walks the contents of the directory inode
+ * @dir_ino looking for the converted Unicode name. If the name is found in the
+ * directory, the corresponding inode is loaded by calling ntfs_iget() on its
+ * inode number and the inode is associated with the dentry @dent via a call to
+ * d_splice_alias().
+ *
+ * If the name is not found in the directory, a NULL inode is inserted into the
+ * dentry @dent via a call to d_add(). The dentry is then termed a negative
+ * dentry.
+ *
+ * Only if an actual error occurs, do we return an error via ERR_PTR().
+ *
+ * In order to handle the case insensitivity issues of NTFS with regards to the
+ * dcache and the dcache requiring only one dentry per directory, we deal with
+ * dentry aliases that only differ in case in ->ntfs_lookup() while maintaining
+ * a case sensitive dcache. This means that we get the full benefit of dcache
+ * speed when the file/directory is looked up with the same case as returned by
+ * ->ntfs_readdir() but that a lookup for any other case (or for the short file
+ * name) will not find anything in dcache and will enter ->ntfs_lookup()
+ * instead, where we search the directory for a fully matching file name
+ * (including case) and if that is not found, we search for a file name that
+ * matches with different case and if that has non-POSIX semantics we return
+ * that. We actually do only one search (case sensitive) and keep tabs on
+ * whether we have found a case insensitive match in the process.
+ *
+ * To simplify matters for us, we do not treat the short vs long filenames as
+ * two hard links but instead if the lookup matches a short filename, we
+ * return the dentry for the corresponding long filename instead.
+ *
+ * There are three cases we need to distinguish here:
+ *
+ * 1) @dent perfectly matches (i.e. including case) a directory entry with a
+ *    file name in the WIN32 or POSIX namespaces. In this case
+ *    ntfs_lookup_inode_by_name() will return with name set to NULL and we
+ *    just d_splice_alias() @dent.
+ * 2) @dent matches (not including case) a directory entry with a file name in
+ *    the WIN32 namespace. In this case ntfs_lookup_inode_by_name() will return
+ *    with name set to point to a kmalloc()ed ntfs_name structure containing
+ *    the properly cased little endian Unicode name. We convert the name to the
+ *    current NLS code page, search if a dentry with this name already exists
+ *    and if so return that instead of @dent.  At this point things are
+ *    complicated by the possibility of 'disconnected' dentries due to NFS
+ *    which we deal with appropriately (see the code comments).  The VFS will
+ *    then destroy the old @dent and use the one we returned.  If a dentry is
+ *    not found, we allocate a new one, d_splice_alias() it, and return it as
+ *    above.
+ * 3) @dent matches either perfectly or not (i.e. we don't care about case) a
+ *    directory entry with a file name in the DOS namespace. In this case
+ *    ntfs_lookup_inode_by_name() will return with name set to point to a
+ *    kmalloc()ed ntfs_name structure containing the mft reference (cpu endian)
+ *    of the inode. We use the mft reference to read the inode and to find the
+ *    file name in the WIN32 namespace corresponding to the matched short file
+ *    name. We then convert the name to the current NLS code page, and proceed
+ *    searching for a dentry with this name, etc, as in case 2), above.
+ *
+ * Locking: Caller must hold i_mutex on the directory.
+ */
+static struct dentry *ntfs_lookup(struct inode *dir_ino, struct dentry *dent,
+		unsigned int flags)
+{
+	ntfs_volume *vol = NTFS_SB(dir_ino->i_sb);
+	struct inode *dent_inode;
+	ntfschar *uname;
+	ntfs_name *name = NULL;
+	MFT_REF mref;
+	unsigned long dent_ino;
+	int uname_len;
+
+	ntfs_debug("Looking up %pd in directory inode 0x%lx.",
+			dent, dir_ino->i_ino);
+	/* Convert the name of the dentry to Unicode. */
+	uname_len = ntfs_nlstoucs(vol, dent->d_name.name, dent->d_name.len,
+			&uname);
+	if (uname_len < 0) {
+		if (uname_len != -ENAMETOOLONG)
+			ntfs_error(vol->sb, "Failed to convert name to "
+					"Unicode.");
+		return ERR_PTR(uname_len);
+	}
+	mref = ntfs_lookup_inode_by_name(NTFS_I(dir_ino), uname, uname_len,
+			&name);
+	kmem_cache_free(ntfs_name_cache, uname);
+	if (!IS_ERR_MREF(mref)) {
+		dent_ino = MREF(mref);
+		ntfs_debug("Found inode 0x%lx. Calling ntfs_iget.", dent_ino);
+		dent_inode = ntfs_iget(vol->sb, dent_ino);
+		if (likely(!IS_ERR(dent_inode))) {
+			/* Consistency check. */
+			if (is_bad_inode(dent_inode) || MSEQNO(mref) ==
+					NTFS_I(dent_inode)->seq_no ||
+					dent_ino == FILE_MFT) {
+				/* Perfect WIN32/POSIX match. -- Case 1. */
+				if (!name) {
+					ntfs_debug("Done.  (Case 1.)");
+					return d_splice_alias(dent_inode, dent);
+				}
+				/*
+				 * We are too indented.  Handle imperfect
+				 * matches and short file names further below.
+				 */
+				goto handle_name;
+			}
+			ntfs_error(vol->sb, "Found stale reference to inode "
+					"0x%lx (reference sequence number = "
+					"0x%x, inode sequence number = 0x%x), "
+					"returning -EIO. Run chkdsk.",
+					dent_ino, MSEQNO(mref),
+					NTFS_I(dent_inode)->seq_no);
+			iput(dent_inode);
+			dent_inode = ERR_PTR(-EIO);
+		} else
+			ntfs_error(vol->sb, "ntfs_iget(0x%lx) failed with "
+					"error code %li.", dent_ino,
+					PTR_ERR(dent_inode));
+		kfree(name);
+		/* Return the error code. */
+		return (struct dentry *)dent_inode;
+	}
+	/* It is guaranteed that @name is no longer allocated at this point. */
+	if (MREF_ERR(mref) == -ENOENT) {
+		ntfs_debug("Entry was not found, adding negative dentry.");
+		/* The dcache will handle negative entries. */
+		d_add(dent, NULL);
+		ntfs_debug("Done.");
+		return NULL;
+	}
+	ntfs_error(vol->sb, "ntfs_lookup_ino_by_name() failed with error "
+			"code %i.", -MREF_ERR(mref));
+	return ERR_PTR(MREF_ERR(mref));
+	// TODO: Consider moving this lot to a separate function! (AIA)
+handle_name:
+   {
+	MFT_RECORD *m;
+	ntfs_attr_search_ctx *ctx;
+	ntfs_inode *ni = NTFS_I(dent_inode);
+	int err;
+	struct qstr nls_name;
+
+	nls_name.name = NULL;
+	if (name->type != FILE_NAME_DOS) {			/* Case 2. */
+		ntfs_debug("Case 2.");
+		nls_name.len = (unsigned)ntfs_ucstonls(vol,
+				(ntfschar*)&name->name, name->len,
+				(unsigned char**)&nls_name.name, 0);
+		kfree(name);
+	} else /* if (name->type == FILE_NAME_DOS) */ {		/* Case 3. */
+		FILE_NAME_ATTR *fn;
+
+		ntfs_debug("Case 3.");
+		kfree(name);
+
+		/* Find the WIN32 name corresponding to the matched DOS name. */
+		ni = NTFS_I(dent_inode);
+		m = map_mft_record(ni);
+		if (IS_ERR(m)) {
+			err = PTR_ERR(m);
+			m = NULL;
+			ctx = NULL;
+			goto err_out;
+		}
+		ctx = ntfs_attr_get_search_ctx(ni, m);
+		if (unlikely(!ctx)) {
+			err = -ENOMEM;
+			goto err_out;
+		}
+		do {
+			ATTR_RECORD *a;
+			u32 val_len;
+
+			err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, 0, 0,
+					NULL, 0, ctx);
+			if (unlikely(err)) {
+				ntfs_error(vol->sb, "Inode corrupt: No WIN32 "
+						"namespace counterpart to DOS "
+						"file name. Run chkdsk.");
+				if (err == -ENOENT)
+					err = -EIO;
+				goto err_out;
+			}
+			/* Consistency checks. */
+			a = ctx->attr;
+			if (a->non_resident || a->flags)
+				goto eio_err_out;
+			val_len = le32_to_cpu(a->data.resident.value_length);
+			if (le16_to_cpu(a->data.resident.value_offset) +
+					val_len > le32_to_cpu(a->length))
+				goto eio_err_out;
+			fn = (FILE_NAME_ATTR*)((u8*)ctx->attr + le16_to_cpu(
+					ctx->attr->data.resident.value_offset));
+			if ((u32)(fn->file_name_length * sizeof(ntfschar) +
+					sizeof(FILE_NAME_ATTR)) > val_len)
+				goto eio_err_out;
+		} while (fn->file_name_type != FILE_NAME_WIN32);
+
+		/* Convert the found WIN32 name to current NLS code page. */
+		nls_name.len = (unsigned)ntfs_ucstonls(vol,
+				(ntfschar*)&fn->file_name, fn->file_name_length,
+				(unsigned char**)&nls_name.name, 0);
+
+		ntfs_attr_put_search_ctx(ctx);
+		unmap_mft_record(ni);
+	}
+	m = NULL;
+	ctx = NULL;
+
+	/* Check if a conversion error occurred. */
+	if ((signed)nls_name.len < 0) {
+		err = (signed)nls_name.len;
+		goto err_out;
+	}
+	nls_name.hash = full_name_hash(nls_name.name, nls_name.len);
+
+	dent = d_add_ci(dent, dent_inode, &nls_name);
+	kfree(nls_name.name);
+	return dent;
+
+eio_err_out:
+	ntfs_error(vol->sb, "Illegal file name attribute. Run chkdsk.");
+	err = -EIO;
+err_out:
+	if (ctx)
+		ntfs_attr_put_search_ctx(ctx);
+	if (m)
+		unmap_mft_record(ni);
+	iput(dent_inode);
+	ntfs_error(vol->sb, "Failed, returning error code %i.", err);
+	return ERR_PTR(err);
+   }
+}
+
+/**
+ * Inode operations for directories.
+ */
+const struct inode_operations ntfs_dir_inode_ops = {
+	.lookup	= ntfs_lookup,	/* VFS: Lookup directory. */
+};
+
+/**
+ * ntfs_get_parent - find the dentry of the parent of a given directory dentry
+ * @child_dent:		dentry of the directory whose parent directory to find
+ *
+ * Find the dentry for the parent directory of the directory specified by the
+ * dentry @child_dent.  This function is called from
+ * fs/exportfs/expfs.c::find_exported_dentry() which in turn is called from the
+ * default ->decode_fh() which is export_decode_fh() in the same file.
+ *
+ * The code is based on the ext3 ->get_parent() implementation found in
+ * fs/ext3/namei.c::ext3_get_parent().
+ *
+ * Note: ntfs_get_parent() is called with @d_inode(child_dent)->i_mutex down.
+ *
+ * Return the dentry of the parent directory on success or the error code on
+ * error (IS_ERR() is true).
+ */
+static struct dentry *ntfs_get_parent(struct dentry *child_dent)
+{
+	struct inode *vi = d_inode(child_dent);
+	ntfs_inode *ni = NTFS_I(vi);
+	MFT_RECORD *mrec;
+	ntfs_attr_search_ctx *ctx;
+	ATTR_RECORD *attr;
+	FILE_NAME_ATTR *fn;
+	unsigned long parent_ino;
+	int err;
+
+	ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
+	/* Get the mft record of the inode belonging to the child dentry. */
+	mrec = map_mft_record(ni);
+	if (IS_ERR(mrec))
+		return (struct dentry *)mrec;
+	/* Find the first file name attribute in the mft record. */
+	ctx = ntfs_attr_get_search_ctx(ni, mrec);
+	if (unlikely(!ctx)) {
+		unmap_mft_record(ni);
+		return ERR_PTR(-ENOMEM);
+	}
+try_next:
+	err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, CASE_SENSITIVE, 0, NULL,
+			0, ctx);
+	if (unlikely(err)) {
+		ntfs_attr_put_search_ctx(ctx);
+		unmap_mft_record(ni);
+		if (err == -ENOENT)
+			ntfs_error(vi->i_sb, "Inode 0x%lx does not have a "
+					"file name attribute.  Run chkdsk.",
+					vi->i_ino);
+		return ERR_PTR(err);
+	}
+	attr = ctx->attr;
+	if (unlikely(attr->non_resident))
+		goto try_next;
+	fn = (FILE_NAME_ATTR *)((u8 *)attr +
+			le16_to_cpu(attr->data.resident.value_offset));
+	if (unlikely((u8 *)fn + le32_to_cpu(attr->data.resident.value_length) >
+			(u8*)attr + le32_to_cpu(attr->length)))
+		goto try_next;
+	/* Get the inode number of the parent directory. */
+	parent_ino = MREF_LE(fn->parent_directory);
+	/* Release the search context and the mft record of the child. */
+	ntfs_attr_put_search_ctx(ctx);
+	unmap_mft_record(ni);
+
+	return d_obtain_alias(ntfs_iget(vi->i_sb, parent_ino));
+}
+
+static struct inode *ntfs_nfs_get_inode(struct super_block *sb,
+		u64 ino, u32 generation)
+{
+	struct inode *inode;
+
+	inode = ntfs_iget(sb, ino);
+	if (!IS_ERR(inode)) {
+		if (is_bad_inode(inode) || inode->i_generation != generation) {
+			iput(inode);
+			inode = ERR_PTR(-ESTALE);
+		}
+	}
+
+	return inode;
+}
+
+static struct dentry *ntfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    ntfs_nfs_get_inode);
+}
+
+static struct dentry *ntfs_fh_to_parent(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    ntfs_nfs_get_inode);
+}
+
+/**
+ * Export operations allowing NFS exporting of mounted NTFS partitions.
+ *
+ * We use the default ->encode_fh() for now.  Note that they
+ * use 32 bits to store the inode number which is an unsigned long so on 64-bit
+ * architectures is usually 64 bits so it would all fail horribly on huge
+ * volumes.  I guess we need to define our own encode and decode fh functions
+ * that store 64-bit inode numbers at some point but for now we will ignore the
+ * problem...
+ *
+ * We also use the default ->get_name() helper (used by ->decode_fh() via
+ * fs/exportfs/expfs.c::find_exported_dentry()) as that is completely fs
+ * independent.
+ *
+ * The default ->get_parent() just returns -EACCES so we have to provide our
+ * own and the default ->get_dentry() is incompatible with NTFS due to not
+ * allowing the inode number 0 which is used in NTFS for the system file $MFT
+ * and due to using iget() whereas NTFS needs ntfs_iget().
+ */
+const struct export_operations ntfs_export_ops = {
+	.get_parent	= ntfs_get_parent,	/* Find the parent of a given
+						   directory. */
+	.fh_to_dentry	= ntfs_fh_to_dentry,
+	.fh_to_parent	= ntfs_fh_to_parent,
+};