/* * 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/security.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, struct nameidata *nd) { 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 %s in directory inode 0x%lx.", dent->d_name.name, 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: { struct dentry *real_dent, *new_dent; 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); /* * Note: No need for dent->d_lock lock as i_mutex is held on the * parent inode. */ /* Does a dentry matching the nls_name exist already? */ real_dent = d_lookup(dent->d_parent, &nls_name); /* If not, create it now. */ if (!real_dent) { real_dent = d_alloc(dent->d_parent, &nls_name); kfree(nls_name.name); if (!real_dent) { err = -ENOMEM; goto err_out; } new_dent = d_splice_alias(dent_inode, real_dent); if (new_dent) dput(real_dent); else new_dent = real_dent; ntfs_debug("Done. (Created new dentry.)"); return new_dent; } kfree(nls_name.name); /* Matching dentry exists, check if it is negative. */ if (real_dent->d_inode) { if (unlikely(real_dent->d_inode != dent_inode)) { /* This can happen because bad inodes are unhashed. */ BUG_ON(!is_bad_inode(dent_inode)); BUG_ON(!is_bad_inode(real_dent->d_inode)); } /* * Already have the inode and the dentry attached, decrement * the reference count to balance the ntfs_iget() we did * earlier on. We found the dentry using d_lookup() so it * cannot be disconnected and thus we do not need to worry * about any NFS/disconnectedness issues here. */ iput(dent_inode); ntfs_debug("Done. (Already had inode and dentry.)"); return real_dent; } /* * Negative dentry: instantiate it unless the inode is a directory and * has a 'disconnected' dentry (i.e. IS_ROOT and DCACHE_DISCONNECTED), * in which case d_move() that in place of the found dentry. */ if (!S_ISDIR(dent_inode->i_mode)) { /* Not a directory; everything is easy. */ d_instantiate(real_dent, dent_inode); ntfs_debug("Done. (Already had negative file dentry.)"); return real_dent; } spin_lock(&dcache_lock); if (list_empty(&dent_inode->i_dentry)) { /* * Directory without a 'disconnected' dentry; we need to do * d_instantiate() by hand because it takes dcache_lock which * we already hold. */ list_add(&real_dent->d_alias, &dent_inode->i_dentry); real_dent->d_inode = dent_inode; spin_unlock(&dcache_lock); security_d_instantiate(real_dent, dent_inode); ntfs_debug("Done. (Already had negative directory dentry.)"); return real_dent; } /* * Directory with a 'disconnected' dentry; get a reference to the * 'disconnected' dentry. */ new_dent = list_entry(dent_inode->i_dentry.next, struct dentry, d_alias); dget_locked(new_dent); spin_unlock(&dcache_lock); /* Do security vodoo. */ security_d_instantiate(real_dent, dent_inode); /* Move new_dent in place of real_dent. */ d_move(new_dent, real_dent); /* Balance the ntfs_iget() we did above. */ iput(dent_inode); /* Throw away real_dent. */ dput(real_dent); /* Use new_dent as the actual dentry. */ ntfs_debug("Done. (Already had negative, disconnected directory " "dentry.)"); return new_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 @child_dent->d_inode->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 = child_dent->d_inode; ntfs_inode *ni = NTFS_I(vi); MFT_RECORD *mrec; ntfs_attr_search_ctx *ctx; ATTR_RECORD *attr; FILE_NAME_ATTR *fn; struct inode *parent_vi; struct dentry *parent_dent; 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); /* Get the inode of the parent directory. */ parent_vi = ntfs_iget(vi->i_sb, parent_ino); if (IS_ERR(parent_vi) || unlikely(is_bad_inode(parent_vi))) { if (!IS_ERR(parent_vi)) iput(parent_vi); ntfs_error(vi->i_sb, "Failed to get parent directory inode " "0x%lx of child inode 0x%lx.", parent_ino, vi->i_ino); return ERR_PTR(-EACCES); } /* Finally get a dentry for the parent directory and return it. */ parent_dent = d_alloc_anon(parent_vi); if (unlikely(!parent_dent)) { iput(parent_vi); return ERR_PTR(-ENOMEM); } ntfs_debug("Done for inode 0x%lx.", vi->i_ino); return parent_dent; } /** * ntfs_get_dentry - find a dentry for the inode from a file handle sub-fragment * @sb: super block identifying the mounted ntfs volume * @fh: the file handle sub-fragment * * Find a dentry for the inode given a file handle sub-fragment. 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 closely based on the default ->get_dentry() helper * fs/exportfs/expfs.c::get_object(). * * The @fh contains two 32-bit unsigned values, the first one is the inode * number and the second one is the inode generation. * * Return the dentry on success or the error code on error (IS_ERR() is true). */ static struct dentry *ntfs_get_dentry(struct super_block *sb, void *fh) { struct inode *vi; struct dentry *dent; unsigned long ino = ((u32 *)fh)[0]; u32 gen = ((u32 *)fh)[1]; ntfs_debug("Entering for inode 0x%lx, generation 0x%x.", ino, gen); vi = ntfs_iget(sb, ino); if (IS_ERR(vi)) { ntfs_error(sb, "Failed to get inode 0x%lx.", ino); return (struct dentry *)vi; } if (unlikely(is_bad_inode(vi) || vi->i_generation != gen)) { /* We didn't find the right inode. */ ntfs_error(sb, "Inode 0x%lx, bad count: %d %d or version 0x%x " "0x%x.", vi->i_ino, vi->i_nlink, atomic_read(&vi->i_count), vi->i_generation, gen); iput(vi); return ERR_PTR(-ESTALE); } /* Now find a dentry. If possible, get a well-connected one. */ dent = d_alloc_anon(vi); if (unlikely(!dent)) { iput(vi); return ERR_PTR(-ENOMEM); } ntfs_debug("Done for inode 0x%lx, generation 0x%x.", ino, gen); return dent; } /** * Export operations allowing NFS exporting of mounted NTFS partitions. * * We use the default ->decode_fh() and ->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(). */ struct export_operations ntfs_export_ops = { .get_parent = ntfs_get_parent, /* Find the parent of a given directory. */ .get_dentry = ntfs_get_dentry, /* Find a dentry for the inode given a file handle sub-fragment. */ };