Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/* dir.c: AFS filesystem directory handling

 *

 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.

 * Written by David Howells (dhowells@redhat.com)

 *

 * This program 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.

 */

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/fs.h>

#include <linux/pagemap.h>

#include <linux/ctype.h>

#include <linux/sched.h>

#include "internal.h"

static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,

                                 struct nameidata *nd);

static int afs_dir_open(struct inode *inode, struct file *file);

static int afs_readdir(struct file *file, void *dirent, filldir_t filldir);

static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd);

static int afs_d_delete(struct dentry *dentry);

static void afs_d_release(struct dentry *dentry);

static int afs_lookup_filldir(void *_cookie, const char *name, int nlen,

                                  loff_t fpos, u64 ino, unsigned dtype);

static int afs_create(struct inode *dir, struct dentry *dentry, int mode,

                      struct nameidata *nd);

static int afs_mkdir(struct inode *dir, struct dentry *dentry, int mode);

static int afs_rmdir(struct inode *dir, struct dentry *dentry);

static int afs_unlink(struct inode *dir, struct dentry *dentry);

static int afs_link(struct dentry *from, struct inode *dir,

                    struct dentry *dentry);

static int afs_symlink(struct inode *dir, struct dentry *dentry,

                       const char *content);

static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,

                      struct inode *new_dir, struct dentry *new_dentry);

const struct file_operations afs_dir_file_operations = {

        .open           = afs_dir_open,

        .release        = afs_release,

        .readdir        = afs_readdir,

        .lock           = afs_lock,

};

const struct inode_operations afs_dir_inode_operations = {

        .create         = afs_create,

        .lookup         = afs_lookup,

        .link           = afs_link,

        .unlink         = afs_unlink,

        .symlink        = afs_symlink,

        .mkdir          = afs_mkdir,

        .rmdir          = afs_rmdir,

        .rename         = afs_rename,

        .permission     = afs_permission,

        .getattr        = afs_getattr,

        .setattr        = afs_setattr,

};

static struct dentry_operations afs_fs_dentry_operations = {

        .d_revalidate   = afs_d_revalidate,

        .d_delete       = afs_d_delete,

        .d_release      = afs_d_release,

};

#define AFS_DIR_HASHTBL_SIZE    128

#define AFS_DIR_DIRENT_SIZE     32

#define AFS_DIRENT_PER_BLOCK    64

union afs_dirent {

        struct {

                uint8_t         valid;

                uint8_t         unused[1];

                __be16          hash_next;

                __be32          vnode;

                __be32          unique;

                uint8_t         name[16];

                uint8_t         overflow[4];    /* if any char of the name (inc

                                                 * NUL) reaches here, consume

                                                 * the next dirent too */

        } u;

        uint8_t extended_name[32];

};

/* AFS directory page header (one at the beginning of every 2048-byte chunk) */

struct afs_dir_pagehdr {

        __be16          npages;

        __be16          magic;

#define AFS_DIR_MAGIC htons(1234)

        uint8_t         nentries;

        uint8_t         bitmap[8];

        uint8_t         pad[19];

};

/* directory block layout */

union afs_dir_block {

        struct afs_dir_pagehdr pagehdr;

        struct {

                struct afs_dir_pagehdr  pagehdr;

                uint8_t                 alloc_ctrs[128];

                /* dir hash table */

                uint16_t                hashtable[AFS_DIR_HASHTBL_SIZE];

        } hdr;

        union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];

};

/* layout on a linux VM page */

struct afs_dir_page {

        union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];

};

struct afs_lookup_cookie {

        struct afs_fid  fid;

        const char      *name;

        size_t          nlen;

        int             found;

};

/*

 * check that a directory page is valid

 */

static inline void afs_dir_check_page(struct inode *dir, struct page *page)

{

        struct afs_dir_page *dbuf;

        loff_t latter;

        int tmp, qty;

#if 0

        /* check the page count */

        qty = desc.size / sizeof(dbuf->blocks[0]);

        if (qty == 0)

                goto error;

        if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {

                printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",

                       __FUNCTION__, dir->i_ino, qty,

                       ntohs(dbuf->blocks[0].pagehdr.npages));

                goto error;

        }

#endif

        /* determine how many magic numbers there should be in this page */

        latter = dir->i_size - page_offset(page);

        if (latter >= PAGE_SIZE)

                qty = PAGE_SIZE;

        else

                qty = latter;

        qty /= sizeof(union afs_dir_block);

        /* check them */

        dbuf = page_address(page);

        for (tmp = 0; tmp < qty; tmp++) {

                if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {

                        printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",

                               __FUNCTION__, dir->i_ino, tmp, qty,

                               ntohs(dbuf->blocks[tmp].pagehdr.magic));

                        goto error;

                }

        }

        SetPageChecked(page);

        return;

error:

        SetPageChecked(page);

        SetPageError(page);

}

/*

 * discard a page cached in the pagecache

 */

static inline void afs_dir_put_page(struct page *page)

{

        kunmap(page);

        page_cache_release(page);

}

/*

 * get a page into the pagecache

 */

static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,

                                     struct key *key)

{

        struct page *page;

        struct file file = {

                .private_data = key,

        };

        _enter("{%lu},%lu", dir->i_ino, index);

        page = read_mapping_page(dir->i_mapping, index, &file);

        if (!IS_ERR(page)) {

                kmap(page);

                if (!PageChecked(page))

                        afs_dir_check_page(dir, page);

                if (PageError(page))

                        goto fail;

        }

        return page;

fail:

        afs_dir_put_page(page);

        _leave(" = -EIO");

        return ERR_PTR(-EIO);

}

/*

 * open an AFS directory file

 */

static int afs_dir_open(struct inode *inode, struct file *file)

{

        _enter("{%lu}", inode->i_ino);

        BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);

        BUILD_BUG_ON(sizeof(union afs_dirent) != 32);

        if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))

                return -ENOENT;

        return afs_open(inode, file);

}

/*

 * deal with one block in an AFS directory

 */

static int afs_dir_iterate_block(unsigned *fpos,

                                 union afs_dir_block *block,

                                 unsigned blkoff,

                                 void *cookie,

                                 filldir_t filldir)

{

        union afs_dirent *dire;

        unsigned offset, next, curr;

        size_t nlen;

        int tmp, ret;

        _enter("%u,%x,%p,,",*fpos,blkoff,block);

        curr = (*fpos - blkoff) / sizeof(union afs_dirent);

        /* walk through the block, an entry at a time */

        for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;

             offset < AFS_DIRENT_PER_BLOCK;

             offset = next

             ) {

                next = offset + 1;

                /* skip entries marked unused in the bitmap */

                if (!(block->pagehdr.bitmap[offset / 8] &

                      (1 << (offset % 8)))) {

                        _debug("ENT[%Zu.%u]: unused",

                               blkoff / sizeof(union afs_dir_block), offset);

                        if (offset >= curr)

                                *fpos = blkoff +

                                        next * sizeof(union afs_dirent);

                        continue;

                }

                /* got a valid entry */

                dire = &block->dirents[offset];

                nlen = strnlen(dire->u.name,

                               sizeof(*block) -

                               offset * sizeof(union afs_dirent));

                _debug("ENT[%Zu.%u]: %s %Zu \"%s\"",

                       blkoff / sizeof(union afs_dir_block), offset,

                       (offset < curr ? "skip" : "fill"),

                       nlen, dire->u.name);

                /* work out where the next possible entry is */

                for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_dirent)) {

                        if (next >= AFS_DIRENT_PER_BLOCK) {

                                _debug("ENT[%Zu.%u]:"

                                       " %u travelled beyond end dir block"

                                       " (len %u/%Zu)",

                                       blkoff / sizeof(union afs_dir_block),

                                       offset, next, tmp, nlen);

                                return -EIO;

                        }

                        if (!(block->pagehdr.bitmap[next / 8] &

                              (1 << (next % 8)))) {

                                _debug("ENT[%Zu.%u]:"

                                       " %u unmarked extension (len %u/%Zu)",

                                       blkoff / sizeof(union afs_dir_block),

                                       offset, next, tmp, nlen);

                                return -EIO;

                        }

                        _debug("ENT[%Zu.%u]: ext %u/%Zu",

                               blkoff / sizeof(union afs_dir_block),

                               next, tmp, nlen);

                        next++;

                }

                /* skip if starts before the current position */

                if (offset < curr)

                        continue;

                /* found the next entry */

                ret = filldir(cookie,

                              dire->u.name,

                              nlen,

                              blkoff + offset * sizeof(union afs_dirent),

                              ntohl(dire->u.vnode),

                              filldir == afs_lookup_filldir ?

                              ntohl(dire->u.unique) : DT_UNKNOWN);

                if (ret < 0) {

                        _leave(" = 0 [full]");

                        return 0;

                }

                *fpos = blkoff + next * sizeof(union afs_dirent);

        }

        _leave(" = 1 [more]");

        return 1;

}

/*

 * iterate through the data blob that lists the contents of an AFS directory

 */

static int afs_dir_iterate(struct inode *dir, unsigned *fpos, void *cookie,

                           filldir_t filldir, struct key *key)

{

        union afs_dir_block *dblock;

        struct afs_dir_page *dbuf;

        struct page *page;

        unsigned blkoff, limit;

        int ret;

        _enter("{%lu},%u,,", dir->i_ino, *fpos);

        if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {

                _leave(" = -ESTALE");

                return -ESTALE;

        }

        /* round the file position up to the next entry boundary */

        *fpos += sizeof(union afs_dirent) - 1;

        *fpos &= ~(sizeof(union afs_dirent) - 1);

        /* walk through the blocks in sequence */

        ret = 0;

        while (*fpos < dir->i_size) {

                blkoff = *fpos & ~(sizeof(union afs_dir_block) - 1);

                /* fetch the appropriate page from the directory */

                page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);

                if (IS_ERR(page)) {

                        ret = PTR_ERR(page);

                        break;

                }

                limit = blkoff & ~(PAGE_SIZE - 1);

                dbuf = page_address(page);

                /* deal with the individual blocks stashed on this page */

                do {

                        dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /

                                               sizeof(union afs_dir_block)];

                        ret = afs_dir_iterate_block(fpos, dblock, blkoff,

                                                    cookie, filldir);

                        if (ret != 1) {

                                afs_dir_put_page(page);

                                goto out;

                        }

                        blkoff += sizeof(union afs_dir_block);

                } while (*fpos < dir->i_size && blkoff < limit);

                afs_dir_put_page(page);

                ret = 0;

        }

out:

        _leave(" = %d", ret);

        return ret;

}

/*

 * read an AFS directory

 */

static int afs_readdir(struct file *file, void *cookie, filldir_t filldir)

{

        unsigned fpos;

        int ret;

        _enter("{%Ld,{%lu}}",

               file->f_pos, file->f_path.dentry->d_inode->i_ino);

        ASSERT(file->private_data != NULL);

        fpos = file->f_pos;

        ret = afs_dir_iterate(file->f_path.dentry->d_inode, &fpos,

                              cookie, filldir, file->private_data);

        file->f_pos = fpos;

        _leave(" = %d", ret);

        return ret;

}

/*

 * search the directory for a name

 * - if afs_dir_iterate_block() spots this function, it'll pass the FID

 *   uniquifier through dtype

 */

static int afs_lookup_filldir(void *_cookie, const char *name, int nlen,

                              loff_t fpos, u64 ino, unsigned dtype)

{

        struct afs_lookup_cookie *cookie = _cookie;

        _enter("{%s,%Zu},%s,%u,,%llu,%u",

               cookie->name, cookie->nlen, name, nlen,

               (unsigned long long) ino, dtype);

        /* insanity checks first */

        BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);

        BUILD_BUG_ON(sizeof(union afs_dirent) != 32);

        if (cookie->nlen != nlen || memcmp(cookie->name, name, nlen) != 0) {

                _leave(" = 0 [no]");

                return 0;

        }

        cookie->fid.vnode = ino;

        cookie->fid.unique = dtype;

        cookie->found = 1;

        _leave(" = -1 [found]");

        return -1;

}

/*

 * do a lookup in a directory

 * - just returns the FID the dentry name maps to if found

 */

static int afs_do_lookup(struct inode *dir, struct dentry *dentry,

                         struct afs_fid *fid, struct key *key)

{

        struct afs_lookup_cookie cookie;

        struct afs_super_info *as;

        unsigned fpos;

        int ret;

        _enter("{%lu},%p{%s},", dir->i_ino, dentry, dentry->d_name.name);

        as = dir->i_sb->s_fs_info;

        /* search the directory */

        cookie.name     = dentry->d_name.name;

        cookie.nlen     = dentry->d_name.len;

        cookie.fid.vid  = as->volume->vid;

        cookie.found    = 0;

        fpos = 0;

        ret = afs_dir_iterate(dir, &fpos, &cookie, afs_lookup_filldir,

                              key);

        if (ret < 0) {

                _leave(" = %d [iter]", ret);

                return ret;

        }

        ret = -ENOENT;

        if (!cookie.found) {

                _leave(" = -ENOENT [not found]");

                return -ENOENT;

        }

        *fid = cookie.fid;

        _leave(" = 0 { vn=%u u=%u }", fid->vnode, fid->unique);

        return 0;

}

/*

 * look up an entry in a directory

 */

static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,

                                 struct nameidata *nd)

{

        struct afs_vnode *vnode;

        struct afs_fid fid;

        struct inode *inode;

        struct key *key;

        int ret;

        vnode = AFS_FS_I(dir);

        _enter("{%x:%u},%p{%s},",

               vnode->fid.vid, vnode->fid.vnode, dentry, dentry->d_name.name);

        ASSERTCMP(dentry->d_inode, ==, NULL);

        if (dentry->d_name.len >= AFSNAMEMAX) {

                _leave(" = -ENAMETOOLONG");

                return ERR_PTR(-ENAMETOOLONG);

        }

        if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {

                _leave(" = -ESTALE");

                return ERR_PTR(-ESTALE);

        }

        key = afs_request_key(vnode->volume->cell);

        if (IS_ERR(key)) {

                _leave(" = %ld [key]", PTR_ERR(key));

                return ERR_PTR(PTR_ERR(key));

        }

        ret = afs_validate(vnode, key);

        if (ret < 0) {

                key_put(key);

                _leave(" = %d [val]", ret);

                return ERR_PTR(ret);

        }

        ret = afs_do_lookup(dir, dentry, &fid, key);

        if (ret < 0) {

                key_put(key);

                if (ret == -ENOENT) {

                        d_add(dentry, NULL);

                        _leave(" = NULL [negative]");

                        return NULL;

                }

                _leave(" = %d [do]", ret);

                return ERR_PTR(ret);

        }

        dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;

        /* instantiate the dentry */

        inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL);

        key_put(key);

        if (IS_ERR(inode)) {

                _leave(" = %ld", PTR_ERR(inode));

                return ERR_PTR(PTR_ERR(inode));

        }

        dentry->d_op = &afs_fs_dentry_operations;

        d_add(dentry, inode);

        _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%lu }",

               fid.vnode,

               fid.unique,

               dentry->d_inode->i_ino,

               dentry->d_inode->i_version);

        return NULL;

}

/*

 * check that a dentry lookup hit has found a valid entry

 * - NOTE! the hit can be a negative hit too, so we can't assume we have an

 *   inode

 */

static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)

{

        struct afs_vnode *vnode, *dir;

        struct afs_fid fid;

        struct dentry *parent;

        struct key *key;

        void *dir_version;

        int ret;

        vnode = AFS_FS_I(dentry->d_inode);

        if (dentry->d_inode)

                _enter("{v={%x:%u} n=%s fl=%lx},",

                       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,

                       vnode->flags);

        else

                _enter("{neg n=%s}", dentry->d_name.name);

        key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);

        if (IS_ERR(key))

                key = NULL;

        /* lock down the parent dentry so we can peer at it */

        parent = dget_parent(dentry);

        if (!parent->d_inode)

                goto out_bad;

        dir = AFS_FS_I(parent->d_inode);

        /* validate the parent directory */

        if (test_bit(AFS_VNODE_MODIFIED, &dir->flags))

                afs_validate(dir, key);

        if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {

                _debug("%s: parent dir deleted", dentry->d_name.name);

                goto out_bad;

        }

        dir_version = (void *) (unsigned long) dir->status.data_version;

        if (dentry->d_fsdata == dir_version)

                goto out_valid; /* the dir contents are unchanged */

        _debug("dir modified");

        /* search the directory for this vnode */

        ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);

        switch (ret) {

        case 0:

                /* the filename maps to something */

                if (!dentry->d_inode)

                        goto out_bad;

                if (is_bad_inode(dentry->d_inode)) {

                        printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",

                               parent->d_name.name, dentry->d_name.name);

                        goto out_bad;

                }

                /* if the vnode ID has changed, then the dirent points to a

                 * different file */

                if (fid.vnode != vnode->fid.vnode) {

                        _debug("%s: dirent changed [%u != %u]",

                               dentry->d_name.name, fid.vnode,

                               vnode->fid.vnode);

                        goto not_found;

                }

                /* if the vnode ID uniqifier has changed, then the file has

                 * been deleted and replaced, and the original vnode ID has

                 * been reused */

                if (fid.unique != vnode->fid.unique) {

                        _debug("%s: file deleted (uq %u -> %u I:%lu)",

                               dentry->d_name.name, fid.unique,

                               vnode->fid.unique, dentry->d_inode->i_version);

                        spin_lock(&vnode->lock);

                        set_bit(AFS_VNODE_DELETED, &vnode->flags);

                        spin_unlock(&vnode->lock);

                        goto not_found;

                }

                goto out_valid;

        case -ENOENT:

                /* the filename is unknown */

                _debug("%s: dirent not found", dentry->d_name.name);

                if (dentry->d_inode)

                        goto not_found;

                goto out_valid;

        default: