don't put symlink bodies in pagecache into highmem

[mirror_ubuntu-zesty-kernel.git] / fs / minix / inode.c

/*
 *  linux/fs/minix/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Copyright (C) 1996  Gertjan van Wingerde
 *      Minix V2 fs support.
 *
 *  Modified for 680x0 by Andreas Schwab
 *  Updated to filesystem version 3 by Daniel Aragones
 */

#include <linux/module.h>
#include "minix.h"
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/vfs.h>
#include <linux/writeback.h>

static int minix_write_inode(struct inode *inode,
                struct writeback_control *wbc);
static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
static int minix_remount (struct super_block * sb, int * flags, char * data);

static void minix_evict_inode(struct inode *inode)
{
        truncate_inode_pages_final(&inode->i_data);
        if (!inode->i_nlink) {
                inode->i_size = 0;
                minix_truncate(inode);
        }
        invalidate_inode_buffers(inode);
        clear_inode(inode);
        if (!inode->i_nlink)
                minix_free_inode(inode);
}

static void minix_put_super(struct super_block *sb)
{
        int i;
        struct minix_sb_info *sbi = minix_sb(sb);

        if (!(sb->s_flags & MS_RDONLY)) {
                if (sbi->s_version != MINIX_V3)  /* s_state is now out from V3 sb */
                        sbi->s_ms->s_state = sbi->s_mount_state;
                mark_buffer_dirty(sbi->s_sbh);
        }
        for (i = 0; i < sbi->s_imap_blocks; i++)
                brelse(sbi->s_imap[i]);
        for (i = 0; i < sbi->s_zmap_blocks; i++)
                brelse(sbi->s_zmap[i]);
        brelse (sbi->s_sbh);
        kfree(sbi->s_imap);
        sb->s_fs_info = NULL;
        kfree(sbi);
}

static struct kmem_cache * minix_inode_cachep;

static struct inode *minix_alloc_inode(struct super_block *sb)
{
        struct minix_inode_info *ei;
        ei = kmem_cache_alloc(minix_inode_cachep, GFP_KERNEL);
        if (!ei)
                return NULL;
        return &ei->vfs_inode;
}

static void minix_i_callback(struct rcu_head *head)
{
        struct inode *inode = container_of(head, struct inode, i_rcu);
        kmem_cache_free(minix_inode_cachep, minix_i(inode));
}

static void minix_destroy_inode(struct inode *inode)
{
        call_rcu(&inode->i_rcu, minix_i_callback);
}

static void init_once(void *foo)
{
        struct minix_inode_info *ei = (struct minix_inode_info *) foo;

        inode_init_once(&ei->vfs_inode);
}

static int __init init_inodecache(void)
{
        minix_inode_cachep = kmem_cache_create("minix_inode_cache",
                                             sizeof(struct minix_inode_info),
                                             0, (SLAB_RECLAIM_ACCOUNT|
                                                SLAB_MEM_SPREAD),
                                             init_once);
        if (minix_inode_cachep == NULL)
                return -ENOMEM;
        return 0;
}

static void destroy_inodecache(void)
{
        /*
         * Make sure all delayed rcu free inodes are flushed before we
         * destroy cache.
         */
        rcu_barrier();
        kmem_cache_destroy(minix_inode_cachep);
}

static const struct super_operations minix_sops = {
        .alloc_inode    = minix_alloc_inode,
        .destroy_inode  = minix_destroy_inode,
        .write_inode    = minix_write_inode,
        .evict_inode    = minix_evict_inode,
        .put_super      = minix_put_super,
        .statfs         = minix_statfs,
        .remount_fs     = minix_remount,
};

static int minix_remount (struct super_block * sb, int * flags, char * data)
{
        struct minix_sb_info * sbi = minix_sb(sb);
        struct minix_super_block * ms;

        sync_filesystem(sb);
        ms = sbi->s_ms;
        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
                return 0;
        if (*flags & MS_RDONLY) {
                if (ms->s_state & MINIX_VALID_FS ||
                    !(sbi->s_mount_state & MINIX_VALID_FS))
                        return 0;
                /* Mounting a rw partition read-only. */
                if (sbi->s_version != MINIX_V3)
                        ms->s_state = sbi->s_mount_state;
                mark_buffer_dirty(sbi->s_sbh);
        } else {
                /* Mount a partition which is read-only, read-write. */
                if (sbi->s_version != MINIX_V3) {
                        sbi->s_mount_state = ms->s_state;
                        ms->s_state &= ~MINIX_VALID_FS;
                } else {
                        sbi->s_mount_state = MINIX_VALID_FS;
                }
                mark_buffer_dirty(sbi->s_sbh);

                if (!(sbi->s_mount_state & MINIX_VALID_FS))
                        printk("MINIX-fs warning: remounting unchecked fs, "
                                "running fsck is recommended\n");
                else if ((sbi->s_mount_state & MINIX_ERROR_FS))
                        printk("MINIX-fs warning: remounting fs with errors, "
                                "running fsck is recommended\n");
        }
        return 0;
}

static int minix_fill_super(struct super_block *s, void *data, int silent)
{
        struct buffer_head *bh;
        struct buffer_head **map;
        struct minix_super_block *ms;
        struct minix3_super_block *m3s = NULL;
        unsigned long i, block;
        struct inode *root_inode;
        struct minix_sb_info *sbi;
        int ret = -EINVAL;

        sbi = kzalloc(sizeof(struct minix_sb_info), GFP_KERNEL);
        if (!sbi)
                return -ENOMEM;
        s->s_fs_info = sbi;

        BUILD_BUG_ON(32 != sizeof (struct minix_inode));
        BUILD_BUG_ON(64 != sizeof(struct minix2_inode));

        if (!sb_set_blocksize(s, BLOCK_SIZE))
                goto out_bad_hblock;

        if (!(bh = sb_bread(s, 1)))
                goto out_bad_sb;

        ms = (struct minix_super_block *) bh->b_data;
        sbi->s_ms = ms;
        sbi->s_sbh = bh;
        sbi->s_mount_state = ms->s_state;
        sbi->s_ninodes = ms->s_ninodes;
        sbi->s_nzones = ms->s_nzones;
        sbi->s_imap_blocks = ms->s_imap_blocks;
        sbi->s_zmap_blocks = ms->s_zmap_blocks;
        sbi->s_firstdatazone = ms->s_firstdatazone;
        sbi->s_log_zone_size = ms->s_log_zone_size;
        sbi->s_max_size = ms->s_max_size;
        s->s_magic = ms->s_magic;
        if (s->s_magic == MINIX_SUPER_MAGIC) {
                sbi->s_version = MINIX_V1;
                sbi->s_dirsize = 16;
                sbi->s_namelen = 14;
                s->s_max_links = MINIX_LINK_MAX;
        } else if (s->s_magic == MINIX_SUPER_MAGIC2) {
                sbi->s_version = MINIX_V1;
                sbi->s_dirsize = 32;
                sbi->s_namelen = 30;
                s->s_max_links = MINIX_LINK_MAX;
        } else if (s->s_magic == MINIX2_SUPER_MAGIC) {
                sbi->s_version = MINIX_V2;
                sbi->s_nzones = ms->s_zones;
                sbi->s_dirsize = 16;
                sbi->s_namelen = 14;
                s->s_max_links = MINIX2_LINK_MAX;
        } else if (s->s_magic == MINIX2_SUPER_MAGIC2) {
                sbi->s_version = MINIX_V2;
                sbi->s_nzones = ms->s_zones;
                sbi->s_dirsize = 32;
                sbi->s_namelen = 30;
                s->s_max_links = MINIX2_LINK_MAX;
        } else if ( *(__u16 *)(bh->b_data + 24) == MINIX3_SUPER_MAGIC) {
                m3s = (struct minix3_super_block *) bh->b_data;
                s->s_magic = m3s->s_magic;
                sbi->s_imap_blocks = m3s->s_imap_blocks;
                sbi->s_zmap_blocks = m3s->s_zmap_blocks;
                sbi->s_firstdatazone = m3s->s_firstdatazone;
                sbi->s_log_zone_size = m3s->s_log_zone_size;
                sbi->s_max_size = m3s->s_max_size;
                sbi->s_ninodes = m3s->s_ninodes;
                sbi->s_nzones = m3s->s_zones;
                sbi->s_dirsize = 64;
                sbi->s_namelen = 60;
                sbi->s_version = MINIX_V3;
                sbi->s_mount_state = MINIX_VALID_FS;
                sb_set_blocksize(s, m3s->s_blocksize);
                s->s_max_links = MINIX2_LINK_MAX;
        } else
                goto out_no_fs;

        /*
         * Allocate the buffer map to keep the superblock small.
         */
        if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
                goto out_illegal_sb;
        i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
        map = kzalloc(i, GFP_KERNEL);
        if (!map)
                goto out_no_map;
        sbi->s_imap = &map[0];
        sbi->s_zmap = &map[sbi->s_imap_blocks];

        block=2;
        for (i=0 ; i < sbi->s_imap_blocks ; i++) {
                if (!(sbi->s_imap[i]=sb_bread(s, block)))
                        goto out_no_bitmap;
                block++;
        }
        for (i=0 ; i < sbi->s_zmap_blocks ; i++) {
                if (!(sbi->s_zmap[i]=sb_bread(s, block)))
                        goto out_no_bitmap;
                block++;
        }

        minix_set_bit(0,sbi->s_imap[0]->b_data);
        minix_set_bit(0,sbi->s_zmap[0]->b_data);

        /* Apparently minix can create filesystems that allocate more blocks for
         * the bitmaps than needed.  We simply ignore that, but verify it didn't
         * create one with not enough blocks and bail out if so.
         */
        block = minix_blocks_needed(sbi->s_ninodes, s->s_blocksize);
        if (sbi->s_imap_blocks < block) {
                printk("MINIX-fs: file system does not have enough "
                                "imap blocks allocated.  Refusing to mount.\n");
                goto out_no_bitmap;
        }

        block = minix_blocks_needed(
                        (sbi->s_nzones - sbi->s_firstdatazone + 1),
                        s->s_blocksize);
        if (sbi->s_zmap_blocks < block) {
                printk("MINIX-fs: file system does not have enough "
                                "zmap blocks allocated.  Refusing to mount.\n");
                goto out_no_bitmap;
        }

        /* set up enough so that it can read an inode */
        s->s_op = &minix_sops;
        root_inode = minix_iget(s, MINIX_ROOT_INO);
        if (IS_ERR(root_inode)) {
                ret = PTR_ERR(root_inode);
                goto out_no_root;
        }

        ret = -ENOMEM;
        s->s_root = d_make_root(root_inode);
        if (!s->s_root)
                goto out_no_root;

        if (!(s->s_flags & MS_RDONLY)) {
                if (sbi->s_version != MINIX_V3) /* s_state is now out from V3 sb */
                        ms->s_state &= ~MINIX_VALID_FS;
                mark_buffer_dirty(bh);
        }
        if (!(sbi->s_mount_state & MINIX_VALID_FS))
                printk("MINIX-fs: mounting unchecked file system, "
                        "running fsck is recommended\n");
        else if (sbi->s_mount_state & MINIX_ERROR_FS)
                printk("MINIX-fs: mounting file system with errors, "
                        "running fsck is recommended\n");

        return 0;

out_no_root:
        if (!silent)
                printk("MINIX-fs: get root inode failed\n");
        goto out_freemap;

out_no_bitmap:
        printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
out_freemap:
        for (i = 0; i < sbi->s_imap_blocks; i++)
                brelse(sbi->s_imap[i]);
        for (i = 0; i < sbi->s_zmap_blocks; i++)
                brelse(sbi->s_zmap[i]);
        kfree(sbi->s_imap);
        goto out_release;

out_no_map:
        ret = -ENOMEM;
        if (!silent)
                printk("MINIX-fs: can't allocate map\n");
        goto out_release;

out_illegal_sb:
        if (!silent)
                printk("MINIX-fs: bad superblock\n");
        goto out_release;

out_no_fs:
        if (!silent)
                printk("VFS: Can't find a Minix filesystem V1 | V2 | V3 "
                       "on device %s.\n", s->s_id);
out_release:
        brelse(bh);
        goto out;

out_bad_hblock:
        printk("MINIX-fs: blocksize too small for device\n");
        goto out;

out_bad_sb:
        printk("MINIX-fs: unable to read superblock\n");
out:
        s->s_fs_info = NULL;
        kfree(sbi);
        return ret;
}

static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_sb;
        struct minix_sb_info *sbi = minix_sb(sb);
        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
        buf->f_type = sb->s_magic;
        buf->f_bsize = sb->s_blocksize;
        buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
        buf->f_bfree = minix_count_free_blocks(sb);
        buf->f_bavail = buf->f_bfree;
        buf->f_files = sbi->s_ninodes;
        buf->f_ffree = minix_count_free_inodes(sb);
        buf->f_namelen = sbi->s_namelen;
        buf->f_fsid.val[0] = (u32)id;
        buf->f_fsid.val[1] = (u32)(id >> 32);

        return 0;
}

static int minix_get_block(struct inode *inode, sector_t block,
                    struct buffer_head *bh_result, int create)
{
        if (INODE_VERSION(inode) == MINIX_V1)
                return V1_minix_get_block(inode, block, bh_result, create);
        else
                return V2_minix_get_block(inode, block, bh_result, create);
}

static int minix_writepage(struct page *page, struct writeback_control *wbc)
{
        return block_write_full_page(page, minix_get_block, wbc);
}

static int minix_readpage(struct file *file, struct page *page)
{
        return block_read_full_page(page,minix_get_block);
}

int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len)
{
        return __block_write_begin(page, pos, len, minix_get_block);
}

static void minix_write_failed(struct address_space *mapping, loff_t to)
{
        struct inode *inode = mapping->host;

        if (to > inode->i_size) {
                truncate_pagecache(inode, inode->i_size);
                minix_truncate(inode);
        }
}

static int minix_write_begin(struct file *file, struct address_space *mapping,
                        loff_t pos, unsigned len, unsigned flags,
                        struct page **pagep, void **fsdata)
{
        int ret;

        ret = block_write_begin(mapping, pos, len, flags, pagep,
                                minix_get_block);
        if (unlikely(ret))
                minix_write_failed(mapping, pos + len);

        return ret;
}

static sector_t minix_bmap(struct address_space *mapping, sector_t block)
{
        return generic_block_bmap(mapping,block,minix_get_block);
}

static const struct address_space_operations minix_aops = {
        .readpage = minix_readpage,
        .writepage = minix_writepage,
        .write_begin = minix_write_begin,
        .write_end = generic_write_end,
        .bmap = minix_bmap
};

static const struct inode_operations minix_symlink_inode_operations = {
        .readlink       = generic_readlink,
        .follow_link    = page_follow_link_light,
        .put_link       = page_put_link,
        .getattr        = minix_getattr,
};

void minix_set_inode(struct inode *inode, dev_t rdev)
{
        if (S_ISREG(inode->i_mode)) {
                inode->i_op = &minix_file_inode_operations;
                inode->i_fop = &minix_file_operations;
                inode->i_mapping->a_ops = &minix_aops;
        } else if (S_ISDIR(inode->i_mode)) {
                inode->i_op = &minix_dir_inode_operations;
                inode->i_fop = &minix_dir_operations;
                inode->i_mapping->a_ops = &minix_aops;
        } else if (S_ISLNK(inode->i_mode)) {
                inode->i_op = &minix_symlink_inode_operations;
                inode_nohighmem(inode);
                inode->i_mapping->a_ops = &minix_aops;
        } else
                init_special_inode(inode, inode->i_mode, rdev);
}

/*
 * The minix V1 function to read an inode.
 */
static struct inode *V1_minix_iget(struct inode *inode)
{
        struct buffer_head * bh;
        struct minix_inode * raw_inode;
        struct minix_inode_info *minix_inode = minix_i(inode);
        int i;

        raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
        if (!raw_inode) {
                iget_failed(inode);
                return ERR_PTR(-EIO);
        }
        inode->i_mode = raw_inode->i_mode;
        i_uid_write(inode, raw_inode->i_uid);
        i_gid_write(inode, raw_inode->i_gid);
        set_nlink(inode, raw_inode->i_nlinks);
        inode->i_size = raw_inode->i_size;
        inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = raw_inode->i_time;
        inode->i_mtime.tv_nsec = 0;
        inode->i_atime.tv_nsec = 0;
        inode->i_ctime.tv_nsec = 0;
        inode->i_blocks = 0;
        for (i = 0; i < 9; i++)
                minix_inode->u.i1_data[i] = raw_inode->i_zone[i];
        minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
        brelse(bh);
        unlock_new_inode(inode);
        return inode;
}

/*
 * The minix V2 function to read an inode.
 */
static struct inode *V2_minix_iget(struct inode *inode)
{
        struct buffer_head * bh;
        struct minix2_inode * raw_inode;
        struct minix_inode_info *minix_inode = minix_i(inode);
        int i;

        raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
        if (!raw_inode) {
                iget_failed(inode);
                return ERR_PTR(-EIO);
        }
        inode->i_mode = raw_inode->i_mode;
        i_uid_write(inode, raw_inode->i_uid);
        i_gid_write(inode, raw_inode->i_gid);
        set_nlink(inode, raw_inode->i_nlinks);
        inode->i_size = raw_inode->i_size;
        inode->i_mtime.tv_sec = raw_inode->i_mtime;
        inode->i_atime.tv_sec = raw_inode->i_atime;
        inode->i_ctime.tv_sec = raw_inode->i_ctime;
        inode->i_mtime.tv_nsec = 0;
        inode->i_atime.tv_nsec = 0;
        inode->i_ctime.tv_nsec = 0;
        inode->i_blocks = 0;
        for (i = 0; i < 10; i++)
                minix_inode->u.i2_data[i] = raw_inode->i_zone[i];
        minix_set_inode(inode, old_decode_dev(raw_inode->i_zone[0]));
        brelse(bh);
        unlock_new_inode(inode);
        return inode;
}

/*
 * The global function to read an inode.
 */
struct inode *minix_iget(struct super_block *sb, unsigned long ino)
{
        struct inode *inode;

        inode = iget_locked(sb, ino);
        if (!inode)
                return ERR_PTR(-ENOMEM);
        if (!(inode->i_state & I_NEW))
                return inode;

        if (INODE_VERSION(inode) == MINIX_V1)
                return V1_minix_iget(inode);
        else
                return V2_minix_iget(inode);
}

/*
 * The minix V1 function to synchronize an inode.
 */
static struct buffer_head * V1_minix_update_inode(struct inode * inode)
{
        struct buffer_head * bh;
        struct minix_inode * raw_inode;
        struct minix_inode_info *minix_inode = minix_i(inode);
        int i;

        raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
        if (!raw_inode)
                return NULL;
        raw_inode->i_mode = inode->i_mode;
        raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
        raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
        raw_inode->i_nlinks = inode->i_nlink;
        raw_inode->i_size = inode->i_size;
        raw_inode->i_time = inode->i_mtime.tv_sec;
        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
                raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
        else for (i = 0; i < 9; i++)
                raw_inode->i_zone[i] = minix_inode->u.i1_data[i];
        mark_buffer_dirty(bh);
        return bh;
}

/*
 * The minix V2 function to synchronize an inode.
 */
static struct buffer_head * V2_minix_update_inode(struct inode * inode)
{
        struct buffer_head * bh;
        struct minix2_inode * raw_inode;
        struct minix_inode_info *minix_inode = minix_i(inode);
        int i;

        raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
        if (!raw_inode)
                return NULL;
        raw_inode->i_mode = inode->i_mode;
        raw_inode->i_uid = fs_high2lowuid(i_uid_read(inode));
        raw_inode->i_gid = fs_high2lowgid(i_gid_read(inode));
        raw_inode->i_nlinks = inode->i_nlink;
        raw_inode->i_size = inode->i_size;
        raw_inode->i_mtime = inode->i_mtime.tv_sec;
        raw_inode->i_atime = inode->i_atime.tv_sec;
        raw_inode->i_ctime = inode->i_ctime.tv_sec;
        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
                raw_inode->i_zone[0] = old_encode_dev(inode->i_rdev);
        else for (i = 0; i < 10; i++)
                raw_inode->i_zone[i] = minix_inode->u.i2_data[i];
        mark_buffer_dirty(bh);
        return bh;
}

static int minix_write_inode(struct inode *inode, struct writeback_control *wbc)
{
        int err = 0;
        struct buffer_head *bh;

        if (INODE_VERSION(inode) == MINIX_V1)
                bh = V1_minix_update_inode(inode);
        else
                bh = V2_minix_update_inode(inode);
        if (!bh)
                return -EIO;
        if (wbc->sync_mode == WB_SYNC_ALL && buffer_dirty(bh)) {
                sync_dirty_buffer(bh);
                if (buffer_req(bh) && !buffer_uptodate(bh)) {
                        printk("IO error syncing minix inode [%s:%08lx]\n",
                                inode->i_sb->s_id, inode->i_ino);
                        err = -EIO;
                }
        }
        brelse (bh);
        return err;
}

int minix_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
        struct super_block *sb = dentry->d_sb;
        generic_fillattr(d_inode(dentry), stat);
        if (INODE_VERSION(d_inode(dentry)) == MINIX_V1)
                stat->blocks = (BLOCK_SIZE / 512) * V1_minix_blocks(stat->size, sb);
        else
                stat->blocks = (sb->s_blocksize / 512) * V2_minix_blocks(stat->size, sb);
        stat->blksize = sb->s_blocksize;
        return 0;
}

/*
 * The function that is called for file truncation.
 */
void minix_truncate(struct inode * inode)
{
        if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
                return;
        if (INODE_VERSION(inode) == MINIX_V1)
                V1_minix_truncate(inode);
        else
                V2_minix_truncate(inode);
}

static struct dentry *minix_mount(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *data)
{
        return mount_bdev(fs_type, flags, dev_name, data, minix_fill_super);
}

static struct file_system_type minix_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "minix",
        .mount          = minix_mount,
        .kill_sb        = kill_block_super,
        .fs_flags       = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("minix");

static int __init init_minix_fs(void)
{
        int err = init_inodecache();
        if (err)
                goto out1;
        err = register_filesystem(&minix_fs_type);
        if (err)
                goto out;
        return 0;
out:
        destroy_inodecache();
out1:
        return err;
}

static void __exit exit_minix_fs(void)
{
        unregister_filesystem(&minix_fs_type);
        destroy_inodecache();
}

module_init(init_minix_fs)
module_exit(exit_minix_fs)
MODULE_LICENSE("GPL");