namei.c

Go to the documentation of this file.

/*
 * namei.c
 *
 * PURPOSE
 *      Inode name handling routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *      This file is distributed under the terms of the GNU General Public
 *      License (GPL). Copies of the GPL can be obtained from:
 *              ftp://prep.ai.mit.edu/pub/gnu/GPL
 *      Each contributing author retains all rights to their own work.
 *
 *  (C) 1998-2004 Ben Fennema
 *  (C) 1999-2000 Stelias Computing Inc
 *
 * HISTORY
 *
 *  12/12/98 blf  Created. Split out the lookup code from dir.c
 *  04/19/99 blf  link, mknod, symlink support
 */

#include "udfdecl.h"

#include "udf_i.h"
#include "udf_sb.h"
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include <linux/sched.h>
#include <linux/crc-itu-t.h>
#include <linux/exportfs.h>

static inline int udf_match(int len1, const unsigned char *name1, int len2,
                const unsigned char *name2)
{
    if (len1 != len2)
        return 0;

    return !memcmp(name1, name2, len1);
}

int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
         struct fileIdentDesc *sfi, struct udf_fileident_bh *fibh,
         uint8_t *impuse, uint8_t *fileident)
{
    uint16_t crclen = fibh->eoffset - fibh->soffset - sizeof(struct tag);
    uint16_t crc;
    int offset;
    uint16_t liu = le16_to_cpu(cfi->lengthOfImpUse);
    uint8_t lfi = cfi->lengthFileIdent;
    int padlen = fibh->eoffset - fibh->soffset - liu - lfi -
        sizeof(struct fileIdentDesc);
    int adinicb = 0;

    if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
        adinicb = 1;

    offset = fibh->soffset + sizeof(struct fileIdentDesc);

    if (impuse) {
        if (adinicb || (offset + liu < 0)) {
            memcpy((uint8_t *)sfi->impUse, impuse, liu);
        } else if (offset >= 0) {
            memcpy(fibh->ebh->b_data + offset, impuse, liu);
        } else {
            memcpy((uint8_t *)sfi->impUse, impuse, -offset);
            memcpy(fibh->ebh->b_data, impuse - offset,
                liu + offset);
        }
    }

    offset += liu;

    if (fileident) {
        if (adinicb || (offset + lfi < 0)) {
            memcpy((uint8_t *)sfi->fileIdent + liu, fileident, lfi);
        } else if (offset >= 0) {
            memcpy(fibh->ebh->b_data + offset, fileident, lfi);
        } else {
            memcpy((uint8_t *)sfi->fileIdent + liu, fileident,
                -offset);
            memcpy(fibh->ebh->b_data, fileident - offset,
                lfi + offset);
        }
    }

    offset += lfi;

    if (adinicb || (offset + padlen < 0)) {
        memset((uint8_t *)sfi->padding + liu + lfi, 0x00, padlen);
    } else if (offset >= 0) {
        memset(fibh->ebh->b_data + offset, 0x00, padlen);
    } else {
        memset((uint8_t *)sfi->padding + liu + lfi, 0x00, -offset);
        memset(fibh->ebh->b_data, 0x00, padlen + offset);
    }

    crc = crc_itu_t(0, (uint8_t *)cfi + sizeof(struct tag),
              sizeof(struct fileIdentDesc) - sizeof(struct tag));

    if (fibh->sbh == fibh->ebh) {
        crc = crc_itu_t(crc, (uint8_t *)sfi->impUse,
                  crclen + sizeof(struct tag) -
                  sizeof(struct fileIdentDesc));
    } else if (sizeof(struct fileIdentDesc) >= -fibh->soffset) {
        crc = crc_itu_t(crc, fibh->ebh->b_data +
                    sizeof(struct fileIdentDesc) +
                    fibh->soffset,
                  crclen + sizeof(struct tag) -
                    sizeof(struct fileIdentDesc));
    } else {
        crc = crc_itu_t(crc, (uint8_t *)sfi->impUse,
                  -fibh->soffset - sizeof(struct fileIdentDesc));
        crc = crc_itu_t(crc, fibh->ebh->b_data, fibh->eoffset);
    }

    cfi->descTag.descCRC = cpu_to_le16(crc);
    cfi->descTag.descCRCLength = cpu_to_le16(crclen);
    cfi->descTag.tagChecksum = udf_tag_checksum(&cfi->descTag);

    if (adinicb || (sizeof(struct fileIdentDesc) <= -fibh->soffset)) {
        memcpy((uint8_t *)sfi, (uint8_t *)cfi,
            sizeof(struct fileIdentDesc));
    } else {
        memcpy((uint8_t *)sfi, (uint8_t *)cfi, -fibh->soffset);
        memcpy(fibh->ebh->b_data, (uint8_t *)cfi - fibh->soffset,
               sizeof(struct fileIdentDesc) + fibh->soffset);
    }

    if (adinicb) {
        mark_inode_dirty(inode);
    } else {
        if (fibh->sbh != fibh->ebh)
            mark_buffer_dirty_inode(fibh->ebh, inode);
        mark_buffer_dirty_inode(fibh->sbh, inode);
    }
    return 0;
}

static struct fileIdentDesc *udf_find_entry(struct inode *dir,
                        const struct qstr *child,
                        struct udf_fileident_bh *fibh,
                        struct fileIdentDesc *cfi)
{
    struct fileIdentDesc *fi = NULL;
    loff_t f_pos;
    int block, flen;
    unsigned char *fname = NULL;
    unsigned char *nameptr;
    uint8_t lfi;
    uint16_t liu;
    loff_t size;
    struct kernel_lb_addr eloc;
    uint32_t elen;
    sector_t offset;
    struct extent_position epos = {};
    struct udf_inode_info *dinfo = UDF_I(dir);
    int isdotdot = child->len == 2 &&
        child->name[0] == '.' && child->name[1] == '.';

    size = udf_ext0_offset(dir) + dir->i_size;
    f_pos = udf_ext0_offset(dir);

    fibh->sbh = fibh->ebh = NULL;
    fibh->soffset = fibh->eoffset = f_pos & (dir->i_sb->s_blocksize - 1);
    if (dinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
        if (inode_bmap(dir, f_pos >> dir->i_sb->s_blocksize_bits, &epos,
            &eloc, &elen, &offset) != (EXT_RECORDED_ALLOCATED >> 30))
            goto out_err;
        block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
        if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
            if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
                epos.offset -= sizeof(struct short_ad);
            else if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
                epos.offset -= sizeof(struct long_ad);
        } else
            offset = 0;

        fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
        if (!fibh->sbh)
            goto out_err;
    }

    fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
    if (!fname)
        goto out_err;

    while (f_pos < size) {
        fi = udf_fileident_read(dir, &f_pos, fibh, cfi, &epos, &eloc,
                    &elen, &offset);
        if (!fi)
            goto out_err;

        liu = le16_to_cpu(cfi->lengthOfImpUse);
        lfi = cfi->lengthFileIdent;

        if (fibh->sbh == fibh->ebh) {
            nameptr = fi->fileIdent + liu;
        } else {
            int poffset;    /* Unpaded ending offset */

            poffset = fibh->soffset + sizeof(struct fileIdentDesc) +
                    liu + lfi;

            if (poffset >= lfi)
                nameptr = (uint8_t *)(fibh->ebh->b_data +
                              poffset - lfi);
            else {
                nameptr = fname;
                memcpy(nameptr, fi->fileIdent + liu,
                    lfi - poffset);
                memcpy(nameptr + lfi - poffset,
                    fibh->ebh->b_data, poffset);
            }
        }

        if ((cfi->fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
            if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
                continue;
        }

        if ((cfi->fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
            if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
                continue;
        }

        if ((cfi->fileCharacteristics & FID_FILE_CHAR_PARENT) &&
            isdotdot)
            goto out_ok;

        if (!lfi)
            continue;

        flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
        if (flen && udf_match(flen, fname, child->len, child->name))
            goto out_ok;
    }

out_err:
    fi = NULL;
    if (fibh->sbh != fibh->ebh)
        brelse(fibh->ebh);
    brelse(fibh->sbh);
out_ok:
    brelse(epos.bh);
    kfree(fname);

    return fi;
}

static struct dentry *udf_lookup(struct inode *dir, struct dentry *dentry,
                 unsigned int flags)
{
    struct inode *inode = NULL;
    struct fileIdentDesc cfi;
    struct udf_fileident_bh fibh;

    if (dentry->d_name.len > UDF_NAME_LEN - 2)
        return ERR_PTR(-ENAMETOOLONG);

#ifdef UDF_RECOVERY
    /* temporary shorthand for specifying files by inode number */
    if (!strncmp(dentry->d_name.name, ".B=", 3)) {
        struct kernel_lb_addr lb = {
            .logicalBlockNum = 0,
            .partitionReferenceNum =
                simple_strtoul(dentry->d_name.name + 3,
                        NULL, 0),
        };
        inode = udf_iget(dir->i_sb, lb);
        if (!inode) {
            return ERR_PTR(-EACCES);
        }
    } else
#endif /* UDF_RECOVERY */

    if (udf_find_entry(dir, &dentry->d_name, &fibh, &cfi)) {
        struct kernel_lb_addr loc;

        if (fibh.sbh != fibh.ebh)
            brelse(fibh.ebh);
        brelse(fibh.sbh);

        loc = lelb_to_cpu(cfi.icb.extLocation);
        inode = udf_iget(dir->i_sb, &loc);
        if (!inode) {
            return ERR_PTR(-EACCES);
        }
    }

    return d_splice_alias(inode, dentry);
}

static struct fileIdentDesc *udf_add_entry(struct inode *dir,
                       struct dentry *dentry,
                       struct udf_fileident_bh *fibh,
                       struct fileIdentDesc *cfi, int *err)
{
    struct super_block *sb = dir->i_sb;
    struct fileIdentDesc *fi = NULL;
    unsigned char *name = NULL;
    int namelen;
    loff_t f_pos;
    loff_t size = udf_ext0_offset(dir) + dir->i_size;
    int nfidlen;
    uint8_t lfi;
    uint16_t liu;
    int block;
    struct kernel_lb_addr eloc;
    uint32_t elen = 0;
    sector_t offset;
    struct extent_position epos = {};
    struct udf_inode_info *dinfo;

    fibh->sbh = fibh->ebh = NULL;
    name = kmalloc(UDF_NAME_LEN, GFP_NOFS);
    if (!name) {
        *err = -ENOMEM;
        goto out_err;
    }

    if (dentry) {
        if (!dentry->d_name.len) {
            *err = -EINVAL;
            goto out_err;
        }
        namelen = udf_put_filename(sb, dentry->d_name.name, name,
                         dentry->d_name.len);
        if (!namelen) {
            *err = -ENAMETOOLONG;
            goto out_err;
        }
    } else {
        namelen = 0;
    }

    nfidlen = (sizeof(struct fileIdentDesc) + namelen + 3) & ~3;

    f_pos = udf_ext0_offset(dir);

    fibh->soffset = fibh->eoffset = f_pos & (dir->i_sb->s_blocksize - 1);
    dinfo = UDF_I(dir);
    if (dinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
        if (inode_bmap(dir, f_pos >> dir->i_sb->s_blocksize_bits, &epos,
            &eloc, &elen, &offset) != (EXT_RECORDED_ALLOCATED >> 30)) {
            block = udf_get_lb_pblock(dir->i_sb,
                    &dinfo->i_location, 0);
            fibh->soffset = fibh->eoffset = sb->s_blocksize;
            goto add;
        }
        block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
        if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
            if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
                epos.offset -= sizeof(struct short_ad);
            else if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
                epos.offset -= sizeof(struct long_ad);
        } else
            offset = 0;

        fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
        if (!fibh->sbh) {
            *err = -EIO;
            goto out_err;
        }

        block = dinfo->i_location.logicalBlockNum;
    }

    while (f_pos < size) {
        fi = udf_fileident_read(dir, &f_pos, fibh, cfi, &epos, &eloc,
                    &elen, &offset);

        if (!fi) {
            *err = -EIO;
            goto out_err;
        }

        liu = le16_to_cpu(cfi->lengthOfImpUse);
        lfi = cfi->lengthFileIdent;

        if ((cfi->fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
            if (((sizeof(struct fileIdentDesc) +
                    liu + lfi + 3) & ~3) == nfidlen) {
                cfi->descTag.tagSerialNum = cpu_to_le16(1);
                cfi->fileVersionNum = cpu_to_le16(1);
                cfi->fileCharacteristics = 0;
                cfi->lengthFileIdent = namelen;
                cfi->lengthOfImpUse = cpu_to_le16(0);
                if (!udf_write_fi(dir, cfi, fi, fibh, NULL,
                          name))
                    goto out_ok;
                else {
                    *err = -EIO;
                    goto out_err;
                }
            }
        }
    }

add:
    f_pos += nfidlen;

    if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB &&
        sb->s_blocksize - fibh->eoffset < nfidlen) {
        brelse(epos.bh);
        epos.bh = NULL;
        fibh->soffset -= udf_ext0_offset(dir);
        fibh->eoffset -= udf_ext0_offset(dir);
        f_pos -= udf_ext0_offset(dir);
        if (fibh->sbh != fibh->ebh)
            brelse(fibh->ebh);
        brelse(fibh->sbh);
        fibh->sbh = fibh->ebh =
                udf_expand_dir_adinicb(dir, &block, err);
        if (!fibh->sbh)
            goto out_err;
        epos.block = dinfo->i_location;
        epos.offset = udf_file_entry_alloc_offset(dir);
        /* Load extent udf_expand_dir_adinicb() has created */
        udf_current_aext(dir, &epos, &eloc, &elen, 1);
    }

    /* Entry fits into current block? */
    if (sb->s_blocksize - fibh->eoffset >= nfidlen) {
        fibh->soffset = fibh->eoffset;
        fibh->eoffset += nfidlen;
        if (fibh->sbh != fibh->ebh) {
            brelse(fibh->sbh);
            fibh->sbh = fibh->ebh;
        }

        if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
            block = dinfo->i_location.logicalBlockNum;
            fi = (struct fileIdentDesc *)
                    (dinfo->i_ext.i_data +
                     fibh->soffset -
                     udf_ext0_offset(dir) +
                     dinfo->i_lenEAttr);
        } else {
            block = eloc.logicalBlockNum +
                    ((elen - 1) >>
                        dir->i_sb->s_blocksize_bits);
            fi = (struct fileIdentDesc *)
                (fibh->sbh->b_data + fibh->soffset);
        }
    } else {
        /* Round up last extent in the file */
        elen = (elen + sb->s_blocksize - 1) & ~(sb->s_blocksize - 1);
        if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
            epos.offset -= sizeof(struct short_ad);
        else if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
            epos.offset -= sizeof(struct long_ad);
        udf_write_aext(dir, &epos, &eloc, elen, 1);
        dinfo->i_lenExtents = (dinfo->i_lenExtents + sb->s_blocksize
                    - 1) & ~(sb->s_blocksize - 1);

        fibh->soffset = fibh->eoffset - sb->s_blocksize;
        fibh->eoffset += nfidlen - sb->s_blocksize;
        if (fibh->sbh != fibh->ebh) {
            brelse(fibh->sbh);
            fibh->sbh = fibh->ebh;
        }

        block = eloc.logicalBlockNum + ((elen - 1) >>
                        dir->i_sb->s_blocksize_bits);
        fibh->ebh = udf_bread(dir,
                f_pos >> dir->i_sb->s_blocksize_bits, 1, err);
        if (!fibh->ebh)
            goto out_err;
        /* Extents could have been merged, invalidate our position */
        brelse(epos.bh);
        epos.bh = NULL;
        epos.block = dinfo->i_location;
        epos.offset = udf_file_entry_alloc_offset(dir);

        if (!fibh->soffset) {
            /* Find the freshly allocated block */
            while (udf_next_aext(dir, &epos, &eloc, &elen, 1) ==
                (EXT_RECORDED_ALLOCATED >> 30))
                ;
            block = eloc.logicalBlockNum + ((elen - 1) >>
                    dir->i_sb->s_blocksize_bits);
            brelse(fibh->sbh);
            fibh->sbh = fibh->ebh;
            fi = (struct fileIdentDesc *)(fibh->sbh->b_data);
        } else {
            fi = (struct fileIdentDesc *)
                (fibh->sbh->b_data + sb->s_blocksize +
                    fibh->soffset);
        }
    }

    memset(cfi, 0, sizeof(struct fileIdentDesc));
    if (UDF_SB(sb)->s_udfrev >= 0x0200)
        udf_new_tag((char *)cfi, TAG_IDENT_FID, 3, 1, block,
                sizeof(struct tag));
    else
        udf_new_tag((char *)cfi, TAG_IDENT_FID, 2, 1, block,
                sizeof(struct tag));
    cfi->fileVersionNum = cpu_to_le16(1);
    cfi->lengthFileIdent = namelen;
    cfi->lengthOfImpUse = cpu_to_le16(0);
    if (!udf_write_fi(dir, cfi, fi, fibh, NULL, name)) {
        dir->i_size += nfidlen;
        if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
            dinfo->i_lenAlloc += nfidlen;
        else {
            /* Find the last extent and truncate it to proper size */
            while (udf_next_aext(dir, &epos, &eloc, &elen, 1) ==
                (EXT_RECORDED_ALLOCATED >> 30))
                ;
            elen -= dinfo->i_lenExtents - dir->i_size;
            if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
                epos.offset -= sizeof(struct short_ad);
            else if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
                epos.offset -= sizeof(struct long_ad);
            udf_write_aext(dir, &epos, &eloc, elen, 1);
            dinfo->i_lenExtents = dir->i_size;
        }

        mark_inode_dirty(dir);
        goto out_ok;
    } else {
        *err = -EIO;
        goto out_err;
    }

out_err:
    fi = NULL;
    if (fibh->sbh != fibh->ebh)
        brelse(fibh->ebh);
    brelse(fibh->sbh);
out_ok:
    brelse(epos.bh);
    kfree(name);
    return fi;
}

static int udf_delete_entry(struct inode *inode, struct fileIdentDesc *fi,
                struct udf_fileident_bh *fibh,
                struct fileIdentDesc *cfi)
{
    cfi->fileCharacteristics |= FID_FILE_CHAR_DELETED;

    if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT))
        memset(&(cfi->icb), 0x00, sizeof(struct long_ad));

    return udf_write_fi(inode, cfi, fi, fibh, NULL, NULL);
}

static int udf_create(struct inode *dir, struct dentry *dentry, umode_t mode,
              bool excl)
{
    struct udf_fileident_bh fibh;
    struct inode *inode;
    struct fileIdentDesc cfi, *fi;
    int err;
    struct udf_inode_info *iinfo;

    inode = udf_new_inode(dir, mode, &err);
    if (!inode) {
        return err;
    }

    iinfo = UDF_I(inode);
    if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
        inode->i_data.a_ops = &udf_adinicb_aops;
    else
        inode->i_data.a_ops = &udf_aops;
    inode->i_op = &udf_file_inode_operations;
    inode->i_fop = &udf_file_operations;
    mark_inode_dirty(inode);

    fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err);
    if (!fi) {
        inode_dec_link_count(inode);
        iput(inode);
        return err;
    }
    cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
    cfi.icb.extLocation = cpu_to_lelb(iinfo->i_location);
    *(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
        cpu_to_le32(iinfo->i_unique & 0x00000000FFFFFFFFUL);
    udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
    if (UDF_I(dir)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
        mark_inode_dirty(dir);
    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);
    d_instantiate(dentry, inode);

    return 0;
}

static int udf_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
             dev_t rdev)
{
    struct inode *inode;
    struct udf_fileident_bh fibh;
    struct fileIdentDesc cfi, *fi;
    int err;
    struct udf_inode_info *iinfo;

    if (!old_valid_dev(rdev))
        return -EINVAL;

    err = -EIO;
    inode = udf_new_inode(dir, mode, &err);
    if (!inode)
        goto out;

    iinfo = UDF_I(inode);
    init_special_inode(inode, mode, rdev);
    fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err);
    if (!fi) {
        inode_dec_link_count(inode);
        iput(inode);
        return err;
    }
    cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
    cfi.icb.extLocation = cpu_to_lelb(iinfo->i_location);
    *(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
        cpu_to_le32(iinfo->i_unique & 0x00000000FFFFFFFFUL);
    udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
    if (UDF_I(dir)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
        mark_inode_dirty(dir);
    mark_inode_dirty(inode);

    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);
    d_instantiate(dentry, inode);
    err = 0;

out:
    return err;
}

static int udf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
    struct inode *inode;
    struct udf_fileident_bh fibh;
    struct fileIdentDesc cfi, *fi;
    int err;
    struct udf_inode_info *dinfo = UDF_I(dir);
    struct udf_inode_info *iinfo;

    err = -EIO;
    inode = udf_new_inode(dir, S_IFDIR | mode, &err);
    if (!inode)
        goto out;

    iinfo = UDF_I(inode);
    inode->i_op = &udf_dir_inode_operations;
    inode->i_fop = &udf_dir_operations;
    fi = udf_add_entry(inode, NULL, &fibh, &cfi, &err);
    if (!fi) {
        inode_dec_link_count(inode);
        iput(inode);
        goto out;
    }
    set_nlink(inode, 2);
    cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
    cfi.icb.extLocation = cpu_to_lelb(dinfo->i_location);
    *(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
        cpu_to_le32(dinfo->i_unique & 0x00000000FFFFFFFFUL);
    cfi.fileCharacteristics =
            FID_FILE_CHAR_DIRECTORY | FID_FILE_CHAR_PARENT;
    udf_write_fi(inode, &cfi, fi, &fibh, NULL, NULL);
    brelse(fibh.sbh);
    mark_inode_dirty(inode);

    fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err);
    if (!fi) {
        clear_nlink(inode);
        mark_inode_dirty(inode);
        iput(inode);
        goto out;
    }
    cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
    cfi.icb.extLocation = cpu_to_lelb(iinfo->i_location);
    *(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
        cpu_to_le32(iinfo->i_unique & 0x00000000FFFFFFFFUL);
    cfi.fileCharacteristics |= FID_FILE_CHAR_DIRECTORY;
    udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
    inc_nlink(dir);
    mark_inode_dirty(dir);
    d_instantiate(dentry, inode);
    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);
    err = 0;

out:
    return err;
}

static int empty_dir(struct inode *dir)
{
    struct fileIdentDesc *fi, cfi;
    struct udf_fileident_bh fibh;
    loff_t f_pos;
    loff_t size = udf_ext0_offset(dir) + dir->i_size;
    int block;
    struct kernel_lb_addr eloc;
    uint32_t elen;
    sector_t offset;
    struct extent_position epos = {};
    struct udf_inode_info *dinfo = UDF_I(dir);

    f_pos = udf_ext0_offset(dir);
    fibh.soffset = fibh.eoffset = f_pos & (dir->i_sb->s_blocksize - 1);

    if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
        fibh.sbh = fibh.ebh = NULL;
    else if (inode_bmap(dir, f_pos >> dir->i_sb->s_blocksize_bits,
                  &epos, &eloc, &elen, &offset) ==
                    (EXT_RECORDED_ALLOCATED >> 30)) {
        block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
        if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
            if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
                epos.offset -= sizeof(struct short_ad);
            else if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
                epos.offset -= sizeof(struct long_ad);
        } else
            offset = 0;

        fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block);
        if (!fibh.sbh) {
            brelse(epos.bh);
            return 0;
        }
    } else {
        brelse(epos.bh);
        return 0;
    }

    while (f_pos < size) {
        fi = udf_fileident_read(dir, &f_pos, &fibh, &cfi, &epos, &eloc,
                    &elen, &offset);
        if (!fi) {
            if (fibh.sbh != fibh.ebh)
                brelse(fibh.ebh);
            brelse(fibh.sbh);
            brelse(epos.bh);
            return 0;
        }

        if (cfi.lengthFileIdent &&
            (cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) == 0) {
            if (fibh.sbh != fibh.ebh)
                brelse(fibh.ebh);
            brelse(fibh.sbh);
            brelse(epos.bh);
            return 0;
        }
    }

    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);
    brelse(epos.bh);

    return 1;
}

static int udf_rmdir(struct inode *dir, struct dentry *dentry)
{
    int retval;
    struct inode *inode = dentry->d_inode;
    struct udf_fileident_bh fibh;
    struct fileIdentDesc *fi, cfi;
    struct kernel_lb_addr tloc;

    retval = -ENOENT;
    fi = udf_find_entry(dir, &dentry->d_name, &fibh, &cfi);
    if (!fi)
        goto out;

    retval = -EIO;
    tloc = lelb_to_cpu(cfi.icb.extLocation);
    if (udf_get_lb_pblock(dir->i_sb, &tloc, 0) != inode->i_ino)
        goto end_rmdir;
    retval = -ENOTEMPTY;
    if (!empty_dir(inode))
        goto end_rmdir;
    retval = udf_delete_entry(dir, fi, &fibh, &cfi);
    if (retval)
        goto end_rmdir;
    if (inode->i_nlink != 2)
        udf_warn(inode->i_sb, "empty directory has nlink != 2 (%d)\n",
             inode->i_nlink);
    clear_nlink(inode);
    inode->i_size = 0;
    inode_dec_link_count(dir);
    inode->i_ctime = dir->i_ctime = dir->i_mtime =
                        current_fs_time(dir->i_sb);
    mark_inode_dirty(dir);

end_rmdir:
    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);

out:
    return retval;
}

static int udf_unlink(struct inode *dir, struct dentry *dentry)
{
    int retval;
    struct inode *inode = dentry->d_inode;
    struct udf_fileident_bh fibh;
    struct fileIdentDesc *fi;
    struct fileIdentDesc cfi;
    struct kernel_lb_addr tloc;

    retval = -ENOENT;
    fi = udf_find_entry(dir, &dentry->d_name, &fibh, &cfi);
    if (!fi)
        goto out;

    retval = -EIO;
    tloc = lelb_to_cpu(cfi.icb.extLocation);
    if (udf_get_lb_pblock(dir->i_sb, &tloc, 0) != inode->i_ino)
        goto end_unlink;

    if (!inode->i_nlink) {
        udf_debug("Deleting nonexistent file (%lu), %d\n",
              inode->i_ino, inode->i_nlink);
        set_nlink(inode, 1);
    }
    retval = udf_delete_entry(dir, fi, &fibh, &cfi);
    if (retval)
        goto end_unlink;
    dir->i_ctime = dir->i_mtime = current_fs_time(dir->i_sb);
    mark_inode_dirty(dir);
    inode_dec_link_count(inode);
    inode->i_ctime = dir->i_ctime;
    retval = 0;

end_unlink:
    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);

out:
    return retval;
}

static int udf_symlink(struct inode *dir, struct dentry *dentry,
               const char *symname)
{
    struct inode *inode;
    struct pathComponent *pc;
    const char *compstart;
    struct udf_fileident_bh fibh;
    struct extent_position epos = {};
    int eoffset, elen = 0;
    struct fileIdentDesc *fi;
    struct fileIdentDesc cfi;
    uint8_t *ea;
    int err;
    int block;
    unsigned char *name = NULL;
    int namelen;
    struct udf_inode_info *iinfo;
    struct super_block *sb = dir->i_sb;

    inode = udf_new_inode(dir, S_IFLNK | S_IRWXUGO, &err);
    if (!inode)
        goto out;

    iinfo = UDF_I(inode);
    down_write(&iinfo->i_data_sem);
    name = kmalloc(UDF_NAME_LEN, GFP_NOFS);
    if (!name) {
        err = -ENOMEM;
        goto out_no_entry;
    }

    inode->i_data.a_ops = &udf_symlink_aops;
    inode->i_op = &udf_symlink_inode_operations;

    if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
        struct kernel_lb_addr eloc;
        uint32_t bsize;

        block = udf_new_block(sb, inode,
                iinfo->i_location.partitionReferenceNum,
                iinfo->i_location.logicalBlockNum, &err);
        if (!block)
            goto out_no_entry;
        epos.block = iinfo->i_location;
        epos.offset = udf_file_entry_alloc_offset(inode);
        epos.bh = NULL;
        eloc.logicalBlockNum = block;
        eloc.partitionReferenceNum =
                iinfo->i_location.partitionReferenceNum;
        bsize = sb->s_blocksize;
        iinfo->i_lenExtents = bsize;
        udf_add_aext(inode, &epos, &eloc, bsize, 0);
        brelse(epos.bh);

        block = udf_get_pblock(sb, block,
                iinfo->i_location.partitionReferenceNum,
                0);
        epos.bh = udf_tgetblk(sb, block);
        lock_buffer(epos.bh);
        memset(epos.bh->b_data, 0x00, bsize);
        set_buffer_uptodate(epos.bh);
        unlock_buffer(epos.bh);
        mark_buffer_dirty_inode(epos.bh, inode);
        ea = epos.bh->b_data + udf_ext0_offset(inode);
    } else
        ea = iinfo->i_ext.i_data + iinfo->i_lenEAttr;

    eoffset = sb->s_blocksize - udf_ext0_offset(inode);
    pc = (struct pathComponent *)ea;

    if (*symname == '/') {
        do {
            symname++;
        } while (*symname == '/');

        pc->componentType = 1;
        pc->lengthComponentIdent = 0;
        pc->componentFileVersionNum = 0;
        elen += sizeof(struct pathComponent);
    }

    err = -ENAMETOOLONG;

    while (*symname) {
        if (elen + sizeof(struct pathComponent) > eoffset)
            goto out_no_entry;

        pc = (struct pathComponent *)(ea + elen);

        compstart = symname;

        do {
            symname++;
        } while (*symname && *symname != '/');

        pc->componentType = 5;
        pc->lengthComponentIdent = 0;
        pc->componentFileVersionNum = 0;
        if (compstart[0] == '.') {
            if ((symname - compstart) == 1)
                pc->componentType = 4;
            else if ((symname - compstart) == 2 &&
                    compstart[1] == '.')
                pc->componentType = 3;
        }

        if (pc->componentType == 5) {
            namelen = udf_put_filename(sb, compstart, name,
                           symname - compstart);
            if (!namelen)
                goto out_no_entry;

            if (elen + sizeof(struct pathComponent) + namelen >
                    eoffset)
                goto out_no_entry;
            else
                pc->lengthComponentIdent = namelen;

            memcpy(pc->componentIdent, name, namelen);
        }

        elen += sizeof(struct pathComponent) + pc->lengthComponentIdent;

        if (*symname) {
            do {
                symname++;
            } while (*symname == '/');
        }
    }

    brelse(epos.bh);
    inode->i_size = elen;
    if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
        iinfo->i_lenAlloc = inode->i_size;
    else
        udf_truncate_tail_extent(inode);
    mark_inode_dirty(inode);

    fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err);
    if (!fi)
        goto out_no_entry;
    cfi.icb.extLength = cpu_to_le32(sb->s_blocksize);
    cfi.icb.extLocation = cpu_to_lelb(iinfo->i_location);
    if (UDF_SB(inode->i_sb)->s_lvid_bh) {
        *(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
            cpu_to_le32(lvid_get_unique_id(sb));
    }
    udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
    if (UDF_I(dir)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
        mark_inode_dirty(dir);
    up_write(&iinfo->i_data_sem);
    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);
    d_instantiate(dentry, inode);
    err = 0;

out:
    kfree(name);
    return err;

out_no_entry:
    up_write(&iinfo->i_data_sem);
    inode_dec_link_count(inode);
    iput(inode);
    goto out;
}

static int udf_link(struct dentry *old_dentry, struct inode *dir,
            struct dentry *dentry)
{
    struct inode *inode = old_dentry->d_inode;
    struct udf_fileident_bh fibh;
    struct fileIdentDesc cfi, *fi;
    int err;

    fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err);
    if (!fi) {
        return err;
    }
    cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
    cfi.icb.extLocation = cpu_to_lelb(UDF_I(inode)->i_location);
    if (UDF_SB(inode->i_sb)->s_lvid_bh) {
        *(__le32 *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
            cpu_to_le32(lvid_get_unique_id(inode->i_sb));
    }
    udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
    if (UDF_I(dir)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
        mark_inode_dirty(dir);

    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);
    inc_nlink(inode);
    inode->i_ctime = current_fs_time(inode->i_sb);
    mark_inode_dirty(inode);
    ihold(inode);
    d_instantiate(dentry, inode);

    return 0;
}

/* Anybody can rename anything with this: the permission checks are left to the
 * higher-level routines.
 */
static int udf_rename(struct inode *old_dir, struct dentry *old_dentry,
              struct inode *new_dir, struct dentry *new_dentry)
{
    struct inode *old_inode = old_dentry->d_inode;
    struct inode *new_inode = new_dentry->d_inode;
    struct udf_fileident_bh ofibh, nfibh;
    struct fileIdentDesc *ofi = NULL, *nfi = NULL, *dir_fi = NULL;
    struct fileIdentDesc ocfi, ncfi;
    struct buffer_head *dir_bh = NULL;
    int retval = -ENOENT;
    struct kernel_lb_addr tloc;
    struct udf_inode_info *old_iinfo = UDF_I(old_inode);

    ofi = udf_find_entry(old_dir, &old_dentry->d_name, &ofibh, &ocfi);
    if (ofi) {
        if (ofibh.sbh != ofibh.ebh)
            brelse(ofibh.ebh);
        brelse(ofibh.sbh);
    }
    tloc = lelb_to_cpu(ocfi.icb.extLocation);
    if (!ofi || udf_get_lb_pblock(old_dir->i_sb, &tloc, 0)
        != old_inode->i_ino)
        goto end_rename;

    nfi = udf_find_entry(new_dir, &new_dentry->d_name, &nfibh, &ncfi);
    if (nfi) {
        if (!new_inode) {
            if (nfibh.sbh != nfibh.ebh)
                brelse(nfibh.ebh);
            brelse(nfibh.sbh);
            nfi = NULL;
        }
    }
    if (S_ISDIR(old_inode->i_mode)) {
        int offset = udf_ext0_offset(old_inode);

        if (new_inode) {
            retval = -ENOTEMPTY;
            if (!empty_dir(new_inode))
                goto end_rename;
        }
        retval = -EIO;
        if (old_iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
            dir_fi = udf_get_fileident(
                    old_iinfo->i_ext.i_data -
                      (old_iinfo->i_efe ?
                       sizeof(struct extendedFileEntry) :
                       sizeof(struct fileEntry)),
                    old_inode->i_sb->s_blocksize, &offset);
        } else {
            dir_bh = udf_bread(old_inode, 0, 0, &retval);
            if (!dir_bh)
                goto end_rename;
            dir_fi = udf_get_fileident(dir_bh->b_data,
                    old_inode->i_sb->s_blocksize, &offset);
        }
        if (!dir_fi)
            goto end_rename;
        tloc = lelb_to_cpu(dir_fi->icb.extLocation);
        if (udf_get_lb_pblock(old_inode->i_sb, &tloc, 0) !=
                old_dir->i_ino)
            goto end_rename;
    }
    if (!nfi) {
        nfi = udf_add_entry(new_dir, new_dentry, &nfibh, &ncfi,
                    &retval);
        if (!nfi)
            goto end_rename;
    }

    /*
     * Like most other Unix systems, set the ctime for inodes on a
     * rename.
     */
    old_inode->i_ctime = current_fs_time(old_inode->i_sb);
    mark_inode_dirty(old_inode);

    /*
     * ok, that's it
     */
    ncfi.fileVersionNum = ocfi.fileVersionNum;
    ncfi.fileCharacteristics = ocfi.fileCharacteristics;
    memcpy(&(ncfi.icb), &(ocfi.icb), sizeof(struct long_ad));
    udf_write_fi(new_dir, &ncfi, nfi, &nfibh, NULL, NULL);

    /* The old fid may have moved - find it again */
    ofi = udf_find_entry(old_dir, &old_dentry->d_name, &ofibh, &ocfi);
    udf_delete_entry(old_dir, ofi, &ofibh, &ocfi);

    if (new_inode) {
        new_inode->i_ctime = current_fs_time(new_inode->i_sb);
        inode_dec_link_count(new_inode);
    }
    old_dir->i_ctime = old_dir->i_mtime = current_fs_time(old_dir->i_sb);
    mark_inode_dirty(old_dir);

    if (dir_fi) {
        dir_fi->icb.extLocation = cpu_to_lelb(UDF_I(new_dir)->i_location);
        udf_update_tag((char *)dir_fi,
                (sizeof(struct fileIdentDesc) +
                le16_to_cpu(dir_fi->lengthOfImpUse) + 3) & ~3);
        if (old_iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
            mark_inode_dirty(old_inode);
        else
            mark_buffer_dirty_inode(dir_bh, old_inode);

        inode_dec_link_count(old_dir);
        if (new_inode)
            inode_dec_link_count(new_inode);
        else {
            inc_nlink(new_dir);
            mark_inode_dirty(new_dir);
        }
    }

    if (ofi) {
        if (ofibh.sbh != ofibh.ebh)
            brelse(ofibh.ebh);
        brelse(ofibh.sbh);
    }

    retval = 0;

end_rename:
    brelse(dir_bh);
    if (nfi) {
        if (nfibh.sbh != nfibh.ebh)
            brelse(nfibh.ebh);
        brelse(nfibh.sbh);
    }

    return retval;
}

static struct dentry *udf_get_parent(struct dentry *child)
{
    struct kernel_lb_addr tloc;
    struct inode *inode = NULL;
    struct qstr dotdot = QSTR_INIT("..", 2);
    struct fileIdentDesc cfi;
    struct udf_fileident_bh fibh;

    if (!udf_find_entry(child->d_inode, &dotdot, &fibh, &cfi))
        goto out_unlock;

    if (fibh.sbh != fibh.ebh)
        brelse(fibh.ebh);
    brelse(fibh.sbh);

    tloc = lelb_to_cpu(cfi.icb.extLocation);
    inode = udf_iget(child->d_inode->i_sb, &tloc);
    if (!inode)
        goto out_unlock;

    return d_obtain_alias(inode);
out_unlock:
    return ERR_PTR(-EACCES);
}


static struct dentry *udf_nfs_get_inode(struct super_block *sb, u32 block,
                    u16 partref, __u32 generation)
{
    struct inode *inode;
    struct kernel_lb_addr loc;

    if (block == 0)
        return ERR_PTR(-ESTALE);

    loc.logicalBlockNum = block;
    loc.partitionReferenceNum = partref;
    inode = udf_iget(sb, &loc);

    if (inode == NULL)
        return ERR_PTR(-ENOMEM);

    if (generation && inode->i_generation != generation) {
        iput(inode);
        return ERR_PTR(-ESTALE);
    }
    return d_obtain_alias(inode);
}

static struct dentry *udf_fh_to_dentry(struct super_block *sb,
                       struct fid *fid, int fh_len, int fh_type)
{
    if ((fh_len != 3 && fh_len != 5) ||
        (fh_type != FILEID_UDF_WITH_PARENT &&
         fh_type != FILEID_UDF_WITHOUT_PARENT))
        return NULL;

    return udf_nfs_get_inode(sb, fid->udf.block, fid->udf.partref,
            fid->udf.generation);
}

static struct dentry *udf_fh_to_parent(struct super_block *sb,
                       struct fid *fid, int fh_len, int fh_type)
{
    if (fh_len != 5 || fh_type != FILEID_UDF_WITH_PARENT)
        return NULL;

    return udf_nfs_get_inode(sb, fid->udf.parent_block,
                 fid->udf.parent_partref,
                 fid->udf.parent_generation);
}
static int udf_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
             struct inode *parent)
{
    int len = *lenp;
    struct kernel_lb_addr location = UDF_I(inode)->i_location;
    struct fid *fid = (struct fid *)fh;
    int type = FILEID_UDF_WITHOUT_PARENT;

    if (parent && (len < 5)) {
        *lenp = 5;
        return 255;
    } else if (len < 3) {
        *lenp = 3;
        return 255;
    }

    *lenp = 3;
    fid->udf.block = location.logicalBlockNum;
    fid->udf.partref = location.partitionReferenceNum;
    fid->udf.parent_partref = 0;
    fid->udf.generation = inode->i_generation;

    if (parent) {
        location = UDF_I(parent)->i_location;
        fid->udf.parent_block = location.logicalBlockNum;
        fid->udf.parent_partref = location.partitionReferenceNum;
        fid->udf.parent_generation = inode->i_generation;
        *lenp = 5;
        type = FILEID_UDF_WITH_PARENT;
    }

    return type;
}

const struct export_operations udf_export_ops = {
    .encode_fh  = udf_encode_fh,
    .fh_to_dentry   = udf_fh_to_dentry,
    .fh_to_parent   = udf_fh_to_parent,
    .get_parent     = udf_get_parent,
};

const struct inode_operations udf_dir_inode_operations = {
    .lookup             = udf_lookup,
    .create             = udf_create,
    .link               = udf_link,
    .unlink             = udf_unlink,
    .symlink            = udf_symlink,
    .mkdir              = udf_mkdir,
    .rmdir              = udf_rmdir,
    .mknod              = udf_mknod,
    .rename             = udf_rename,
};
const struct inode_operations udf_symlink_inode_operations = {
    .readlink   = generic_readlink,
    .follow_link    = page_follow_link_light,
    .put_link   = page_put_link,
};