xfs_dir2.c

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/*
 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it would 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; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_dir2.h"
#include "xfs_dir2_format.h"
#include "xfs_dir2_priv.h"
#include "xfs_error.h"
#include "xfs_vnodeops.h"
#include "xfs_trace.h"

struct xfs_name xfs_name_dotdot = { (unsigned char *)"..", 2};

/*
 * ASCII case-insensitive (ie. A-Z) support for directories that was
 * used in IRIX.
 */
STATIC xfs_dahash_t
xfs_ascii_ci_hashname(
    struct xfs_name *name)
{
    xfs_dahash_t    hash;
    int     i;

    for (i = 0, hash = 0; i < name->len; i++)
        hash = tolower(name->name[i]) ^ rol32(hash, 7);

    return hash;
}

STATIC enum xfs_dacmp
xfs_ascii_ci_compname(
    struct xfs_da_args *args,
    const unsigned char *name,
    int     len)
{
    enum xfs_dacmp  result;
    int     i;

    if (args->namelen != len)
        return XFS_CMP_DIFFERENT;

    result = XFS_CMP_EXACT;
    for (i = 0; i < len; i++) {
        if (args->name[i] == name[i])
            continue;
        if (tolower(args->name[i]) != tolower(name[i]))
            return XFS_CMP_DIFFERENT;
        result = XFS_CMP_CASE;
    }

    return result;
}

static struct xfs_nameops xfs_ascii_ci_nameops = {
    .hashname   = xfs_ascii_ci_hashname,
    .compname   = xfs_ascii_ci_compname,
};

void
xfs_dir_mount(
    xfs_mount_t *mp)
{
    ASSERT(xfs_sb_version_hasdirv2(&mp->m_sb));
    ASSERT((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) <=
           XFS_MAX_BLOCKSIZE);
    mp->m_dirblksize = 1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog);
    mp->m_dirblkfsbs = 1 << mp->m_sb.sb_dirblklog;
    mp->m_dirdatablk = xfs_dir2_db_to_da(mp, XFS_DIR2_DATA_FIRSTDB(mp));
    mp->m_dirleafblk = xfs_dir2_db_to_da(mp, XFS_DIR2_LEAF_FIRSTDB(mp));
    mp->m_dirfreeblk = xfs_dir2_db_to_da(mp, XFS_DIR2_FREE_FIRSTDB(mp));
    mp->m_attr_node_ents =
        (mp->m_sb.sb_blocksize - (uint)sizeof(xfs_da_node_hdr_t)) /
        (uint)sizeof(xfs_da_node_entry_t);
    mp->m_dir_node_ents =
        (mp->m_dirblksize - (uint)sizeof(xfs_da_node_hdr_t)) /
        (uint)sizeof(xfs_da_node_entry_t);
    mp->m_dir_magicpct = (mp->m_dirblksize * 37) / 100;
    if (xfs_sb_version_hasasciici(&mp->m_sb))
        mp->m_dirnameops = &xfs_ascii_ci_nameops;
    else
        mp->m_dirnameops = &xfs_default_nameops;
}

/*
 * Return 1 if directory contains only "." and "..".
 */
int
xfs_dir_isempty(
    xfs_inode_t *dp)
{
    xfs_dir2_sf_hdr_t   *sfp;

    ASSERT(S_ISDIR(dp->i_d.di_mode));
    if (dp->i_d.di_size == 0)   /* might happen during shutdown. */
        return 1;
    if (dp->i_d.di_size > XFS_IFORK_DSIZE(dp))
        return 0;
    sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
    return !sfp->count;
}

/*
 * Validate a given inode number.
 */
int
xfs_dir_ino_validate(
    xfs_mount_t *mp,
    xfs_ino_t   ino)
{
    xfs_agblock_t   agblkno;
    xfs_agino_t agino;
    xfs_agnumber_t  agno;
    int     ino_ok;
    int     ioff;

    agno = XFS_INO_TO_AGNO(mp, ino);
    agblkno = XFS_INO_TO_AGBNO(mp, ino);
    ioff = XFS_INO_TO_OFFSET(mp, ino);
    agino = XFS_OFFBNO_TO_AGINO(mp, agblkno, ioff);
    ino_ok =
        agno < mp->m_sb.sb_agcount &&
        agblkno < mp->m_sb.sb_agblocks &&
        agblkno != 0 &&
        ioff < (1 << mp->m_sb.sb_inopblog) &&
        XFS_AGINO_TO_INO(mp, agno, agino) == ino;
    if (unlikely(XFS_TEST_ERROR(!ino_ok, mp, XFS_ERRTAG_DIR_INO_VALIDATE,
            XFS_RANDOM_DIR_INO_VALIDATE))) {
        xfs_warn(mp, "Invalid inode number 0x%Lx",
                (unsigned long long) ino);
        XFS_ERROR_REPORT("xfs_dir_ino_validate", XFS_ERRLEVEL_LOW, mp);
        return XFS_ERROR(EFSCORRUPTED);
    }
    return 0;
}

/*
 * Initialize a directory with its "." and ".." entries.
 */
int
xfs_dir_init(
    xfs_trans_t *tp,
    xfs_inode_t *dp,
    xfs_inode_t *pdp)
{
    xfs_da_args_t   args;
    int     error;

    memset((char *)&args, 0, sizeof(args));
    args.dp = dp;
    args.trans = tp;
    ASSERT(S_ISDIR(dp->i_d.di_mode));
    if ((error = xfs_dir_ino_validate(tp->t_mountp, pdp->i_ino)))
        return error;
    return xfs_dir2_sf_create(&args, pdp->i_ino);
}

/*
  Enter a name in a directory.
 */
int
xfs_dir_createname(
    xfs_trans_t     *tp,
    xfs_inode_t     *dp,
    struct xfs_name     *name,
    xfs_ino_t       inum,       /* new entry inode number */
    xfs_fsblock_t       *first,     /* bmap's firstblock */
    xfs_bmap_free_t     *flist,     /* bmap's freeblock list */
    xfs_extlen_t        total)      /* bmap's total block count */
{
    xfs_da_args_t       args;
    int         rval;
    int         v;      /* type-checking value */

    ASSERT(S_ISDIR(dp->i_d.di_mode));
    if ((rval = xfs_dir_ino_validate(tp->t_mountp, inum)))
        return rval;
    XFS_STATS_INC(xs_dir_create);

    memset(&args, 0, sizeof(xfs_da_args_t));
    args.name = name->name;
    args.namelen = name->len;
    args.hashval = dp->i_mount->m_dirnameops->hashname(name);
    args.inumber = inum;
    args.dp = dp;
    args.firstblock = first;
    args.flist = flist;
    args.total = total;
    args.whichfork = XFS_DATA_FORK;
    args.trans = tp;
    args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;

    if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
        rval = xfs_dir2_sf_addname(&args);
    else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_block_addname(&args);
    else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_leaf_addname(&args);
    else
        rval = xfs_dir2_node_addname(&args);
    return rval;
}

/*
 * If doing a CI lookup and case-insensitive match, dup actual name into
 * args.value. Return EEXIST for success (ie. name found) or an error.
 */
int
xfs_dir_cilookup_result(
    struct xfs_da_args *args,
    const unsigned char *name,
    int     len)
{
    if (args->cmpresult == XFS_CMP_DIFFERENT)
        return ENOENT;
    if (args->cmpresult != XFS_CMP_CASE ||
                    !(args->op_flags & XFS_DA_OP_CILOOKUP))
        return EEXIST;

    args->value = kmem_alloc(len, KM_NOFS | KM_MAYFAIL);
    if (!args->value)
        return ENOMEM;

    memcpy(args->value, name, len);
    args->valuelen = len;
    return EEXIST;
}

/*
 * Lookup a name in a directory, give back the inode number.
 * If ci_name is not NULL, returns the actual name in ci_name if it differs
 * to name, or ci_name->name is set to NULL for an exact match.
 */

int
xfs_dir_lookup(
    xfs_trans_t *tp,
    xfs_inode_t *dp,
    struct xfs_name *name,
    xfs_ino_t   *inum,      /* out: inode number */
    struct xfs_name *ci_name)   /* out: actual name if CI match */
{
    xfs_da_args_t   args;
    int     rval;
    int     v;      /* type-checking value */

    ASSERT(S_ISDIR(dp->i_d.di_mode));
    XFS_STATS_INC(xs_dir_lookup);

    memset(&args, 0, sizeof(xfs_da_args_t));
    args.name = name->name;
    args.namelen = name->len;
    args.hashval = dp->i_mount->m_dirnameops->hashname(name);
    args.dp = dp;
    args.whichfork = XFS_DATA_FORK;
    args.trans = tp;
    args.op_flags = XFS_DA_OP_OKNOENT;
    if (ci_name)
        args.op_flags |= XFS_DA_OP_CILOOKUP;

    if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
        rval = xfs_dir2_sf_lookup(&args);
    else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_block_lookup(&args);
    else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_leaf_lookup(&args);
    else
        rval = xfs_dir2_node_lookup(&args);
    if (rval == EEXIST)
        rval = 0;
    if (!rval) {
        *inum = args.inumber;
        if (ci_name) {
            ci_name->name = args.value;
            ci_name->len = args.valuelen;
        }
    }
    return rval;
}

/*
 * Remove an entry from a directory.
 */
int
xfs_dir_removename(
    xfs_trans_t *tp,
    xfs_inode_t *dp,
    struct xfs_name *name,
    xfs_ino_t   ino,
    xfs_fsblock_t   *first,     /* bmap's firstblock */
    xfs_bmap_free_t *flist,     /* bmap's freeblock list */
    xfs_extlen_t    total)      /* bmap's total block count */
{
    xfs_da_args_t   args;
    int     rval;
    int     v;      /* type-checking value */

    ASSERT(S_ISDIR(dp->i_d.di_mode));
    XFS_STATS_INC(xs_dir_remove);

    memset(&args, 0, sizeof(xfs_da_args_t));
    args.name = name->name;
    args.namelen = name->len;
    args.hashval = dp->i_mount->m_dirnameops->hashname(name);
    args.inumber = ino;
    args.dp = dp;
    args.firstblock = first;
    args.flist = flist;
    args.total = total;
    args.whichfork = XFS_DATA_FORK;
    args.trans = tp;

    if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
        rval = xfs_dir2_sf_removename(&args);
    else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_block_removename(&args);
    else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_leaf_removename(&args);
    else
        rval = xfs_dir2_node_removename(&args);
    return rval;
}

/*
 * Read a directory.
 */
int
xfs_readdir(
    xfs_inode_t *dp,
    void        *dirent,
    size_t      bufsize,
    xfs_off_t   *offset,
    filldir_t   filldir)
{
    int     rval;       /* return value */
    int     v;      /* type-checking value */

    trace_xfs_readdir(dp);

    if (XFS_FORCED_SHUTDOWN(dp->i_mount))
        return XFS_ERROR(EIO);

    ASSERT(S_ISDIR(dp->i_d.di_mode));
    XFS_STATS_INC(xs_dir_getdents);

    if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
        rval = xfs_dir2_sf_getdents(dp, dirent, offset, filldir);
    else if ((rval = xfs_dir2_isblock(NULL, dp, &v)))
        ;
    else if (v)
        rval = xfs_dir2_block_getdents(dp, dirent, offset, filldir);
    else
        rval = xfs_dir2_leaf_getdents(dp, dirent, bufsize, offset,
                          filldir);
    return rval;
}

/*
 * Replace the inode number of a directory entry.
 */
int
xfs_dir_replace(
    xfs_trans_t *tp,
    xfs_inode_t *dp,
    struct xfs_name *name,      /* name of entry to replace */
    xfs_ino_t   inum,       /* new inode number */
    xfs_fsblock_t   *first,     /* bmap's firstblock */
    xfs_bmap_free_t *flist,     /* bmap's freeblock list */
    xfs_extlen_t    total)      /* bmap's total block count */
{
    xfs_da_args_t   args;
    int     rval;
    int     v;      /* type-checking value */

    ASSERT(S_ISDIR(dp->i_d.di_mode));

    if ((rval = xfs_dir_ino_validate(tp->t_mountp, inum)))
        return rval;

    memset(&args, 0, sizeof(xfs_da_args_t));
    args.name = name->name;
    args.namelen = name->len;
    args.hashval = dp->i_mount->m_dirnameops->hashname(name);
    args.inumber = inum;
    args.dp = dp;
    args.firstblock = first;
    args.flist = flist;
    args.total = total;
    args.whichfork = XFS_DATA_FORK;
    args.trans = tp;

    if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
        rval = xfs_dir2_sf_replace(&args);
    else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_block_replace(&args);
    else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_leaf_replace(&args);
    else
        rval = xfs_dir2_node_replace(&args);
    return rval;
}

/*
 * See if this entry can be added to the directory without allocating space.
 * First checks that the caller couldn't reserve enough space (resblks = 0).
 */
int
xfs_dir_canenter(
    xfs_trans_t *tp,
    xfs_inode_t *dp,
    struct xfs_name *name,      /* name of entry to add */
    uint        resblks)
{
    xfs_da_args_t   args;
    int     rval;
    int     v;      /* type-checking value */

    if (resblks)
        return 0;

    ASSERT(S_ISDIR(dp->i_d.di_mode));

    memset(&args, 0, sizeof(xfs_da_args_t));
    args.name = name->name;
    args.namelen = name->len;
    args.hashval = dp->i_mount->m_dirnameops->hashname(name);
    args.dp = dp;
    args.whichfork = XFS_DATA_FORK;
    args.trans = tp;
    args.op_flags = XFS_DA_OP_JUSTCHECK | XFS_DA_OP_ADDNAME |
                            XFS_DA_OP_OKNOENT;

    if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
        rval = xfs_dir2_sf_addname(&args);
    else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_block_addname(&args);
    else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
        return rval;
    else if (v)
        rval = xfs_dir2_leaf_addname(&args);
    else
        rval = xfs_dir2_node_addname(&args);
    return rval;
}

/*
 * Utility routines.
 */

/*
 * Add a block to the directory.
 *
 * This routine is for data and free blocks, not leaf/node blocks which are
 * handled by xfs_da_grow_inode.
 */
int
xfs_dir2_grow_inode(
    struct xfs_da_args  *args,
    int         space,  /* v2 dir's space XFS_DIR2_xxx_SPACE */
    xfs_dir2_db_t       *dbp)   /* out: block number added */
{
    struct xfs_inode    *dp = args->dp;
    struct xfs_mount    *mp = dp->i_mount;
    xfs_fileoff_t       bno;    /* directory offset of new block */
    int         count;  /* count of filesystem blocks */
    int         error;

    trace_xfs_dir2_grow_inode(args, space);

    /*
     * Set lowest possible block in the space requested.
     */
    bno = XFS_B_TO_FSBT(mp, space * XFS_DIR2_SPACE_SIZE);
    count = mp->m_dirblkfsbs;

    error = xfs_da_grow_inode_int(args, &bno, count);
    if (error)
        return error;

    *dbp = xfs_dir2_da_to_db(mp, (xfs_dablk_t)bno);

    /*
     * Update file's size if this is the data space and it grew.
     */
    if (space == XFS_DIR2_DATA_SPACE) {
        xfs_fsize_t size;       /* directory file (data) size */

        size = XFS_FSB_TO_B(mp, bno + count);
        if (size > dp->i_d.di_size) {
            dp->i_d.di_size = size;
            xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);
        }
    }
    return 0;
}

/*
 * See if the directory is a single-block form directory.
 */
int
xfs_dir2_isblock(
    xfs_trans_t *tp,
    xfs_inode_t *dp,
    int     *vp)        /* out: 1 is block, 0 is not block */
{
    xfs_fileoff_t   last;       /* last file offset */
    xfs_mount_t *mp;
    int     rval;

    mp = dp->i_mount;
    if ((rval = xfs_bmap_last_offset(tp, dp, &last, XFS_DATA_FORK)))
        return rval;
    rval = XFS_FSB_TO_B(mp, last) == mp->m_dirblksize;
    ASSERT(rval == 0 || dp->i_d.di_size == mp->m_dirblksize);
    *vp = rval;
    return 0;
}

/*
 * See if the directory is a single-leaf form directory.
 */
int
xfs_dir2_isleaf(
    xfs_trans_t *tp,
    xfs_inode_t *dp,
    int     *vp)        /* out: 1 is leaf, 0 is not leaf */
{
    xfs_fileoff_t   last;       /* last file offset */
    xfs_mount_t *mp;
    int     rval;

    mp = dp->i_mount;
    if ((rval = xfs_bmap_last_offset(tp, dp, &last, XFS_DATA_FORK)))
        return rval;
    *vp = last == mp->m_dirleafblk + (1 << mp->m_sb.sb_dirblklog);
    return 0;
}

/*
 * Remove the given block from the directory.
 * This routine is used for data and free blocks, leaf/node are done
 * by xfs_da_shrink_inode.
 */
int
xfs_dir2_shrink_inode(
    xfs_da_args_t   *args,
    xfs_dir2_db_t   db,
    struct xfs_buf  *bp)
{
    xfs_fileoff_t   bno;        /* directory file offset */
    xfs_dablk_t da;     /* directory file offset */
    int     done;       /* bunmap is finished */
    xfs_inode_t *dp;
    int     error;
    xfs_mount_t *mp;
    xfs_trans_t *tp;

    trace_xfs_dir2_shrink_inode(args, db);

    dp = args->dp;
    mp = dp->i_mount;
    tp = args->trans;
    da = xfs_dir2_db_to_da(mp, db);
    /*
     * Unmap the fsblock(s).
     */
    if ((error = xfs_bunmapi(tp, dp, da, mp->m_dirblkfsbs,
            XFS_BMAPI_METADATA, 0, args->firstblock, args->flist,
            &done))) {
        /*
         * ENOSPC actually can happen if we're in a removename with
         * no space reservation, and the resulting block removal
         * would cause a bmap btree split or conversion from extents
         * to btree.  This can only happen for un-fragmented
         * directory blocks, since you need to be punching out
         * the middle of an extent.
         * In this case we need to leave the block in the file,
         * and not binval it.
         * So the block has to be in a consistent empty state
         * and appropriately logged.
         * We don't free up the buffer, the caller can tell it
         * hasn't happened since it got an error back.
         */
        return error;
    }
    ASSERT(done);
    /*
     * Invalidate the buffer from the transaction.
     */
    xfs_trans_binval(tp, bp);
    /*
     * If it's not a data block, we're done.
     */
    if (db >= XFS_DIR2_LEAF_FIRSTDB(mp))
        return 0;
    /*
     * If the block isn't the last one in the directory, we're done.
     */
    if (dp->i_d.di_size > xfs_dir2_db_off_to_byte(mp, db + 1, 0))
        return 0;
    bno = da;
    if ((error = xfs_bmap_last_before(tp, dp, &bno, XFS_DATA_FORK))) {
        /*
         * This can't really happen unless there's kernel corruption.
         */
        return error;
    }
    if (db == mp->m_dirdatablk)
        ASSERT(bno == 0);
    else
        ASSERT(bno > 0);
    /*
     * Set the size to the new last block.
     */
    dp->i_d.di_size = XFS_FSB_TO_B(mp, bno);
    xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
    return 0;
}