fs: xfs: libxfs: constify xfs_nameops structures

[thirdparty/xfsprogs-dev.git] / libxfs / xfs_dir2.c

/*
 * 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 "libxfs_priv.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_trace.h"

struct xfs_name xfs_name_dotdot = { (unsigned char *)"..", 2, XFS_DIR3_FT_DIR };

/*
 * @mode, if set, indicates that the type field needs to be set up.
 * This uses the transformation from file mode to DT_* as defined in linux/fs.h
 * for file type specification. This will be propagated into the directory
 * structure if appropriate for the given operation and filesystem config.
 */
const unsigned char xfs_mode_to_ftype[S_IFMT >> S_SHIFT] = {
        [0]                     = XFS_DIR3_FT_UNKNOWN,
        [S_IFREG >> S_SHIFT]    = XFS_DIR3_FT_REG_FILE,
        [S_IFDIR >> S_SHIFT]    = XFS_DIR3_FT_DIR,
        [S_IFCHR >> S_SHIFT]    = XFS_DIR3_FT_CHRDEV,
        [S_IFBLK >> S_SHIFT]    = XFS_DIR3_FT_BLKDEV,
        [S_IFIFO >> S_SHIFT]    = XFS_DIR3_FT_FIFO,
        [S_IFSOCK >> S_SHIFT]   = XFS_DIR3_FT_SOCK,
        [S_IFLNK >> S_SHIFT]    = XFS_DIR3_FT_SYMLINK,
};

/*
 * 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 const struct xfs_nameops xfs_ascii_ci_nameops = {
        .hashname       = xfs_ascii_ci_hashname,
        .compname       = xfs_ascii_ci_compname,
};

int
xfs_da_mount(
        struct xfs_mount        *mp)
{
        struct xfs_da_geometry  *dageo;
        int                     nodehdr_size;


        ASSERT(mp->m_sb.sb_versionnum & XFS_SB_VERSION_DIRV2BIT);
        ASSERT((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) <=
               XFS_MAX_BLOCKSIZE);

        mp->m_dir_inode_ops = xfs_dir_get_ops(mp, NULL);
        mp->m_nondir_inode_ops = xfs_nondir_get_ops(mp, NULL);

        nodehdr_size = mp->m_dir_inode_ops->node_hdr_size;
        mp->m_dir_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
                                    KM_SLEEP | KM_MAYFAIL);
        mp->m_attr_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
                                     KM_SLEEP | KM_MAYFAIL);
        if (!mp->m_dir_geo || !mp->m_attr_geo) {
                kmem_free(mp->m_dir_geo);
                kmem_free(mp->m_attr_geo);
                return -ENOMEM;
        }

        /* set up directory geometry */
        dageo = mp->m_dir_geo;
        dageo->blklog = mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog;
        dageo->fsblog = mp->m_sb.sb_blocklog;
        dageo->blksize = 1 << dageo->blklog;
        dageo->fsbcount = 1 << mp->m_sb.sb_dirblklog;

        /*
         * Now we've set up the block conversion variables, we can calculate the
         * segment block constants using the geometry structure.
         */
        dageo->datablk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_DATA_OFFSET);
        dageo->leafblk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_LEAF_OFFSET);
        dageo->freeblk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_FREE_OFFSET);
        dageo->node_ents = (dageo->blksize - nodehdr_size) /
                                (uint)sizeof(xfs_da_node_entry_t);
        dageo->magicpct = (dageo->blksize * 37) / 100;

        /* set up attribute geometry - single fsb only */
        dageo = mp->m_attr_geo;
        dageo->blklog = mp->m_sb.sb_blocklog;
        dageo->fsblog = mp->m_sb.sb_blocklog;
        dageo->blksize = 1 << dageo->blklog;
        dageo->fsbcount = 1;
        dageo->node_ents = (dageo->blksize - nodehdr_size) /
                                (uint)sizeof(xfs_da_node_entry_t);
        dageo->magicpct = (dageo->blksize * 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 0;
}

void
xfs_da_unmount(
        struct xfs_mount        *mp)
{
        kmem_free(mp->m_dir_geo);
        kmem_free(mp->m_attr_geo);
}

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

        ASSERT(S_ISDIR(VFS_I(dp)->i_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 -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)
{
        struct xfs_da_args *args;
        int             error;

        ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
        error = xfs_dir_ino_validate(tp->t_mountp, pdp->i_ino);
        if (error)
                return error;

        args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
        if (!args)
                return -ENOMEM;

        args->geo = dp->i_mount->m_dir_geo;
        args->dp = dp;
        args->trans = tp;
        error = xfs_dir2_sf_create(args, pdp->i_ino);
        kmem_free(args);
        return error;
}

/*
 * Enter a name in a directory, or check for available space.
 * If inum is 0, only the available space test is performed.
 */
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 */
        struct xfs_defer_ops    *dfops,         /* bmap's freeblock list */
        xfs_extlen_t            total)          /* bmap's total block count */
{
        struct xfs_da_args      *args;
        int                     rval;
        int                     v;              /* type-checking value */

        ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
        if (inum) {
                rval = xfs_dir_ino_validate(tp->t_mountp, inum);
                if (rval)
                        return rval;
                XFS_STATS_INC(dp->i_mount, xs_dir_create);
        }

        args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
        if (!args)
                return -ENOMEM;

        args->geo = dp->i_mount->m_dir_geo;
        args->name = name->name;
        args->namelen = name->len;
        args->filetype = name->type;
        args->hashval = dp->i_mount->m_dirnameops->hashname(name);
        args->inumber = inum;
        args->dp = dp;
        args->firstblock = first;
        args->dfops = dfops;
        args->total = total;
        args->whichfork = XFS_DATA_FORK;
        args->trans = tp;
        args->op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
        if (!inum)
                args->op_flags |= XFS_DA_OP_JUSTCHECK;

        if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
                rval = xfs_dir2_sf_addname(args);
                goto out_free;
        }

        rval = xfs_dir2_isblock(args, &v);
        if (rval)
                goto out_free;
        if (v) {
                rval = xfs_dir2_block_addname(args);
                goto out_free;
        }

        rval = xfs_dir2_isleaf(args, &v);
        if (rval)
                goto out_free;
        if (v)
                rval = xfs_dir2_leaf_addname(args);
        else
                rval = xfs_dir2_node_addname(args);

out_free:
        kmem_free(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 */
{
        struct xfs_da_args *args;
        int             rval;
        int             v;              /* type-checking value */
        int             lock_mode;

        ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
        XFS_STATS_INC(dp->i_mount, xs_dir_lookup);

        /*
         * We need to use KM_NOFS here so that lockdep will not throw false
         * positive deadlock warnings on a non-transactional lookup path. It is
         * safe to recurse into inode recalim in that case, but lockdep can't
         * easily be taught about it. Hence KM_NOFS avoids having to add more
         * lockdep Doing this avoids having to add a bunch of lockdep class
         * annotations into the reclaim path for the ilock.
         */
        args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
        args->geo = dp->i_mount->m_dir_geo;
        args->name = name->name;
        args->namelen = name->len;
        args->filetype = name->type;
        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;

        lock_mode = xfs_ilock_data_map_shared(dp);
        if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
                rval = xfs_dir2_sf_lookup(args);
                goto out_check_rval;
        }

        rval = xfs_dir2_isblock(args, &v);
        if (rval)
                goto out_free;
        if (v) {
                rval = xfs_dir2_block_lookup(args);
                goto out_check_rval;
        }

        rval = xfs_dir2_isleaf(args, &v);
        if (rval)
                goto out_free;
        if (v)
                rval = xfs_dir2_leaf_lookup(args);
        else
                rval = xfs_dir2_node_lookup(args);

out_check_rval:
        if (rval == -EEXIST)
                rval = 0;
        if (!rval) {
                *inum = args->inumber;
                if (ci_name) {
                        ci_name->name = args->value;
                        ci_name->len = args->valuelen;
                }
        }
out_free:
        xfs_iunlock(dp, lock_mode);
        kmem_free(args);
        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 */
        struct xfs_defer_ops    *dfops,         /* bmap's freeblock list */
        xfs_extlen_t    total)          /* bmap's total block count */
{
        struct xfs_da_args *args;
        int             rval;
        int             v;              /* type-checking value */

        ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
        XFS_STATS_INC(dp->i_mount, xs_dir_remove);

        args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
        if (!args)
                return -ENOMEM;

        args->geo = dp->i_mount->m_dir_geo;
        args->name = name->name;
        args->namelen = name->len;
        args->filetype = name->type;
        args->hashval = dp->i_mount->m_dirnameops->hashname(name);
        args->inumber = ino;
        args->dp = dp;
        args->firstblock = first;
        args->dfops = dfops;
        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);
                goto out_free;
        }

        rval = xfs_dir2_isblock(args, &v);
        if (rval)
                goto out_free;
        if (v) {
                rval = xfs_dir2_block_removename(args);
                goto out_free;
        }

        rval = xfs_dir2_isleaf(args, &v);
        if (rval)
                goto out_free;
        if (v)
                rval = xfs_dir2_leaf_removename(args);
        else
                rval = xfs_dir2_node_removename(args);
out_free:
        kmem_free(args);
        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 */
        struct xfs_defer_ops    *dfops,         /* bmap's freeblock list */
        xfs_extlen_t    total)          /* bmap's total block count */
{
        struct xfs_da_args *args;
        int             rval;
        int             v;              /* type-checking value */

        ASSERT(S_ISDIR(VFS_I(dp)->i_mode));

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

        args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
        if (!args)
                return -ENOMEM;

        args->geo = dp->i_mount->m_dir_geo;
        args->name = name->name;
        args->namelen = name->len;
        args->filetype = name->type;
        args->hashval = dp->i_mount->m_dirnameops->hashname(name);
        args->inumber = inum;
        args->dp = dp;
        args->firstblock = first;
        args->dfops = dfops;
        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);
                goto out_free;
        }

        rval = xfs_dir2_isblock(args, &v);
        if (rval)
                goto out_free;
        if (v) {
                rval = xfs_dir2_block_replace(args);
                goto out_free;
        }

        rval = xfs_dir2_isleaf(args, &v);
        if (rval)
                goto out_free;
        if (v)
                rval = xfs_dir2_leaf_replace(args);
        else
                rval = xfs_dir2_node_replace(args);
out_free:
        kmem_free(args);
        return rval;
}

/*
 * See if this entry can be added to the directory without allocating space.
 */
int
xfs_dir_canenter(
        xfs_trans_t     *tp,
        xfs_inode_t     *dp,
        struct xfs_name *name)          /* name of entry to add */
{
        return xfs_dir_createname(tp, dp, name, 0, NULL, NULL, 0);
}

/*
 * 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 = args->geo->fsbcount;

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

        *dbp = xfs_dir2_da_to_db(args->geo, (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(
        struct xfs_da_args      *args,
        int                     *vp)    /* out: 1 is block, 0 is not block */
{
        xfs_fileoff_t           last;   /* last file offset */
        int                     rval;

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

/*
 * See if the directory is a single-leaf form directory.
 */
int
xfs_dir2_isleaf(
        struct xfs_da_args      *args,
        int                     *vp)    /* out: 1 is block, 0 is not block */
{
        xfs_fileoff_t           last;   /* last file offset */
        int                     rval;

        if ((rval = xfs_bmap_last_offset(args->dp, &last, XFS_DATA_FORK)))
                return rval;
        *vp = last == args->geo->leafblk + args->geo->fsbcount;
        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(args->geo, db);

        /* Unmap the fsblock(s). */
        error = xfs_bunmapi(tp, dp, da, args->geo->fsbcount, 0, 0,
                            args->firstblock, args->dfops, &done);
        if (error) {
                /*
                 * 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_byte_to_db(args->geo, XFS_DIR2_LEAF_OFFSET))
                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(args->geo, 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 == args->geo->datablk)
                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;
}