[mirror_ubuntu-jammy-kernel.git] / fs / xfs / libxfs / xfs_dir2.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_errortag.h"
#include "xfs_error.h"
#include "xfs_trace.h"

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

/*
 * Convert inode mode to directory entry filetype
 */
unsigned char
xfs_mode_to_ftype(
        int             mode)
{
        switch (mode & S_IFMT) {
        case S_IFREG:
                return XFS_DIR3_FT_REG_FILE;
        case S_IFDIR:
                return XFS_DIR3_FT_DIR;
        case S_IFCHR:
                return XFS_DIR3_FT_CHRDEV;
        case S_IFBLK:
                return XFS_DIR3_FT_BLKDEV;
        case S_IFIFO:
                return XFS_DIR3_FT_FIFO;
        case S_IFSOCK:
                return XFS_DIR3_FT_SOCK;
        case S_IFLNK:
                return XFS_DIR3_FT_SYMLINK;
        default:
                return XFS_DIR3_FT_UNKNOWN;
        }
}

/*
 * ASCII case-insensitive (ie. A-Z) support for directories that was
 * used in IRIX.
 */
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;
}

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;
}

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


        ASSERT(mp->m_sb.sb_versionnum & XFS_SB_VERSION_DIRV2BIT);
        ASSERT(xfs_dir2_dirblock_bytes(&mp->m_sb) <= XFS_MAX_BLOCKSIZE);

        mp->m_dir_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
                                    KM_MAYFAIL);
        mp->m_attr_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
                                     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 = xfs_dir2_dirblock_bytes(&mp->m_sb);
        dageo->fsbcount = 1 << mp->m_sb.sb_dirblklog;
        if (xfs_has_crc(mp)) {
                dageo->node_hdr_size = sizeof(struct xfs_da3_node_hdr);
                dageo->leaf_hdr_size = sizeof(struct xfs_dir3_leaf_hdr);
                dageo->free_hdr_size = sizeof(struct xfs_dir3_free_hdr);
                dageo->data_entry_offset =
                                sizeof(struct xfs_dir3_data_hdr);
        } else {
                dageo->node_hdr_size = sizeof(struct xfs_da_node_hdr);
                dageo->leaf_hdr_size = sizeof(struct xfs_dir2_leaf_hdr);
                dageo->free_hdr_size = sizeof(struct xfs_dir2_free_hdr);
                dageo->data_entry_offset =
                                sizeof(struct xfs_dir2_data_hdr);
        }
        dageo->leaf_max_ents = (dageo->blksize - dageo->leaf_hdr_size) /
                        sizeof(struct xfs_dir2_leaf_entry);
        dageo->free_max_bests = (dageo->blksize - dageo->free_hdr_size) /
                        sizeof(xfs_dir2_data_off_t);

        dageo->data_first_offset = dageo->data_entry_offset +
                        xfs_dir2_data_entsize(mp, 1) +
                        xfs_dir2_data_entsize(mp, 2);

        /*
         * 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 - dageo->node_hdr_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_hdr_size = mp->m_dir_geo->node_hdr_size;
        dageo->node_ents = (dageo->blksize - dageo->node_hdr_size) /
                                (uint)sizeof(xfs_da_node_entry_t);
        dageo->magicpct = (dageo->blksize * 37) / 100;
        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_disk_size == 0)       /* might happen during shutdown. */
                return 1;
        if (dp->i_disk_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)
{
        bool            ino_ok = xfs_verify_dir_ino(mp, ino);

        if (XFS_IS_CORRUPT(mp, !ino_ok) ||
            XFS_TEST_ERROR(false, mp, XFS_ERRTAG_DIR_INO_VALIDATE)) {
                xfs_warn(mp, "Invalid inode number 0x%Lx",
                                (unsigned long long) ino);
                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_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(
        struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        struct xfs_name         *name,
        xfs_ino_t               inum,           /* new entry inode number */
        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_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 = xfs_dir2_hashname(dp->i_mount, name);
        args->inumber = inum;
        args->dp = dp;
        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_df.if_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_NOFS);
        args->geo = dp->i_mount->m_dir_geo;
        args->name = name->name;
        args->namelen = name->len;
        args->filetype = name->type;
        args->hashval = xfs_dir2_hashname(dp->i_mount, 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_df.if_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(
        struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        struct xfs_name         *name,
        xfs_ino_t               ino,
        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_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 = xfs_dir2_hashname(dp->i_mount, name);
        args->inumber = ino;
        args->dp = dp;
        args->total = total;
        args->whichfork = XFS_DATA_FORK;
        args->trans = tp;

        if (dp->i_df.if_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(
        struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        struct xfs_name         *name,          /* name of entry to replace */
        xfs_ino_t               inum,           /* new inode number */
        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_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 = xfs_dir2_hashname(dp->i_mount, name);
        args->inumber = inum;
        args->dp = dp;
        args->total = total;
        args->whichfork = XFS_DATA_FORK;
        args->trans = tp;

        if (dp->i_df.if_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, 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_disk_size) {
                        dp->i_disk_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;
        if (XFS_IS_CORRUPT(args->dp->i_mount,
                           rval != 0 &&
                           args->dp->i_disk_size != args->geo->blksize))
                return -EFSCORRUPTED;
        *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(
        struct xfs_da_args      *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 */
        struct xfs_inode        *dp;
        int                     error;
        struct xfs_mount        *mp;
        struct xfs_trans        *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, &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_disk_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_disk_size = XFS_FSB_TO_B(mp, bno);
        xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
        return 0;
}

/* Returns true if the directory entry name is valid. */
bool
xfs_dir2_namecheck(
        const void      *name,
        size_t          length)
{
        /*
         * MAXNAMELEN includes the trailing null, but (name/length) leave it
         * out, so use >= for the length check.
         */
        if (length >= MAXNAMELEN)
                return false;

        /* There shouldn't be any slashes or nulls here */
        return !memchr(name, '/', length) && !memchr(name, 0, length);
}

xfs_dahash_t
xfs_dir2_hashname(
        struct xfs_mount        *mp,
        struct xfs_name         *name)
{
        if (unlikely(xfs_has_asciici(mp)))
                return xfs_ascii_ci_hashname(name);
        return xfs_da_hashname(name->name, name->len);
}

enum xfs_dacmp
xfs_dir2_compname(
        struct xfs_da_args      *args,
        const unsigned char     *name,
        int                     len)
{
        if (unlikely(xfs_has_asciici(args->dp->i_mount)))
                return xfs_ascii_ci_compname(args, name, len);
        return xfs_da_compname(args, name, len);
}