// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_btree.h"
#include "xfs_log_format.h"
#include "xfs_inode.h"
#include "xfs_ialloc.h"
#include "xfs_da_format.h"
#include "xfs_reflink.h"
#include "xfs_rmap.h"
#include "xfs_bmap_util.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/btree.h"

/*
 * Grab total control of the inode metadata.  It doesn't matter here if
 * the file data is still changing; exclusive access to the metadata is
 * the goal.
 */
int
xchk_setup_inode(
        struct xfs_scrub        *sc,
        struct xfs_inode        *ip)
{
        int                     error;

        /*
         * Try to get the inode.  If the verifiers fail, we try again
         * in raw mode.
         */
        error = xchk_get_inode(sc, ip);
        switch (error) {
        case 0:
                break;
        case -EFSCORRUPTED:
        case -EFSBADCRC:
                return xchk_trans_alloc(sc, 0);
        default:
                return error;
        }

        /* Got the inode, lock it and we're ready to go. */
        sc->ilock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
        xfs_ilock(sc->ip, sc->ilock_flags);
        error = xchk_trans_alloc(sc, 0);
        if (error)
                goto out;
        sc->ilock_flags |= XFS_ILOCK_EXCL;
        xfs_ilock(sc->ip, XFS_ILOCK_EXCL);

out:
        /* scrub teardown will unlock and release the inode for us */
        return error;
}

/* Inode core */

/* Validate di_extsize hint. */
STATIC void
xchk_inode_extsize(
        struct xfs_scrub        *sc,
        struct xfs_dinode       *dip,
        xfs_ino_t               ino,
        uint16_t                mode,
        uint16_t                flags)
{
        xfs_failaddr_t          fa;

        fa = xfs_inode_validate_extsize(sc->mp, be32_to_cpu(dip->di_extsize),
                        mode, flags);
        if (fa)
                xchk_ino_set_corrupt(sc, ino);
}

/*
 * Validate di_cowextsize hint.
 *
 * The rules are documented at xfs_ioctl_setattr_check_cowextsize().
 * These functions must be kept in sync with each other.
 */
STATIC void
xchk_inode_cowextsize(
        struct xfs_scrub        *sc,
        struct xfs_dinode       *dip,
        xfs_ino_t               ino,
        uint16_t                mode,
        uint16_t                flags,
        uint64_t                flags2)
{
        xfs_failaddr_t          fa;

        fa = xfs_inode_validate_cowextsize(sc->mp,
                        be32_to_cpu(dip->di_cowextsize), mode, flags,
                        flags2);
        if (fa)
                xchk_ino_set_corrupt(sc, ino);
}

/* Make sure the di_flags make sense for the inode. */
STATIC void
xchk_inode_flags(
        struct xfs_scrub        *sc,
        struct xfs_dinode       *dip,
        xfs_ino_t               ino,
        uint16_t                mode,
        uint16_t                flags)
{
        struct xfs_mount        *mp = sc->mp;

        /* di_flags are all taken, last bit cannot be used */
        if (flags & ~XFS_DIFLAG_ANY)
                goto bad;

        /* rt flags require rt device */
        if ((flags & (XFS_DIFLAG_REALTIME | XFS_DIFLAG_RTINHERIT)) &&
            !mp->m_rtdev_targp)
                goto bad;

        /* new rt bitmap flag only valid for rbmino */
        if ((flags & XFS_DIFLAG_NEWRTBM) && ino != mp->m_sb.sb_rbmino)
                goto bad;

        /* directory-only flags */
        if ((flags & (XFS_DIFLAG_RTINHERIT |
                     XFS_DIFLAG_EXTSZINHERIT |
                     XFS_DIFLAG_PROJINHERIT |
                     XFS_DIFLAG_NOSYMLINKS)) &&
            !S_ISDIR(mode))
                goto bad;

        /* file-only flags */
        if ((flags & (XFS_DIFLAG_REALTIME | FS_XFLAG_EXTSIZE)) &&
            !S_ISREG(mode))
                goto bad;

        /* filestreams and rt make no sense */
        if ((flags & XFS_DIFLAG_FILESTREAM) && (flags & XFS_DIFLAG_REALTIME))
                goto bad;

        return;
bad:
        xchk_ino_set_corrupt(sc, ino);
}

/* Make sure the di_flags2 make sense for the inode. */
STATIC void
xchk_inode_flags2(
        struct xfs_scrub        *sc,
        struct xfs_dinode       *dip,
        xfs_ino_t               ino,
        uint16_t                mode,
        uint16_t                flags,
        uint64_t                flags2)
{
        struct xfs_mount        *mp = sc->mp;

        /* Unknown di_flags2 could be from a future kernel */
        if (flags2 & ~XFS_DIFLAG2_ANY)
                xchk_ino_set_warning(sc, ino);

        /* reflink flag requires reflink feature */
        if ((flags2 & XFS_DIFLAG2_REFLINK) &&
            !xfs_sb_version_hasreflink(&mp->m_sb))
                goto bad;

        /* cowextsize flag is checked w.r.t. mode separately */

        /* file/dir-only flags */
        if ((flags2 & XFS_DIFLAG2_DAX) && !(S_ISREG(mode) || S_ISDIR(mode)))
                goto bad;

        /* file-only flags */
        if ((flags2 & XFS_DIFLAG2_REFLINK) && !S_ISREG(mode))
                goto bad;

        /* realtime and reflink make no sense, currently */
        if ((flags & XFS_DIFLAG_REALTIME) && (flags2 & XFS_DIFLAG2_REFLINK))
                goto bad;

        /* dax and reflink make no sense, currently */
        if ((flags2 & XFS_DIFLAG2_DAX) && (flags2 & XFS_DIFLAG2_REFLINK))
                goto bad;

        return;
bad:
        xchk_ino_set_corrupt(sc, ino);
}

/* Scrub all the ondisk inode fields. */
STATIC void
xchk_dinode(
        struct xfs_scrub        *sc,
        struct xfs_dinode       *dip,
        xfs_ino_t               ino)
{
        struct xfs_mount        *mp = sc->mp;
        size_t                  fork_recs;
        unsigned long long      isize;
        uint64_t                flags2;
        uint32_t                nextents;
        uint16_t                flags;
        uint16_t                mode;

        flags = be16_to_cpu(dip->di_flags);
        if (dip->di_version >= 3)
                flags2 = be64_to_cpu(dip->di_flags2);
        else
                flags2 = 0;

        /* di_mode */
        mode = be16_to_cpu(dip->di_mode);
        switch (mode & S_IFMT) {
        case S_IFLNK:
        case S_IFREG:
        case S_IFDIR:
        case S_IFCHR:
        case S_IFBLK:
        case S_IFIFO:
        case S_IFSOCK:
                /* mode is recognized */
                break;
        default:
                xchk_ino_set_corrupt(sc, ino);
                break;
        }

        /* v1/v2 fields */
        switch (dip->di_version) {
        case 1:
                /*
                 * We autoconvert v1 inodes into v2 inodes on writeout,
                 * so just mark this inode for preening.
                 */
                xchk_ino_set_preen(sc, ino);
                break;
        case 2:
        case 3:
                if (dip->di_onlink != 0)
                        xchk_ino_set_corrupt(sc, ino);

                if (dip->di_mode == 0 && sc->ip)
                        xchk_ino_set_corrupt(sc, ino);

                if (dip->di_projid_hi != 0 &&
                    !xfs_sb_version_hasprojid32bit(&mp->m_sb))
                        xchk_ino_set_corrupt(sc, ino);
                break;
        default:
                xchk_ino_set_corrupt(sc, ino);
                return;
        }

        /*
         * di_uid/di_gid -- -1 isn't invalid, but there's no way that
         * userspace could have created that.
         */
        if (dip->di_uid == cpu_to_be32(-1U) ||
            dip->di_gid == cpu_to_be32(-1U))
                xchk_ino_set_warning(sc, ino);

        /* di_format */
        switch (dip->di_format) {
        case XFS_DINODE_FMT_DEV:
                if (!S_ISCHR(mode) && !S_ISBLK(mode) &&
                    !S_ISFIFO(mode) && !S_ISSOCK(mode))
                        xchk_ino_set_corrupt(sc, ino);
                break;
        case XFS_DINODE_FMT_LOCAL:
                if (!S_ISDIR(mode) && !S_ISLNK(mode))
                        xchk_ino_set_corrupt(sc, ino);
                break;
        case XFS_DINODE_FMT_EXTENTS:
                if (!S_ISREG(mode) && !S_ISDIR(mode) && !S_ISLNK(mode))
                        xchk_ino_set_corrupt(sc, ino);
                break;
        case XFS_DINODE_FMT_BTREE:
                if (!S_ISREG(mode) && !S_ISDIR(mode))
                        xchk_ino_set_corrupt(sc, ino);
                break;
        case XFS_DINODE_FMT_UUID:
        default:
                xchk_ino_set_corrupt(sc, ino);
                break;
        }

        /* di_[amc]time.nsec */
        if (be32_to_cpu(dip->di_atime.t_nsec) >= NSEC_PER_SEC)
                xchk_ino_set_corrupt(sc, ino);
        if (be32_to_cpu(dip->di_mtime.t_nsec) >= NSEC_PER_SEC)
                xchk_ino_set_corrupt(sc, ino);
        if (be32_to_cpu(dip->di_ctime.t_nsec) >= NSEC_PER_SEC)
                xchk_ino_set_corrupt(sc, ino);

        /*
         * di_size.  xfs_dinode_verify checks for things that screw up
         * the VFS such as the upper bit being set and zero-length
         * symlinks/directories, but we can do more here.
         */
        isize = be64_to_cpu(dip->di_size);
        if (isize & (1ULL << 63))
                xchk_ino_set_corrupt(sc, ino);

        /* Devices, fifos, and sockets must have zero size */
        if (!S_ISDIR(mode) && !S_ISREG(mode) && !S_ISLNK(mode) && isize != 0)
                xchk_ino_set_corrupt(sc, ino);

        /* Directories can't be larger than the data section size (32G) */
        if (S_ISDIR(mode) && (isize == 0 || isize >= XFS_DIR2_SPACE_SIZE))
                xchk_ino_set_corrupt(sc, ino);

        /* Symlinks can't be larger than SYMLINK_MAXLEN */
        if (S_ISLNK(mode) && (isize == 0 || isize >= XFS_SYMLINK_MAXLEN))
                xchk_ino_set_corrupt(sc, ino);

        /*
         * Warn if the running kernel can't handle the kinds of offsets
         * needed to deal with the file size.  In other words, if the
         * pagecache can't cache all the blocks in this file due to
         * overly large offsets, flag the inode for admin review.
         */
        if (isize >= mp->m_super->s_maxbytes)
                xchk_ino_set_warning(sc, ino);

        /* di_nblocks */
        if (flags2 & XFS_DIFLAG2_REFLINK) {
                ; /* nblocks can exceed dblocks */
        } else if (flags & XFS_DIFLAG_REALTIME) {
                /*
                 * nblocks is the sum of data extents (in the rtdev),
                 * attr extents (in the datadev), and both forks' bmbt
                 * blocks (in the datadev).  This clumsy check is the
                 * best we can do without cross-referencing with the
                 * inode forks.
                 */
                if (be64_to_cpu(dip->di_nblocks) >=
                    mp->m_sb.sb_dblocks + mp->m_sb.sb_rblocks)
                        xchk_ino_set_corrupt(sc, ino);
        } else {
                if (be64_to_cpu(dip->di_nblocks) >= mp->m_sb.sb_dblocks)
                        xchk_ino_set_corrupt(sc, ino);
        }

        xchk_inode_flags(sc, dip, ino, mode, flags);

        xchk_inode_extsize(sc, dip, ino, mode, flags);

        /* di_nextents */
        nextents = be32_to_cpu(dip->di_nextents);
        fork_recs =  XFS_DFORK_DSIZE(dip, mp) / sizeof(struct xfs_bmbt_rec);
        switch (dip->di_format) {
        case XFS_DINODE_FMT_EXTENTS:
                if (nextents > fork_recs)
                        xchk_ino_set_corrupt(sc, ino);
                break;
        case XFS_DINODE_FMT_BTREE:
                if (nextents <= fork_recs)
                        xchk_ino_set_corrupt(sc, ino);
                break;
        default:
                if (nextents != 0)
                        xchk_ino_set_corrupt(sc, ino);
                break;
        }

        /* di_forkoff */
        if (XFS_DFORK_APTR(dip) >= (char *)dip + mp->m_sb.sb_inodesize)
                xchk_ino_set_corrupt(sc, ino);
        if (dip->di_anextents != 0 && dip->di_forkoff == 0)
                xchk_ino_set_corrupt(sc, ino);
        if (dip->di_forkoff == 0 && dip->di_aformat != XFS_DINODE_FMT_EXTENTS)
                xchk_ino_set_corrupt(sc, ino);

        /* di_aformat */
        if (dip->di_aformat != XFS_DINODE_FMT_LOCAL &&
            dip->di_aformat != XFS_DINODE_FMT_EXTENTS &&
            dip->di_aformat != XFS_DINODE_FMT_BTREE)
                xchk_ino_set_corrupt(sc, ino);

        /* di_anextents */
        nextents = be16_to_cpu(dip->di_anextents);
        fork_recs =  XFS_DFORK_ASIZE(dip, mp) / sizeof(struct xfs_bmbt_rec);
        switch (dip->di_aformat) {
        case XFS_DINODE_FMT_EXTENTS:
                if (nextents > fork_recs)
                        xchk_ino_set_corrupt(sc, ino);
                break;
        case XFS_DINODE_FMT_BTREE:
                if (nextents <= fork_recs)
                        xchk_ino_set_corrupt(sc, ino);
                break;
        default:
                if (nextents != 0)
                        xchk_ino_set_corrupt(sc, ino);
        }

        if (dip->di_version >= 3) {
                if (be32_to_cpu(dip->di_crtime.t_nsec) >= NSEC_PER_SEC)
                        xchk_ino_set_corrupt(sc, ino);
                xchk_inode_flags2(sc, dip, ino, mode, flags, flags2);
                xchk_inode_cowextsize(sc, dip, ino, mode, flags,
                                flags2);
        }
}

/*
 * Make sure the finobt doesn't think this inode is free.
 * We don't have to check the inobt ourselves because we got the inode via
 * IGET_UNTRUSTED, which checks the inobt for us.
 */
static void
xchk_inode_xref_finobt(
        struct xfs_scrub                *sc,
        xfs_ino_t                       ino)
{
        struct xfs_inobt_rec_incore     rec;
        xfs_agino_t                     agino;
        int                             has_record;
        int                             error;

        if (!sc->sa.fino_cur || xchk_skip_xref(sc->sm))
                return;

        agino = XFS_INO_TO_AGINO(sc->mp, ino);

        /*
         * Try to get the finobt record.  If we can't get it, then we're
         * in good shape.
         */
        error = xfs_inobt_lookup(sc->sa.fino_cur, agino, XFS_LOOKUP_LE,
                        &has_record);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.fino_cur) ||
            !has_record)
                return;

        error = xfs_inobt_get_rec(sc->sa.fino_cur, &rec, &has_record);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.fino_cur) ||
            !has_record)
                return;

        /*
         * Otherwise, make sure this record either doesn't cover this inode,
         * or that it does but it's marked present.
         */
        if (rec.ir_startino > agino ||
            rec.ir_startino + XFS_INODES_PER_CHUNK <= agino)
                return;

        if (rec.ir_free & XFS_INOBT_MASK(agino - rec.ir_startino))
                xchk_btree_xref_set_corrupt(sc, sc->sa.fino_cur, 0);
}

/* Cross reference the inode fields with the forks. */
STATIC void
xchk_inode_xref_bmap(
        struct xfs_scrub        *sc,
        struct xfs_dinode       *dip)
{
        xfs_extnum_t            nextents;
        xfs_filblks_t           count;
        xfs_filblks_t           acount;
        int                     error;

        if (xchk_skip_xref(sc->sm))
                return;

        /* Walk all the extents to check nextents/naextents/nblocks. */
        error = xfs_bmap_count_blocks(sc->tp, sc->ip, XFS_DATA_FORK,
                        &nextents, &count);
        if (!xchk_should_check_xref(sc, &error, NULL))
                return;
        if (nextents < be32_to_cpu(dip->di_nextents))
                xchk_ino_xref_set_corrupt(sc, sc->ip->i_ino);

        error = xfs_bmap_count_blocks(sc->tp, sc->ip, XFS_ATTR_FORK,
                        &nextents, &acount);
        if (!xchk_should_check_xref(sc, &error, NULL))
                return;
        if (nextents != be16_to_cpu(dip->di_anextents))
                xchk_ino_xref_set_corrupt(sc, sc->ip->i_ino);

        /* Check nblocks against the inode. */
        if (count + acount != be64_to_cpu(dip->di_nblocks))
                xchk_ino_xref_set_corrupt(sc, sc->ip->i_ino);
}

/* Cross-reference with the other btrees. */
STATIC void
xchk_inode_xref(
        struct xfs_scrub        *sc,
        xfs_ino_t               ino,
        struct xfs_dinode       *dip)
{
        xfs_agnumber_t          agno;
        xfs_agblock_t           agbno;
        int                     error;

        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        agno = XFS_INO_TO_AGNO(sc->mp, ino);
        agbno = XFS_INO_TO_AGBNO(sc->mp, ino);

        error = xchk_ag_init(sc, agno, &sc->sa);
        if (!xchk_xref_process_error(sc, agno, agbno, &error))
                return;

        xchk_xref_is_used_space(sc, agbno, 1);
        xchk_inode_xref_finobt(sc, ino);
        xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_INODES);
        xchk_xref_is_not_shared(sc, agbno, 1);
        xchk_inode_xref_bmap(sc, dip);

        xchk_ag_free(sc, &sc->sa);
}

/*
 * If the reflink iflag disagrees with a scan for shared data fork extents,
 * either flag an error (shared extents w/ no flag) or a preen (flag set w/o
 * any shared extents).  We already checked for reflink iflag set on a non
 * reflink filesystem.
 */
static void
xchk_inode_check_reflink_iflag(
        struct xfs_scrub        *sc,
        xfs_ino_t               ino)
{
        struct xfs_mount        *mp = sc->mp;
        bool                    has_shared;
        int                     error;

        if (!xfs_sb_version_hasreflink(&mp->m_sb))
                return;

        error = xfs_reflink_inode_has_shared_extents(sc->tp, sc->ip,
                        &has_shared);
        if (!xchk_xref_process_error(sc, XFS_INO_TO_AGNO(mp, ino),
                        XFS_INO_TO_AGBNO(mp, ino), &error))
                return;
        if (xfs_is_reflink_inode(sc->ip) && !has_shared)
                xchk_ino_set_preen(sc, ino);
        else if (!xfs_is_reflink_inode(sc->ip) && has_shared)
                xchk_ino_set_corrupt(sc, ino);
}

/* Scrub an inode. */
int
xchk_inode(
        struct xfs_scrub        *sc)
{
        struct xfs_dinode       di;
        int                     error = 0;

        /*
         * If sc->ip is NULL, that means that the setup function called
         * xfs_iget to look up the inode.  xfs_iget returned a EFSCORRUPTED
         * and a NULL inode, so flag the corruption error and return.
         */
        if (!sc->ip) {
                xchk_ino_set_corrupt(sc, sc->sm->sm_ino);
                return 0;
        }

        /* Scrub the inode core. */
        xfs_inode_to_disk(sc->ip, &di, 0);
        xchk_dinode(sc, &di, sc->ip->i_ino);
        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                goto out;

        /*
         * Look for discrepancies between file's data blocks and the reflink
         * iflag.  We already checked the iflag against the file mode when
         * we scrubbed the dinode.
         */
        if (S_ISREG(VFS_I(sc->ip)->i_mode))
                xchk_inode_check_reflink_iflag(sc, sc->ip->i_ino);

        xchk_inode_xref(sc, sc->ip->i_ino, &di);
out:
        return error;
}