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

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#include "libxfs_priv.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_defer.h"
#include "xfs_inode.h"
#include "xfs_errortag.h"
#include "xfs_cksum.h"
#include "xfs_trans.h"
#include "xfs_ialloc.h"
#include "xfs_dir2.h"

/*
 * Check that none of the inode's in the buffer have a next
 * unlinked field of 0.
 */
#if defined(DEBUG)
void
xfs_inobp_check(
        xfs_mount_t     *mp,
        xfs_buf_t       *bp)
{
        int             i;
        int             j;
        xfs_dinode_t    *dip;

        j = mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog;

        for (i = 0; i < j; i++) {
                dip = xfs_buf_offset(bp, i * mp->m_sb.sb_inodesize);
                if (!dip->di_next_unlinked)  {
                        xfs_alert(mp,
        "Detected bogus zero next_unlinked field in inode %d buffer 0x%llx.",
                                i, (long long)bp->b_bn);
                }
        }
}
#endif

bool
xfs_dinode_good_version(
        struct xfs_mount *mp,
        __u8            version)
{
        if (xfs_sb_version_hascrc(&mp->m_sb))
                return version == 3;

        return version == 1 || version == 2;
}

/*
 * If we are doing readahead on an inode buffer, we might be in log recovery
 * reading an inode allocation buffer that hasn't yet been replayed, and hence
 * has not had the inode cores stamped into it. Hence for readahead, the buffer
 * may be potentially invalid.
 *
 * If the readahead buffer is invalid, we need to mark it with an error and
 * clear the DONE status of the buffer so that a followup read will re-read it
 * from disk. We don't report the error otherwise to avoid warnings during log
 * recovery and we don't get unnecssary panics on debug kernels. We use EIO here
 * because all we want to do is say readahead failed; there is no-one to report
 * the error to, so this will distinguish it from a non-ra verifier failure.
 * Changes to this readahead error behavour also need to be reflected in
 * xfs_dquot_buf_readahead_verify().
 */
static void
xfs_inode_buf_verify(
        struct xfs_buf  *bp,
        bool            readahead)
{
        struct xfs_mount *mp = bp->b_target->bt_mount;
        xfs_agnumber_t  agno;
        int             i;
        int             ni;

        /*
         * Validate the magic number and version of every inode in the buffer
         */
        agno = xfs_daddr_to_agno(mp, XFS_BUF_ADDR(bp));
        ni = XFS_BB_TO_FSB(mp, bp->b_length) * mp->m_sb.sb_inopblock;
        for (i = 0; i < ni; i++) {
                int             di_ok;
                xfs_dinode_t    *dip;
                xfs_agino_t     unlinked_ino;

                dip = xfs_buf_offset(bp, (i << mp->m_sb.sb_inodelog));
                unlinked_ino = be32_to_cpu(dip->di_next_unlinked);
                di_ok = dip->di_magic == cpu_to_be16(XFS_DINODE_MAGIC) &&
                        xfs_dinode_good_version(mp, dip->di_version) &&
                        (unlinked_ino == NULLAGINO ||
                         xfs_verify_agino(mp, agno, unlinked_ino));
                if (unlikely(XFS_TEST_ERROR(!di_ok, mp,
                                                XFS_ERRTAG_ITOBP_INOTOBP))) {
                        if (readahead) {
                                bp->b_flags &= ~XBF_DONE;
                                xfs_buf_ioerror(bp, -EIO);
                                return;
                        }

#ifdef DEBUG
                        xfs_alert(mp,
                                "bad inode magic/vsn daddr %lld #%d (magic=%x)",
                                (unsigned long long)bp->b_bn, i,
                                be16_to_cpu(dip->di_magic));
#endif
                        xfs_buf_verifier_error(bp, -EFSCORRUPTED,
                                        __func__, dip, sizeof(*dip),
                                        NULL);
                        return;
                }
        }
}


static void
xfs_inode_buf_read_verify(
        struct xfs_buf  *bp)
{
        xfs_inode_buf_verify(bp, false);
}

static void
xfs_inode_buf_readahead_verify(
        struct xfs_buf  *bp)
{
        xfs_inode_buf_verify(bp, true);
}

static void
xfs_inode_buf_write_verify(
        struct xfs_buf  *bp)
{
        xfs_inode_buf_verify(bp, false);
}

const struct xfs_buf_ops xfs_inode_buf_ops = {
        .name = "xfs_inode",
        .verify_read = xfs_inode_buf_read_verify,
        .verify_write = xfs_inode_buf_write_verify,
};

const struct xfs_buf_ops xfs_inode_buf_ra_ops = {
        .name = "xxfs_inode_ra",
        .verify_read = xfs_inode_buf_readahead_verify,
        .verify_write = xfs_inode_buf_write_verify,
};


/*
 * This routine is called to map an inode to the buffer containing the on-disk
 * version of the inode.  It returns a pointer to the buffer containing the
 * on-disk inode in the bpp parameter, and in the dipp parameter it returns a
 * pointer to the on-disk inode within that buffer.
 *
 * If a non-zero error is returned, then the contents of bpp and dipp are
 * undefined.
 */
int
xfs_imap_to_bp(
        struct xfs_mount        *mp,
        struct xfs_trans        *tp,
        struct xfs_imap         *imap,
        struct xfs_dinode       **dipp,
        struct xfs_buf          **bpp,
        uint                    buf_flags,
        uint                    iget_flags)
{
        struct xfs_buf          *bp;
        int                     error;

        buf_flags |= XBF_UNMAPPED;
        error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, imap->im_blkno,
                                   (int)imap->im_len, buf_flags, &bp,
                                   &xfs_inode_buf_ops);
        if (error) {
                if (error == -EAGAIN) {
                        ASSERT(buf_flags & XBF_TRYLOCK);
                        return error;
                }
                xfs_warn(mp, "%s: xfs_trans_read_buf() returned error %d.",
                        __func__, error);
                return error;
        }

        *bpp = bp;
        *dipp = xfs_buf_offset(bp, imap->im_boffset);
        return 0;
}

void
xfs_inode_from_disk(
        struct xfs_inode        *ip,
        struct xfs_dinode       *from)
{
        struct xfs_icdinode     *to = &ip->i_d;
        struct inode            *inode = VFS_I(ip);


        /*
         * Convert v1 inodes immediately to v2 inode format as this is the
         * minimum inode version format we support in the rest of the code.
         */
        to->di_version = from->di_version;
        if (to->di_version == 1) {
                set_nlink(inode, be16_to_cpu(from->di_onlink));
                to->di_projid_lo = 0;
                to->di_projid_hi = 0;
                to->di_version = 2;
        } else {
                set_nlink(inode, be32_to_cpu(from->di_nlink));
                to->di_projid_lo = be16_to_cpu(from->di_projid_lo);
                to->di_projid_hi = be16_to_cpu(from->di_projid_hi);
        }

        to->di_format = from->di_format;
        to->di_uid = be32_to_cpu(from->di_uid);
        to->di_gid = be32_to_cpu(from->di_gid);
        to->di_flushiter = be16_to_cpu(from->di_flushiter);

        /*
         * Time is signed, so need to convert to signed 32 bit before
         * storing in inode timestamp which may be 64 bit. Otherwise
         * a time before epoch is converted to a time long after epoch
         * on 64 bit systems.
         */
        inode->i_atime.tv_sec = (int)be32_to_cpu(from->di_atime.t_sec);
        inode->i_atime.tv_nsec = (int)be32_to_cpu(from->di_atime.t_nsec);
        inode->i_mtime.tv_sec = (int)be32_to_cpu(from->di_mtime.t_sec);
        inode->i_mtime.tv_nsec = (int)be32_to_cpu(from->di_mtime.t_nsec);
        inode->i_ctime.tv_sec = (int)be32_to_cpu(from->di_ctime.t_sec);
        inode->i_ctime.tv_nsec = (int)be32_to_cpu(from->di_ctime.t_nsec);
        inode->i_generation = be32_to_cpu(from->di_gen);
        inode->i_mode = be16_to_cpu(from->di_mode);

        to->di_size = be64_to_cpu(from->di_size);
        to->di_nblocks = be64_to_cpu(from->di_nblocks);
        to->di_extsize = be32_to_cpu(from->di_extsize);
        to->di_nextents = be32_to_cpu(from->di_nextents);
        to->di_anextents = be16_to_cpu(from->di_anextents);
        to->di_forkoff = from->di_forkoff;
        to->di_aformat  = from->di_aformat;
        to->di_dmevmask = be32_to_cpu(from->di_dmevmask);
        to->di_dmstate  = be16_to_cpu(from->di_dmstate);
        to->di_flags    = be16_to_cpu(from->di_flags);

        if (to->di_version == 3) {
                inode_set_iversion_queried(inode,
                                           be64_to_cpu(from->di_changecount));
                to->di_crtime.t_sec = be32_to_cpu(from->di_crtime.t_sec);
                to->di_crtime.t_nsec = be32_to_cpu(from->di_crtime.t_nsec);
                to->di_flags2 = be64_to_cpu(from->di_flags2);
                to->di_cowextsize = be32_to_cpu(from->di_cowextsize);
        }
}

void
xfs_inode_to_disk(
        struct xfs_inode        *ip,
        struct xfs_dinode       *to,
        xfs_lsn_t               lsn)
{
        struct xfs_icdinode     *from = &ip->i_d;
        struct inode            *inode = VFS_I(ip);

        to->di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
        to->di_onlink = 0;

        to->di_version = from->di_version;
        to->di_format = from->di_format;
        to->di_uid = cpu_to_be32(from->di_uid);
        to->di_gid = cpu_to_be32(from->di_gid);
        to->di_projid_lo = cpu_to_be16(from->di_projid_lo);
        to->di_projid_hi = cpu_to_be16(from->di_projid_hi);

        memset(to->di_pad, 0, sizeof(to->di_pad));
        to->di_atime.t_sec = cpu_to_be32(inode->i_atime.tv_sec);
        to->di_atime.t_nsec = cpu_to_be32(inode->i_atime.tv_nsec);
        to->di_mtime.t_sec = cpu_to_be32(inode->i_mtime.tv_sec);
        to->di_mtime.t_nsec = cpu_to_be32(inode->i_mtime.tv_nsec);
        to->di_ctime.t_sec = cpu_to_be32(inode->i_ctime.tv_sec);
        to->di_ctime.t_nsec = cpu_to_be32(inode->i_ctime.tv_nsec);
        to->di_nlink = cpu_to_be32(inode->i_nlink);
        to->di_gen = cpu_to_be32(inode->i_generation);
        to->di_mode = cpu_to_be16(inode->i_mode);

        to->di_size = cpu_to_be64(from->di_size);
        to->di_nblocks = cpu_to_be64(from->di_nblocks);
        to->di_extsize = cpu_to_be32(from->di_extsize);
        to->di_nextents = cpu_to_be32(from->di_nextents);
        to->di_anextents = cpu_to_be16(from->di_anextents);
        to->di_forkoff = from->di_forkoff;
        to->di_aformat = from->di_aformat;
        to->di_dmevmask = cpu_to_be32(from->di_dmevmask);
        to->di_dmstate = cpu_to_be16(from->di_dmstate);
        to->di_flags = cpu_to_be16(from->di_flags);

        if (from->di_version == 3) {
                to->di_changecount = cpu_to_be64(inode_peek_iversion(inode));
                to->di_crtime.t_sec = cpu_to_be32(from->di_crtime.t_sec);
                to->di_crtime.t_nsec = cpu_to_be32(from->di_crtime.t_nsec);
                to->di_flags2 = cpu_to_be64(from->di_flags2);
                to->di_cowextsize = cpu_to_be32(from->di_cowextsize);
                to->di_ino = cpu_to_be64(ip->i_ino);
                to->di_lsn = cpu_to_be64(lsn);
                memset(to->di_pad2, 0, sizeof(to->di_pad2));
                uuid_copy(&to->di_uuid, &ip->i_mount->m_sb.sb_meta_uuid);
                to->di_flushiter = 0;
        } else {
                to->di_flushiter = cpu_to_be16(from->di_flushiter);
        }
}

void
xfs_log_dinode_to_disk(
        struct xfs_log_dinode   *from,
        struct xfs_dinode       *to)
{
        to->di_magic = cpu_to_be16(from->di_magic);
        to->di_mode = cpu_to_be16(from->di_mode);
        to->di_version = from->di_version;
        to->di_format = from->di_format;
        to->di_onlink = 0;
        to->di_uid = cpu_to_be32(from->di_uid);
        to->di_gid = cpu_to_be32(from->di_gid);
        to->di_nlink = cpu_to_be32(from->di_nlink);
        to->di_projid_lo = cpu_to_be16(from->di_projid_lo);
        to->di_projid_hi = cpu_to_be16(from->di_projid_hi);
        memcpy(to->di_pad, from->di_pad, sizeof(to->di_pad));

        to->di_atime.t_sec = cpu_to_be32(from->di_atime.t_sec);
        to->di_atime.t_nsec = cpu_to_be32(from->di_atime.t_nsec);
        to->di_mtime.t_sec = cpu_to_be32(from->di_mtime.t_sec);
        to->di_mtime.t_nsec = cpu_to_be32(from->di_mtime.t_nsec);
        to->di_ctime.t_sec = cpu_to_be32(from->di_ctime.t_sec);
        to->di_ctime.t_nsec = cpu_to_be32(from->di_ctime.t_nsec);

        to->di_size = cpu_to_be64(from->di_size);
        to->di_nblocks = cpu_to_be64(from->di_nblocks);
        to->di_extsize = cpu_to_be32(from->di_extsize);
        to->di_nextents = cpu_to_be32(from->di_nextents);
        to->di_anextents = cpu_to_be16(from->di_anextents);
        to->di_forkoff = from->di_forkoff;
        to->di_aformat = from->di_aformat;
        to->di_dmevmask = cpu_to_be32(from->di_dmevmask);
        to->di_dmstate = cpu_to_be16(from->di_dmstate);
        to->di_flags = cpu_to_be16(from->di_flags);
        to->di_gen = cpu_to_be32(from->di_gen);

        if (from->di_version == 3) {
                to->di_changecount = cpu_to_be64(from->di_changecount);
                to->di_crtime.t_sec = cpu_to_be32(from->di_crtime.t_sec);
                to->di_crtime.t_nsec = cpu_to_be32(from->di_crtime.t_nsec);
                to->di_flags2 = cpu_to_be64(from->di_flags2);
                to->di_cowextsize = cpu_to_be32(from->di_cowextsize);
                to->di_ino = cpu_to_be64(from->di_ino);
                to->di_lsn = cpu_to_be64(from->di_lsn);
                memcpy(to->di_pad2, from->di_pad2, sizeof(to->di_pad2));
                uuid_copy(&to->di_uuid, &from->di_uuid);
                to->di_flushiter = 0;
        } else {
                to->di_flushiter = cpu_to_be16(from->di_flushiter);
        }
}

xfs_failaddr_t
xfs_dinode_verify(
        struct xfs_mount        *mp,
        xfs_ino_t               ino,
        struct xfs_dinode       *dip)
{
        xfs_failaddr_t          fa;
        uint16_t                mode;
        uint16_t                flags;
        uint64_t                flags2;
        uint64_t                di_size;

        if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
                return __this_address;

        /* Verify v3 integrity information first */
        if (dip->di_version >= 3) {
                if (!xfs_sb_version_hascrc(&mp->m_sb))
                        return __this_address;
                if (!xfs_verify_cksum((char *)dip, mp->m_sb.sb_inodesize,
                                      XFS_DINODE_CRC_OFF))
                        return __this_address;
                if (be64_to_cpu(dip->di_ino) != ino)
                        return __this_address;
                if (!uuid_equal(&dip->di_uuid, &mp->m_sb.sb_meta_uuid))
                        return __this_address;
        }

        /* don't allow invalid i_size */
        di_size = be64_to_cpu(dip->di_size);
        if (di_size & (1ULL << 63))
                return __this_address;

        mode = be16_to_cpu(dip->di_mode);
        if (mode && xfs_mode_to_ftype(mode) == XFS_DIR3_FT_UNKNOWN)
                return __this_address;

        /* No zero-length symlinks/dirs. */
        if ((S_ISLNK(mode) || S_ISDIR(mode)) && di_size == 0)
                return __this_address;

        /* Fork checks carried over from xfs_iformat_fork */
        if (mode &&
            be32_to_cpu(dip->di_nextents) + be16_to_cpu(dip->di_anextents) >
                        be64_to_cpu(dip->di_nblocks))
                return __this_address;

        if (mode && XFS_DFORK_BOFF(dip) > mp->m_sb.sb_inodesize)
                return __this_address;

        flags = be16_to_cpu(dip->di_flags);

        if (mode && (flags & XFS_DIFLAG_REALTIME) && !mp->m_rtdev_targp)
                return __this_address;

        /* Do we have appropriate data fork formats for the mode? */
        switch (mode & S_IFMT) {
        case S_IFIFO:
        case S_IFCHR:
        case S_IFBLK:
        case S_IFSOCK:
                if (dip->di_format != XFS_DINODE_FMT_DEV)
                        return __this_address;
                break;
        case S_IFREG:
        case S_IFLNK:
        case S_IFDIR:
                switch (dip->di_format) {
                case XFS_DINODE_FMT_LOCAL:
                        /*
                         * no local regular files yet
                         */
                        if (S_ISREG(mode))
                                return __this_address;
                        if (di_size > XFS_DFORK_DSIZE(dip, mp))
                                return __this_address;
                        if (dip->di_nextents)
                                return __this_address;
                        /* fall through */
                case XFS_DINODE_FMT_EXTENTS:
                case XFS_DINODE_FMT_BTREE:
                        break;
                default:
                        return __this_address;
                }
                break;
        case 0:
                /* Uninitialized inode ok. */
                break;
        default:
                return __this_address;
        }

        if (XFS_DFORK_Q(dip)) {
                switch (dip->di_aformat) {
                case XFS_DINODE_FMT_LOCAL:
                        if (dip->di_anextents)
                                return __this_address;
                /* fall through */
                case XFS_DINODE_FMT_EXTENTS:
                case XFS_DINODE_FMT_BTREE:
                        break;
                default:
                        return __this_address;
                }
        } else {
                /*
                 * If there is no fork offset, this may be a freshly-made inode
                 * in a new disk cluster, in which case di_aformat is zeroed.
                 * Otherwise, such an inode must be in EXTENTS format; this goes
                 * for freed inodes as well.
                 */
                switch (dip->di_aformat) {
                case 0:
                case XFS_DINODE_FMT_EXTENTS:
                        break;
                default:
                        return __this_address;
                }
                if (dip->di_anextents)
                        return __this_address;
        }

        /* extent size hint validation */
        fa = xfs_inode_validate_extsize(mp, be32_to_cpu(dip->di_extsize),
                        mode, flags);
        if (fa)
                return fa;

        /* only version 3 or greater inodes are extensively verified here */
        if (dip->di_version < 3)
                return NULL;

        flags2 = be64_to_cpu(dip->di_flags2);

        /* don't allow reflink/cowextsize if we don't have reflink */
        if ((flags2 & (XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE)) &&
             !xfs_sb_version_hasreflink(&mp->m_sb))
                return __this_address;

        /* only regular files get reflink */
        if ((flags2 & XFS_DIFLAG2_REFLINK) && (mode & S_IFMT) != S_IFREG)
                return __this_address;

        /* don't let reflink and realtime mix */
        if ((flags2 & XFS_DIFLAG2_REFLINK) && (flags & XFS_DIFLAG_REALTIME))
                return __this_address;

        /* don't let reflink and dax mix */
        if ((flags2 & XFS_DIFLAG2_REFLINK) && (flags2 & XFS_DIFLAG2_DAX))
                return __this_address;

        /* COW extent size hint validation */
        fa = xfs_inode_validate_cowextsize(mp, be32_to_cpu(dip->di_cowextsize),
                        mode, flags, flags2);
        if (fa)
                return fa;

        return NULL;
}

void
xfs_dinode_calc_crc(
        struct xfs_mount        *mp,
        struct xfs_dinode       *dip)
{
        uint32_t                crc;

        if (dip->di_version < 3)
                return;

        ASSERT(xfs_sb_version_hascrc(&mp->m_sb));
        crc = xfs_start_cksum_update((char *)dip, mp->m_sb.sb_inodesize,
                              XFS_DINODE_CRC_OFF);
        dip->di_crc = xfs_end_cksum(crc);
}

/*
 * Read the disk inode attributes into the in-core inode structure.
 *
 * For version 5 superblocks, if we are initialising a new inode and we are not
 * utilising the XFS_MOUNT_IKEEP inode cluster mode, we can simple build the new
 * inode core with a random generation number. If we are keeping inodes around,
 * we need to read the inode cluster to get the existing generation number off
 * disk. Further, if we are using version 4 superblocks (i.e. v1/v2 inode
 * format) then log recovery is dependent on the di_flushiter field being
 * initialised from the current on-disk value and hence we must also read the
 * inode off disk.
 */
int
xfs_iread(
        xfs_mount_t     *mp,
        xfs_trans_t     *tp,
        xfs_inode_t     *ip,
        uint            iget_flags)
{
        xfs_buf_t       *bp;
        xfs_dinode_t    *dip;
        xfs_failaddr_t  fa;
        int             error;

        /*
         * Fill in the location information in the in-core inode.
         */
        error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, iget_flags);
        if (error)
                return error;

        /* shortcut IO on inode allocation if possible */
        if ((iget_flags & XFS_IGET_CREATE) &&
            xfs_sb_version_hascrc(&mp->m_sb) &&
            !(mp->m_flags & XFS_MOUNT_IKEEP)) {
                /* initialise the on-disk inode core */
                memset(&ip->i_d, 0, sizeof(ip->i_d));
                VFS_I(ip)->i_generation = prandom_u32();
                ip->i_d.di_version = 3;
                return 0;
        }

        /*
         * Get pointers to the on-disk inode and the buffer containing it.
         */
        error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &bp, 0, iget_flags);
        if (error)
                return error;

        /* even unallocated inodes are verified */
        fa = xfs_dinode_verify(mp, ip->i_ino, dip);
        if (fa) {
                xfs_inode_verifier_error(ip, -EFSCORRUPTED, "dinode", dip,
                                sizeof(*dip), fa);
                error = -EFSCORRUPTED;
                goto out_brelse;
        }

        /*
         * If the on-disk inode is already linked to a directory
         * entry, copy all of the inode into the in-core inode.
         * xfs_iformat_fork() handles copying in the inode format
         * specific information.
         * Otherwise, just get the truly permanent information.
         */
        if (dip->di_mode) {
                xfs_inode_from_disk(ip, dip);
                error = xfs_iformat_fork(ip, dip);
                if (error)  {
#ifdef DEBUG
                        xfs_alert(mp, "%s: xfs_iformat() returned error %d",
                                __func__, error);
#endif /* DEBUG */
                        goto out_brelse;
                }
        } else {
                /*
                 * Partial initialisation of the in-core inode. Just the bits
                 * that xfs_ialloc won't overwrite or relies on being correct.
                 */
                ip->i_d.di_version = dip->di_version;
                VFS_I(ip)->i_generation = be32_to_cpu(dip->di_gen);
                ip->i_d.di_flushiter = be16_to_cpu(dip->di_flushiter);

                /*
                 * Make sure to pull in the mode here as well in
                 * case the inode is released without being used.
                 * This ensures that xfs_inactive() will see that
                 * the inode is already free and not try to mess
                 * with the uninitialized part of it.
                 */
                VFS_I(ip)->i_mode = 0;
        }

        ASSERT(ip->i_d.di_version >= 2);
        ip->i_delayed_blks = 0;

        /*
         * Mark the buffer containing the inode as something to keep
         * around for a while.  This helps to keep recently accessed
         * meta-data in-core longer.
         */
        xfs_buf_set_ref(bp, XFS_INO_REF);

        /*
         * Use xfs_trans_brelse() to release the buffer containing the on-disk
         * inode, because it was acquired with xfs_trans_read_buf() in
         * xfs_imap_to_bp() above.  If tp is NULL, this is just a normal
         * brelse().  If we're within a transaction, then xfs_trans_brelse()
         * will only release the buffer if it is not dirty within the
         * transaction.  It will be OK to release the buffer in this case,
         * because inodes on disk are never destroyed and we will be locking the
         * new in-core inode before putting it in the cache where other
         * processes can find it.  Thus we don't have to worry about the inode
         * being changed just because we released the buffer.
         */
 out_brelse:
        xfs_trans_brelse(tp, bp);
        return error;
}

/*
 * Validate di_extsize hint.
 *
 * The rules are documented at xfs_ioctl_setattr_check_extsize().
 * These functions must be kept in sync with each other.
 */
xfs_failaddr_t
xfs_inode_validate_extsize(
        struct xfs_mount                *mp,
        uint32_t                        extsize,
        uint16_t                        mode,
        uint16_t                        flags)
{
        bool                            rt_flag;
        bool                            hint_flag;
        bool                            inherit_flag;
        uint32_t                        extsize_bytes;
        uint32_t                        blocksize_bytes;

        rt_flag = (flags & XFS_DIFLAG_REALTIME);
        hint_flag = (flags & XFS_DIFLAG_EXTSIZE);
        inherit_flag = (flags & XFS_DIFLAG_EXTSZINHERIT);
        extsize_bytes = XFS_FSB_TO_B(mp, extsize);

        if (rt_flag)
                blocksize_bytes = mp->m_sb.sb_rextsize << mp->m_sb.sb_blocklog;
        else
                blocksize_bytes = mp->m_sb.sb_blocksize;

        if ((hint_flag || inherit_flag) && !(S_ISDIR(mode) || S_ISREG(mode)))
                return __this_address;

        if (hint_flag && !S_ISREG(mode))
                return __this_address;

        if (inherit_flag && !S_ISDIR(mode))
                return __this_address;

        if ((hint_flag || inherit_flag) && extsize == 0)
                return __this_address;

        if (!(hint_flag || inherit_flag) && extsize != 0)
                return __this_address;

        if (extsize_bytes % blocksize_bytes)
                return __this_address;

        if (extsize > MAXEXTLEN)
                return __this_address;

        if (!rt_flag && extsize > mp->m_sb.sb_agblocks / 2)
                return __this_address;

        return NULL;
}

/*
 * Validate di_cowextsize hint.
 *
 * The rules are documented at xfs_ioctl_setattr_check_cowextsize().
 * These functions must be kept in sync with each other.
 */
xfs_failaddr_t
xfs_inode_validate_cowextsize(
        struct xfs_mount                *mp,
        uint32_t                        cowextsize,
        uint16_t                        mode,
        uint16_t                        flags,
        uint64_t                        flags2)
{
        bool                            rt_flag;
        bool                            hint_flag;
        uint32_t                        cowextsize_bytes;

        rt_flag = (flags & XFS_DIFLAG_REALTIME);
        hint_flag = (flags2 & XFS_DIFLAG2_COWEXTSIZE);
        cowextsize_bytes = XFS_FSB_TO_B(mp, cowextsize);

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

        if (hint_flag && !(S_ISDIR(mode) || S_ISREG(mode)))
                return __this_address;

        if (hint_flag && cowextsize == 0)
                return __this_address;

        if (!hint_flag && cowextsize != 0)
                return __this_address;

        if (hint_flag && rt_flag)
                return __this_address;

        if (cowextsize_bytes % mp->m_sb.sb_blocksize)
                return __this_address;

        if (cowextsize > MAXEXTLEN)
                return __this_address;

        if (cowextsize > mp->m_sb.sb_agblocks / 2)
                return __this_address;

        return NULL;
}