/* * Copyright (c) 2000-2006 Silicon Graphics, Inc. * All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation. * * This program is distributed in the hope that it would be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include "xfs.h" #include "xfs_fs.h" #include "xfs_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_error.h" #include "xfs_cksum.h" #include "xfs_icache.h" #include "xfs_trans.h" #include "xfs_ialloc.h" #include "xfs_dir2.h" #include /* * 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; }