From ca8fd7a0c6aa835e8014830b290cb965e85ac88e Mon Sep 17 00:00:00 2001 From: Anton Altaparmakov Date: Sat, 25 Jun 2005 16:31:27 +0100 Subject: NTFS: Detect the case when Windows has been suspended to disk on the volume to be mounted and if this is the case do not allow (re)mounting read-write. This is done by parsing hiberfil.sys if present. Signed-off-by: Anton Altaparmakov --- fs/ntfs/super.c | 179 ++++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 168 insertions(+), 11 deletions(-) (limited to 'fs/ntfs/super.c') diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c index 92e1d28219b..41aa8eb6755 100644 --- a/fs/ntfs/super.c +++ b/fs/ntfs/super.c @@ -1156,6 +1156,124 @@ static BOOL load_and_check_logfile(ntfs_volume *vol) return TRUE; } +#define NTFS_HIBERFIL_HEADER_SIZE 4096 + +/** + * check_windows_hibernation_status - check if Windows is suspended on a volume + * @vol: ntfs super block of device to check + * + * Check if Windows is hibernated on the ntfs volume @vol. This is done by + * looking for the file hiberfil.sys in the root directory of the volume. If + * the file is not present Windows is definitely not suspended. + * + * If hiberfil.sys exists and is less than 4kiB in size it means Windows is + * definitely suspended (this volume is not the system volume). Caveat: on a + * system with many volumes it is possible that the < 4kiB check is bogus but + * for now this should do fine. + * + * If hiberfil.sys exists and is larger than 4kiB in size, we need to read the + * hiberfil header (which is the first 4kiB). If this begins with "hibr", + * Windows is definitely suspended. If it is completely full of zeroes, + * Windows is definitely not hibernated. Any other case is treated as if + * Windows is suspended. This caters for the above mentioned caveat of a + * system with many volumes where no "hibr" magic would be present and there is + * no zero header. + * + * Return 0 if Windows is not hibernated on the volume, >0 if Windows is + * hibernated on the volume, and -errno on error. + */ +static int check_windows_hibernation_status(ntfs_volume *vol) +{ + MFT_REF mref; + struct inode *vi; + ntfs_inode *ni; + struct page *page; + u32 *kaddr, *kend; + ntfs_name *name = NULL; + int ret = 1; + static const ntfschar hiberfil[13] = { const_cpu_to_le16('h'), + const_cpu_to_le16('i'), const_cpu_to_le16('b'), + const_cpu_to_le16('e'), const_cpu_to_le16('r'), + const_cpu_to_le16('f'), const_cpu_to_le16('i'), + const_cpu_to_le16('l'), const_cpu_to_le16('.'), + const_cpu_to_le16('s'), const_cpu_to_le16('y'), + const_cpu_to_le16('s'), 0 }; + + ntfs_debug("Entering."); + /* + * Find the inode number for the hibernation file by looking up the + * filename hiberfil.sys in the root directory. + */ + down(&vol->root_ino->i_sem); + mref = ntfs_lookup_inode_by_name(NTFS_I(vol->root_ino), hiberfil, 12, + &name); + up(&vol->root_ino->i_sem); + if (IS_ERR_MREF(mref)) { + ret = MREF_ERR(mref); + /* If the file does not exist, Windows is not hibernated. */ + if (ret == -ENOENT) { + ntfs_debug("hiberfil.sys not present. Windows is not " + "hibernated on the volume."); + return 0; + } + /* A real error occured. */ + ntfs_error(vol->sb, "Failed to find inode number for " + "hiberfil.sys."); + return ret; + } + /* We do not care for the type of match that was found. */ + kfree(name); + /* Get the inode. */ + vi = ntfs_iget(vol->sb, MREF(mref)); + if (IS_ERR(vi) || is_bad_inode(vi)) { + if (!IS_ERR(vi)) + iput(vi); + ntfs_error(vol->sb, "Failed to load hiberfil.sys."); + return IS_ERR(vi) ? PTR_ERR(vi) : -EIO; + } + if (unlikely(i_size_read(vi) < NTFS_HIBERFIL_HEADER_SIZE)) { + ntfs_debug("hiberfil.sys is smaller than 4kiB (0x%llx). " + "Windows is hibernated on the volume. This " + "is not the system volume.", i_size_read(vi)); + goto iput_out; + } + ni = NTFS_I(vi); + page = ntfs_map_page(vi->i_mapping, 0); + if (IS_ERR(page)) { + ntfs_error(vol->sb, "Failed to read from hiberfil.sys."); + ret = PTR_ERR(page); + goto iput_out; + } + kaddr = (u32*)page_address(page); + if (*(le32*)kaddr == const_cpu_to_le32(0x72626968)/*'hibr'*/) { + ntfs_debug("Magic \"hibr\" found in hiberfil.sys. Windows is " + "hibernated on the volume. This is the " + "system volume."); + goto unm_iput_out; + } + kend = kaddr + NTFS_HIBERFIL_HEADER_SIZE/sizeof(*kaddr); + do { + if (unlikely(*kaddr)) { + ntfs_debug("hiberfil.sys is larger than 4kiB " + "(0x%llx), does not contain the " + "\"hibr\" magic, and does not have a " + "zero header. Windows is hibernated " + "on the volume. This is not the " + "system volume.", i_size_read(vi)); + goto unm_iput_out; + } + } while (++kaddr < kend); + ntfs_debug("hiberfil.sys contains a zero header. Windows is not " + "hibernated on the volume. This is the system " + "volume."); + ret = 0; +unm_iput_out: + ntfs_unmap_page(page); +iput_out: + iput(vi); + return ret; +} + /** * load_and_init_quota - load and setup the quota file for a volume if present * @vol: ntfs super block describing device whose quota file to load @@ -1570,6 +1688,9 @@ static BOOL load_system_files(ntfs_volume *vol) MFT_RECORD *m; VOLUME_INFORMATION *vi; ntfs_attr_search_ctx *ctx; +#ifdef NTFS_RW + int err; +#endif /* NTFS_RW */ ntfs_debug("Entering."); #ifdef NTFS_RW @@ -1746,6 +1867,50 @@ get_ctx_vol_failed: /* This will prevent a read-write remount. */ NVolSetErrors(vol); } +#endif /* NTFS_RW */ + /* Get the root directory inode so we can do path lookups. */ + vol->root_ino = ntfs_iget(sb, FILE_root); + if (IS_ERR(vol->root_ino) || is_bad_inode(vol->root_ino)) { + if (!IS_ERR(vol->root_ino)) + iput(vol->root_ino); + ntfs_error(sb, "Failed to load root directory."); + goto iput_logfile_err_out; + } +#ifdef NTFS_RW + /* + * Check if Windows is suspended to disk on the target volume. If it + * is hibernated, we must not write *anything* to the disk so set + * NVolErrors() without setting the dirty volume flag and mount + * read-only. This will prevent read-write remounting and it will also + * prevent all writes. + */ + err = check_windows_hibernation_status(vol); + if (unlikely(err)) { + static const char *es1a = "Failed to determine if Windows is " + "hibernated"; + static const char *es1b = "Windows is hibernated"; + static const char *es2 = ". Run chkdsk."; + const char *es1; + + es1 = err < 0 ? es1a : es1b; + /* If a read-write mount, convert it to a read-only mount. */ + if (!(sb->s_flags & MS_RDONLY)) { + if (!(vol->on_errors & (ON_ERRORS_REMOUNT_RO | + ON_ERRORS_CONTINUE))) { + ntfs_error(sb, "%s and neither on_errors=" + "continue nor on_errors=" + "remount-ro was specified%s", + es1, es2); + goto iput_root_err_out; + } + sb->s_flags |= MS_RDONLY | MS_NOATIME | MS_NODIRATIME; + ntfs_error(sb, "%s. Mounting read-only%s", es1, es2); + } else + ntfs_warning(sb, "%s. Will not be able to remount " + "read-write%s", es1, es2); + /* This will prevent a read-write remount. */ + NVolSetErrors(vol); + } /* If (still) a read-write mount, mark the volume dirty. */ if (!(sb->s_flags & MS_RDONLY) && ntfs_set_volume_flags(vol, VOLUME_IS_DIRTY)) { @@ -1759,7 +1924,7 @@ get_ctx_vol_failed: ntfs_error(sb, "%s and neither on_errors=continue nor " "on_errors=remount-ro was specified%s", es1, es2); - goto iput_logfile_err_out; + goto iput_root_err_out; } ntfs_error(sb, "%s. Mounting read-only%s", es1, es2); sb->s_flags |= MS_RDONLY | MS_NOATIME | MS_NODIRATIME; @@ -1786,7 +1951,7 @@ get_ctx_vol_failed: ntfs_error(sb, "%s and neither on_errors=continue nor " "on_errors=remount-ro was specified%s", es1, es2); - goto iput_logfile_err_out; + goto iput_root_err_out; } ntfs_error(sb, "%s. Mounting read-only%s", es1, es2); sb->s_flags |= MS_RDONLY | MS_NOATIME | MS_NODIRATIME; @@ -1805,21 +1970,13 @@ get_ctx_vol_failed: ntfs_error(sb, "%s and neither on_errors=continue nor " "on_errors=remount-ro was specified%s", es1, es2); - goto iput_logfile_err_out; + goto iput_root_err_out; } ntfs_error(sb, "%s. Mounting read-only%s", es1, es2); sb->s_flags |= MS_RDONLY | MS_NOATIME | MS_NODIRATIME; NVolSetErrors(vol); } #endif /* NTFS_RW */ - /* Get the root directory inode. */ - vol->root_ino = ntfs_iget(sb, FILE_root); - if (IS_ERR(vol->root_ino) || is_bad_inode(vol->root_ino)) { - if (!IS_ERR(vol->root_ino)) - iput(vol->root_ino); - ntfs_error(sb, "Failed to load root directory."); - goto iput_logfile_err_out; - } /* If on NTFS versions before 3.0, we are done. */ if (unlikely(vol->major_ver < 3)) return TRUE; -- cgit v1.2.3