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NTFS: Detect the case when Windows has been suspended to disk on the volume

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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 <aia21@cantab.net>
This commit is contained in:
Anton Altaparmakov
2005-06-25 16:31:27 +01:00
parent 9f993fe463
commit ca8fd7a0c6
2 changed files with 171 additions and 11 deletions
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179
fs/ntfs/super.c
View File

@@ -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;