/**
* map_mft_record_page - map the page in which a specific mft record resides
* @ni: ntfs inode whose mft record page to map
*
* This maps the page in which the mft record of the ntfs inode @ni is situated
* and returns a pointer to the mft record within the mapped page.
*
* Return value needs to be checked with IS_ERR() and if that is true PTR_ERR()
* contains the negative error code returned.
*/
static inline MFT_RECORD *map_mft_record_page(ntfs_inode *ni)
{
ntfs_volume *vol = ni->vol;
struct inode *mft_vi = vol->mft_ino;
struct page *page;
unsigned long index, ofs, end_index;
BUG_ON(ni->page);
/*
* The index into the page cache and the offset within the page cache
* page of the wanted mft record. FIXME: We need to check for
* overflowing the unsigned long, but I don't think we would ever get
* here if the volume was that big...
*/
index = ni->mft_no << vol->mft_record_size_bits >> PAGE_CACHE_SHIFT;
ofs = (ni->mft_no << vol->mft_record_size_bits) & ~PAGE_CACHE_MASK;
/* The maximum valid index into the page cache for $MFT's data. */
end_index = mft_vi->i_size >> PAGE_CACHE_SHIFT;
/* If the wanted index is out of bounds the mft record doesn't exist. */
if (unlikely(index >= end_index)) {
if (index > end_index || (mft_vi->i_size & ~PAGE_CACHE_MASK) <
ofs + vol->mft_record_size) {
page = ERR_PTR(-ENOENT);
goto err_out;
}
}
/* Read, map, and pin the page. */
page = ntfs_map_page(mft_vi->i_mapping, index);
if (likely(!IS_ERR(page))) {
ni->page = page;
ni->page_ofs = ofs;
return page_address(page) + ofs;
}
err_out:
ni->page = NULL;
ni->page_ofs = 0;
ntfs_error(vol->sb, "Failed with error code %lu.", -PTR_ERR(page));
return (void*)page;
}
/**
* ntfs_stamp_usnjrnl - stamp the transaction log ($UsnJrnl) on an ntfs volume
* @vol: ntfs volume on which to stamp the transaction log
*
* Stamp the transaction log ($UsnJrnl) on the ntfs volume @vol and return
* 'true' on success and 'false' on error.
*
* This function assumes that the transaction log has already been loaded and
* consistency checked by a call to fs/ntfs/super.c::load_and_init_usnjrnl().
*/
bool ntfs_stamp_usnjrnl(ntfs_volume *vol)
{
ntfs_debug("Entering.");
if (likely(!NVolUsnJrnlStamped(vol))) {
sle64 stamp;
struct page *page;
USN_HEADER *uh;
page = ntfs_map_page(vol->usnjrnl_max_ino->i_mapping, 0);
if (IS_ERR(page)) {
ntfs_error(vol->sb, "Failed to read from "
"$UsnJrnl/$DATA/$Max attribute.");
return false;
}
uh = (USN_HEADER*)page_address(page);
stamp = get_current_ntfs_time();
ntfs_debug("Stamping transaction log ($UsnJrnl): old "
"journal_id 0x%llx, old lowest_valid_usn "
"0x%llx, new journal_id 0x%llx, new "
"lowest_valid_usn 0x%llx.",
(long long)sle64_to_cpu(uh->journal_id),
(long long)sle64_to_cpu(uh->lowest_valid_usn),
(long long)sle64_to_cpu(stamp),
i_size_read(vol->usnjrnl_j_ino));
uh->lowest_valid_usn =
cpu_to_sle64(i_size_read(vol->usnjrnl_j_ino));
uh->journal_id = stamp;
flush_dcache_page(page);
set_page_dirty(page);
ntfs_unmap_page(page);
/* Set the flag so we do not have to do it again on remount. */
NVolSetUsnJrnlStamped(vol);
}
ntfs_debug("Done.");
return true;
}
