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authorAnton Altaparmakov <aia21@cantab.net>2005-10-11 09:59:40 -0400
committerAnton Altaparmakov <aia21@cantab.net>2005-10-11 09:59:40 -0400
commit29f5f3c141c58b0a4c0765c77da612271875bcce (patch)
tree5e3f7c988636a72c280e85ed3b78d5fd44338c22 /fs
parent29b8990513b077dc388b0756acd31465e5c21441 (diff)
NTFS: Remove address space operations ->prepare_write and ->commit_write in
preparation for the big rewrite of write(2) support in ntfs. Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
Diffstat (limited to 'fs')
-rw-r--r--fs/ntfs/aops.c827
1 files changed, 0 insertions, 827 deletions
diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
index 5e80c07c6a4d..8f23c60030c0 100644
--- a/fs/ntfs/aops.c
+++ b/fs/ntfs/aops.c
@@ -1542,830 +1542,6 @@ err_out:
1542 return err; 1542 return err;
1543} 1543}
1544 1544
1545/**
1546 * ntfs_prepare_nonresident_write -
1547 *
1548 */
1549static int ntfs_prepare_nonresident_write(struct page *page,
1550 unsigned from, unsigned to)
1551{
1552 VCN vcn;
1553 LCN lcn;
1554 s64 initialized_size;
1555 loff_t i_size;
1556 sector_t block, ablock, iblock;
1557 struct inode *vi;
1558 ntfs_inode *ni;
1559 ntfs_volume *vol;
1560 runlist_element *rl;
1561 struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
1562 unsigned long flags;
1563 unsigned int vcn_ofs, block_start, block_end, blocksize;
1564 int err;
1565 BOOL is_retry;
1566 unsigned char blocksize_bits;
1567
1568 vi = page->mapping->host;
1569 ni = NTFS_I(vi);
1570 vol = ni->vol;
1571
1572 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
1573 "0x%lx, from = %u, to = %u.", ni->mft_no, ni->type,
1574 page->index, from, to);
1575
1576 BUG_ON(!NInoNonResident(ni));
1577
1578 blocksize_bits = vi->i_blkbits;
1579 blocksize = 1 << blocksize_bits;
1580
1581 /*
1582 * create_empty_buffers() will create uptodate/dirty buffers if the
1583 * page is uptodate/dirty.
1584 */
1585 if (!page_has_buffers(page))
1586 create_empty_buffers(page, blocksize, 0);
1587 bh = head = page_buffers(page);
1588 if (unlikely(!bh))
1589 return -ENOMEM;
1590
1591 /* The first block in the page. */
1592 block = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
1593
1594 read_lock_irqsave(&ni->size_lock, flags);
1595 /*
1596 * The first out of bounds block for the allocated size. No need to
1597 * round up as allocated_size is in multiples of cluster size and the
1598 * minimum cluster size is 512 bytes, which is equal to the smallest
1599 * blocksize.
1600 */
1601 ablock = ni->allocated_size >> blocksize_bits;
1602 i_size = i_size_read(vi);
1603 initialized_size = ni->initialized_size;
1604 read_unlock_irqrestore(&ni->size_lock, flags);
1605
1606 /* The last (fully or partially) initialized block. */
1607 iblock = initialized_size >> blocksize_bits;
1608
1609 /* Loop through all the buffers in the page. */
1610 block_start = 0;
1611 rl = NULL;
1612 err = 0;
1613 do {
1614 block_end = block_start + blocksize;
1615 /*
1616 * If buffer @bh is outside the write, just mark it uptodate
1617 * if the page is uptodate and continue with the next buffer.
1618 */
1619 if (block_end <= from || block_start >= to) {
1620 if (PageUptodate(page)) {
1621 if (!buffer_uptodate(bh))
1622 set_buffer_uptodate(bh);
1623 }
1624 continue;
1625 }
1626 /*
1627 * @bh is at least partially being written to.
1628 * Make sure it is not marked as new.
1629 */
1630 //if (buffer_new(bh))
1631 // clear_buffer_new(bh);
1632
1633 if (block >= ablock) {
1634 // TODO: block is above allocated_size, need to
1635 // allocate it. Best done in one go to accommodate not
1636 // only block but all above blocks up to and including:
1637 // ((page->index << PAGE_CACHE_SHIFT) + to + blocksize
1638 // - 1) >> blobksize_bits. Obviously will need to round
1639 // up to next cluster boundary, too. This should be
1640 // done with a helper function, so it can be reused.
1641 ntfs_error(vol->sb, "Writing beyond allocated size "
1642 "is not supported yet. Sorry.");
1643 err = -EOPNOTSUPP;
1644 goto err_out;
1645 // Need to update ablock.
1646 // Need to set_buffer_new() on all block bhs that are
1647 // newly allocated.
1648 }
1649 /*
1650 * Now we have enough allocated size to fulfill the whole
1651 * request, i.e. block < ablock is true.
1652 */
1653 if (unlikely((block >= iblock) &&
1654 (initialized_size < i_size))) {
1655 /*
1656 * If this page is fully outside initialized size, zero
1657 * out all pages between the current initialized size
1658 * and the current page. Just use ntfs_readpage() to do
1659 * the zeroing transparently.
1660 */
1661 if (block > iblock) {
1662 // TODO:
1663 // For each page do:
1664 // - read_cache_page()
1665 // Again for each page do:
1666 // - wait_on_page_locked()
1667 // - Check (PageUptodate(page) &&
1668 // !PageError(page))
1669 // Update initialized size in the attribute and
1670 // in the inode.
1671 // Again, for each page do:
1672 // __set_page_dirty_buffers();
1673 // page_cache_release()
1674 // We don't need to wait on the writes.
1675 // Update iblock.
1676 }
1677 /*
1678 * The current page straddles initialized size. Zero
1679 * all non-uptodate buffers and set them uptodate (and
1680 * dirty?). Note, there aren't any non-uptodate buffers
1681 * if the page is uptodate.
1682 * FIXME: For an uptodate page, the buffers may need to
1683 * be written out because they were not initialized on
1684 * disk before.
1685 */
1686 if (!PageUptodate(page)) {
1687 // TODO:
1688 // Zero any non-uptodate buffers up to i_size.
1689 // Set them uptodate and dirty.
1690 }
1691 // TODO:
1692 // Update initialized size in the attribute and in the
1693 // inode (up to i_size).
1694 // Update iblock.
1695 // FIXME: This is inefficient. Try to batch the two
1696 // size changes to happen in one go.
1697 ntfs_error(vol->sb, "Writing beyond initialized size "
1698 "is not supported yet. Sorry.");
1699 err = -EOPNOTSUPP;
1700 goto err_out;
1701 // Do NOT set_buffer_new() BUT DO clear buffer range
1702 // outside write request range.
1703 // set_buffer_uptodate() on complete buffers as well as
1704 // set_buffer_dirty().
1705 }
1706
1707 /* Need to map unmapped buffers. */
1708 if (!buffer_mapped(bh)) {
1709 /* Unmapped buffer. Need to map it. */
1710 bh->b_bdev = vol->sb->s_bdev;
1711
1712 /* Convert block into corresponding vcn and offset. */
1713 vcn = (VCN)block << blocksize_bits >>
1714 vol->cluster_size_bits;
1715 vcn_ofs = ((VCN)block << blocksize_bits) &
1716 vol->cluster_size_mask;
1717
1718 is_retry = FALSE;
1719 if (!rl) {
1720lock_retry_remap:
1721 down_read(&ni->runlist.lock);
1722 rl = ni->runlist.rl;
1723 }
1724 if (likely(rl != NULL)) {
1725 /* Seek to element containing target vcn. */
1726 while (rl->length && rl[1].vcn <= vcn)
1727 rl++;
1728 lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
1729 } else
1730 lcn = LCN_RL_NOT_MAPPED;
1731 if (unlikely(lcn < 0)) {
1732 /*
1733 * We extended the attribute allocation above.
1734 * If we hit an ENOENT here it means that the
1735 * allocation was insufficient which is a bug.
1736 */
1737 BUG_ON(lcn == LCN_ENOENT);
1738
1739 /* It is a hole, need to instantiate it. */
1740 if (lcn == LCN_HOLE) {
1741 // TODO: Instantiate the hole.
1742 // clear_buffer_new(bh);
1743 // unmap_underlying_metadata(bh->b_bdev,
1744 // bh->b_blocknr);
1745 // For non-uptodate buffers, need to
1746 // zero out the region outside the
1747 // request in this bh or all bhs,
1748 // depending on what we implemented
1749 // above.
1750 // Need to flush_dcache_page().
1751 // Or could use set_buffer_new()
1752 // instead?
1753 ntfs_error(vol->sb, "Writing into "
1754 "sparse regions is "
1755 "not supported yet. "
1756 "Sorry.");
1757 err = -EOPNOTSUPP;
1758 if (!rl)
1759 up_read(&ni->runlist.lock);
1760 goto err_out;
1761 } else if (!is_retry &&
1762 lcn == LCN_RL_NOT_MAPPED) {
1763 is_retry = TRUE;
1764 /*
1765 * Attempt to map runlist, dropping
1766 * lock for the duration.
1767 */
1768 up_read(&ni->runlist.lock);
1769 err = ntfs_map_runlist(ni, vcn);
1770 if (likely(!err))
1771 goto lock_retry_remap;
1772 rl = NULL;
1773 } else if (!rl)
1774 up_read(&ni->runlist.lock);
1775 /*
1776 * Failed to map the buffer, even after
1777 * retrying.
1778 */
1779 if (!err)
1780 err = -EIO;
1781 bh->b_blocknr = -1;
1782 ntfs_error(vol->sb, "Failed to write to inode "
1783 "0x%lx, attribute type 0x%x, "
1784 "vcn 0x%llx, offset 0x%x "
1785 "because its location on disk "
1786 "could not be determined%s "
1787 "(error code %i).",
1788 ni->mft_no, ni->type,
1789 (unsigned long long)vcn,
1790 vcn_ofs, is_retry ? " even "
1791 "after retrying" : "", err);
1792 goto err_out;
1793 }
1794 /* We now have a successful remap, i.e. lcn >= 0. */
1795
1796 /* Setup buffer head to correct block. */
1797 bh->b_blocknr = ((lcn << vol->cluster_size_bits)
1798 + vcn_ofs) >> blocksize_bits;
1799 set_buffer_mapped(bh);
1800
1801 // FIXME: Something analogous to this is needed for
1802 // each newly allocated block, i.e. BH_New.
1803 // FIXME: Might need to take this out of the
1804 // if (!buffer_mapped(bh)) {}, depending on how we
1805 // implement things during the allocated_size and
1806 // initialized_size extension code above.
1807 if (buffer_new(bh)) {
1808 clear_buffer_new(bh);
1809 unmap_underlying_metadata(bh->b_bdev,
1810 bh->b_blocknr);
1811 if (PageUptodate(page)) {
1812 set_buffer_uptodate(bh);
1813 continue;
1814 }
1815 /*
1816 * Page is _not_ uptodate, zero surrounding
1817 * region. NOTE: This is how we decide if to
1818 * zero or not!
1819 */
1820 if (block_end > to || block_start < from) {
1821 void *kaddr;
1822
1823 kaddr = kmap_atomic(page, KM_USER0);
1824 if (block_end > to)
1825 memset(kaddr + to, 0,
1826 block_end - to);
1827 if (block_start < from)
1828 memset(kaddr + block_start, 0,
1829 from -
1830 block_start);
1831 flush_dcache_page(page);
1832 kunmap_atomic(kaddr, KM_USER0);
1833 }
1834 continue;
1835 }
1836 }
1837 /* @bh is mapped, set it uptodate if the page is uptodate. */
1838 if (PageUptodate(page)) {
1839 if (!buffer_uptodate(bh))
1840 set_buffer_uptodate(bh);
1841 continue;
1842 }
1843 /*
1844 * The page is not uptodate. The buffer is mapped. If it is not
1845 * uptodate, and it is only partially being written to, we need
1846 * to read the buffer in before the write, i.e. right now.
1847 */
1848 if (!buffer_uptodate(bh) &&
1849 (block_start < from || block_end > to)) {
1850 ll_rw_block(READ, 1, &bh);
1851 *wait_bh++ = bh;
1852 }
1853 } while (block++, block_start = block_end,
1854 (bh = bh->b_this_page) != head);
1855
1856 /* Release the lock if we took it. */
1857 if (rl) {
1858 up_read(&ni->runlist.lock);
1859 rl = NULL;
1860 }
1861
1862 /* If we issued read requests, let them complete. */
1863 while (wait_bh > wait) {
1864 wait_on_buffer(*--wait_bh);
1865 if (!buffer_uptodate(*wait_bh))
1866 return -EIO;
1867 }
1868
1869 ntfs_debug("Done.");
1870 return 0;
1871err_out:
1872 /*
1873 * Zero out any newly allocated blocks to avoid exposing stale data.
1874 * If BH_New is set, we know that the block was newly allocated in the
1875 * above loop.
1876 * FIXME: What about initialized_size increments? Have we done all the
1877 * required zeroing above? If not this error handling is broken, and
1878 * in particular the if (block_end <= from) check is completely bogus.
1879 */
1880 bh = head;
1881 block_start = 0;
1882 is_retry = FALSE;
1883 do {
1884 block_end = block_start + blocksize;
1885 if (block_end <= from)
1886 continue;
1887 if (block_start >= to)
1888 break;
1889 if (buffer_new(bh)) {
1890 void *kaddr;
1891
1892 clear_buffer_new(bh);
1893 kaddr = kmap_atomic(page, KM_USER0);
1894 memset(kaddr + block_start, 0, bh->b_size);
1895 kunmap_atomic(kaddr, KM_USER0);
1896 set_buffer_uptodate(bh);
1897 mark_buffer_dirty(bh);
1898 is_retry = TRUE;
1899 }
1900 } while (block_start = block_end, (bh = bh->b_this_page) != head);
1901 if (is_retry)
1902 flush_dcache_page(page);
1903 if (rl)
1904 up_read(&ni->runlist.lock);
1905 return err;
1906}
1907
1908/**
1909 * ntfs_prepare_write - prepare a page for receiving data
1910 *
1911 * This is called from generic_file_write() with i_sem held on the inode
1912 * (@page->mapping->host). The @page is locked but not kmap()ped. The source
1913 * data has not yet been copied into the @page.
1914 *
1915 * Need to extend the attribute/fill in holes if necessary, create blocks and
1916 * make partially overwritten blocks uptodate,
1917 *
1918 * i_size is not to be modified yet.
1919 *
1920 * Return 0 on success or -errno on error.
1921 *
1922 * Should be using block_prepare_write() [support for sparse files] or
1923 * cont_prepare_write() [no support for sparse files]. Cannot do that due to
1924 * ntfs specifics but can look at them for implementation guidance.
1925 *
1926 * Note: In the range, @from is inclusive and @to is exclusive, i.e. @from is
1927 * the first byte in the page that will be written to and @to is the first byte
1928 * after the last byte that will be written to.
1929 */
1930static int ntfs_prepare_write(struct file *file, struct page *page,
1931 unsigned from, unsigned to)
1932{
1933 s64 new_size;
1934 loff_t i_size;
1935 struct inode *vi = page->mapping->host;
1936 ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
1937 ntfs_volume *vol = ni->vol;
1938 ntfs_attr_search_ctx *ctx = NULL;
1939 MFT_RECORD *m = NULL;
1940 ATTR_RECORD *a;
1941 u8 *kaddr;
1942 u32 attr_len;
1943 int err;
1944
1945 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
1946 "0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
1947 page->index, from, to);
1948 BUG_ON(!PageLocked(page));
1949 BUG_ON(from > PAGE_CACHE_SIZE);
1950 BUG_ON(to > PAGE_CACHE_SIZE);
1951 BUG_ON(from > to);
1952 BUG_ON(NInoMstProtected(ni));
1953 /*
1954 * If a previous ntfs_truncate() failed, repeat it and abort if it
1955 * fails again.
1956 */
1957 if (unlikely(NInoTruncateFailed(ni))) {
1958 down_write(&vi->i_alloc_sem);
1959 err = ntfs_truncate(vi);
1960 up_write(&vi->i_alloc_sem);
1961 if (err || NInoTruncateFailed(ni)) {
1962 if (!err)
1963 err = -EIO;
1964 goto err_out;
1965 }
1966 }
1967 /* If the attribute is not resident, deal with it elsewhere. */
1968 if (NInoNonResident(ni)) {
1969 /*
1970 * Only unnamed $DATA attributes can be compressed, encrypted,
1971 * and/or sparse.
1972 */
1973 if (ni->type == AT_DATA && !ni->name_len) {
1974 /* If file is encrypted, deny access, just like NT4. */
1975 if (NInoEncrypted(ni)) {
1976 ntfs_debug("Denying write access to encrypted "
1977 "file.");
1978 return -EACCES;
1979 }
1980 /* Compressed data streams are handled in compress.c. */
1981 if (NInoCompressed(ni)) {
1982 // TODO: Implement and replace this check with
1983 // return ntfs_write_compressed_block(page);
1984 ntfs_error(vi->i_sb, "Writing to compressed "
1985 "files is not supported yet. "
1986 "Sorry.");
1987 return -EOPNOTSUPP;
1988 }
1989 // TODO: Implement and remove this check.
1990 if (NInoSparse(ni)) {
1991 ntfs_error(vi->i_sb, "Writing to sparse files "
1992 "is not supported yet. Sorry.");
1993 return -EOPNOTSUPP;
1994 }
1995 }
1996 /* Normal data stream. */
1997 return ntfs_prepare_nonresident_write(page, from, to);
1998 }
1999 /*
2000 * Attribute is resident, implying it is not compressed, encrypted, or
2001 * sparse.
2002 */
2003 BUG_ON(page_has_buffers(page));
2004 new_size = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
2005 /* If we do not need to resize the attribute allocation we are done. */
2006 if (new_size <= i_size_read(vi))
2007 goto done;
2008 /* Map, pin, and lock the (base) mft record. */
2009 if (!NInoAttr(ni))
2010 base_ni = ni;
2011 else
2012 base_ni = ni->ext.base_ntfs_ino;
2013 m = map_mft_record(base_ni);
2014 if (IS_ERR(m)) {
2015 err = PTR_ERR(m);
2016 m = NULL;
2017 ctx = NULL;
2018 goto err_out;
2019 }
2020 ctx = ntfs_attr_get_search_ctx(base_ni, m);
2021 if (unlikely(!ctx)) {
2022 err = -ENOMEM;
2023 goto err_out;
2024 }
2025 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
2026 CASE_SENSITIVE, 0, NULL, 0, ctx);
2027 if (unlikely(err)) {
2028 if (err == -ENOENT)
2029 err = -EIO;
2030 goto err_out;
2031 }
2032 m = ctx->mrec;
2033 a = ctx->attr;
2034 /* The total length of the attribute value. */
2035 attr_len = le32_to_cpu(a->data.resident.value_length);
2036 /* Fix an eventual previous failure of ntfs_commit_write(). */
2037 i_size = i_size_read(vi);
2038 if (unlikely(attr_len > i_size)) {
2039 attr_len = i_size;
2040 a->data.resident.value_length = cpu_to_le32(attr_len);
2041 }
2042 /* If we do not need to resize the attribute allocation we are done. */
2043 if (new_size <= attr_len)
2044 goto done_unm;
2045 /* Check if new size is allowed in $AttrDef. */
2046 err = ntfs_attr_size_bounds_check(vol, ni->type, new_size);
2047 if (unlikely(err)) {
2048 if (err == -ERANGE) {
2049 ntfs_error(vol->sb, "Write would cause the inode "
2050 "0x%lx to exceed the maximum size for "
2051 "its attribute type (0x%x). Aborting "
2052 "write.", vi->i_ino,
2053 le32_to_cpu(ni->type));
2054 } else {
2055 ntfs_error(vol->sb, "Inode 0x%lx has unknown "
2056 "attribute type 0x%x. Aborting "
2057 "write.", vi->i_ino,
2058 le32_to_cpu(ni->type));
2059 err = -EIO;
2060 }
2061 goto err_out2;
2062 }
2063 /*
2064 * Extend the attribute record to be able to store the new attribute
2065 * size.
2066 */
2067 if (new_size >= vol->mft_record_size || ntfs_attr_record_resize(m, a,
2068 le16_to_cpu(a->data.resident.value_offset) +
2069 new_size)) {
2070 /* Not enough space in the mft record. */
2071 ntfs_error(vol->sb, "Not enough space in the mft record for "
2072 "the resized attribute value. This is not "
2073 "supported yet. Aborting write.");
2074 err = -EOPNOTSUPP;
2075 goto err_out2;
2076 }
2077 /*
2078 * We have enough space in the mft record to fit the write. This
2079 * implies the attribute is smaller than the mft record and hence the
2080 * attribute must be in a single page and hence page->index must be 0.
2081 */
2082 BUG_ON(page->index);
2083 /*
2084 * If the beginning of the write is past the old size, enlarge the
2085 * attribute value up to the beginning of the write and fill it with
2086 * zeroes.
2087 */
2088 if (from > attr_len) {
2089 memset((u8*)a + le16_to_cpu(a->data.resident.value_offset) +
2090 attr_len, 0, from - attr_len);
2091 a->data.resident.value_length = cpu_to_le32(from);
2092 /* Zero the corresponding area in the page as well. */
2093 if (PageUptodate(page)) {
2094 kaddr = kmap_atomic(page, KM_USER0);
2095 memset(kaddr + attr_len, 0, from - attr_len);
2096 kunmap_atomic(kaddr, KM_USER0);
2097 flush_dcache_page(page);
2098 }
2099 }
2100 flush_dcache_mft_record_page(ctx->ntfs_ino);
2101 mark_mft_record_dirty(ctx->ntfs_ino);
2102done_unm:
2103 ntfs_attr_put_search_ctx(ctx);
2104 unmap_mft_record(base_ni);
2105 /*
2106 * Because resident attributes are handled by memcpy() to/from the
2107 * corresponding MFT record, and because this form of i/o is byte
2108 * aligned rather than block aligned, there is no need to bring the
2109 * page uptodate here as in the non-resident case where we need to
2110 * bring the buffers straddled by the write uptodate before
2111 * generic_file_write() does the copying from userspace.
2112 *
2113 * We thus defer the uptodate bringing of the page region outside the
2114 * region written to to ntfs_commit_write(), which makes the code
2115 * simpler and saves one atomic kmap which is good.
2116 */
2117done:
2118 ntfs_debug("Done.");
2119 return 0;
2120err_out:
2121 if (err == -ENOMEM)
2122 ntfs_warning(vi->i_sb, "Error allocating memory required to "
2123 "prepare the write.");
2124 else {
2125 ntfs_error(vi->i_sb, "Resident attribute prepare write failed "
2126 "with error %i.", err);
2127 NVolSetErrors(vol);
2128 make_bad_inode(vi);
2129 }
2130err_out2:
2131 if (ctx)
2132 ntfs_attr_put_search_ctx(ctx);
2133 if (m)
2134 unmap_mft_record(base_ni);
2135 return err;
2136}
2137
2138/**
2139 * ntfs_commit_nonresident_write -
2140 *
2141 */
2142static int ntfs_commit_nonresident_write(struct page *page,
2143 unsigned from, unsigned to)
2144{
2145 s64 pos = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
2146 struct inode *vi = page->mapping->host;
2147 struct buffer_head *bh, *head;
2148 unsigned int block_start, block_end, blocksize;
2149 BOOL partial;
2150
2151 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
2152 "0x%lx, from = %u, to = %u.", vi->i_ino,
2153 NTFS_I(vi)->type, page->index, from, to);
2154 blocksize = 1 << vi->i_blkbits;
2155
2156 // FIXME: We need a whole slew of special cases in here for compressed
2157 // files for example...
2158 // For now, we know ntfs_prepare_write() would have failed so we can't
2159 // get here in any of the cases which we have to special case, so we
2160 // are just a ripped off, unrolled generic_commit_write().
2161
2162 bh = head = page_buffers(page);
2163 block_start = 0;
2164 partial = FALSE;
2165 do {
2166 block_end = block_start + blocksize;
2167 if (block_end <= from || block_start >= to) {
2168 if (!buffer_uptodate(bh))
2169 partial = TRUE;
2170 } else {
2171 set_buffer_uptodate(bh);
2172 mark_buffer_dirty(bh);
2173 }
2174 } while (block_start = block_end, (bh = bh->b_this_page) != head);
2175 /*
2176 * If this is a partial write which happened to make all buffers
2177 * uptodate then we can optimize away a bogus ->readpage() for the next
2178 * read(). Here we 'discover' whether the page went uptodate as a
2179 * result of this (potentially partial) write.
2180 */
2181 if (!partial)
2182 SetPageUptodate(page);
2183 /*
2184 * Not convinced about this at all. See disparity comment above. For
2185 * now we know ntfs_prepare_write() would have failed in the write
2186 * exceeds i_size case, so this will never trigger which is fine.
2187 */
2188 if (pos > i_size_read(vi)) {
2189 ntfs_error(vi->i_sb, "Writing beyond the existing file size is "
2190 "not supported yet. Sorry.");
2191 return -EOPNOTSUPP;
2192 // vi->i_size = pos;
2193 // mark_inode_dirty(vi);
2194 }
2195 ntfs_debug("Done.");
2196 return 0;
2197}
2198
2199/**
2200 * ntfs_commit_write - commit the received data
2201 *
2202 * This is called from generic_file_write() with i_sem held on the inode
2203 * (@page->mapping->host). The @page is locked but not kmap()ped. The source
2204 * data has already been copied into the @page. ntfs_prepare_write() has been
2205 * called before the data copied and it returned success so we can take the
2206 * results of various BUG checks and some error handling for granted.
2207 *
2208 * Need to mark modified blocks dirty so they get written out later when
2209 * ntfs_writepage() is invoked by the VM.
2210 *
2211 * Return 0 on success or -errno on error.
2212 *
2213 * Should be using generic_commit_write(). This marks buffers uptodate and
2214 * dirty, sets the page uptodate if all buffers in the page are uptodate, and
2215 * updates i_size if the end of io is beyond i_size. In that case, it also
2216 * marks the inode dirty.
2217 *
2218 * Cannot use generic_commit_write() due to ntfs specialities but can look at
2219 * it for implementation guidance.
2220 *
2221 * If things have gone as outlined in ntfs_prepare_write(), then we do not
2222 * need to do any page content modifications here at all, except in the write
2223 * to resident attribute case, where we need to do the uptodate bringing here
2224 * which we combine with the copying into the mft record which means we save
2225 * one atomic kmap.
2226 */
2227static int ntfs_commit_write(struct file *file, struct page *page,
2228 unsigned from, unsigned to)
2229{
2230 struct inode *vi = page->mapping->host;
2231 ntfs_inode *base_ni, *ni = NTFS_I(vi);
2232 char *kaddr, *kattr;
2233 ntfs_attr_search_ctx *ctx;
2234 MFT_RECORD *m;
2235 ATTR_RECORD *a;
2236 u32 attr_len;
2237 int err;
2238
2239 ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
2240 "0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
2241 page->index, from, to);
2242 /* If the attribute is not resident, deal with it elsewhere. */
2243 if (NInoNonResident(ni)) {
2244 /* Only unnamed $DATA attributes can be compressed/encrypted. */
2245 if (ni->type == AT_DATA && !ni->name_len) {
2246 /* Encrypted files need separate handling. */
2247 if (NInoEncrypted(ni)) {
2248 // We never get here at present!
2249 BUG();
2250 }
2251 /* Compressed data streams are handled in compress.c. */
2252 if (NInoCompressed(ni)) {
2253 // TODO: Implement this!
2254 // return ntfs_write_compressed_block(page);
2255 // We never get here at present!
2256 BUG();
2257 }
2258 }
2259 /* Normal data stream. */
2260 return ntfs_commit_nonresident_write(page, from, to);
2261 }
2262 /*
2263 * Attribute is resident, implying it is not compressed, encrypted, or
2264 * sparse.
2265 */
2266 if (!NInoAttr(ni))
2267 base_ni = ni;
2268 else
2269 base_ni = ni->ext.base_ntfs_ino;
2270 /* Map, pin, and lock the mft record. */
2271 m = map_mft_record(base_ni);
2272 if (IS_ERR(m)) {
2273 err = PTR_ERR(m);
2274 m = NULL;
2275 ctx = NULL;
2276 goto err_out;
2277 }
2278 ctx = ntfs_attr_get_search_ctx(base_ni, m);
2279 if (unlikely(!ctx)) {
2280 err = -ENOMEM;
2281 goto err_out;
2282 }
2283 err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
2284 CASE_SENSITIVE, 0, NULL, 0, ctx);
2285 if (unlikely(err)) {
2286 if (err == -ENOENT)
2287 err = -EIO;
2288 goto err_out;
2289 }
2290 a = ctx->attr;
2291 /* The total length of the attribute value. */
2292 attr_len = le32_to_cpu(a->data.resident.value_length);
2293 BUG_ON(from > attr_len);
2294 kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
2295 kaddr = kmap_atomic(page, KM_USER0);
2296 /* Copy the received data from the page to the mft record. */
2297 memcpy(kattr + from, kaddr + from, to - from);
2298 /* Update the attribute length if necessary. */
2299 if (to > attr_len) {
2300 attr_len = to;
2301 a->data.resident.value_length = cpu_to_le32(attr_len);
2302 }
2303 /*
2304 * If the page is not uptodate, bring the out of bounds area(s)
2305 * uptodate by copying data from the mft record to the page.
2306 */
2307 if (!PageUptodate(page)) {
2308 if (from > 0)
2309 memcpy(kaddr, kattr, from);
2310 if (to < attr_len)
2311 memcpy(kaddr + to, kattr + to, attr_len - to);
2312 /* Zero the region outside the end of the attribute value. */
2313 if (attr_len < PAGE_CACHE_SIZE)
2314 memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
2315 /*
2316 * The probability of not having done any of the above is
2317 * extremely small, so we just flush unconditionally.
2318 */
2319 flush_dcache_page(page);
2320 SetPageUptodate(page);
2321 }
2322 kunmap_atomic(kaddr, KM_USER0);
2323 /* Update i_size if necessary. */
2324 if (i_size_read(vi) < attr_len) {
2325 unsigned long flags;
2326
2327 write_lock_irqsave(&ni->size_lock, flags);
2328 ni->allocated_size = ni->initialized_size = attr_len;
2329 i_size_write(vi, attr_len);
2330 write_unlock_irqrestore(&ni->size_lock, flags);
2331 }
2332 /* Mark the mft record dirty, so it gets written back. */
2333 flush_dcache_mft_record_page(ctx->ntfs_ino);
2334 mark_mft_record_dirty(ctx->ntfs_ino);
2335 ntfs_attr_put_search_ctx(ctx);
2336 unmap_mft_record(base_ni);
2337 ntfs_debug("Done.");
2338 return 0;
2339err_out:
2340 if (err == -ENOMEM) {
2341 ntfs_warning(vi->i_sb, "Error allocating memory required to "
2342 "commit the write.");
2343 if (PageUptodate(page)) {
2344 ntfs_warning(vi->i_sb, "Page is uptodate, setting "
2345 "dirty so the write will be retried "
2346 "later on by the VM.");
2347 /*
2348 * Put the page on mapping->dirty_pages, but leave its
2349 * buffers' dirty state as-is.
2350 */
2351 __set_page_dirty_nobuffers(page);
2352 err = 0;
2353 } else
2354 ntfs_error(vi->i_sb, "Page is not uptodate. Written "
2355 "data has been lost.");
2356 } else {
2357 ntfs_error(vi->i_sb, "Resident attribute commit write failed "
2358 "with error %i.", err);
2359 NVolSetErrors(ni->vol);
2360 make_bad_inode(vi);
2361 }
2362 if (ctx)
2363 ntfs_attr_put_search_ctx(ctx);
2364 if (m)
2365 unmap_mft_record(base_ni);
2366 return err;
2367}
2368
2369#endif /* NTFS_RW */ 1545#endif /* NTFS_RW */
2370 1546
2371/** 1547/**
@@ -2377,9 +1553,6 @@ struct address_space_operations ntfs_aops = {
2377 disk request queue. */ 1553 disk request queue. */
2378#ifdef NTFS_RW 1554#ifdef NTFS_RW
2379 .writepage = ntfs_writepage, /* Write dirty page to disk. */ 1555 .writepage = ntfs_writepage, /* Write dirty page to disk. */
2380 .prepare_write = ntfs_prepare_write, /* Prepare page and buffers
2381 ready to receive data. */
2382 .commit_write = ntfs_commit_write, /* Commit received data. */
2383#endif /* NTFS_RW */ 1556#endif /* NTFS_RW */
2384}; 1557};
2385 1558
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-18 18:09:57 -0500