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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/ntfs/aops.c
downloadlinux-linaro-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/ntfs/aops.c')
-rw-r--r--fs/ntfs/aops.c2324
1 files changed, 2324 insertions, 0 deletions
diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
new file mode 100644
index 00000000000..45d56e41ed9
--- /dev/null
+++ b/fs/ntfs/aops.c
@@ -0,0 +1,2324 @@
+/**
+ * aops.c - NTFS kernel address space operations and page cache handling.
+ * Part of the Linux-NTFS project.
+ *
+ * Copyright (c) 2001-2004 Anton Altaparmakov
+ * Copyright (c) 2002 Richard Russon
+ *
+ * This program/include file 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program/include file is distributed in the hope that it will 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 (in the main directory of the Linux-NTFS
+ * distribution in the file COPYING); if not, write to the Free Software
+ * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+
+#include "aops.h"
+#include "attrib.h"
+#include "debug.h"
+#include "inode.h"
+#include "mft.h"
+#include "runlist.h"
+#include "types.h"
+#include "ntfs.h"
+
+/**
+ * ntfs_end_buffer_async_read - async io completion for reading attributes
+ * @bh: buffer head on which io is completed
+ * @uptodate: whether @bh is now uptodate or not
+ *
+ * Asynchronous I/O completion handler for reading pages belonging to the
+ * attribute address space of an inode. The inodes can either be files or
+ * directories or they can be fake inodes describing some attribute.
+ *
+ * If NInoMstProtected(), perform the post read mst fixups when all IO on the
+ * page has been completed and mark the page uptodate or set the error bit on
+ * the page. To determine the size of the records that need fixing up, we
+ * cheat a little bit by setting the index_block_size in ntfs_inode to the ntfs
+ * record size, and index_block_size_bits, to the log(base 2) of the ntfs
+ * record size.
+ */
+static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
+{
+ static DEFINE_SPINLOCK(page_uptodate_lock);
+ unsigned long flags;
+ struct buffer_head *tmp;
+ struct page *page;
+ ntfs_inode *ni;
+ int page_uptodate = 1;
+
+ page = bh->b_page;
+ ni = NTFS_I(page->mapping->host);
+
+ if (likely(uptodate)) {
+ s64 file_ofs;
+
+ set_buffer_uptodate(bh);
+
+ file_ofs = ((s64)page->index << PAGE_CACHE_SHIFT) +
+ bh_offset(bh);
+ /* Check for the current buffer head overflowing. */
+ if (file_ofs + bh->b_size > ni->initialized_size) {
+ char *addr;
+ int ofs = 0;
+
+ if (file_ofs < ni->initialized_size)
+ ofs = ni->initialized_size - file_ofs;
+ addr = kmap_atomic(page, KM_BIO_SRC_IRQ);
+ memset(addr + bh_offset(bh) + ofs, 0, bh->b_size - ofs);
+ flush_dcache_page(page);
+ kunmap_atomic(addr, KM_BIO_SRC_IRQ);
+ }
+ } else {
+ clear_buffer_uptodate(bh);
+ ntfs_error(ni->vol->sb, "Buffer I/O error, logical block %llu.",
+ (unsigned long long)bh->b_blocknr);
+ SetPageError(page);
+ }
+ spin_lock_irqsave(&page_uptodate_lock, flags);
+ clear_buffer_async_read(bh);
+ unlock_buffer(bh);
+ tmp = bh;
+ do {
+ if (!buffer_uptodate(tmp))
+ page_uptodate = 0;
+ if (buffer_async_read(tmp)) {
+ if (likely(buffer_locked(tmp)))
+ goto still_busy;
+ /* Async buffers must be locked. */
+ BUG();
+ }
+ tmp = tmp->b_this_page;
+ } while (tmp != bh);
+ spin_unlock_irqrestore(&page_uptodate_lock, flags);
+ /*
+ * If none of the buffers had errors then we can set the page uptodate,
+ * but we first have to perform the post read mst fixups, if the
+ * attribute is mst protected, i.e. if NInoMstProteced(ni) is true.
+ * Note we ignore fixup errors as those are detected when
+ * map_mft_record() is called which gives us per record granularity
+ * rather than per page granularity.
+ */
+ if (!NInoMstProtected(ni)) {
+ if (likely(page_uptodate && !PageError(page)))
+ SetPageUptodate(page);
+ } else {
+ char *addr;
+ unsigned int i, recs;
+ u32 rec_size;
+
+ rec_size = ni->itype.index.block_size;
+ recs = PAGE_CACHE_SIZE / rec_size;
+ /* Should have been verified before we got here... */
+ BUG_ON(!recs);
+ addr = kmap_atomic(page, KM_BIO_SRC_IRQ);
+ for (i = 0; i < recs; i++)
+ post_read_mst_fixup((NTFS_RECORD*)(addr +
+ i * rec_size), rec_size);
+ flush_dcache_page(page);
+ kunmap_atomic(addr, KM_BIO_SRC_IRQ);
+ if (likely(!PageError(page) && page_uptodate))
+ SetPageUptodate(page);
+ }
+ unlock_page(page);
+ return;
+still_busy:
+ spin_unlock_irqrestore(&page_uptodate_lock, flags);
+ return;
+}
+
+/**
+ * ntfs_read_block - fill a @page of an address space with data
+ * @page: page cache page to fill with data
+ *
+ * Fill the page @page of the address space belonging to the @page->host inode.
+ * We read each buffer asynchronously and when all buffers are read in, our io
+ * completion handler ntfs_end_buffer_read_async(), if required, automatically
+ * applies the mst fixups to the page before finally marking it uptodate and
+ * unlocking it.
+ *
+ * We only enforce allocated_size limit because i_size is checked for in
+ * generic_file_read().
+ *
+ * Return 0 on success and -errno on error.
+ *
+ * Contains an adapted version of fs/buffer.c::block_read_full_page().
+ */
+static int ntfs_read_block(struct page *page)
+{
+ VCN vcn;
+ LCN lcn;
+ ntfs_inode *ni;
+ ntfs_volume *vol;
+ runlist_element *rl;
+ struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
+ sector_t iblock, lblock, zblock;
+ unsigned int blocksize, vcn_ofs;
+ int i, nr;
+ unsigned char blocksize_bits;
+
+ ni = NTFS_I(page->mapping->host);
+ vol = ni->vol;
+
+ /* $MFT/$DATA must have its complete runlist in memory at all times. */
+ BUG_ON(!ni->runlist.rl && !ni->mft_no && !NInoAttr(ni));
+
+ blocksize_bits = VFS_I(ni)->i_blkbits;
+ blocksize = 1 << blocksize_bits;
+
+ if (!page_has_buffers(page))
+ create_empty_buffers(page, blocksize, 0);
+ bh = head = page_buffers(page);
+ if (unlikely(!bh)) {
+ unlock_page(page);
+ return -ENOMEM;
+ }
+
+ iblock = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
+ lblock = (ni->allocated_size + blocksize - 1) >> blocksize_bits;
+ zblock = (ni->initialized_size + blocksize - 1) >> blocksize_bits;
+
+ /* Loop through all the buffers in the page. */
+ rl = NULL;
+ nr = i = 0;
+ do {
+ u8 *kaddr;
+
+ if (unlikely(buffer_uptodate(bh)))
+ continue;
+ if (unlikely(buffer_mapped(bh))) {
+ arr[nr++] = bh;
+ continue;
+ }
+ bh->b_bdev = vol->sb->s_bdev;
+ /* Is the block within the allowed limits? */
+ if (iblock < lblock) {
+ BOOL is_retry = FALSE;
+
+ /* Convert iblock into corresponding vcn and offset. */
+ vcn = (VCN)iblock << blocksize_bits >>
+ vol->cluster_size_bits;
+ vcn_ofs = ((VCN)iblock << blocksize_bits) &
+ vol->cluster_size_mask;
+ if (!rl) {
+lock_retry_remap:
+ down_read(&ni->runlist.lock);
+ rl = ni->runlist.rl;
+ }
+ if (likely(rl != NULL)) {
+ /* Seek to element containing target vcn. */
+ while (rl->length && rl[1].vcn <= vcn)
+ rl++;
+ lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
+ } else
+ lcn = LCN_RL_NOT_MAPPED;
+ /* Successful remap. */
+ if (lcn >= 0) {
+ /* Setup buffer head to correct block. */
+ bh->b_blocknr = ((lcn << vol->cluster_size_bits)
+ + vcn_ofs) >> blocksize_bits;
+ set_buffer_mapped(bh);
+ /* Only read initialized data blocks. */
+ if (iblock < zblock) {
+ arr[nr++] = bh;
+ continue;
+ }
+ /* Fully non-initialized data block, zero it. */
+ goto handle_zblock;
+ }
+ /* It is a hole, need to zero it. */
+ if (lcn == LCN_HOLE)
+ goto handle_hole;
+ /* If first try and runlist unmapped, map and retry. */
+ if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
+ int err;
+ is_retry = TRUE;
+ /*
+ * Attempt to map runlist, dropping lock for
+ * the duration.
+ */
+ up_read(&ni->runlist.lock);
+ err = ntfs_map_runlist(ni, vcn);
+ if (likely(!err))
+ goto lock_retry_remap;
+ rl = NULL;
+ lcn = err;
+ }
+ /* Hard error, zero out region. */
+ bh->b_blocknr = -1;
+ SetPageError(page);
+ ntfs_error(vol->sb, "Failed to read from inode 0x%lx, "
+ "attribute type 0x%x, vcn 0x%llx, "
+ "offset 0x%x because its location on "
+ "disk could not be determined%s "
+ "(error code %lli).", ni->mft_no,
+ ni->type, (unsigned long long)vcn,
+ vcn_ofs, is_retry ? " even after "
+ "retrying" : "", (long long)lcn);
+ }
+ /*
+ * Either iblock was outside lblock limits or
+ * ntfs_rl_vcn_to_lcn() returned error. Just zero that portion
+ * of the page and set the buffer uptodate.
+ */
+handle_hole:
+ bh->b_blocknr = -1UL;
+ clear_buffer_mapped(bh);
+handle_zblock:
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr + i * blocksize, 0, blocksize);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ set_buffer_uptodate(bh);
+ } while (i++, iblock++, (bh = bh->b_this_page) != head);
+
+ /* Release the lock if we took it. */
+ if (rl)
+ up_read(&ni->runlist.lock);
+
+ /* Check we have at least one buffer ready for i/o. */
+ if (nr) {
+ struct buffer_head *tbh;
+
+ /* Lock the buffers. */
+ for (i = 0; i < nr; i++) {
+ tbh = arr[i];
+ lock_buffer(tbh);
+ tbh->b_end_io = ntfs_end_buffer_async_read;
+ set_buffer_async_read(tbh);
+ }
+ /* Finally, start i/o on the buffers. */
+ for (i = 0; i < nr; i++) {
+ tbh = arr[i];
+ if (likely(!buffer_uptodate(tbh)))
+ submit_bh(READ, tbh);
+ else
+ ntfs_end_buffer_async_read(tbh, 1);
+ }
+ return 0;
+ }
+ /* No i/o was scheduled on any of the buffers. */
+ if (likely(!PageError(page)))
+ SetPageUptodate(page);
+ else /* Signal synchronous i/o error. */
+ nr = -EIO;
+ unlock_page(page);
+ return nr;
+}
+
+/**
+ * ntfs_readpage - fill a @page of a @file with data from the device
+ * @file: open file to which the page @page belongs or NULL
+ * @page: page cache page to fill with data
+ *
+ * For non-resident attributes, ntfs_readpage() fills the @page of the open
+ * file @file by calling the ntfs version of the generic block_read_full_page()
+ * function, ntfs_read_block(), which in turn creates and reads in the buffers
+ * associated with the page asynchronously.
+ *
+ * For resident attributes, OTOH, ntfs_readpage() fills @page by copying the
+ * data from the mft record (which at this stage is most likely in memory) and
+ * fills the remainder with zeroes. Thus, in this case, I/O is synchronous, as
+ * even if the mft record is not cached at this point in time, we need to wait
+ * for it to be read in before we can do the copy.
+ *
+ * Return 0 on success and -errno on error.
+ */
+static int ntfs_readpage(struct file *file, struct page *page)
+{
+ loff_t i_size;
+ ntfs_inode *ni, *base_ni;
+ u8 *kaddr;
+ ntfs_attr_search_ctx *ctx;
+ MFT_RECORD *mrec;
+ u32 attr_len;
+ int err = 0;
+
+ BUG_ON(!PageLocked(page));
+ /*
+ * This can potentially happen because we clear PageUptodate() during
+ * ntfs_writepage() of MstProtected() attributes.
+ */
+ if (PageUptodate(page)) {
+ unlock_page(page);
+ return 0;
+ }
+ ni = NTFS_I(page->mapping->host);
+
+ /* NInoNonResident() == NInoIndexAllocPresent() */
+ if (NInoNonResident(ni)) {
+ /*
+ * Only unnamed $DATA attributes can be compressed or
+ * encrypted.
+ */
+ if (ni->type == AT_DATA && !ni->name_len) {
+ /* If file is encrypted, deny access, just like NT4. */
+ if (NInoEncrypted(ni)) {
+ err = -EACCES;
+ goto err_out;
+ }
+ /* Compressed data streams are handled in compress.c. */
+ if (NInoCompressed(ni))
+ return ntfs_read_compressed_block(page);
+ }
+ /* Normal data stream. */
+ return ntfs_read_block(page);
+ }
+ /*
+ * Attribute is resident, implying it is not compressed or encrypted.
+ * This also means the attribute is smaller than an mft record and
+ * hence smaller than a page, so can simply zero out any pages with
+ * index above 0. We can also do this if the file size is 0.
+ */
+ if (unlikely(page->index > 0 || !i_size_read(VFS_I(ni)))) {
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr, 0, PAGE_CACHE_SIZE);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ goto done;
+ }
+ if (!NInoAttr(ni))
+ base_ni = ni;
+ else
+ base_ni = ni->ext.base_ntfs_ino;
+ /* Map, pin, and lock the mft record. */
+ mrec = map_mft_record(base_ni);
+ if (IS_ERR(mrec)) {
+ err = PTR_ERR(mrec);
+ goto err_out;
+ }
+ ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
+ if (unlikely(!ctx)) {
+ err = -ENOMEM;
+ goto unm_err_out;
+ }
+ err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+ CASE_SENSITIVE, 0, NULL, 0, ctx);
+ if (unlikely(err))
+ goto put_unm_err_out;
+ attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
+ i_size = i_size_read(VFS_I(ni));
+ if (unlikely(attr_len > i_size))
+ attr_len = i_size;
+ kaddr = kmap_atomic(page, KM_USER0);
+ /* Copy the data to the page. */
+ memcpy(kaddr, (u8*)ctx->attr +
+ le16_to_cpu(ctx->attr->data.resident.value_offset),
+ attr_len);
+ /* Zero the remainder of the page. */
+ memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+put_unm_err_out:
+ ntfs_attr_put_search_ctx(ctx);
+unm_err_out:
+ unmap_mft_record(base_ni);
+done:
+ SetPageUptodate(page);
+err_out:
+ unlock_page(page);
+ return err;
+}
+
+#ifdef NTFS_RW
+
+/**
+ * ntfs_write_block - write a @page to the backing store
+ * @page: page cache page to write out
+ * @wbc: writeback control structure
+ *
+ * This function is for writing pages belonging to non-resident, non-mst
+ * protected attributes to their backing store.
+ *
+ * For a page with buffers, map and write the dirty buffers asynchronously
+ * under page writeback. For a page without buffers, create buffers for the
+ * page, then proceed as above.
+ *
+ * If a page doesn't have buffers the page dirty state is definitive. If a page
+ * does have buffers, the page dirty state is just a hint, and the buffer dirty
+ * state is definitive. (A hint which has rules: dirty buffers against a clean
+ * page is illegal. Other combinations are legal and need to be handled. In
+ * particular a dirty page containing clean buffers for example.)
+ *
+ * Return 0 on success and -errno on error.
+ *
+ * Based on ntfs_read_block() and __block_write_full_page().
+ */
+static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
+{
+ VCN vcn;
+ LCN lcn;
+ sector_t block, dblock, iblock;
+ struct inode *vi;
+ ntfs_inode *ni;
+ ntfs_volume *vol;
+ runlist_element *rl;
+ struct buffer_head *bh, *head;
+ unsigned int blocksize, vcn_ofs;
+ int err;
+ BOOL need_end_writeback;
+ unsigned char blocksize_bits;
+
+ vi = page->mapping->host;
+ ni = NTFS_I(vi);
+ vol = ni->vol;
+
+ ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
+ "0x%lx.", ni->mft_no, ni->type, page->index);
+
+ BUG_ON(!NInoNonResident(ni));
+ BUG_ON(NInoMstProtected(ni));
+
+ blocksize_bits = vi->i_blkbits;
+ blocksize = 1 << blocksize_bits;
+
+ if (!page_has_buffers(page)) {
+ BUG_ON(!PageUptodate(page));
+ create_empty_buffers(page, blocksize,
+ (1 << BH_Uptodate) | (1 << BH_Dirty));
+ }
+ bh = head = page_buffers(page);
+ if (unlikely(!bh)) {
+ ntfs_warning(vol->sb, "Error allocating page buffers. "
+ "Redirtying page so we try again later.");
+ /*
+ * Put the page back on mapping->dirty_pages, but leave its
+ * buffer's dirty state as-is.
+ */
+ redirty_page_for_writepage(wbc, page);
+ unlock_page(page);
+ return 0;
+ }
+
+ /* NOTE: Different naming scheme to ntfs_read_block()! */
+
+ /* The first block in the page. */
+ block = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
+
+ /* The first out of bounds block for the data size. */
+ dblock = (vi->i_size + blocksize - 1) >> blocksize_bits;
+
+ /* The last (fully or partially) initialized block. */
+ iblock = ni->initialized_size >> blocksize_bits;
+
+ /*
+ * Be very careful. We have no exclusion from __set_page_dirty_buffers
+ * here, and the (potentially unmapped) buffers may become dirty at
+ * any time. If a buffer becomes dirty here after we've inspected it
+ * then we just miss that fact, and the page stays dirty.
+ *
+ * Buffers outside i_size may be dirtied by __set_page_dirty_buffers;
+ * handle that here by just cleaning them.
+ */
+
+ /*
+ * Loop through all the buffers in the page, mapping all the dirty
+ * buffers to disk addresses and handling any aliases from the
+ * underlying block device's mapping.
+ */
+ rl = NULL;
+ err = 0;
+ do {
+ BOOL is_retry = FALSE;
+
+ if (unlikely(block >= dblock)) {
+ /*
+ * Mapped buffers outside i_size will occur, because
+ * this page can be outside i_size when there is a
+ * truncate in progress. The contents of such buffers
+ * were zeroed by ntfs_writepage().
+ *
+ * FIXME: What about the small race window where
+ * ntfs_writepage() has not done any clearing because
+ * the page was within i_size but before we get here,
+ * vmtruncate() modifies i_size?
+ */
+ clear_buffer_dirty(bh);
+ set_buffer_uptodate(bh);
+ continue;
+ }
+
+ /* Clean buffers are not written out, so no need to map them. */
+ if (!buffer_dirty(bh))
+ continue;
+
+ /* Make sure we have enough initialized size. */
+ if (unlikely((block >= iblock) &&
+ (ni->initialized_size < vi->i_size))) {
+ /*
+ * If this page is fully outside initialized size, zero
+ * out all pages between the current initialized size
+ * and the current page. Just use ntfs_readpage() to do
+ * the zeroing transparently.
+ */
+ if (block > iblock) {
+ // TODO:
+ // For each page do:
+ // - read_cache_page()
+ // Again for each page do:
+ // - wait_on_page_locked()
+ // - Check (PageUptodate(page) &&
+ // !PageError(page))
+ // Update initialized size in the attribute and
+ // in the inode.
+ // Again, for each page do:
+ // __set_page_dirty_buffers();
+ // page_cache_release()
+ // We don't need to wait on the writes.
+ // Update iblock.
+ }
+ /*
+ * The current page straddles initialized size. Zero
+ * all non-uptodate buffers and set them uptodate (and
+ * dirty?). Note, there aren't any non-uptodate buffers
+ * if the page is uptodate.
+ * FIXME: For an uptodate page, the buffers may need to
+ * be written out because they were not initialized on
+ * disk before.
+ */
+ if (!PageUptodate(page)) {
+ // TODO:
+ // Zero any non-uptodate buffers up to i_size.
+ // Set them uptodate and dirty.
+ }
+ // TODO:
+ // Update initialized size in the attribute and in the
+ // inode (up to i_size).
+ // Update iblock.
+ // FIXME: This is inefficient. Try to batch the two
+ // size changes to happen in one go.
+ ntfs_error(vol->sb, "Writing beyond initialized size "
+ "is not supported yet. Sorry.");
+ err = -EOPNOTSUPP;
+ break;
+ // Do NOT set_buffer_new() BUT DO clear buffer range
+ // outside write request range.
+ // set_buffer_uptodate() on complete buffers as well as
+ // set_buffer_dirty().
+ }
+
+ /* No need to map buffers that are already mapped. */
+ if (buffer_mapped(bh))
+ continue;
+
+ /* Unmapped, dirty buffer. Need to map it. */
+ bh->b_bdev = vol->sb->s_bdev;
+
+ /* Convert block into corresponding vcn and offset. */
+ vcn = (VCN)block << blocksize_bits;
+ vcn_ofs = vcn & vol->cluster_size_mask;
+ vcn >>= vol->cluster_size_bits;
+ if (!rl) {
+lock_retry_remap:
+ down_read(&ni->runlist.lock);
+ rl = ni->runlist.rl;
+ }
+ if (likely(rl != NULL)) {
+ /* Seek to element containing target vcn. */
+ while (rl->length && rl[1].vcn <= vcn)
+ rl++;
+ lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
+ } else
+ lcn = LCN_RL_NOT_MAPPED;
+ /* Successful remap. */
+ if (lcn >= 0) {
+ /* Setup buffer head to point to correct block. */
+ bh->b_blocknr = ((lcn << vol->cluster_size_bits) +
+ vcn_ofs) >> blocksize_bits;
+ set_buffer_mapped(bh);
+ continue;
+ }
+ /* It is a hole, need to instantiate it. */
+ if (lcn == LCN_HOLE) {
+ // TODO: Instantiate the hole.
+ // clear_buffer_new(bh);
+ // unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+ ntfs_error(vol->sb, "Writing into sparse regions is "
+ "not supported yet. Sorry.");
+ err = -EOPNOTSUPP;
+ break;
+ }
+ /* If first try and runlist unmapped, map and retry. */
+ if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
+ is_retry = TRUE;
+ /*
+ * Attempt to map runlist, dropping lock for
+ * the duration.
+ */
+ up_read(&ni->runlist.lock);
+ err = ntfs_map_runlist(ni, vcn);
+ if (likely(!err))
+ goto lock_retry_remap;
+ rl = NULL;
+ lcn = err;
+ }
+ /* Failed to map the buffer, even after retrying. */
+ bh->b_blocknr = -1;
+ ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
+ "attribute type 0x%x, vcn 0x%llx, offset 0x%x "
+ "because its location on disk could not be "
+ "determined%s (error code %lli).", ni->mft_no,
+ ni->type, (unsigned long long)vcn,
+ vcn_ofs, is_retry ? " even after "
+ "retrying" : "", (long long)lcn);
+ if (!err)
+ err = -EIO;
+ break;
+ } while (block++, (bh = bh->b_this_page) != head);
+
+ /* Release the lock if we took it. */
+ if (rl)
+ up_read(&ni->runlist.lock);
+
+ /* For the error case, need to reset bh to the beginning. */
+ bh = head;
+
+ /* Just an optimization, so ->readpage() isn't called later. */
+ if (unlikely(!PageUptodate(page))) {
+ int uptodate = 1;
+ do {
+ if (!buffer_uptodate(bh)) {
+ uptodate = 0;
+ bh = head;
+ break;
+ }
+ } while ((bh = bh->b_this_page) != head);
+ if (uptodate)
+ SetPageUptodate(page);
+ }
+
+ /* Setup all mapped, dirty buffers for async write i/o. */
+ do {
+ get_bh(bh);
+ if (buffer_mapped(bh) && buffer_dirty(bh)) {
+ lock_buffer(bh);
+ if (test_clear_buffer_dirty(bh)) {
+ BUG_ON(!buffer_uptodate(bh));
+ mark_buffer_async_write(bh);
+ } else
+ unlock_buffer(bh);
+ } else if (unlikely(err)) {
+ /*
+ * For the error case. The buffer may have been set
+ * dirty during attachment to a dirty page.
+ */
+ if (err != -ENOMEM)
+ clear_buffer_dirty(bh);
+ }
+ } while ((bh = bh->b_this_page) != head);
+
+ if (unlikely(err)) {
+ // TODO: Remove the -EOPNOTSUPP check later on...
+ if (unlikely(err == -EOPNOTSUPP))
+ err = 0;
+ else if (err == -ENOMEM) {
+ ntfs_warning(vol->sb, "Error allocating memory. "
+ "Redirtying page so we try again "
+ "later.");
+ /*
+ * Put the page back on mapping->dirty_pages, but
+ * leave its buffer's dirty state as-is.
+ */
+ redirty_page_for_writepage(wbc, page);
+ err = 0;
+ } else
+ SetPageError(page);
+ }
+
+ BUG_ON(PageWriteback(page));
+ set_page_writeback(page); /* Keeps try_to_free_buffers() away. */
+ unlock_page(page);
+
+ /*
+ * Submit the prepared buffers for i/o. Note the page is unlocked,
+ * and the async write i/o completion handler can end_page_writeback()
+ * at any time after the *first* submit_bh(). So the buffers can then
+ * disappear...
+ */
+ need_end_writeback = TRUE;
+ do {
+ struct buffer_head *next = bh->b_this_page;
+ if (buffer_async_write(bh)) {
+ submit_bh(WRITE, bh);
+ need_end_writeback = FALSE;
+ }
+ put_bh(bh);
+ bh = next;
+ } while (bh != head);
+
+ /* If no i/o was started, need to end_page_writeback(). */
+ if (unlikely(need_end_writeback))
+ end_page_writeback(page);
+
+ ntfs_debug("Done.");
+ return err;
+}
+
+/**
+ * ntfs_write_mst_block - write a @page to the backing store
+ * @page: page cache page to write out
+ * @wbc: writeback control structure
+ *
+ * This function is for writing pages belonging to non-resident, mst protected
+ * attributes to their backing store. The only supported attributes are index
+ * allocation and $MFT/$DATA. Both directory inodes and index inodes are
+ * supported for the index allocation case.
+ *
+ * The page must remain locked for the duration of the write because we apply
+ * the mst fixups, write, and then undo the fixups, so if we were to unlock the
+ * page before undoing the fixups, any other user of the page will see the
+ * page contents as corrupt.
+ *
+ * We clear the page uptodate flag for the duration of the function to ensure
+ * exclusion for the $MFT/$DATA case against someone mapping an mft record we
+ * are about to apply the mst fixups to.
+ *
+ * Return 0 on success and -errno on error.
+ *
+ * Based on ntfs_write_block(), ntfs_mft_writepage(), and
+ * write_mft_record_nolock().
+ */
+static int ntfs_write_mst_block(struct page *page,
+ struct writeback_control *wbc)
+{
+ sector_t block, dblock, rec_block;
+ struct inode *vi = page->mapping->host;
+ ntfs_inode *ni = NTFS_I(vi);
+ ntfs_volume *vol = ni->vol;
+ u8 *kaddr;
+ unsigned char bh_size_bits = vi->i_blkbits;
+ unsigned int bh_size = 1 << bh_size_bits;
+ unsigned int rec_size = ni->itype.index.block_size;
+ ntfs_inode *locked_nis[PAGE_CACHE_SIZE / rec_size];
+ struct buffer_head *bh, *head, *tbh, *rec_start_bh;
+ int max_bhs = PAGE_CACHE_SIZE / bh_size;
+ struct buffer_head *bhs[max_bhs];
+ runlist_element *rl;
+ int i, nr_locked_nis, nr_recs, nr_bhs, bhs_per_rec, err, err2;
+ unsigned rec_size_bits;
+ BOOL sync, is_mft, page_is_dirty, rec_is_dirty;
+
+ ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
+ "0x%lx.", vi->i_ino, ni->type, page->index);
+ BUG_ON(!NInoNonResident(ni));
+ BUG_ON(!NInoMstProtected(ni));
+ is_mft = (S_ISREG(vi->i_mode) && !vi->i_ino);
+ /*
+ * NOTE: ntfs_write_mst_block() would be called for $MFTMirr if a page
+ * in its page cache were to be marked dirty. However this should
+ * never happen with the current driver and considering we do not
+ * handle this case here we do want to BUG(), at least for now.
+ */
+ BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
+ (NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
+ BUG_ON(!max_bhs);
+
+ /* Were we called for sync purposes? */
+ sync = (wbc->sync_mode == WB_SYNC_ALL);
+
+ /* Make sure we have mapped buffers. */
+ BUG_ON(!page_has_buffers(page));
+ bh = head = page_buffers(page);
+ BUG_ON(!bh);
+
+ rec_size_bits = ni->itype.index.block_size_bits;
+ BUG_ON(!(PAGE_CACHE_SIZE >> rec_size_bits));
+ bhs_per_rec = rec_size >> bh_size_bits;
+ BUG_ON(!bhs_per_rec);
+
+ /* The first block in the page. */
+ rec_block = block = (sector_t)page->index <<
+ (PAGE_CACHE_SHIFT - bh_size_bits);
+
+ /* The first out of bounds block for the data size. */
+ dblock = (vi->i_size + bh_size - 1) >> bh_size_bits;
+
+ rl = NULL;
+ err = err2 = nr_bhs = nr_recs = nr_locked_nis = 0;
+ page_is_dirty = rec_is_dirty = FALSE;
+ rec_start_bh = NULL;
+ do {
+ BOOL is_retry = FALSE;
+
+ if (likely(block < rec_block)) {
+ if (unlikely(block >= dblock)) {
+ clear_buffer_dirty(bh);
+ continue;
+ }
+ /*
+ * This block is not the first one in the record. We
+ * ignore the buffer's dirty state because we could
+ * have raced with a parallel mark_ntfs_record_dirty().
+ */
+ if (!rec_is_dirty)
+ continue;
+ if (unlikely(err2)) {
+ if (err2 != -ENOMEM)
+ clear_buffer_dirty(bh);
+ continue;
+ }
+ } else /* if (block == rec_block) */ {
+ BUG_ON(block > rec_block);
+ /* This block is the first one in the record. */
+ rec_block += bhs_per_rec;
+ err2 = 0;
+ if (unlikely(block >= dblock)) {
+ clear_buffer_dirty(bh);
+ continue;
+ }
+ if (!buffer_dirty(bh)) {
+ /* Clean records are not written out. */
+ rec_is_dirty = FALSE;
+ continue;
+ }
+ rec_is_dirty = TRUE;
+ rec_start_bh = bh;
+ }
+ /* Need to map the buffer if it is not mapped already. */
+ if (unlikely(!buffer_mapped(bh))) {
+ VCN vcn;
+ LCN lcn;
+ unsigned int vcn_ofs;
+
+ /* Obtain the vcn and offset of the current block. */
+ vcn = (VCN)block << bh_size_bits;
+ vcn_ofs = vcn & vol->cluster_size_mask;
+ vcn >>= vol->cluster_size_bits;
+ if (!rl) {
+lock_retry_remap:
+ down_read(&ni->runlist.lock);
+ rl = ni->runlist.rl;
+ }
+ if (likely(rl != NULL)) {
+ /* Seek to element containing target vcn. */
+ while (rl->length && rl[1].vcn <= vcn)
+ rl++;
+ lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
+ } else
+ lcn = LCN_RL_NOT_MAPPED;
+ /* Successful remap. */
+ if (likely(lcn >= 0)) {
+ /* Setup buffer head to correct block. */
+ bh->b_blocknr = ((lcn <<
+ vol->cluster_size_bits) +
+ vcn_ofs) >> bh_size_bits;
+ set_buffer_mapped(bh);
+ } else {
+ /*
+ * Remap failed. Retry to map the runlist once
+ * unless we are working on $MFT which always
+ * has the whole of its runlist in memory.
+ */
+ if (!is_mft && !is_retry &&
+ lcn == LCN_RL_NOT_MAPPED) {
+ is_retry = TRUE;
+ /*
+ * Attempt to map runlist, dropping
+ * lock for the duration.
+ */
+ up_read(&ni->runlist.lock);
+ err2 = ntfs_map_runlist(ni, vcn);
+ if (likely(!err2))
+ goto lock_retry_remap;
+ if (err2 == -ENOMEM)
+ page_is_dirty = TRUE;
+ lcn = err2;
+ } else
+ err2 = -EIO;
+ /* Hard error. Abort writing this record. */
+ if (!err || err == -ENOMEM)
+ err = err2;
+ bh->b_blocknr = -1;
+ ntfs_error(vol->sb, "Cannot write ntfs record "
+ "0x%llx (inode 0x%lx, "
+ "attribute type 0x%x) because "
+ "its location on disk could "
+ "not be determined (error "
+ "code %lli).", (s64)block <<
+ bh_size_bits >>
+ vol->mft_record_size_bits,
+ ni->mft_no, ni->type,
+ (long long)lcn);
+ /*
+ * If this is not the first buffer, remove the
+ * buffers in this record from the list of
+ * buffers to write and clear their dirty bit
+ * if not error -ENOMEM.
+ */
+ if (rec_start_bh != bh) {
+ while (bhs[--nr_bhs] != rec_start_bh)
+ ;
+ if (err2 != -ENOMEM) {
+ do {
+ clear_buffer_dirty(
+ rec_start_bh);
+ } while ((rec_start_bh =
+ rec_start_bh->
+ b_this_page) !=
+ bh);
+ }
+ }
+ continue;
+ }
+ }
+ BUG_ON(!buffer_uptodate(bh));
+ BUG_ON(nr_bhs >= max_bhs);
+ bhs[nr_bhs++] = bh;
+ } while (block++, (bh = bh->b_this_page) != head);
+ if (unlikely(rl))
+ up_read(&ni->runlist.lock);
+ /* If there were no dirty buffers, we are done. */
+ if (!nr_bhs)
+ goto done;
+ /* Map the page so we can access its contents. */
+ kaddr = kmap(page);
+ /* Clear the page uptodate flag whilst the mst fixups are applied. */
+ BUG_ON(!PageUptodate(page));
+ ClearPageUptodate(page);
+ for (i = 0; i < nr_bhs; i++) {
+ unsigned int ofs;
+
+ /* Skip buffers which are not at the beginning of records. */
+ if (i % bhs_per_rec)
+ continue;
+ tbh = bhs[i];
+ ofs = bh_offset(tbh);
+ if (is_mft) {
+ ntfs_inode *tni;
+ unsigned long mft_no;
+
+ /* Get the mft record number. */
+ mft_no = (((s64)page->index << PAGE_CACHE_SHIFT) + ofs)
+ >> rec_size_bits;
+ /* Check whether to write this mft record. */
+ tni = NULL;
+ if (!ntfs_may_write_mft_record(vol, mft_no,
+ (MFT_RECORD*)(kaddr + ofs), &tni)) {
+ /*
+ * The record should not be written. This
+ * means we need to redirty the page before
+ * returning.
+ */
+ page_is_dirty = TRUE;
+ /*
+ * Remove the buffers in this mft record from
+ * the list of buffers to write.
+ */
+ do {
+ bhs[i] = NULL;
+ } while (++i % bhs_per_rec);
+ continue;
+ }
+ /*
+ * The record should be written. If a locked ntfs
+ * inode was returned, add it to the array of locked
+ * ntfs inodes.
+ */
+ if (tni)
+ locked_nis[nr_locked_nis++] = tni;
+ }
+ /* Apply the mst protection fixups. */
+ err2 = pre_write_mst_fixup((NTFS_RECORD*)(kaddr + ofs),
+ rec_size);
+ if (unlikely(err2)) {
+ if (!err || err == -ENOMEM)
+ err = -EIO;
+ ntfs_error(vol->sb, "Failed to apply mst fixups "
+ "(inode 0x%lx, attribute type 0x%x, "
+ "page index 0x%lx, page offset 0x%x)!"
+ " Unmount and run chkdsk.", vi->i_ino,
+ ni->type, page->index, ofs);
+ /*
+ * Mark all the buffers in this record clean as we do
+ * not want to write corrupt data to disk.
+ */
+ do {
+ clear_buffer_dirty(bhs[i]);
+ bhs[i] = NULL;
+ } while (++i % bhs_per_rec);
+ continue;
+ }
+ nr_recs++;
+ }
+ /* If no records are to be written out, we are done. */
+ if (!nr_recs)
+ goto unm_done;
+ flush_dcache_page(page);
+ /* Lock buffers and start synchronous write i/o on them. */
+ for (i = 0; i < nr_bhs; i++) {
+ tbh = bhs[i];
+ if (!tbh)
+ continue;
+ if (unlikely(test_set_buffer_locked(tbh)))
+ BUG();
+ /* The buffer dirty state is now irrelevant, just clean it. */
+ clear_buffer_dirty(tbh);
+ BUG_ON(!buffer_uptodate(tbh));
+ BUG_ON(!buffer_mapped(tbh));
+ get_bh(tbh);
+ tbh->b_end_io = end_buffer_write_sync;
+ submit_bh(WRITE, tbh);
+ }
+ /* Synchronize the mft mirror now if not @sync. */
+ if (is_mft && !sync)
+ goto do_mirror;
+do_wait:
+ /* Wait on i/o completion of buffers. */
+ for (i = 0; i < nr_bhs; i++) {
+ tbh = bhs[i];
+ if (!tbh)
+ continue;
+ wait_on_buffer(tbh);
+ if (unlikely(!buffer_uptodate(tbh))) {
+ ntfs_error(vol->sb, "I/O error while writing ntfs "
+ "record buffer (inode 0x%lx, "
+ "attribute type 0x%x, page index "
+ "0x%lx, page offset 0x%lx)! Unmount "
+ "and run chkdsk.", vi->i_ino, ni->type,
+ page->index, bh_offset(tbh));
+ if (!err || err == -ENOMEM)
+ err = -EIO;
+ /*
+ * Set the buffer uptodate so the page and buffer
+ * states do not become out of sync.
+ */
+ set_buffer_uptodate(tbh);
+ }
+ }
+ /* If @sync, now synchronize the mft mirror. */
+ if (is_mft && sync) {
+do_mirror:
+ for (i = 0; i < nr_bhs; i++) {
+ unsigned long mft_no;
+ unsigned int ofs;
+
+ /*
+ * Skip buffers which are not at the beginning of
+ * records.
+ */
+ if (i % bhs_per_rec)
+ continue;
+ tbh = bhs[i];
+ /* Skip removed buffers (and hence records). */
+ if (!tbh)
+ continue;
+ ofs = bh_offset(tbh);
+ /* Get the mft record number. */
+ mft_no = (((s64)page->index << PAGE_CACHE_SHIFT) + ofs)
+ >> rec_size_bits;
+ if (mft_no < vol->mftmirr_size)
+ ntfs_sync_mft_mirror(vol, mft_no,
+ (MFT_RECORD*)(kaddr + ofs),
+ sync);
+ }
+ if (!sync)
+ goto do_wait;
+ }
+ /* Remove the mst protection fixups again. */
+ for (i = 0; i < nr_bhs; i++) {
+ if (!(i % bhs_per_rec)) {
+ tbh = bhs[i];
+ if (!tbh)
+ continue;
+ post_write_mst_fixup((NTFS_RECORD*)(kaddr +
+ bh_offset(tbh)));
+ }
+ }
+ flush_dcache_page(page);
+unm_done:
+ /* Unlock any locked inodes. */
+ while (nr_locked_nis-- > 0) {
+ ntfs_inode *tni, *base_tni;
+
+ tni = locked_nis[nr_locked_nis];
+ /* Get the base inode. */
+ down(&tni->extent_lock);
+ if (tni->nr_extents >= 0)
+ base_tni = tni;
+ else {
+ base_tni = tni->ext.base_ntfs_ino;
+ BUG_ON(!base_tni);
+ }
+ up(&tni->extent_lock);
+ ntfs_debug("Unlocking %s inode 0x%lx.",
+ tni == base_tni ? "base" : "extent",
+ tni->mft_no);
+ up(&tni->mrec_lock);
+ atomic_dec(&tni->count);
+ iput(VFS_I(base_tni));
+ }
+ SetPageUptodate(page);
+ kunmap(page);
+done:
+ if (unlikely(err && err != -ENOMEM)) {
+ /*
+ * Set page error if there is only one ntfs record in the page.
+ * Otherwise we would loose per-record granularity.
+ */
+ if (ni->itype.index.block_size == PAGE_CACHE_SIZE)
+ SetPageError(page);
+ NVolSetErrors(vol);
+ }
+ if (page_is_dirty) {
+ ntfs_debug("Page still contains one or more dirty ntfs "
+ "records. Redirtying the page starting at "
+ "record 0x%lx.", page->index <<
+ (PAGE_CACHE_SHIFT - rec_size_bits));
+ redirty_page_for_writepage(wbc, page);
+ unlock_page(page);
+ } else {
+ /*
+ * Keep the VM happy. This must be done otherwise the
+ * radix-tree tag PAGECACHE_TAG_DIRTY remains set even though
+ * the page is clean.
+ */
+ BUG_ON(PageWriteback(page));
+ set_page_writeback(page);
+ unlock_page(page);
+ end_page_writeback(page);
+ }
+ if (likely(!err))
+ ntfs_debug("Done.");
+ return err;
+}
+
+/**
+ * ntfs_writepage - write a @page to the backing store
+ * @page: page cache page to write out
+ * @wbc: writeback control structure
+ *
+ * This is called from the VM when it wants to have a dirty ntfs page cache
+ * page cleaned. The VM has already locked the page and marked it clean.
+ *
+ * For non-resident attributes, ntfs_writepage() writes the @page by calling
+ * the ntfs version of the generic block_write_full_page() function,
+ * ntfs_write_block(), which in turn if necessary creates and writes the
+ * buffers associated with the page asynchronously.
+ *
+ * For resident attributes, OTOH, ntfs_writepage() writes the @page by copying
+ * the data to the mft record (which at this stage is most likely in memory).
+ * The mft record is then marked dirty and written out asynchronously via the
+ * vfs inode dirty code path for the inode the mft record belongs to or via the
+ * vm page dirty code path for the page the mft record is in.
+ *
+ * Based on ntfs_readpage() and fs/buffer.c::block_write_full_page().
+ *
+ * Return 0 on success and -errno on error.
+ */
+static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+ loff_t i_size;
+ struct inode *vi;
+ ntfs_inode *ni, *base_ni;
+ char *kaddr;
+ ntfs_attr_search_ctx *ctx;
+ MFT_RECORD *m;
+ u32 attr_len;
+ int err;
+
+ BUG_ON(!PageLocked(page));
+
+ vi = page->mapping->host;
+ i_size = i_size_read(vi);
+
+ /* Is the page fully outside i_size? (truncate in progress) */
+ if (unlikely(page->index >= (i_size + PAGE_CACHE_SIZE - 1) >>
+ PAGE_CACHE_SHIFT)) {
+ /*
+ * The page may have dirty, unmapped buffers. Make them
+ * freeable here, so the page does not leak.
+ */
+ block_invalidatepage(page, 0);
+ unlock_page(page);
+ ntfs_debug("Write outside i_size - truncated?");
+ return 0;
+ }
+ ni = NTFS_I(vi);
+
+ /* NInoNonResident() == NInoIndexAllocPresent() */
+ if (NInoNonResident(ni)) {
+ /*
+ * Only unnamed $DATA attributes can be compressed, encrypted,
+ * and/or sparse.
+ */
+ if (ni->type == AT_DATA && !ni->name_len) {
+ /* If file is encrypted, deny access, just like NT4. */
+ if (NInoEncrypted(ni)) {
+ unlock_page(page);
+ ntfs_debug("Denying write access to encrypted "
+ "file.");
+ return -EACCES;
+ }
+ /* Compressed data streams are handled in compress.c. */
+ if (NInoCompressed(ni)) {
+ // TODO: Implement and replace this check with
+ // return ntfs_write_compressed_block(page);
+ unlock_page(page);
+ ntfs_error(vi->i_sb, "Writing to compressed "
+ "files is not supported yet. "
+ "Sorry.");
+ return -EOPNOTSUPP;
+ }
+ // TODO: Implement and remove this check.
+ if (NInoSparse(ni)) {
+ unlock_page(page);
+ ntfs_error(vi->i_sb, "Writing to sparse files "
+ "is not supported yet. Sorry.");
+ return -EOPNOTSUPP;
+ }
+ }
+ /* We have to zero every time due to mmap-at-end-of-file. */
+ if (page->index >= (i_size >> PAGE_CACHE_SHIFT)) {
+ /* The page straddles i_size. */
+ unsigned int ofs = i_size & ~PAGE_CACHE_MASK;
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr + ofs, 0, PAGE_CACHE_SIZE - ofs);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ }
+ /* Handle mst protected attributes. */
+ if (NInoMstProtected(ni))
+ return ntfs_write_mst_block(page, wbc);
+ /* Normal data stream. */
+ return ntfs_write_block(page, wbc);
+ }
+ /*
+ * Attribute is resident, implying it is not compressed, encrypted,
+ * sparse, or mst protected. This also means the attribute is smaller
+ * than an mft record and hence smaller than a page, so can simply
+ * return error on any pages with index above 0.
+ */
+ BUG_ON(page_has_buffers(page));
+ BUG_ON(!PageUptodate(page));
+ if (unlikely(page->index > 0)) {
+ ntfs_error(vi->i_sb, "BUG()! page->index (0x%lx) > 0. "
+ "Aborting write.", page->index);
+ BUG_ON(PageWriteback(page));
+ set_page_writeback(page);
+ unlock_page(page);
+ end_page_writeback(page);
+ return -EIO;
+ }
+ if (!NInoAttr(ni))
+ base_ni = ni;
+ else
+ base_ni = ni->ext.base_ntfs_ino;
+ /* Map, pin, and lock the mft record. */
+ m = map_mft_record(base_ni);
+ if (IS_ERR(m)) {
+ err = PTR_ERR(m);
+ m = NULL;
+ ctx = NULL;
+ goto err_out;
+ }
+ ctx = ntfs_attr_get_search_ctx(base_ni, m);
+ if (unlikely(!ctx)) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+ err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+ CASE_SENSITIVE, 0, NULL, 0, ctx);
+ if (unlikely(err))
+ goto err_out;
+ /*
+ * Keep the VM happy. This must be done otherwise the radix-tree tag
+ * PAGECACHE_TAG_DIRTY remains set even though the page is clean.
+ */
+ BUG_ON(PageWriteback(page));
+ set_page_writeback(page);
+ unlock_page(page);
+
+ /*
+ * Here, we don't need to zero the out of bounds area everytime because
+ * the below memcpy() already takes care of the mmap-at-end-of-file
+ * requirements. If the file is converted to a non-resident one, then
+ * the code path use is switched to the non-resident one where the
+ * zeroing happens on each ntfs_writepage() invocation.
+ *
+ * The above also applies nicely when i_size is decreased.
+ *
+ * When i_size is increased, the memory between the old and new i_size
+ * _must_ be zeroed (or overwritten with new data). Otherwise we will
+ * expose data to userspace/disk which should never have been exposed.
+ *
+ * FIXME: Ensure that i_size increases do the zeroing/overwriting and
+ * if we cannot guarantee that, then enable the zeroing below. If the
+ * zeroing below is enabled, we MUST move the unlock_page() from above
+ * to after the kunmap_atomic(), i.e. just before the
+ * end_page_writeback().
+ * UPDATE: ntfs_prepare/commit_write() do the zeroing on i_size
+ * increases for resident attributes so those are ok.
+ * TODO: ntfs_truncate(), others?
+ */
+
+ attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
+ i_size = i_size_read(VFS_I(ni));
+ kaddr = kmap_atomic(page, KM_USER0);
+ if (unlikely(attr_len > i_size)) {
+ /* Zero out of bounds area in the mft record. */
+ memset((u8*)ctx->attr + le16_to_cpu(
+ ctx->attr->data.resident.value_offset) +
+ i_size, 0, attr_len - i_size);
+ attr_len = i_size;
+ }
+ /* Copy the data from the page to the mft record. */
+ memcpy((u8*)ctx->attr +
+ le16_to_cpu(ctx->attr->data.resident.value_offset),
+ kaddr, attr_len);
+ flush_dcache_mft_record_page(ctx->ntfs_ino);
+ /* Zero out of bounds area in the page cache page. */
+ memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+
+ end_page_writeback(page);
+
+ /* Mark the mft record dirty, so it gets written back. */
+ mark_mft_record_dirty(ctx->ntfs_ino);
+ ntfs_attr_put_search_ctx(ctx);
+ unmap_mft_record(base_ni);
+ return 0;
+err_out:
+ if (err == -ENOMEM) {
+ ntfs_warning(vi->i_sb, "Error allocating memory. Redirtying "
+ "page so we try again later.");
+ /*
+ * Put the page back on mapping->dirty_pages, but leave its
+ * buffers' dirty state as-is.
+ */
+ redirty_page_for_writepage(wbc, page);
+ err = 0;
+ } else {
+ ntfs_error(vi->i_sb, "Resident attribute write failed with "
+ "error %i. Setting page error flag.", err);
+ SetPageError(page);
+ }
+ unlock_page(page);
+ if (ctx)
+ ntfs_attr_put_search_ctx(ctx);
+ if (m)
+ unmap_mft_record(base_ni);
+ return err;
+}
+
+/**
+ * ntfs_prepare_nonresident_write -
+ *
+ */
+static int ntfs_prepare_nonresident_write(struct page *page,
+ unsigned from, unsigned to)
+{
+ VCN vcn;
+ LCN lcn;
+ sector_t block, ablock, iblock;
+ struct inode *vi;
+ ntfs_inode *ni;
+ ntfs_volume *vol;
+ runlist_element *rl;
+ struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
+ unsigned int vcn_ofs, block_start, block_end, blocksize;
+ int err;
+ BOOL is_retry;
+ unsigned char blocksize_bits;
+
+ vi = page->mapping->host;
+ ni = NTFS_I(vi);
+ vol = ni->vol;
+
+ ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
+ "0x%lx, from = %u, to = %u.", ni->mft_no, ni->type,
+ page->index, from, to);
+
+ BUG_ON(!NInoNonResident(ni));
+
+ blocksize_bits = vi->i_blkbits;
+ blocksize = 1 << blocksize_bits;
+
+ /*
+ * create_empty_buffers() will create uptodate/dirty buffers if the
+ * page is uptodate/dirty.
+ */
+ if (!page_has_buffers(page))
+ create_empty_buffers(page, blocksize, 0);
+ bh = head = page_buffers(page);
+ if (unlikely(!bh))
+ return -ENOMEM;
+
+ /* The first block in the page. */
+ block = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
+
+ /*
+ * The first out of bounds block for the allocated size. No need to
+ * round up as allocated_size is in multiples of cluster size and the
+ * minimum cluster size is 512 bytes, which is equal to the smallest
+ * blocksize.
+ */
+ ablock = ni->allocated_size >> blocksize_bits;
+
+ /* The last (fully or partially) initialized block. */
+ iblock = ni->initialized_size >> blocksize_bits;
+
+ /* Loop through all the buffers in the page. */
+ block_start = 0;
+ rl = NULL;
+ err = 0;
+ do {
+ block_end = block_start + blocksize;
+ /*
+ * If buffer @bh is outside the write, just mark it uptodate
+ * if the page is uptodate and continue with the next buffer.
+ */
+ if (block_end <= from || block_start >= to) {
+ if (PageUptodate(page)) {
+ if (!buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
+ }
+ continue;
+ }
+ /*
+ * @bh is at least partially being written to.
+ * Make sure it is not marked as new.
+ */
+ //if (buffer_new(bh))
+ // clear_buffer_new(bh);
+
+ if (block >= ablock) {
+ // TODO: block is above allocated_size, need to
+ // allocate it. Best done in one go to accommodate not
+ // only block but all above blocks up to and including:
+ // ((page->index << PAGE_CACHE_SHIFT) + to + blocksize
+ // - 1) >> blobksize_bits. Obviously will need to round
+ // up to next cluster boundary, too. This should be
+ // done with a helper function, so it can be reused.
+ ntfs_error(vol->sb, "Writing beyond allocated size "
+ "is not supported yet. Sorry.");
+ err = -EOPNOTSUPP;
+ goto err_out;
+ // Need to update ablock.
+ // Need to set_buffer_new() on all block bhs that are
+ // newly allocated.
+ }
+ /*
+ * Now we have enough allocated size to fulfill the whole
+ * request, i.e. block < ablock is true.
+ */
+ if (unlikely((block >= iblock) &&
+ (ni->initialized_size < vi->i_size))) {
+ /*
+ * If this page is fully outside initialized size, zero
+ * out all pages between the current initialized size
+ * and the current page. Just use ntfs_readpage() to do
+ * the zeroing transparently.
+ */
+ if (block > iblock) {
+ // TODO:
+ // For each page do:
+ // - read_cache_page()
+ // Again for each page do:
+ // - wait_on_page_locked()
+ // - Check (PageUptodate(page) &&
+ // !PageError(page))
+ // Update initialized size in the attribute and
+ // in the inode.
+ // Again, for each page do:
+ // __set_page_dirty_buffers();
+ // page_cache_release()
+ // We don't need to wait on the writes.
+ // Update iblock.
+ }
+ /*
+ * The current page straddles initialized size. Zero
+ * all non-uptodate buffers and set them uptodate (and
+ * dirty?). Note, there aren't any non-uptodate buffers
+ * if the page is uptodate.
+ * FIXME: For an uptodate page, the buffers may need to
+ * be written out because they were not initialized on
+ * disk before.
+ */
+ if (!PageUptodate(page)) {
+ // TODO:
+ // Zero any non-uptodate buffers up to i_size.
+ // Set them uptodate and dirty.
+ }
+ // TODO:
+ // Update initialized size in the attribute and in the
+ // inode (up to i_size).
+ // Update iblock.
+ // FIXME: This is inefficient. Try to batch the two
+ // size changes to happen in one go.
+ ntfs_error(vol->sb, "Writing beyond initialized size "
+ "is not supported yet. Sorry.");
+ err = -EOPNOTSUPP;
+ goto err_out;
+ // Do NOT set_buffer_new() BUT DO clear buffer range
+ // outside write request range.
+ // set_buffer_uptodate() on complete buffers as well as
+ // set_buffer_dirty().
+ }
+
+ /* Need to map unmapped buffers. */
+ if (!buffer_mapped(bh)) {
+ /* Unmapped buffer. Need to map it. */
+ bh->b_bdev = vol->sb->s_bdev;
+
+ /* Convert block into corresponding vcn and offset. */
+ vcn = (VCN)block << blocksize_bits >>
+ vol->cluster_size_bits;
+ vcn_ofs = ((VCN)block << blocksize_bits) &
+ vol->cluster_size_mask;
+
+ is_retry = FALSE;
+ if (!rl) {
+lock_retry_remap:
+ down_read(&ni->runlist.lock);
+ rl = ni->runlist.rl;
+ }
+ if (likely(rl != NULL)) {
+ /* Seek to element containing target vcn. */
+ while (rl->length && rl[1].vcn <= vcn)
+ rl++;
+ lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
+ } else
+ lcn = LCN_RL_NOT_MAPPED;
+ if (unlikely(lcn < 0)) {
+ /*
+ * We extended the attribute allocation above.
+ * If we hit an ENOENT here it means that the
+ * allocation was insufficient which is a bug.
+ */
+ BUG_ON(lcn == LCN_ENOENT);
+
+ /* It is a hole, need to instantiate it. */
+ if (lcn == LCN_HOLE) {
+ // TODO: Instantiate the hole.
+ // clear_buffer_new(bh);
+ // unmap_underlying_metadata(bh->b_bdev,
+ // bh->b_blocknr);
+ // For non-uptodate buffers, need to
+ // zero out the region outside the
+ // request in this bh or all bhs,
+ // depending on what we implemented
+ // above.
+ // Need to flush_dcache_page().
+ // Or could use set_buffer_new()
+ // instead?
+ ntfs_error(vol->sb, "Writing into "
+ "sparse regions is "
+ "not supported yet. "
+ "Sorry.");
+ err = -EOPNOTSUPP;
+ goto err_out;
+ } else if (!is_retry &&
+ lcn == LCN_RL_NOT_MAPPED) {
+ is_retry = TRUE;
+ /*
+ * Attempt to map runlist, dropping
+ * lock for the duration.
+ */
+ up_read(&ni->runlist.lock);
+ err = ntfs_map_runlist(ni, vcn);
+ if (likely(!err))
+ goto lock_retry_remap;
+ rl = NULL;
+ lcn = err;
+ }
+ /*
+ * Failed to map the buffer, even after
+ * retrying.
+ */
+ bh->b_blocknr = -1;
+ ntfs_error(vol->sb, "Failed to write to inode "
+ "0x%lx, attribute type 0x%x, "
+ "vcn 0x%llx, offset 0x%x "
+ "because its location on disk "
+ "could not be determined%s "
+ "(error code %lli).",
+ ni->mft_no, ni->type,
+ (unsigned long long)vcn,
+ vcn_ofs, is_retry ? " even "
+ "after retrying" : "",
+ (long long)lcn);
+ if (!err)
+ err = -EIO;
+ goto err_out;
+ }
+ /* We now have a successful remap, i.e. lcn >= 0. */
+
+ /* Setup buffer head to correct block. */
+ bh->b_blocknr = ((lcn << vol->cluster_size_bits)
+ + vcn_ofs) >> blocksize_bits;
+ set_buffer_mapped(bh);
+
+ // FIXME: Something analogous to this is needed for
+ // each newly allocated block, i.e. BH_New.
+ // FIXME: Might need to take this out of the
+ // if (!buffer_mapped(bh)) {}, depending on how we
+ // implement things during the allocated_size and
+ // initialized_size extension code above.
+ if (buffer_new(bh)) {
+ clear_buffer_new(bh);
+ unmap_underlying_metadata(bh->b_bdev,
+ bh->b_blocknr);
+ if (PageUptodate(page)) {
+ set_buffer_uptodate(bh);
+ continue;
+ }
+ /*
+ * Page is _not_ uptodate, zero surrounding
+ * region. NOTE: This is how we decide if to
+ * zero or not!
+ */
+ if (block_end > to || block_start < from) {
+ void *kaddr;
+
+ kaddr = kmap_atomic(page, KM_USER0);
+ if (block_end > to)
+ memset(kaddr + to, 0,
+ block_end - to);
+ if (block_start < from)
+ memset(kaddr + block_start, 0,
+ from -
+ block_start);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ }
+ continue;
+ }
+ }
+ /* @bh is mapped, set it uptodate if the page is uptodate. */
+ if (PageUptodate(page)) {
+ if (!buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
+ continue;
+ }
+ /*
+ * The page is not uptodate. The buffer is mapped. If it is not
+ * uptodate, and it is only partially being written to, we need
+ * to read the buffer in before the write, i.e. right now.
+ */
+ if (!buffer_uptodate(bh) &&
+ (block_start < from || block_end > to)) {
+ ll_rw_block(READ, 1, &bh);
+ *wait_bh++ = bh;
+ }
+ } while (block++, block_start = block_end,
+ (bh = bh->b_this_page) != head);
+
+ /* Release the lock if we took it. */
+ if (rl) {
+ up_read(&ni->runlist.lock);
+ rl = NULL;
+ }
+
+ /* If we issued read requests, let them complete. */
+ while (wait_bh > wait) {
+ wait_on_buffer(*--wait_bh);
+ if (!buffer_uptodate(*wait_bh))
+ return -EIO;
+ }
+
+ ntfs_debug("Done.");
+ return 0;
+err_out:
+ /*
+ * Zero out any newly allocated blocks to avoid exposing stale data.
+ * If BH_New is set, we know that the block was newly allocated in the
+ * above loop.
+ * FIXME: What about initialized_size increments? Have we done all the
+ * required zeroing above? If not this error handling is broken, and
+ * in particular the if (block_end <= from) check is completely bogus.
+ */
+ bh = head;
+ block_start = 0;
+ is_retry = FALSE;
+ do {
+ block_end = block_start + blocksize;
+ if (block_end <= from)
+ continue;
+ if (block_start >= to)
+ break;
+ if (buffer_new(bh)) {
+ void *kaddr;
+
+ clear_buffer_new(bh);
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr + block_start, 0, bh->b_size);
+ kunmap_atomic(kaddr, KM_USER0);
+ set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
+ is_retry = TRUE;
+ }
+ } while (block_start = block_end, (bh = bh->b_this_page) != head);
+ if (is_retry)
+ flush_dcache_page(page);
+ if (rl)
+ up_read(&ni->runlist.lock);
+ return err;
+}
+
+/**
+ * ntfs_prepare_write - prepare a page for receiving data
+ *
+ * This is called from generic_file_write() with i_sem held on the inode
+ * (@page->mapping->host). The @page is locked but not kmap()ped. The source
+ * data has not yet been copied into the @page.
+ *
+ * Need to extend the attribute/fill in holes if necessary, create blocks and
+ * make partially overwritten blocks uptodate,
+ *
+ * i_size is not to be modified yet.
+ *
+ * Return 0 on success or -errno on error.
+ *
+ * Should be using block_prepare_write() [support for sparse files] or
+ * cont_prepare_write() [no support for sparse files]. Cannot do that due to
+ * ntfs specifics but can look at them for implementation guidance.
+ *
+ * Note: In the range, @from is inclusive and @to is exclusive, i.e. @from is
+ * the first byte in the page that will be written to and @to is the first byte
+ * after the last byte that will be written to.
+ */
+static int ntfs_prepare_write(struct file *file, struct page *page,
+ unsigned from, unsigned to)
+{
+ s64 new_size;
+ struct inode *vi = page->mapping->host;
+ ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
+ ntfs_volume *vol = ni->vol;
+ ntfs_attr_search_ctx *ctx = NULL;
+ MFT_RECORD *m = NULL;
+ ATTR_RECORD *a;
+ u8 *kaddr;
+ u32 attr_len;
+ int err;
+
+ ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
+ "0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
+ page->index, from, to);
+ BUG_ON(!PageLocked(page));
+ BUG_ON(from > PAGE_CACHE_SIZE);
+ BUG_ON(to > PAGE_CACHE_SIZE);
+ BUG_ON(from > to);
+ BUG_ON(NInoMstProtected(ni));
+ /*
+ * If a previous ntfs_truncate() failed, repeat it and abort if it
+ * fails again.
+ */
+ if (unlikely(NInoTruncateFailed(ni))) {
+ down_write(&vi->i_alloc_sem);
+ err = ntfs_truncate(vi);
+ up_write(&vi->i_alloc_sem);
+ if (err || NInoTruncateFailed(ni)) {
+ if (!err)
+ err = -EIO;
+ goto err_out;
+ }
+ }
+ /* If the attribute is not resident, deal with it elsewhere. */
+ if (NInoNonResident(ni)) {
+ /*
+ * Only unnamed $DATA attributes can be compressed, encrypted,
+ * and/or sparse.
+ */
+ if (ni->type == AT_DATA && !ni->name_len) {
+ /* If file is encrypted, deny access, just like NT4. */
+ if (NInoEncrypted(ni)) {
+ ntfs_debug("Denying write access to encrypted "
+ "file.");
+ return -EACCES;
+ }
+ /* Compressed data streams are handled in compress.c. */
+ if (NInoCompressed(ni)) {
+ // TODO: Implement and replace this check with
+ // return ntfs_write_compressed_block(page);
+ ntfs_error(vi->i_sb, "Writing to compressed "
+ "files is not supported yet. "
+ "Sorry.");
+ return -EOPNOTSUPP;
+ }
+ // TODO: Implement and remove this check.
+ if (NInoSparse(ni)) {
+ ntfs_error(vi->i_sb, "Writing to sparse files "
+ "is not supported yet. Sorry.");
+ return -EOPNOTSUPP;
+ }
+ }
+ /* Normal data stream. */
+ return ntfs_prepare_nonresident_write(page, from, to);
+ }
+ /*
+ * Attribute is resident, implying it is not compressed, encrypted, or
+ * sparse.
+ */
+ BUG_ON(page_has_buffers(page));
+ new_size = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
+ /* If we do not need to resize the attribute allocation we are done. */
+ if (new_size <= vi->i_size)
+ goto done;
+
+ // FIXME: We abort for now as this code is not safe.
+ ntfs_error(vi->i_sb, "Changing the file size is not supported yet. "
+ "Sorry.");
+ return -EOPNOTSUPP;
+
+ /* Map, pin, and lock the (base) mft record. */
+ if (!NInoAttr(ni))
+ base_ni = ni;
+ else
+ base_ni = ni->ext.base_ntfs_ino;
+ m = map_mft_record(base_ni);
+ if (IS_ERR(m)) {
+ err = PTR_ERR(m);
+ m = NULL;
+ ctx = NULL;
+ goto err_out;
+ }
+ ctx = ntfs_attr_get_search_ctx(base_ni, m);
+ if (unlikely(!ctx)) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+ err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+ CASE_SENSITIVE, 0, NULL, 0, ctx);
+ if (unlikely(err)) {
+ if (err == -ENOENT)
+ err = -EIO;
+ goto err_out;
+ }
+ m = ctx->mrec;
+ a = ctx->attr;
+ /* The total length of the attribute value. */
+ attr_len = le32_to_cpu(a->data.resident.value_length);
+ BUG_ON(vi->i_size != attr_len);
+ /* Check if new size is allowed in $AttrDef. */
+ err = ntfs_attr_size_bounds_check(vol, ni->type, new_size);
+ if (unlikely(err)) {
+ if (err == -ERANGE) {
+ ntfs_error(vol->sb, "Write would cause the inode "
+ "0x%lx to exceed the maximum size for "
+ "its attribute type (0x%x). Aborting "
+ "write.", vi->i_ino,
+ le32_to_cpu(ni->type));
+ } else {
+ ntfs_error(vol->sb, "Inode 0x%lx has unknown "
+ "attribute type 0x%x. Aborting "
+ "write.", vi->i_ino,
+ le32_to_cpu(ni->type));
+ err = -EIO;
+ }
+ goto err_out2;
+ }
+ /*
+ * Extend the attribute record to be able to store the new attribute
+ * size.
+ */
+ if (new_size >= vol->mft_record_size || ntfs_attr_record_resize(m, a,
+ le16_to_cpu(a->data.resident.value_offset) +
+ new_size)) {
+ /* Not enough space in the mft record. */
+ ntfs_error(vol->sb, "Not enough space in the mft record for "
+ "the resized attribute value. This is not "
+ "supported yet. Aborting write.");
+ err = -EOPNOTSUPP;
+ goto err_out2;
+ }
+ /*
+ * We have enough space in the mft record to fit the write. This
+ * implies the attribute is smaller than the mft record and hence the
+ * attribute must be in a single page and hence page->index must be 0.
+ */
+ BUG_ON(page->index);
+ /*
+ * If the beginning of the write is past the old size, enlarge the
+ * attribute value up to the beginning of the write and fill it with
+ * zeroes.
+ */
+ if (from > attr_len) {
+ memset((u8*)a + le16_to_cpu(a->data.resident.value_offset) +
+ attr_len, 0, from - attr_len);
+ a->data.resident.value_length = cpu_to_le32(from);
+ /* Zero the corresponding area in the page as well. */
+ if (PageUptodate(page)) {
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr + attr_len, 0, from - attr_len);
+ kunmap_atomic(kaddr, KM_USER0);
+ flush_dcache_page(page);
+ }
+ }
+ flush_dcache_mft_record_page(ctx->ntfs_ino);
+ mark_mft_record_dirty(ctx->ntfs_ino);
+ ntfs_attr_put_search_ctx(ctx);
+ unmap_mft_record(base_ni);
+ /*
+ * Because resident attributes are handled by memcpy() to/from the
+ * corresponding MFT record, and because this form of i/o is byte
+ * aligned rather than block aligned, there is no need to bring the
+ * page uptodate here as in the non-resident case where we need to
+ * bring the buffers straddled by the write uptodate before
+ * generic_file_write() does the copying from userspace.
+ *
+ * We thus defer the uptodate bringing of the page region outside the
+ * region written to to ntfs_commit_write(), which makes the code
+ * simpler and saves one atomic kmap which is good.
+ */
+done:
+ ntfs_debug("Done.");
+ return 0;
+err_out:
+ if (err == -ENOMEM)
+ ntfs_warning(vi->i_sb, "Error allocating memory required to "
+ "prepare the write.");
+ else {
+ ntfs_error(vi->i_sb, "Resident attribute prepare write failed "
+ "with error %i.", err);
+ NVolSetErrors(vol);
+ make_bad_inode(vi);
+ }
+err_out2:
+ if (ctx)
+ ntfs_attr_put_search_ctx(ctx);
+ if (m)
+ unmap_mft_record(base_ni);
+ return err;
+}
+
+/**
+ * ntfs_commit_nonresident_write -
+ *
+ */
+static int ntfs_commit_nonresident_write(struct page *page,
+ unsigned from, unsigned to)
+{
+ s64 pos = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
+ struct inode *vi = page->mapping->host;
+ struct buffer_head *bh, *head;
+ unsigned int block_start, block_end, blocksize;
+ BOOL partial;
+
+ ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
+ "0x%lx, from = %u, to = %u.", vi->i_ino,
+ NTFS_I(vi)->type, page->index, from, to);
+ blocksize = 1 << vi->i_blkbits;
+
+ // FIXME: We need a whole slew of special cases in here for compressed
+ // files for example...
+ // For now, we know ntfs_prepare_write() would have failed so we can't
+ // get here in any of the cases which we have to special case, so we
+ // are just a ripped off, unrolled generic_commit_write().
+
+ bh = head = page_buffers(page);
+ block_start = 0;
+ partial = FALSE;
+ do {
+ block_end = block_start + blocksize;
+ if (block_end <= from || block_start >= to) {
+ if (!buffer_uptodate(bh))
+ partial = TRUE;
+ } else {
+ set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
+ }
+ } while (block_start = block_end, (bh = bh->b_this_page) != head);
+ /*
+ * If this is a partial write which happened to make all buffers
+ * uptodate then we can optimize away a bogus ->readpage() for the next
+ * read(). Here we 'discover' whether the page went uptodate as a
+ * result of this (potentially partial) write.
+ */
+ if (!partial)
+ SetPageUptodate(page);
+ /*
+ * Not convinced about this at all. See disparity comment above. For
+ * now we know ntfs_prepare_write() would have failed in the write
+ * exceeds i_size case, so this will never trigger which is fine.
+ */
+ if (pos > vi->i_size) {
+ ntfs_error(vi->i_sb, "Writing beyond the existing file size is "
+ "not supported yet. Sorry.");
+ return -EOPNOTSUPP;
+ // vi->i_size = pos;
+ // mark_inode_dirty(vi);
+ }
+ ntfs_debug("Done.");
+ return 0;
+}
+
+/**
+ * ntfs_commit_write - commit the received data
+ *
+ * This is called from generic_file_write() with i_sem held on the inode
+ * (@page->mapping->host). The @page is locked but not kmap()ped. The source
+ * data has already been copied into the @page. ntfs_prepare_write() has been
+ * called before the data copied and it returned success so we can take the
+ * results of various BUG checks and some error handling for granted.
+ *
+ * Need to mark modified blocks dirty so they get written out later when
+ * ntfs_writepage() is invoked by the VM.
+ *
+ * Return 0 on success or -errno on error.
+ *
+ * Should be using generic_commit_write(). This marks buffers uptodate and
+ * dirty, sets the page uptodate if all buffers in the page are uptodate, and
+ * updates i_size if the end of io is beyond i_size. In that case, it also
+ * marks the inode dirty.
+ *
+ * Cannot use generic_commit_write() due to ntfs specialities but can look at
+ * it for implementation guidance.
+ *
+ * If things have gone as outlined in ntfs_prepare_write(), then we do not
+ * need to do any page content modifications here at all, except in the write
+ * to resident attribute case, where we need to do the uptodate bringing here
+ * which we combine with the copying into the mft record which means we save
+ * one atomic kmap.
+ */
+static int ntfs_commit_write(struct file *file, struct page *page,
+ unsigned from, unsigned to)
+{
+ struct inode *vi = page->mapping->host;
+ ntfs_inode *base_ni, *ni = NTFS_I(vi);
+ char *kaddr, *kattr;
+ ntfs_attr_search_ctx *ctx;
+ MFT_RECORD *m;
+ ATTR_RECORD *a;
+ u32 attr_len;
+ int err;
+
+ ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
+ "0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
+ page->index, from, to);
+ /* If the attribute is not resident, deal with it elsewhere. */
+ if (NInoNonResident(ni)) {
+ /* Only unnamed $DATA attributes can be compressed/encrypted. */
+ if (ni->type == AT_DATA && !ni->name_len) {
+ /* Encrypted files need separate handling. */
+ if (NInoEncrypted(ni)) {
+ // We never get here at present!
+ BUG();
+ }
+ /* Compressed data streams are handled in compress.c. */
+ if (NInoCompressed(ni)) {
+ // TODO: Implement this!
+ // return ntfs_write_compressed_block(page);
+ // We never get here at present!
+ BUG();
+ }
+ }
+ /* Normal data stream. */
+ return ntfs_commit_nonresident_write(page, from, to);
+ }
+ /*
+ * Attribute is resident, implying it is not compressed, encrypted, or
+ * sparse.
+ */
+ if (!NInoAttr(ni))
+ base_ni = ni;
+ else
+ base_ni = ni->ext.base_ntfs_ino;
+ /* Map, pin, and lock the mft record. */
+ m = map_mft_record(base_ni);
+ if (IS_ERR(m)) {
+ err = PTR_ERR(m);
+ m = NULL;
+ ctx = NULL;
+ goto err_out;
+ }
+ ctx = ntfs_attr_get_search_ctx(base_ni, m);
+ if (unlikely(!ctx)) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+ err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+ CASE_SENSITIVE, 0, NULL, 0, ctx);
+ if (unlikely(err)) {
+ if (err == -ENOENT)
+ err = -EIO;
+ goto err_out;
+ }
+ a = ctx->attr;
+ /* The total length of the attribute value. */
+ attr_len = le32_to_cpu(a->data.resident.value_length);
+ BUG_ON(from > attr_len);
+ kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
+ kaddr = kmap_atomic(page, KM_USER0);
+ /* Copy the received data from the page to the mft record. */
+ memcpy(kattr + from, kaddr + from, to - from);
+ /* Update the attribute length if necessary. */
+ if (to > attr_len) {
+ attr_len = to;
+ a->data.resident.value_length = cpu_to_le32(attr_len);
+ }
+ /*
+ * If the page is not uptodate, bring the out of bounds area(s)
+ * uptodate by copying data from the mft record to the page.
+ */
+ if (!PageUptodate(page)) {
+ if (from > 0)
+ memcpy(kaddr, kattr, from);
+ if (to < attr_len)
+ memcpy(kaddr + to, kattr + to, attr_len - to);
+ /* Zero the region outside the end of the attribute value. */
+ if (attr_len < PAGE_CACHE_SIZE)
+ memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
+ /*
+ * The probability of not having done any of the above is
+ * extremely small, so we just flush unconditionally.
+ */
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ }
+ kunmap_atomic(kaddr, KM_USER0);
+ /* Update i_size if necessary. */
+ if (vi->i_size < attr_len) {
+ ni->allocated_size = ni->initialized_size = attr_len;
+ i_size_write(vi, attr_len);
+ }
+ /* Mark the mft record dirty, so it gets written back. */
+ flush_dcache_mft_record_page(ctx->ntfs_ino);
+ mark_mft_record_dirty(ctx->ntfs_ino);
+ ntfs_attr_put_search_ctx(ctx);
+ unmap_mft_record(base_ni);
+ ntfs_debug("Done.");
+ return 0;
+err_out:
+ if (err == -ENOMEM) {
+ ntfs_warning(vi->i_sb, "Error allocating memory required to "
+ "commit the write.");
+ if (PageUptodate(page)) {
+ ntfs_warning(vi->i_sb, "Page is uptodate, setting "
+ "dirty so the write will be retried "
+ "later on by the VM.");
+ /*
+ * Put the page on mapping->dirty_pages, but leave its
+ * buffers' dirty state as-is.
+ */
+ __set_page_dirty_nobuffers(page);
+ err = 0;
+ } else
+ ntfs_error(vi->i_sb, "Page is not uptodate. Written "
+ "data has been lost.");
+ } else {
+ ntfs_error(vi->i_sb, "Resident attribute commit write failed "
+ "with error %i.", err);
+ NVolSetErrors(ni->vol);
+ make_bad_inode(vi);
+ }
+ if (ctx)
+ ntfs_attr_put_search_ctx(ctx);
+ if (m)
+ unmap_mft_record(base_ni);
+ return err;
+}
+
+#endif /* NTFS_RW */
+
+/**
+ * ntfs_aops - general address space operations for inodes and attributes
+ */
+struct address_space_operations ntfs_aops = {
+ .readpage = ntfs_readpage, /* Fill page with data. */
+ .sync_page = block_sync_page, /* Currently, just unplugs the
+ disk request queue. */
+#ifdef NTFS_RW
+ .writepage = ntfs_writepage, /* Write dirty page to disk. */
+ .prepare_write = ntfs_prepare_write, /* Prepare page and buffers
+ ready to receive data. */
+ .commit_write = ntfs_commit_write, /* Commit received data. */
+#endif /* NTFS_RW */
+};
+
+/**
+ * ntfs_mst_aops - general address space operations for mst protecteed inodes
+ * and attributes
+ */
+struct address_space_operations ntfs_mst_aops = {
+ .readpage = ntfs_readpage, /* Fill page with data. */
+ .sync_page = block_sync_page, /* Currently, just unplugs the
+ disk request queue. */
+#ifdef NTFS_RW
+ .writepage = ntfs_writepage, /* Write dirty page to disk. */
+ .set_page_dirty = __set_page_dirty_nobuffers, /* Set the page dirty
+ without touching the buffers
+ belonging to the page. */
+#endif /* NTFS_RW */
+};
+
+#ifdef NTFS_RW
+
+/**
+ * mark_ntfs_record_dirty - mark an ntfs record dirty
+ * @page: page containing the ntfs record to mark dirty
+ * @ofs: byte offset within @page at which the ntfs record begins
+ *
+ * Set the buffers and the page in which the ntfs record is located dirty.
+ *
+ * The latter also marks the vfs inode the ntfs record belongs to dirty
+ * (I_DIRTY_PAGES only).
+ *
+ * If the page does not have buffers, we create them and set them uptodate.
+ * The page may not be locked which is why we need to handle the buffers under
+ * the mapping->private_lock. Once the buffers are marked dirty we no longer
+ * need the lock since try_to_free_buffers() does not free dirty buffers.
+ */
+void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
+ struct address_space *mapping = page->mapping;
+ ntfs_inode *ni = NTFS_I(mapping->host);
+ struct buffer_head *bh, *head, *buffers_to_free = NULL;
+ unsigned int end, bh_size, bh_ofs;
+
+ BUG_ON(!PageUptodate(page));
+ end = ofs + ni->itype.index.block_size;
+ bh_size = 1 << VFS_I(ni)->i_blkbits;
+ spin_lock(&mapping->private_lock);
+ if (unlikely(!page_has_buffers(page))) {
+ spin_unlock(&mapping->private_lock);
+ bh = head = alloc_page_buffers(page, bh_size, 1);
+ spin_lock(&mapping->private_lock);
+ if (likely(!page_has_buffers(page))) {
+ struct buffer_head *tail;
+
+ do {
+ set_buffer_uptodate(bh);
+ tail = bh;
+ bh = bh->b_this_page;
+ } while (bh);
+ tail->b_this_page = head;
+ attach_page_buffers(page, head);
+ } else
+ buffers_to_free = bh;
+ }
+ bh = head = page_buffers(page);
+ do {
+ bh_ofs = bh_offset(bh);
+ if (bh_ofs + bh_size <= ofs)
+ continue;
+ if (unlikely(bh_ofs >= end))
+ break;
+ set_buffer_dirty(bh);
+ } while ((bh = bh->b_this_page) != head);
+ spin_unlock(&mapping->private_lock);
+ __set_page_dirty_nobuffers(page);
+ if (unlikely(buffers_to_free)) {
+ do {
+ bh = buffers_to_free->b_this_page;
+ free_buffer_head(buffers_to_free);
+ buffers_to_free = bh;
+ } while (buffers_to_free);
+ }
+}
+
+#endif /* NTFS_RW */