--- /dev/null
+/*
+ * file.c - NTFS kernel file operations. Part of the Linux-NTFS project.
+ *
+ * Copyright (c) 2001-2015 Anton Altaparmakov and Tuxera Inc.
+ *
+ * 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/backing-dev.h>
+#include <linux/buffer_head.h>
+#include <linux/gfp.h>
+#include <linux/pagemap.h>
+#include <linux/pagevec.h>
+#include <linux/sched.h>
+#include <linux/swap.h>
+#include <linux/uio.h>
+#include <linux/writeback.h>
+
+#include <asm/page.h>
+#include <asm/uaccess.h>
+
+#include "attrib.h"
+#include "bitmap.h"
+#include "inode.h"
+#include "debug.h"
+#include "lcnalloc.h"
+#include "malloc.h"
+#include "mft.h"
+#include "ntfs.h"
+
+/**
+ * ntfs_file_open - called when an inode is about to be opened
+ * @vi: inode to be opened
+ * @filp: file structure describing the inode
+ *
+ * Limit file size to the page cache limit on architectures where unsigned long
+ * is 32-bits. This is the most we can do for now without overflowing the page
+ * cache page index. Doing it this way means we don't run into problems because
+ * of existing too large files. It would be better to allow the user to read
+ * the beginning of the file but I doubt very much anyone is going to hit this
+ * check on a 32-bit architecture, so there is no point in adding the extra
+ * complexity required to support this.
+ *
+ * On 64-bit architectures, the check is hopefully optimized away by the
+ * compiler.
+ *
+ * After the check passes, just call generic_file_open() to do its work.
+ */
+static int ntfs_file_open(struct inode *vi, struct file *filp)
+{
+ if (sizeof(unsigned long) < 8) {
+ if (i_size_read(vi) > MAX_LFS_FILESIZE)
+ return -EOVERFLOW;
+ }
+ return generic_file_open(vi, filp);
+}
+
+#ifdef NTFS_RW
+
+/**
+ * ntfs_attr_extend_initialized - extend the initialized size of an attribute
+ * @ni: ntfs inode of the attribute to extend
+ * @new_init_size: requested new initialized size in bytes
+ *
+ * Extend the initialized size of an attribute described by the ntfs inode @ni
+ * to @new_init_size bytes. This involves zeroing any non-sparse space between
+ * the old initialized size and @new_init_size both in the page cache and on
+ * disk (if relevant complete pages are already uptodate in the page cache then
+ * these are simply marked dirty).
+ *
+ * As a side-effect, the file size (vfs inode->i_size) may be incremented as,
+ * in the resident attribute case, it is tied to the initialized size and, in
+ * the non-resident attribute case, it may not fall below the initialized size.
+ *
+ * Note that if the attribute is resident, we do not need to touch the page
+ * cache at all. This is because if the page cache page is not uptodate we
+ * bring it uptodate later, when doing the write to the mft record since we
+ * then already have the page mapped. And if the page is uptodate, the
+ * non-initialized region will already have been zeroed when the page was
+ * brought uptodate and the region may in fact already have been overwritten
+ * with new data via mmap() based writes, so we cannot just zero it. And since
+ * POSIX specifies that the behaviour of resizing a file whilst it is mmap()ped
+ * is unspecified, we choose not to do zeroing and thus we do not need to touch
+ * the page at all. For a more detailed explanation see ntfs_truncate() in
+ * fs/ntfs/inode.c.
+ *
+ * Return 0 on success and -errno on error. In the case that an error is
+ * encountered it is possible that the initialized size will already have been
+ * incremented some way towards @new_init_size but it is guaranteed that if
+ * this is the case, the necessary zeroing will also have happened and that all
+ * metadata is self-consistent.
+ *
+ * Locking: i_mutex on the vfs inode corrseponsind to the ntfs inode @ni must be
+ * held by the caller.
+ */
+static int ntfs_attr_extend_initialized(ntfs_inode *ni, const s64 new_init_size)
+{
+ s64 old_init_size;
+ loff_t old_i_size;
+ pgoff_t index, end_index;
+ unsigned long flags;
+ struct inode *vi = VFS_I(ni);
+ ntfs_inode *base_ni;
+ MFT_RECORD *m = NULL;
+ ATTR_RECORD *a;
+ ntfs_attr_search_ctx *ctx = NULL;
+ struct address_space *mapping;
+ struct page *page = NULL;
+ u8 *kattr;
+ int err;
+ u32 attr_len;
+
+ read_lock_irqsave(&ni->size_lock, flags);
+ old_init_size = ni->initialized_size;
+ old_i_size = i_size_read(vi);
+ BUG_ON(new_init_size > ni->allocated_size);
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
+ "old_initialized_size 0x%llx, "
+ "new_initialized_size 0x%llx, i_size 0x%llx.",
+ vi->i_ino, (unsigned)le32_to_cpu(ni->type),
+ (unsigned long long)old_init_size,
+ (unsigned long long)new_init_size, old_i_size);
+ if (!NInoAttr(ni))
+ base_ni = ni;
+ else
+ base_ni = ni->ext.base_ntfs_ino;
+ /* Use goto to reduce indentation and we need the label below anyway. */
+ if (NInoNonResident(ni))
+ goto do_non_resident_extend;
+ BUG_ON(old_init_size != old_i_size);
+ m = map_mft_record(base_ni);
+ if (IS_ERR(m)) {
+ err = PTR_ERR(m);
+ m = 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;
+ BUG_ON(a->non_resident);
+ /* The total length of the attribute value. */
+ attr_len = le32_to_cpu(a->data.resident.value_length);
+ BUG_ON(old_i_size != (loff_t)attr_len);
+ /*
+ * Do the zeroing in the mft record and update the attribute size in
+ * the mft record.
+ */
+ kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
+ memset(kattr + attr_len, 0, new_init_size - attr_len);
+ a->data.resident.value_length = cpu_to_le32((u32)new_init_size);
+ /* Finally, update the sizes in the vfs and ntfs inodes. */
+ write_lock_irqsave(&ni->size_lock, flags);
+ i_size_write(vi, new_init_size);
+ ni->initialized_size = new_init_size;
+ write_unlock_irqrestore(&ni->size_lock, flags);
+ goto done;
+do_non_resident_extend:
+ /*
+ * If the new initialized size @new_init_size exceeds the current file
+ * size (vfs inode->i_size), we need to extend the file size to the
+ * new initialized size.
+ */
+ if (new_init_size > old_i_size) {
+ m = map_mft_record(base_ni);
+ if (IS_ERR(m)) {
+ err = PTR_ERR(m);
+ m = 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;
+ BUG_ON(!a->non_resident);
+ BUG_ON(old_i_size != (loff_t)
+ sle64_to_cpu(a->data.non_resident.data_size));
+ a->data.non_resident.data_size = cpu_to_sle64(new_init_size);
+ flush_dcache_mft_record_page(ctx->ntfs_ino);
+ mark_mft_record_dirty(ctx->ntfs_ino);
+ /* Update the file size in the vfs inode. */
+ i_size_write(vi, new_init_size);
+ ntfs_attr_put_search_ctx(ctx);
+ ctx = NULL;
+ unmap_mft_record(base_ni);
+ m = NULL;
+ }
+ mapping = vi->i_mapping;
+ index = old_init_size >> PAGE_CACHE_SHIFT;
+ end_index = (new_init_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ do {
+ /*
+ * Read the page. If the page is not present, this will zero
+ * the uninitialized regions for us.
+ */
+ page = read_mapping_page(mapping, index, NULL);
+ if (IS_ERR(page)) {
+ err = PTR_ERR(page);
+ goto init_err_out;
+ }
+ if (unlikely(PageError(page))) {
+ page_cache_release(page);
+ err = -EIO;
+ goto init_err_out;
+ }
+ /*
+ * Update the initialized size in the ntfs inode. This is
+ * enough to make ntfs_writepage() work.
+ */
+ write_lock_irqsave(&ni->size_lock, flags);
+ ni->initialized_size = (s64)(index + 1) << PAGE_CACHE_SHIFT;
+ if (ni->initialized_size > new_init_size)
+ ni->initialized_size = new_init_size;
+ write_unlock_irqrestore(&ni->size_lock, flags);
+ /* Set the page dirty so it gets written out. */
+ set_page_dirty(page);
+ page_cache_release(page);
+ /*
+ * Play nice with the vm and the rest of the system. This is
+ * very much needed as we can potentially be modifying the
+ * initialised size from a very small value to a really huge
+ * value, e.g.
+ * f = open(somefile, O_TRUNC);
+ * truncate(f, 10GiB);
+ * seek(f, 10GiB);
+ * write(f, 1);
+ * And this would mean we would be marking dirty hundreds of
+ * thousands of pages or as in the above example more than
+ * two and a half million pages!
+ *
+ * TODO: For sparse pages could optimize this workload by using
+ * the FsMisc / MiscFs page bit as a "PageIsSparse" bit. This
+ * would be set in readpage for sparse pages and here we would
+ * not need to mark dirty any pages which have this bit set.
+ * The only caveat is that we have to clear the bit everywhere
+ * where we allocate any clusters that lie in the page or that
+ * contain the page.
+ *
+ * TODO: An even greater optimization would be for us to only
+ * call readpage() on pages which are not in sparse regions as
+ * determined from the runlist. This would greatly reduce the
+ * number of pages we read and make dirty in the case of sparse
+ * files.
+ */
+ balance_dirty_pages_ratelimited(mapping);
+ cond_resched();
+ } while (++index < end_index);
+ read_lock_irqsave(&ni->size_lock, flags);
+ BUG_ON(ni->initialized_size != new_init_size);
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ /* Now bring in sync the initialized_size in the mft record. */
+ m = map_mft_record(base_ni);
+ if (IS_ERR(m)) {
+ err = PTR_ERR(m);
+ m = NULL;
+ goto init_err_out;
+ }
+ ctx = ntfs_attr_get_search_ctx(base_ni, m);
+ if (unlikely(!ctx)) {
+ err = -ENOMEM;
+ goto init_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 init_err_out;
+ }
+ m = ctx->mrec;
+ a = ctx->attr;
+ BUG_ON(!a->non_resident);
+ a->data.non_resident.initialized_size = cpu_to_sle64(new_init_size);
+done:
+ flush_dcache_mft_record_page(ctx->ntfs_ino);
+ mark_mft_record_dirty(ctx->ntfs_ino);
+ if (ctx)
+ ntfs_attr_put_search_ctx(ctx);
+ if (m)
+ unmap_mft_record(base_ni);
+ ntfs_debug("Done, initialized_size 0x%llx, i_size 0x%llx.",
+ (unsigned long long)new_init_size, i_size_read(vi));
+ return 0;
+init_err_out:
+ write_lock_irqsave(&ni->size_lock, flags);
+ ni->initialized_size = old_init_size;
+ write_unlock_irqrestore(&ni->size_lock, flags);
+err_out:
+ if (ctx)
+ ntfs_attr_put_search_ctx(ctx);
+ if (m)
+ unmap_mft_record(base_ni);
+ ntfs_debug("Failed. Returning error code %i.", err);
+ return err;
+}
+
+static ssize_t ntfs_prepare_file_for_write(struct kiocb *iocb,
+ struct iov_iter *from)
+{
+ loff_t pos;
+ s64 end, ll;
+ ssize_t err;
+ unsigned long flags;
+ struct file *file = iocb->ki_filp;
+ struct inode *vi = file_inode(file);
+ ntfs_inode *base_ni, *ni = NTFS_I(vi);
+ ntfs_volume *vol = ni->vol;
+
+ ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, pos "
+ "0x%llx, count 0x%zx.", vi->i_ino,
+ (unsigned)le32_to_cpu(ni->type),
+ (unsigned long long)iocb->ki_pos,
+ iov_iter_count(from));
+ err = generic_write_checks(iocb, from);
+ if (unlikely(err <= 0))
+ goto out;
+ /*
+ * All checks have passed. Before we start doing any writing we want
+ * to abort any totally illegal writes.
+ */
+ BUG_ON(NInoMstProtected(ni));
+ BUG_ON(ni->type != AT_DATA);
+ /* If file is encrypted, deny access, just like NT4. */
+ if (NInoEncrypted(ni)) {
+ /* Only $DATA attributes can be encrypted. */
+ /*
+ * Reminder for later: Encrypted files are _always_
+ * non-resident so that the content can always be encrypted.
+ */
+ ntfs_debug("Denying write access to encrypted file.");
+ err = -EACCES;
+ goto out;
+ }
+ if (NInoCompressed(ni)) {
+ /* Only unnamed $DATA attribute can be compressed. */
+ BUG_ON(ni->name_len);
+ /*
+ * Reminder for later: If resident, the data is not actually
+ * compressed. Only on the switch to non-resident does
+ * compression kick in. This is in contrast to encrypted files
+ * (see above).
+ */
+ ntfs_error(vi->i_sb, "Writing to compressed files is not "
+ "implemented yet. Sorry.");
+ err = -EOPNOTSUPP;
+ goto out;
+ }
+ base_ni = ni;
+ if (NInoAttr(ni))
+ base_ni = ni->ext.base_ntfs_ino;
+ err = file_remove_suid(file);
+ if (unlikely(err))
+ goto out;
+ /*
+ * Our ->update_time method always succeeds thus file_update_time()
+ * cannot fail either so there is no need to check the return code.
+ */
+ file_update_time(file);
+ pos = iocb->ki_pos;
+ /* The first byte after the last cluster being written to. */
+ end = (pos + iov_iter_count(from) + vol->cluster_size_mask) &
+ ~(u64)vol->cluster_size_mask;
+ /*
+ * If the write goes beyond the allocated size, extend the allocation
+ * to cover the whole of the write, rounded up to the nearest cluster.
+ */
+ read_lock_irqsave(&ni->size_lock, flags);
+ ll = ni->allocated_size;
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ if (end > ll) {
+ /*
+ * Extend the allocation without changing the data size.
+ *
+ * Note we ensure the allocation is big enough to at least
+ * write some data but we do not require the allocation to be
+ * complete, i.e. it may be partial.
+ */
+ ll = ntfs_attr_extend_allocation(ni, end, -1, pos);
+ if (likely(ll >= 0)) {
+ BUG_ON(pos >= ll);
+ /* If the extension was partial truncate the write. */
+ if (end > ll) {
+ ntfs_debug("Truncating write to inode 0x%lx, "
+ "attribute type 0x%x, because "
+ "the allocation was only "
+ "partially extended.",
+ vi->i_ino, (unsigned)
+ le32_to_cpu(ni->type));
+ iov_iter_truncate(from, ll - pos);
+ }
+ } else {
+ err = ll;
+ read_lock_irqsave(&ni->size_lock, flags);
+ ll = ni->allocated_size;
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ /* Perform a partial write if possible or fail. */
+ if (pos < ll) {
+ ntfs_debug("Truncating write to inode 0x%lx "
+ "attribute type 0x%x, because "
+ "extending the allocation "
+ "failed (error %d).",
+ vi->i_ino, (unsigned)
+ le32_to_cpu(ni->type),
+ (int)-err);
+ iov_iter_truncate(from, ll - pos);
+ } else {
+ if (err != -ENOSPC)
+ ntfs_error(vi->i_sb, "Cannot perform "
+ "write to inode "
+ "0x%lx, attribute "
+ "type 0x%x, because "
+ "extending the "
+ "allocation failed "
+ "(error %ld).",
+ vi->i_ino, (unsigned)
+ le32_to_cpu(ni->type),
+ (long)-err);
+ else
+ ntfs_debug("Cannot perform write to "
+ "inode 0x%lx, "
+ "attribute type 0x%x, "
+ "because there is not "
+ "space left.",
+ vi->i_ino, (unsigned)
+ le32_to_cpu(ni->type));
+ goto out;
+ }
+ }
+ }
+ /*
+ * If the write starts beyond the initialized size, extend it up to the
+ * beginning of the write and initialize all non-sparse space between
+ * the old initialized size and the new one. This automatically also
+ * increments the vfs inode->i_size to keep it above or equal to the
+ * initialized_size.
+ */
+ read_lock_irqsave(&ni->size_lock, flags);
+ ll = ni->initialized_size;
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ if (pos > ll) {
+ /*
+ * Wait for ongoing direct i/o to complete before proceeding.
+ * New direct i/o cannot start as we hold i_mutex.
+ */
+ inode_dio_wait(vi);
+ err = ntfs_attr_extend_initialized(ni, pos);
+ if (unlikely(err < 0))
+ ntfs_error(vi->i_sb, "Cannot perform write to inode "
+ "0x%lx, attribute type 0x%x, because "
+ "extending the initialized size "
+ "failed (error %d).", vi->i_ino,
+ (unsigned)le32_to_cpu(ni->type),
+ (int)-err);
+ }
+out:
+ return err;
+}
+
+/**
+ * __ntfs_grab_cache_pages - obtain a number of locked pages
+ * @mapping: address space mapping from which to obtain page cache pages
+ * @index: starting index in @mapping at which to begin obtaining pages
+ * @nr_pages: number of page cache pages to obtain
+ * @pages: array of pages in which to return the obtained page cache pages
+ * @cached_page: allocated but as yet unused page
+ *
+ * Obtain @nr_pages locked page cache pages from the mapping @mapping and
+ * starting at index @index.
+ *
+ * If a page is newly created, add it to lru list
+ *
+ * Note, the page locks are obtained in ascending page index order.
+ */
+static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
+ pgoff_t index, const unsigned nr_pages, struct page **pages,
+ struct page **cached_page)
+{
+ int err, nr;
+
+ BUG_ON(!nr_pages);
+ err = nr = 0;
+ do {
+ pages[nr] = find_get_page_flags(mapping, index, FGP_LOCK |
+ FGP_ACCESSED);
+ if (!pages[nr]) {
+ if (!*cached_page) {
+ *cached_page = page_cache_alloc(mapping);
+ if (unlikely(!*cached_page)) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+ }
+ err = add_to_page_cache_lru(*cached_page, mapping,
+ index, GFP_KERNEL);
+ if (unlikely(err)) {
+ if (err == -EEXIST)
+ continue;
+ goto err_out;
+ }
+ pages[nr] = *cached_page;
+ *cached_page = NULL;
+ }
+ index++;
+ nr++;
+ } while (nr < nr_pages);
+out:
+ return err;
+err_out:
+ while (nr > 0) {
+ unlock_page(pages[--nr]);
+ page_cache_release(pages[nr]);
+ }
+ goto out;
+}
+
+static inline int ntfs_submit_bh_for_read(struct buffer_head *bh)
+{
+ lock_buffer(bh);
+ get_bh(bh);
+ bh->b_end_io = end_buffer_read_sync;
+ return submit_bh(READ, bh);
+}
+
+/**
+ * ntfs_prepare_pages_for_non_resident_write - prepare pages for receiving data
+ * @pages: array of destination pages
+ * @nr_pages: number of pages in @pages
+ * @pos: byte position in file at which the write begins
+ * @bytes: number of bytes to be written
+ *
+ * This is called for non-resident attributes from ntfs_file_buffered_write()
+ * with i_mutex held on the inode (@pages[0]->mapping->host). There are
+ * @nr_pages pages in @pages which are locked but not kmap()ped. The source
+ * data has not yet been copied into the @pages.
+ *
+ * Need to fill any holes with actual clusters, allocate buffers if necessary,
+ * ensure all the buffers are mapped, and bring uptodate any buffers that are
+ * only partially being written to.
+ *
+ * If @nr_pages is greater than one, we are guaranteed that the cluster size is
+ * greater than PAGE_CACHE_SIZE, that all pages in @pages are entirely inside
+ * the same cluster and that they are the entirety of that cluster, and that
+ * the cluster is sparse, i.e. we need to allocate a cluster to fill the hole.
+ *
+ * i_size is not to be modified yet.
+ *
+ * Return 0 on success or -errno on error.
+ */
+static int ntfs_prepare_pages_for_non_resident_write(struct page **pages,
+ unsigned nr_pages, s64 pos, size_t bytes)
+{
+ VCN vcn, highest_vcn = 0, cpos, cend, bh_cpos, bh_cend;
+ LCN lcn;
+ s64 bh_pos, vcn_len, end, initialized_size;
+ sector_t lcn_block;
+ struct page *page;
+ struct inode *vi;
+ ntfs_inode *ni, *base_ni = NULL;
+ ntfs_volume *vol;
+ runlist_element *rl, *rl2;
+ struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
+ ntfs_attr_search_ctx *ctx = NULL;
+ MFT_RECORD *m = NULL;
+ ATTR_RECORD *a = NULL;
+ unsigned long flags;
+ u32 attr_rec_len = 0;
+ unsigned blocksize, u;
+ int err, mp_size;
+ bool rl_write_locked, was_hole, is_retry;
+ unsigned char blocksize_bits;
+ struct {
+ u8 runlist_merged:1;
+ u8 mft_attr_mapped:1;
+ u8 mp_rebuilt:1;
+ u8 attr_switched:1;
+ } status = { 0, 0, 0, 0 };
+
+ BUG_ON(!nr_pages);
+ BUG_ON(!pages);
+ BUG_ON(!*pages);
+ vi = pages[0]->mapping->host;
+ ni = NTFS_I(vi);
+ vol = ni->vol;
+ ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
+ "index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%zx.",
+ vi->i_ino, ni->type, pages[0]->index, nr_pages,
+ (long long)pos, bytes);
+ blocksize = vol->sb->s_blocksize;
+ blocksize_bits = vol->sb->s_blocksize_bits;
+ u = 0;
+ do {
+ page = pages[u];
+ BUG_ON(!page);
+ /*
+ * 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);
+ if (unlikely(!page_has_buffers(page)))
+ return -ENOMEM;
+ }
+ } while (++u < nr_pages);
+ rl_write_locked = false;
+ rl = NULL;
+ err = 0;
+ vcn = lcn = -1;
+ vcn_len = 0;
+ lcn_block = -1;
+ was_hole = false;
+ cpos = pos >> vol->cluster_size_bits;
+ end = pos + bytes;
+ cend = (end + vol->cluster_size - 1) >> vol->cluster_size_bits;
+ /*
+ * Loop over each page and for each page over each buffer. Use goto to
+ * reduce indentation.
+ */
+ u = 0;
+do_next_page:
+ page = pages[u];
+ bh_pos = (s64)page->index << PAGE_CACHE_SHIFT;
+ bh = head = page_buffers(page);
+ do {
+ VCN cdelta;
+ s64 bh_end;
+ unsigned bh_cofs;
+
+ /* Clear buffer_new on all buffers to reinitialise state. */
+ if (buffer_new(bh))
+ clear_buffer_new(bh);
+ bh_end = bh_pos + blocksize;
+ bh_cpos = bh_pos >> vol->cluster_size_bits;
+ bh_cofs = bh_pos & vol->cluster_size_mask;
+ if (buffer_mapped(bh)) {
+ /*
+ * The buffer is already mapped. If it is uptodate,
+ * ignore it.
+ */
+ if (buffer_uptodate(bh))
+ continue;
+ /*
+ * The buffer is not uptodate. If the page is uptodate
+ * set the buffer uptodate and otherwise ignore it.
+ */
+ if (PageUptodate(page)) {
+ set_buffer_uptodate(bh);
+ continue;
+ }
+ /*
+ * Neither the page nor the buffer are uptodate. If
+ * the buffer is only partially being written to, we
+ * need to read it in before the write, i.e. now.
+ */
+ if ((bh_pos < pos && bh_end > pos) ||
+ (bh_pos < end && bh_end > end)) {
+ /*
+ * If the buffer is fully or partially within
+ * the initialized size, do an actual read.
+ * Otherwise, simply zero the buffer.
+ */
+ read_lock_irqsave(&ni->size_lock, flags);
+ initialized_size = ni->initialized_size;
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ if (bh_pos < initialized_size) {
+ ntfs_submit_bh_for_read(bh);
+ *wait_bh++ = bh;
+ } else {
+ zero_user(page, bh_offset(bh),
+ blocksize);
+ set_buffer_uptodate(bh);
+ }
+ }
+ continue;
+ }
+ /* Unmapped buffer. Need to map it. */
+ bh->b_bdev = vol->sb->s_bdev;
+ /*
+ * If the current buffer is in the same clusters as the map
+ * cache, there is no need to check the runlist again. The
+ * map cache is made up of @vcn, which is the first cached file
+ * cluster, @vcn_len which is the number of cached file
+ * clusters, @lcn is the device cluster corresponding to @vcn,
+ * and @lcn_block is the block number corresponding to @lcn.
+ */
+ cdelta = bh_cpos - vcn;
+ if (likely(!cdelta || (cdelta > 0 && cdelta < vcn_len))) {
+map_buffer_cached:
+ BUG_ON(lcn < 0);
+ bh->b_blocknr = lcn_block +
+ (cdelta << (vol->cluster_size_bits -
+ blocksize_bits)) +
+ (bh_cofs >> blocksize_bits);
+ set_buffer_mapped(bh);
+ /*
+ * If the page is uptodate so is the buffer. If the
+ * buffer is fully outside the write, we ignore it if
+ * it was already allocated and we mark it dirty so it
+ * gets written out if we allocated it. On the other
+ * hand, if we allocated the buffer but we are not
+ * marking it dirty we set buffer_new so we can do
+ * error recovery.
+ */
+ if (PageUptodate(page)) {
+ if (!buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
+ if (unlikely(was_hole)) {
+ /* We allocated the buffer. */
+ unmap_underlying_metadata(bh->b_bdev,
+ bh->b_blocknr);
+ if (bh_end <= pos || bh_pos >= end)
+ mark_buffer_dirty(bh);
+ else
+ set_buffer_new(bh);
+ }
+ continue;
+ }
+ /* Page is _not_ uptodate. */
+ if (likely(!was_hole)) {
+ /*
+ * Buffer was already allocated. If it is not
+ * uptodate and is only partially being written
+ * to, we need to read it in before the write,
+ * i.e. now.
+ */
+ if (!buffer_uptodate(bh) && bh_pos < end &&
+ bh_end > pos &&
+ (bh_pos < pos ||
+ bh_end > end)) {
+ /*
+ * If the buffer is fully or partially
+ * within the initialized size, do an
+ * actual read. Otherwise, simply zero
+ * the buffer.
+ */
+ read_lock_irqsave(&ni->size_lock,
+ flags);
+ initialized_size = ni->initialized_size;
+ read_unlock_irqrestore(&ni->size_lock,
+ flags);
+ if (bh_pos < initialized_size) {
+ ntfs_submit_bh_for_read(bh);
+ *wait_bh++ = bh;
+ } else {
+ zero_user(page, bh_offset(bh),
+ blocksize);
+ set_buffer_uptodate(bh);
+ }
+ }
+ continue;
+ }
+ /* We allocated the buffer. */
+ unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+ /*
+ * If the buffer is fully outside the write, zero it,
+ * set it uptodate, and mark it dirty so it gets
+ * written out. If it is partially being written to,
+ * zero region surrounding the write but leave it to
+ * commit write to do anything else. Finally, if the
+ * buffer is fully being overwritten, do nothing.
+ */
+ if (bh_end <= pos || bh_pos >= end) {
+ if (!buffer_uptodate(bh)) {
+ zero_user(page, bh_offset(bh),
+ blocksize);
+ set_buffer_uptodate(bh);
+ }
+ mark_buffer_dirty(bh);
+ continue;
+ }
+ set_buffer_new(bh);
+ if (!buffer_uptodate(bh) &&
+ (bh_pos < pos || bh_end > end)) {
+ u8 *kaddr;
+ unsigned pofs;
+
+ kaddr = kmap_atomic(page);
+ if (bh_pos < pos) {
+ pofs = bh_pos & ~PAGE_CACHE_MASK;
+ memset(kaddr + pofs, 0, pos - bh_pos);
+ }
+ if (bh_end > end) {
+ pofs = end & ~PAGE_CACHE_MASK;
+ memset(kaddr + pofs, 0, bh_end - end);
+ }
+ kunmap_atomic(kaddr);
+ flush_dcache_page(page);
+ }
+ continue;
+ }
+ /*
+ * Slow path: this is the first buffer in the cluster. If it
+ * is outside allocated size and is not uptodate, zero it and
+ * set it uptodate.
+ */
+ read_lock_irqsave(&ni->size_lock, flags);
+ initialized_size = ni->allocated_size;
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ if (bh_pos > initialized_size) {
+ if (PageUptodate(page)) {
+ if (!buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
+ } else if (!buffer_uptodate(bh)) {
+ zero_user(page, bh_offset(bh), blocksize);
+ set_buffer_uptodate(bh);
+ }
+ continue;
+ }
+ is_retry = false;
+ if (!rl) {
+ down_read(&ni->runlist.lock);
+retry_remap:
+ rl = ni->runlist.rl;
+ }
+ if (likely(rl != NULL)) {
+ /* Seek to element containing target cluster. */
+ while (rl->length && rl[1].vcn <= bh_cpos)
+ rl++;
+ lcn = ntfs_rl_vcn_to_lcn(rl, bh_cpos);
+ if (likely(lcn >= 0)) {
+ /*
+ * Successful remap, setup the map cache and
+ * use that to deal with the buffer.
+ */
+ was_hole = false;
+ vcn = bh_cpos;
+ vcn_len = rl[1].vcn - vcn;
+ lcn_block = lcn << (vol->cluster_size_bits -
+ blocksize_bits);
+ cdelta = 0;
+ /*
+ * If the number of remaining clusters touched
+ * by the write is smaller or equal to the
+ * number of cached clusters, unlock the
+ * runlist as the map cache will be used from
+ * now on.
+ */
+ if (likely(vcn + vcn_len >= cend)) {
+ if (rl_write_locked) {
+ up_write(&ni->runlist.lock);
+ rl_write_locked = false;
+ } else
+ up_read(&ni->runlist.lock);
+ rl = NULL;
+ }
+ goto map_buffer_cached;
+ }
+ } else
+ lcn = LCN_RL_NOT_MAPPED;
+ /*
+ * If it is not a hole and not out of bounds, the runlist is
+ * probably unmapped so try to map it now.
+ */
+ if (unlikely(lcn != LCN_HOLE && lcn != LCN_ENOENT)) {
+ if (likely(!is_retry && lcn == LCN_RL_NOT_MAPPED)) {
+ /* Attempt to map runlist. */
+ if (!rl_write_locked) {
+ /*
+ * We need the runlist locked for
+ * writing, so if it is locked for
+ * reading relock it now and retry in
+ * case it changed whilst we dropped
+ * the lock.
+ */
+ up_read(&ni->runlist.lock);
+ down_write(&ni->runlist.lock);
+ rl_write_locked = true;
+ goto retry_remap;
+ }
+ err = ntfs_map_runlist_nolock(ni, bh_cpos,
+ NULL);
+ if (likely(!err)) {
+ is_retry = true;
+ goto retry_remap;
+ }
+ /*
+ * If @vcn is out of bounds, pretend @lcn is
+ * LCN_ENOENT. As long as the buffer is out
+ * of bounds this will work fine.
+ */
+ if (err == -ENOENT) {
+ lcn = LCN_ENOENT;
+ err = 0;
+ goto rl_not_mapped_enoent;
+ }
+ } else
+ err = -EIO;
+ /* 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, "
+ "vcn offset 0x%x, because its "
+ "location on disk could not be "
+ "determined%s (error code %i).",
+ ni->mft_no, ni->type,
+ (unsigned long long)bh_cpos,
+ (unsigned)bh_pos &
+ vol->cluster_size_mask,
+ is_retry ? " even after retrying" : "",
+ err);
+ break;
+ }
+rl_not_mapped_enoent:
+ /*
+ * The buffer is in a hole or out of bounds. We need to fill
+ * the hole, unless the buffer is in a cluster which is not
+ * touched by the write, in which case we just leave the buffer
+ * unmapped. This can only happen when the cluster size is
+ * less than the page cache size.
+ */
+ if (unlikely(vol->cluster_size < PAGE_CACHE_SIZE)) {
+ bh_cend = (bh_end + vol->cluster_size - 1) >>
+ vol->cluster_size_bits;
+ if ((bh_cend <= cpos || bh_cpos >= cend)) {
+ bh->b_blocknr = -1;
+ /*
+ * If the buffer is uptodate we skip it. If it
+ * is not but the page is uptodate, we can set
+ * the buffer uptodate. If the page is not
+ * uptodate, we can clear the buffer and set it
+ * uptodate. Whether this is worthwhile is
+ * debatable and this could be removed.
+ */
+ if (PageUptodate(page)) {
+ if (!buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
+ } else if (!buffer_uptodate(bh)) {
+ zero_user(page, bh_offset(bh),
+ blocksize);
+ set_buffer_uptodate(bh);
+ }
+ continue;
+ }
+ }
+ /*
+ * Out of bounds buffer is invalid if it was not really out of
+ * bounds.
+ */
+ BUG_ON(lcn != LCN_HOLE);
+ /*
+ * We need the runlist locked for writing, so if it is locked
+ * for reading relock it now and retry in case it changed
+ * whilst we dropped the lock.
+ */
+ BUG_ON(!rl);
+ if (!rl_write_locked) {
+ up_read(&ni->runlist.lock);
+ down_write(&ni->runlist.lock);
+ rl_write_locked = true;
+ goto retry_remap;
+ }
+ /* Find the previous last allocated cluster. */
+ BUG_ON(rl->lcn != LCN_HOLE);
+ lcn = -1;
+ rl2 = rl;
+ while (--rl2 >= ni->runlist.rl) {
+ if (rl2->lcn >= 0) {
+ lcn = rl2->lcn + rl2->length;
+ break;
+ }
+ }
+ rl2 = ntfs_cluster_alloc(vol, bh_cpos, 1, lcn, DATA_ZONE,
+ false);
+ if (IS_ERR(rl2)) {
+ err = PTR_ERR(rl2);
+ ntfs_debug("Failed to allocate cluster, error code %i.",
+ err);
+ break;
+ }
+ lcn = rl2->lcn;
+ rl = ntfs_runlists_merge(ni->runlist.rl, rl2);
+ if (IS_ERR(rl)) {
+ err = PTR_ERR(rl);
+ if (err != -ENOMEM)
+ err = -EIO;
+ if (ntfs_cluster_free_from_rl(vol, rl2)) {
+ ntfs_error(vol->sb, "Failed to release "
+ "allocated cluster in error "
+ "code path. Run chkdsk to "
+ "recover the lost cluster.");
+ NVolSetErrors(vol);
+ }
+ ntfs_free(rl2);
+ break;
+ }
+ ni->runlist.rl = rl;
+ status.runlist_merged = 1;
+ ntfs_debug("Allocated cluster, lcn 0x%llx.",
+ (unsigned long long)lcn);
+ /* Map and lock the mft record and get the attribute 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);
+ break;
+ }
+ ctx = ntfs_attr_get_search_ctx(base_ni, m);
+ if (unlikely(!ctx)) {
+ err = -ENOMEM;
+ unmap_mft_record(base_ni);
+ break;
+ }
+ status.mft_attr_mapped = 1;
+ err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+ CASE_SENSITIVE, bh_cpos, NULL, 0, ctx);
+ if (unlikely(err)) {
+ if (err == -ENOENT)
+ err = -EIO;
+ break;
+ }
+ m = ctx->mrec;
+ a = ctx->attr;
+ /*
+ * Find the runlist element with which the attribute extent
+ * starts. Note, we cannot use the _attr_ version because we
+ * have mapped the mft record. That is ok because we know the
+ * runlist fragment must be mapped already to have ever gotten
+ * here, so we can just use the _rl_ version.
+ */
+ vcn = sle64_to_cpu(a->data.non_resident.lowest_vcn);
+ rl2 = ntfs_rl_find_vcn_nolock(rl, vcn);
+ BUG_ON(!rl2);
+ BUG_ON(!rl2->length);
+ BUG_ON(rl2->lcn < LCN_HOLE);
+ highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
+ /*
+ * If @highest_vcn is zero, calculate the real highest_vcn
+ * (which can really be zero).
+ */
+ if (!highest_vcn)
+ highest_vcn = (sle64_to_cpu(
+ a->data.non_resident.allocated_size) >>
+ vol->cluster_size_bits) - 1;
+ /*
+ * Determine the size of the mapping pairs array for the new
+ * extent, i.e. the old extent with the hole filled.
+ */
+ mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, vcn,
+ highest_vcn);
+ if (unlikely(mp_size <= 0)) {
+ if (!(err = mp_size))
+ err = -EIO;
+ ntfs_debug("Failed to get size for mapping pairs "
+ "array, error code %i.", err);
+ break;
+ }
+ /*
+ * Resize the attribute record to fit the new mapping pairs
+ * array.
+ */
+ attr_rec_len = le32_to_cpu(a->length);
+ err = ntfs_attr_record_resize(m, a, mp_size + le16_to_cpu(
+ a->data.non_resident.mapping_pairs_offset));
+ if (unlikely(err)) {
+ BUG_ON(err != -ENOSPC);
+ // TODO: Deal with this by using the current attribute
+ // and fill it with as much of the mapping pairs
+ // array as possible. Then loop over each attribute
+ // extent rewriting the mapping pairs arrays as we go
+ // along and if when we reach the end we have not
+ // enough space, try to resize the last attribute
+ // extent and if even that fails, add a new attribute
+ // extent.
+ // We could also try to resize at each step in the hope
+ // that we will not need to rewrite every single extent.
+ // Note, we may need to decompress some extents to fill
+ // the runlist as we are walking the extents...
+ ntfs_error(vol->sb, "Not enough space in the mft "
+ "record for the extended attribute "
+ "record. This case is not "
+ "implemented yet.");
+ err = -EOPNOTSUPP;
+ break ;
+ }
+ status.mp_rebuilt = 1;
+ /*
+ * Generate the mapping pairs array directly into the attribute
+ * record.
+ */
+ err = ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
+ a->data.non_resident.mapping_pairs_offset),
+ mp_size, rl2, vcn, highest_vcn, NULL);
+ if (unlikely(err)) {
+ ntfs_error(vol->sb, "Cannot fill hole in inode 0x%lx, "
+ "attribute type 0x%x, because building "
+ "the mapping pairs failed with error "
+ "code %i.", vi->i_ino,
+ (unsigned)le32_to_cpu(ni->type), err);
+ err = -EIO;
+ break;
+ }
+ /* Update the highest_vcn but only if it was not set. */
+ if (unlikely(!a->data.non_resident.highest_vcn))
+ a->data.non_resident.highest_vcn =
+ cpu_to_sle64(highest_vcn);
+ /*
+ * If the attribute is sparse/compressed, update the compressed
+ * size in the ntfs_inode structure and the attribute record.
+ */
+ if (likely(NInoSparse(ni) || NInoCompressed(ni))) {
+ /*
+ * If we are not in the first attribute extent, switch
+ * to it, but first ensure the changes will make it to
+ * disk later.
+ */
+ if (a->data.non_resident.lowest_vcn) {
+ flush_dcache_mft_record_page(ctx->ntfs_ino);
+ mark_mft_record_dirty(ctx->ntfs_ino);
+ ntfs_attr_reinit_search_ctx(ctx);
+ err = ntfs_attr_lookup(ni->type, ni->name,
+ ni->name_len, CASE_SENSITIVE,
+ 0, NULL, 0, ctx);
+ if (unlikely(err)) {
+ status.attr_switched = 1;
+ break;
+ }
+ /* @m is not used any more so do not set it. */
+ a = ctx->attr;
+ }
+ write_lock_irqsave(&ni->size_lock, flags);
+ ni->itype.compressed.size += vol->cluster_size;
+ a->data.non_resident.compressed_size =
+ cpu_to_sle64(ni->itype.compressed.size);
+ write_unlock_irqrestore(&ni->size_lock, flags);
+ }
+ /* Ensure the changes make it to disk. */
+ 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);
+ /* Successfully filled the hole. */
+ status.runlist_merged = 0;
+ status.mft_attr_mapped = 0;
+ status.mp_rebuilt = 0;
+ /* Setup the map cache and use that to deal with the buffer. */
+ was_hole = true;
+ vcn = bh_cpos;
+ vcn_len = 1;
+ lcn_block = lcn << (vol->cluster_size_bits - blocksize_bits);
+ cdelta = 0;
+ /*
+ * If the number of remaining clusters in the @pages is smaller
+ * or equal to the number of cached clusters, unlock the
+ * runlist as the map cache will be used from now on.
+ */
+ if (likely(vcn + vcn_len >= cend)) {
+ up_write(&ni->runlist.lock);
+ rl_write_locked = false;
+ rl = NULL;
+ }
+ goto map_buffer_cached;
+ } while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
+ /* If there are no errors, do the next page. */
+ if (likely(!err && ++u < nr_pages))
+ goto do_next_page;
+ /* If there are no errors, release the runlist lock if we took it. */
+ if (likely(!err)) {
+ if (unlikely(rl_write_locked)) {
+ up_write(&ni->runlist.lock);
+ rl_write_locked = false;
+ } else if (unlikely(rl))
+ up_read(&ni->runlist.lock);
+ rl = NULL;
+ }
+ /* If we issued read requests, let them complete. */
+ read_lock_irqsave(&ni->size_lock, flags);
+ initialized_size = ni->initialized_size;
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ while (wait_bh > wait) {
+ bh = *--wait_bh;
+ wait_on_buffer(bh);
+ if (likely(buffer_uptodate(bh))) {
+ page = bh->b_page;
+ bh_pos = ((s64)page->index << PAGE_CACHE_SHIFT) +
+ bh_offset(bh);
+ /*
+ * If the buffer overflows the initialized size, need
+ * to zero the overflowing region.
+ */
+ if (unlikely(bh_pos + blocksize > initialized_size)) {
+ int ofs = 0;
+
+ if (likely(bh_pos < initialized_size))
+ ofs = initialized_size - bh_pos;
+ zero_user_segment(page, bh_offset(bh) + ofs,
+ blocksize);
+ }
+ } else /* if (unlikely(!buffer_uptodate(bh))) */
+ err = -EIO;
+ }
+ if (likely(!err)) {
+ /* Clear buffer_new on all buffers. */
+ u = 0;
+ do {
+ bh = head = page_buffers(pages[u]);
+ do {
+ if (buffer_new(bh))
+ clear_buffer_new(bh);
+ } while ((bh = bh->b_this_page) != head);
+ } while (++u < nr_pages);
+ ntfs_debug("Done.");
+ return err;
+ }
+ if (status.attr_switched) {
+ /* Get back to the attribute extent we modified. */
+ ntfs_attr_reinit_search_ctx(ctx);
+ if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+ CASE_SENSITIVE, bh_cpos, NULL, 0, ctx)) {
+ ntfs_error(vol->sb, "Failed to find required "
+ "attribute extent of attribute in "
+ "error code path. Run chkdsk to "
+ "recover.");
+ write_lock_irqsave(&ni->size_lock, flags);
+ ni->itype.compressed.size += vol->cluster_size;
+ write_unlock_irqrestore(&ni->size_lock, flags);
+ flush_dcache_mft_record_page(ctx->ntfs_ino);
+ mark_mft_record_dirty(ctx->ntfs_ino);
+ /*
+ * The only thing that is now wrong is the compressed
+ * size of the base attribute extent which chkdsk
+ * should be able to fix.
+ */
+ NVolSetErrors(vol);
+ } else {
+ m = ctx->mrec;
+ a = ctx->attr;
+ status.attr_switched = 0;
+ }
+ }
+ /*
+ * If the runlist has been modified, need to restore it by punching a
+ * hole into it and we then need to deallocate the on-disk cluster as
+ * well. Note, we only modify the runlist if we are able to generate a
+ * new mapping pairs array, i.e. only when the mapped attribute extent
+ * is not switched.
+ */
+ if (status.runlist_merged && !status.attr_switched) {
+ BUG_ON(!rl_write_locked);
+ /* Make the file cluster we allocated sparse in the runlist. */
+ if (ntfs_rl_punch_nolock(vol, &ni->runlist, bh_cpos, 1)) {
+ ntfs_error(vol->sb, "Failed to punch hole into "
+ "attribute runlist in error code "
+ "path. Run chkdsk to recover the "
+ "lost cluster.");
+ NVolSetErrors(vol);
+ } else /* if (success) */ {
+ status.runlist_merged = 0;
+ /*
+ * Deallocate the on-disk cluster we allocated but only
+ * if we succeeded in punching its vcn out of the
+ * runlist.
+ */
+ down_write(&vol->lcnbmp_lock);
+ if (ntfs_bitmap_clear_bit(vol->lcnbmp_ino, lcn)) {
+ ntfs_error(vol->sb, "Failed to release "
+ "allocated cluster in error "
+ "code path. Run chkdsk to "
+ "recover the lost cluster.");
+ NVolSetErrors(vol);
+ }
+ up_write(&vol->lcnbmp_lock);
+ }
+ }
+ /*
+ * Resize the attribute record to its old size and rebuild the mapping
+ * pairs array. Note, we only can do this if the runlist has been
+ * restored to its old state which also implies that the mapped
+ * attribute extent is not switched.
+ */
+ if (status.mp_rebuilt && !status.runlist_merged) {
+ if (ntfs_attr_record_resize(m, a, attr_rec_len)) {
+ ntfs_error(vol->sb, "Failed to restore attribute "
+ "record in error code path. Run "
+ "chkdsk to recover.");
+ NVolSetErrors(vol);
+ } else /* if (success) */ {
+ if (ntfs_mapping_pairs_build(vol, (u8*)a +
+ le16_to_cpu(a->data.non_resident.
+ mapping_pairs_offset), attr_rec_len -
+ le16_to_cpu(a->data.non_resident.
+ mapping_pairs_offset), ni->runlist.rl,
+ vcn, highest_vcn, NULL)) {
+ ntfs_error(vol->sb, "Failed to restore "
+ "mapping pairs array in error "
+ "code path. Run chkdsk to "
+ "recover.");
+ NVolSetErrors(vol);
+ }
+ flush_dcache_mft_record_page(ctx->ntfs_ino);
+ mark_mft_record_dirty(ctx->ntfs_ino);
+ }
+ }
+ /* Release the mft record and the attribute. */
+ if (status.mft_attr_mapped) {
+ ntfs_attr_put_search_ctx(ctx);
+ unmap_mft_record(base_ni);
+ }
+ /* Release the runlist lock. */
+ if (rl_write_locked)
+ up_write(&ni->runlist.lock);
+ else if (rl)
+ up_read(&ni->runlist.lock);
+ /*
+ * Zero out any newly allocated blocks to avoid exposing stale data.
+ * If BH_New is set, we know that the block was newly allocated above
+ * and that it has not been fully zeroed and marked dirty yet.
+ */
+ nr_pages = u;
+ u = 0;
+ end = bh_cpos << vol->cluster_size_bits;
+ do {
+ page = pages[u];
+ bh = head = page_buffers(page);
+ do {
+ if (u == nr_pages &&
+ ((s64)page->index << PAGE_CACHE_SHIFT) +
+ bh_offset(bh) >= end)
+ break;
+ if (!buffer_new(bh))
+ continue;
+ clear_buffer_new(bh);
+ if (!buffer_uptodate(bh)) {
+ if (PageUptodate(page))
+ set_buffer_uptodate(bh);
+ else {
+ zero_user(page, bh_offset(bh),
+ blocksize);
+ set_buffer_uptodate(bh);
+ }
+ }
+ mark_buffer_dirty(bh);
+ } while ((bh = bh->b_this_page) != head);
+ } while (++u <= nr_pages);
+ ntfs_error(vol->sb, "Failed. Returning error code %i.", err);
+ return err;
+}
+
+static inline void ntfs_flush_dcache_pages(struct page **pages,
+ unsigned nr_pages)
+{
+ BUG_ON(!nr_pages);
+ /*
+ * Warning: Do not do the decrement at the same time as the call to
+ * flush_dcache_page() because it is a NULL macro on i386 and hence the
+ * decrement never happens so the loop never terminates.
+ */
+ do {
+ --nr_pages;
+ flush_dcache_page(pages[nr_pages]);
+ } while (nr_pages > 0);
+}
+
+/**
+ * ntfs_commit_pages_after_non_resident_write - commit the received data
+ * @pages: array of destination pages
+ * @nr_pages: number of pages in @pages
+ * @pos: byte position in file at which the write begins
+ * @bytes: number of bytes to be written
+ *
+ * See description of ntfs_commit_pages_after_write(), below.
+ */
+static inline int ntfs_commit_pages_after_non_resident_write(
+ struct page **pages, const unsigned nr_pages,
+ s64 pos, size_t bytes)
+{
+ s64 end, initialized_size;
+ struct inode *vi;
+ ntfs_inode *ni, *base_ni;
+ struct buffer_head *bh, *head;
+ ntfs_attr_search_ctx *ctx;
+ MFT_RECORD *m;
+ ATTR_RECORD *a;
+ unsigned long flags;
+ unsigned blocksize, u;
+ int err;
+
+ vi = pages[0]->mapping->host;
+ ni = NTFS_I(vi);
+ blocksize = vi->i_sb->s_blocksize;
+ end = pos + bytes;
+ u = 0;
+ do {
+ s64 bh_pos;
+ struct page *page;
+ bool partial;
+
+ page = pages[u];
+ bh_pos = (s64)page->index << PAGE_CACHE_SHIFT;
+ bh = head = page_buffers(page);
+ partial = false;
+ do {
+ s64 bh_end;
+
+ bh_end = bh_pos + blocksize;
+ if (bh_end <= pos || bh_pos >= end) {
+ if (!buffer_uptodate(bh))
+ partial = true;
+ } else {
+ set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
+ }
+ } while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
+ /*
+ * If all buffers are now uptodate but the page is not, set the
+ * page uptodate.
+ */
+ if (!partial && !PageUptodate(page))
+ SetPageUptodate(page);
+ } while (++u < nr_pages);
+ /*
+ * Finally, if we do not need to update initialized_size or i_size we
+ * are finished.
+ */
+ read_lock_irqsave(&ni->size_lock, flags);
+ initialized_size = ni->initialized_size;
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ if (end <= initialized_size) {
+ ntfs_debug("Done.");
+ return 0;
+ }
+ /*
+ * Update initialized_size/i_size as appropriate, both in the inode and
+ * the mft record.
+ */
+ 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;
+ }
+ BUG_ON(!NInoNonResident(ni));
+ 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;
+ BUG_ON(!a->non_resident);
+ write_lock_irqsave(&ni->size_lock, flags);
+ BUG_ON(end > ni->allocated_size);
+ ni->initialized_size = end;
+ a->data.non_resident.initialized_size = cpu_to_sle64(end);
+ if (end > i_size_read(vi)) {
+ i_size_write(vi, end);
+ a->data.non_resident.data_size =
+ a->data.non_resident.initialized_size;
+ }
+ write_unlock_irqrestore(&ni->size_lock, flags);
+ /* 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 (ctx)
+ ntfs_attr_put_search_ctx(ctx);
+ if (m)
+ unmap_mft_record(base_ni);
+ ntfs_error(vi->i_sb, "Failed to update initialized_size/i_size (error "
+ "code %i).", err);
+ if (err != -ENOMEM)
+ NVolSetErrors(ni->vol);
+ return err;
+}
+
+/**
+ * ntfs_commit_pages_after_write - commit the received data
+ * @pages: array of destination pages
+ * @nr_pages: number of pages in @pages
+ * @pos: byte position in file at which the write begins
+ * @bytes: number of bytes to be written
+ *
+ * This is called from ntfs_file_buffered_write() with i_mutex held on the inode
+ * (@pages[0]->mapping->host). There are @nr_pages pages in @pages which are
+ * locked but not kmap()ped. The source data has already been copied into the
+ * @page. ntfs_prepare_pages_for_non_resident_write() has been called before
+ * the data was copied (for non-resident attributes only) and it returned
+ * success.
+ *
+ * Need to set uptodate and mark dirty all buffers within the boundary of the
+ * write. If all buffers in a page are uptodate we set the page uptodate, too.
+ *
+ * Setting the buffers dirty ensures that they get written out later when
+ * ntfs_writepage() is invoked by the VM.
+ *
+ * Finally, we need to update i_size and initialized_size as appropriate both
+ * in the inode and the mft record.
+ *
+ * This is modelled after fs/buffer.c::generic_commit_write(), which 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.
+ *
+ * If things have gone as outlined in
+ * ntfs_prepare_pages_for_non_resident_write(), we do not need to do any page
+ * content modifications here for non-resident attributes. For resident
+ * attributes 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.
+ *
+ * Return 0 on success or -errno on error.
+ */
+static int ntfs_commit_pages_after_write(struct page **pages,
+ const unsigned nr_pages, s64 pos, size_t bytes)
+{
+ s64 end, initialized_size;
+ loff_t i_size;
+ struct inode *vi;
+ ntfs_inode *ni, *base_ni;
+ struct page *page;
+ ntfs_attr_search_ctx *ctx;
+ MFT_RECORD *m;
+ ATTR_RECORD *a;
+ char *kattr, *kaddr;
+ unsigned long flags;
+ u32 attr_len;
+ int err;
+
+ BUG_ON(!nr_pages);
+ BUG_ON(!pages);
+ page = pages[0];
+ BUG_ON(!page);
+ vi = page->mapping->host;
+ ni = NTFS_I(vi);
+ ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
+ "index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%zx.",
+ vi->i_ino, ni->type, page->index, nr_pages,
+ (long long)pos, bytes);
+ if (NInoNonResident(ni))
+ return ntfs_commit_pages_after_non_resident_write(pages,
+ nr_pages, pos, bytes);
+ BUG_ON(nr_pages > 1);
+ /*
+ * 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;
+ BUG_ON(NInoNonResident(ni));
+ /* 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;
+ BUG_ON(a->non_resident);
+ /* The total length of the attribute value. */
+ attr_len = le32_to_cpu(a->data.resident.value_length);
+ i_size = i_size_read(vi);
+ BUG_ON(attr_len != i_size);
+ BUG_ON(pos > attr_len);
+ end = pos + bytes;
+ BUG_ON(end > le32_to_cpu(a->length) -
+ le16_to_cpu(a->data.resident.value_offset));
+ kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
+ kaddr = kmap_atomic(page);
+ /* Copy the received data from the page to the mft record. */
+ memcpy(kattr + pos, kaddr + pos, bytes);
+ /* Update the attribute length if necessary. */
+ if (end > attr_len) {
+ attr_len = end;
+ 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 (pos > 0)
+ memcpy(kaddr, kattr, pos);
+ if (end < attr_len)
+ memcpy(kaddr + end, kattr + end, attr_len - end);
+ /* Zero the region outside the end of the attribute value. */
+ memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ }
+ kunmap_atomic(kaddr);
+ /* Update initialized_size/i_size if necessary. */
+ read_lock_irqsave(&ni->size_lock, flags);
+ initialized_size = ni->initialized_size;
+ BUG_ON(end > ni->allocated_size);
+ read_unlock_irqrestore(&ni->size_lock, flags);
+ BUG_ON(initialized_size != i_size);
+ if (end > initialized_size) {
+ write_lock_irqsave(&ni->size_lock, flags);
+ ni->initialized_size = end;
+ i_size_write(vi, end);
+ write_unlock_irqrestore(&ni->size_lock, flags);
+ }
+ /* 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);
+ }
+ if (ctx)
+ ntfs_attr_put_search_ctx(ctx);
+ if (m)
+ unmap_mft_record(base_ni);
+ return err;
+}
+
+/*
+ * Copy as much as we can into the pages and return the number of bytes which
+ * were successfully copied. If a fault is encountered then clear the pages
+ * out to (ofs + bytes) and return the number of bytes which were copied.
+ */
+static size_t ntfs_copy_from_user_iter(struct page **pages, unsigned nr_pages,
+ unsigned ofs, struct iov_iter *i, size_t bytes)
+{
+ struct page **last_page = pages + nr_pages;
+ size_t total = 0;
+ struct iov_iter data = *i;
+ unsigned len, copied;
+
+ do {
+ len = PAGE_CACHE_SIZE - ofs;
+ if (len > bytes)
+ len = bytes;
+ copied = iov_iter_copy_from_user_atomic(*pages, &data, ofs,
+ len);
+ total += copied;
+ bytes -= copied;
+ if (!bytes)
+ break;
+ iov_iter_advance(&data, copied);
+ if (copied < len)
+ goto err;
+ ofs = 0;
+ } while (++pages < last_page);
+out:
+ return total;
+err:
+ /* Zero the rest of the target like __copy_from_user(). */
+ len = PAGE_CACHE_SIZE - copied;
+ do {
+ if (len > bytes)
+ len = bytes;
+ zero_user(*pages, copied, len);
+ bytes -= len;
+ copied = 0;
+ len = PAGE_CACHE_SIZE;
+ } while (++pages < last_page);
+ goto out;
+}
+
+/**
+ * ntfs_perform_write - perform buffered write to a file
+ * @file: file to write to
+ * @i: iov_iter with data to write
+ * @pos: byte offset in file at which to begin writing to
+ */
+static ssize_t ntfs_perform_write(struct file *file, struct iov_iter *i,
+ loff_t pos)
+{
+ struct address_space *mapping = file->f_mapping;
+ struct inode *vi = mapping->host;
+ ntfs_inode *ni = NTFS_I(vi);
+ ntfs_volume *vol = ni->vol;
+ struct page *pages[NTFS_MAX_PAGES_PER_CLUSTER];
+ struct page *cached_page = NULL;
+ VCN last_vcn;
+ LCN lcn;
+ size_t bytes;
+ ssize_t status, written = 0;
+ unsigned nr_pages;
+
+ ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, pos "
+ "0x%llx, count 0x%lx.", vi->i_ino,
+ (unsigned)le32_to_cpu(ni->type),
+ (unsigned long long)pos,
+ (unsigned long)iov_iter_count(i));
+ /*
+ * If a previous ntfs_truncate() failed, repeat it and abort if it
+ * fails again.
+ */
+ if (unlikely(NInoTruncateFailed(ni))) {
+ int err;
+
+ inode_dio_wait(vi);
+ err = ntfs_truncate(vi);
+ if (err || NInoTruncateFailed(ni)) {
+ if (!err)
+ err = -EIO;
+ ntfs_error(vol->sb, "Cannot perform write to inode "
+ "0x%lx, attribute type 0x%x, because "
+ "ntfs_truncate() failed (error code "
+ "%i).", vi->i_ino,
+ (unsigned)le32_to_cpu(ni->type), err);
+ return err;
+ }
+ }
+ /*
+ * Determine the number of pages per cluster for non-resident
+ * attributes.
+ */
+ nr_pages = 1;
+ if (vol->cluster_size > PAGE_CACHE_SIZE && NInoNonResident(ni))
+ nr_pages = vol->cluster_size >> PAGE_CACHE_SHIFT;
+ last_vcn = -1;
+ do {
+ VCN vcn;
+ pgoff_t idx, start_idx;
+ unsigned ofs, do_pages, u;
+ size_t copied;
+
+ start_idx = idx = pos >> PAGE_CACHE_SHIFT;
+ ofs = pos & ~PAGE_CACHE_MASK;
+ bytes = PAGE_CACHE_SIZE - ofs;
+ do_pages = 1;
+ if (nr_pages > 1) {
+ vcn = pos >> vol->cluster_size_bits;
+ if (vcn != last_vcn) {
+ last_vcn = vcn;
+ /*
+ * Get the lcn of the vcn the write is in. If
+ * it is a hole, need to lock down all pages in
+ * the cluster.
+ */
+ down_read(&ni->runlist.lock);
+ lcn = ntfs_attr_vcn_to_lcn_nolock(ni, pos >>
+ vol->cluster_size_bits, false);
+ up_read(&ni->runlist.lock);
+ if (unlikely(lcn < LCN_HOLE)) {
+ if (lcn == LCN_ENOMEM)
+ status = -ENOMEM;
+ else {
+ status = -EIO;
+ ntfs_error(vol->sb, "Cannot "
+ "perform write to "
+ "inode 0x%lx, "
+ "attribute type 0x%x, "
+ "because the attribute "
+ "is corrupt.",
+ vi->i_ino, (unsigned)
+ le32_to_cpu(ni->type));
+ }
+ break;
+ }
+ if (lcn == LCN_HOLE) {
+ start_idx = (pos & ~(s64)
+ vol->cluster_size_mask)
+ >> PAGE_CACHE_SHIFT;
+ bytes = vol->cluster_size - (pos &
+ vol->cluster_size_mask);
+ do_pages = nr_pages;
+ }
+ }
+ }
+ if (bytes > iov_iter_count(i))
+ bytes = iov_iter_count(i);
+again:
+ /*
+ * Bring in the user page(s) that we will copy from _first_.
+ * Otherwise there is a nasty deadlock on copying from the same
+ * page(s) as we are writing to, without it/them being marked
+ * up-to-date. Note, at present there is nothing to stop the
+ * pages being swapped out between us bringing them into memory
+ * and doing the actual copying.
+ */
+ if (unlikely(iov_iter_fault_in_multipages_readable(i, bytes))) {
+ status = -EFAULT;
+ break;
+ }
+ /* Get and lock @do_pages starting at index @start_idx. */
+ status = __ntfs_grab_cache_pages(mapping, start_idx, do_pages,
+ pages, &cached_page);
+ if (unlikely(status))
+ break;
+ /*
+ * For non-resident attributes, we need to fill any holes with
+ * actual clusters and ensure all bufferes are mapped. We also
+ * need to bring uptodate any buffers that are only partially
+ * being written to.
+ */
+ if (NInoNonResident(ni)) {
+ status = ntfs_prepare_pages_for_non_resident_write(
+ pages, do_pages, pos, bytes);
+ if (unlikely(status)) {
+ do {
+ unlock_page(pages[--do_pages]);
+ page_cache_release(pages[do_pages]);
+ } while (do_pages);
+ break;
+ }
+ }
+ u = (pos >> PAGE_CACHE_SHIFT) - pages[0]->index;
+ copied = ntfs_copy_from_user_iter(pages + u, do_pages - u, ofs,
+ i, bytes);
+ ntfs_flush_dcache_pages(pages + u, do_pages - u);
+ status = 0;
+ if (likely(copied == bytes)) {
+ status = ntfs_commit_pages_after_write(pages, do_pages,
+ pos, bytes);
+ if (!status)
+ status = bytes;
+ }
+ do {
+ unlock_page(pages[--do_pages]);
+ page_cache_release(pages[do_pages]);
+ } while (do_pages);
+ if (unlikely(status < 0))
+ break;
+ copied = status;
+ cond_resched();
+ if (unlikely(!copied)) {
+ size_t sc;
+
+ /*
+ * We failed to copy anything. Fall back to single
+ * segment length write.
+ *
+ * This is needed to avoid possible livelock in the
+ * case that all segments in the iov cannot be copied
+ * at once without a pagefault.
+ */
+ sc = iov_iter_single_seg_count(i);
+ if (bytes > sc)
+ bytes = sc;
+ goto again;
+ }
+ iov_iter_advance(i, copied);
+ pos += copied;
+ written += copied;
+ balance_dirty_pages_ratelimited(mapping);
+ if (fatal_signal_pending(current)) {
+ status = -EINTR;
+ break;
+ }
+ } while (iov_iter_count(i));
+ if (cached_page)
+ page_cache_release(cached_page);
+ ntfs_debug("Done. Returning %s (written 0x%lx, status %li).",
+ written ? "written" : "status", (unsigned long)written,
+ (long)status);
+ return written ? written : status;
+}
+
+/**
+ * ntfs_file_write_iter - simple wrapper for ntfs_file_write_iter_nolock()
+ * @iocb: IO state structure
+ * @from: iov_iter with data to write
+ *
+ * Basically the same as generic_file_write_iter() except that it ends up
+ * up calling ntfs_perform_write() instead of generic_perform_write() and that
+ * O_DIRECT is not implemented.
+ */
+static ssize_t ntfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *vi = file_inode(file);
+ ssize_t written = 0;
+ ssize_t err;
+
+ mutex_lock(&vi->i_mutex);
+ /* We can write back this queue in page reclaim. */
+ current->backing_dev_info = inode_to_bdi(vi);
+ err = ntfs_prepare_file_for_write(iocb, from);
+ if (iov_iter_count(from) && !err)
+ written = ntfs_perform_write(file, from, iocb->ki_pos);
+ current->backing_dev_info = NULL;
+ mutex_unlock(&vi->i_mutex);
+ if (likely(written > 0)) {
+ err = generic_write_sync(file, iocb->ki_pos, written);
+ if (err < 0)
+ written = 0;
+ }
+ iocb->ki_pos += written;
+ return written ? written : err;
+}
+
+/**
+ * ntfs_file_fsync - sync a file to disk
+ * @filp: file to be synced
+ * @datasync: if non-zero only flush user data and not metadata
+ *
+ * Data integrity sync of a file to disk. Used for fsync, fdatasync, and msync
+ * system calls. This function is inspired by fs/buffer.c::file_fsync().
+ *
+ * If @datasync is false, write the mft record and all associated extent mft
+ * records as well as the $DATA attribute and then sync the block device.
+ *
+ * If @datasync is true and the attribute is non-resident, we skip the writing
+ * of the mft record and all associated extent mft records (this might still
+ * happen due to the write_inode_now() call).
+ *
+ * Also, if @datasync is true, we do not wait on the inode to be written out
+ * but we always wait on the page cache pages to be written out.
+ *
+ * Locking: Caller must hold i_mutex on the inode.
+ *
+ * TODO: We should probably also write all attribute/index inodes associated
+ * with this inode but since we have no simple way of getting to them we ignore
+ * this problem for now.
+ */
+static int ntfs_file_fsync(struct file *filp, loff_t start, loff_t end,
+ int datasync)
+{
+ struct inode *vi = filp->f_mapping->host;
+ int err, ret = 0;
+
+ ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
+
+ err = filemap_write_and_wait_range(vi->i_mapping, start, end);
+ if (err)
+ return err;
+ mutex_lock(&vi->i_mutex);
+
+ BUG_ON(S_ISDIR(vi->i_mode));
+ if (!datasync || !NInoNonResident(NTFS_I(vi)))
+ ret = __ntfs_write_inode(vi, 1);
+ write_inode_now(vi, !datasync);
+ /*
+ * NOTE: If we were to use mapping->private_list (see ext2 and
+ * fs/buffer.c) for dirty blocks then we could optimize the below to be
+ * sync_mapping_buffers(vi->i_mapping).
+ */
+ err = sync_blockdev(vi->i_sb->s_bdev);
+ if (unlikely(err && !ret))
+ ret = err;
+ if (likely(!ret))
+ ntfs_debug("Done.");
+ else
+ ntfs_warning(vi->i_sb, "Failed to f%ssync inode 0x%lx. Error "
+ "%u.", datasync ? "data" : "", vi->i_ino, -ret);
+ mutex_unlock(&vi->i_mutex);
+ return ret;
+}
+
+#endif /* NTFS_RW */
+
+const struct file_operations ntfs_file_ops = {
+ .llseek = generic_file_llseek,
+ .read_iter = generic_file_read_iter,
+#ifdef NTFS_RW
+ .write_iter = ntfs_file_write_iter,
+ .fsync = ntfs_file_fsync,
+#endif /* NTFS_RW */
+ .mmap = generic_file_mmap,
+ .open = ntfs_file_open,
+ .splice_read = generic_file_splice_read,
+};
+
+const struct inode_operations ntfs_file_inode_ops = {
+#ifdef NTFS_RW
+ .setattr = ntfs_setattr,
+#endif /* NTFS_RW */
+};
+
+const struct file_operations ntfs_empty_file_ops = {};
+
+const struct inode_operations ntfs_empty_inode_ops = {};
Code Review / kvmfornfv.git / blobdiff