diff options
Diffstat (limited to 'fs/ntfs/aops.c')
| -rw-r--r-- | fs/ntfs/aops.c | 1777 |
1 files changed, 1777 insertions, 0 deletions
diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c new file mode 100644 index 000000000..7521e11db --- /dev/null +++ b/fs/ntfs/aops.c @@ -0,0 +1,1777 @@ +/** + * aops.c - NTFS kernel address space operations and page cache handling. + * + * Copyright (c) 2001-2014 Anton Altaparmakov and Tuxera Inc. + * 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/fs.h> +#include <linux/gfp.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/swap.h> +#include <linux/buffer_head.h> +#include <linux/writeback.h> +#include <linux/bit_spinlock.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) +{ + unsigned long flags; + struct buffer_head *first, *tmp; + struct page *page; + struct inode *vi; + ntfs_inode *ni; + int page_uptodate = 1; + + page = bh->b_page; + vi = page->mapping->host; + ni = NTFS_I(vi); + + if (likely(uptodate)) { + loff_t i_size; + s64 file_ofs, init_size; + + set_buffer_uptodate(bh); + + file_ofs = ((s64)page->index << PAGE_CACHE_SHIFT) + + bh_offset(bh); + read_lock_irqsave(&ni->size_lock, flags); + init_size = ni->initialized_size; + i_size = i_size_read(vi); + read_unlock_irqrestore(&ni->size_lock, flags); + if (unlikely(init_size > i_size)) { + /* Race with shrinking truncate. */ + init_size = i_size; + } + /* Check for the current buffer head overflowing. */ + if (unlikely(file_ofs + bh->b_size > init_size)) { + int ofs; + void *kaddr; + + ofs = 0; + if (file_ofs < init_size) + ofs = init_size - file_ofs; + local_irq_save(flags); + kaddr = kmap_atomic(page); + memset(kaddr + bh_offset(bh) + ofs, 0, + bh->b_size - ofs); + flush_dcache_page(page); + kunmap_atomic(kaddr); + local_irq_restore(flags); + } + } else { + clear_buffer_uptodate(bh); + SetPageError(page); + ntfs_error(ni->vol->sb, "Buffer I/O error, logical block " + "0x%llx.", (unsigned long long)bh->b_blocknr); + } + first = page_buffers(page); + local_irq_save(flags); + bit_spin_lock(BH_Uptodate_Lock, &first->b_state); + 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); + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(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 { + u8 *kaddr; + 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); + local_irq_save(flags); + kaddr = kmap_atomic(page); + for (i = 0; i < recs; i++) + post_read_mst_fixup((NTFS_RECORD*)(kaddr + + i * rec_size), rec_size); + kunmap_atomic(kaddr); + local_irq_restore(flags); + flush_dcache_page(page); + if (likely(page_uptodate && !PageError(page))) + SetPageUptodate(page); + } + unlock_page(page); + return; +still_busy: + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(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) +{ + loff_t i_size; + VCN vcn; + LCN lcn; + s64 init_size; + struct inode *vi; + 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 long flags; + unsigned int blocksize, vcn_ofs; + int i, nr; + unsigned char blocksize_bits; + + vi = page->mapping->host; + ni = NTFS_I(vi); + 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 = vol->sb->s_blocksize; + blocksize_bits = vol->sb->s_blocksize_bits; + + if (!page_has_buffers(page)) { + create_empty_buffers(page, blocksize, 0); + if (unlikely(!page_has_buffers(page))) { + unlock_page(page); + return -ENOMEM; + } + } + bh = head = page_buffers(page); + BUG_ON(!bh); + + /* + * We may be racing with truncate. To avoid some of the problems we + * now take a snapshot of the various sizes and use those for the whole + * of the function. In case of an extending truncate it just means we + * may leave some buffers unmapped which are now allocated. This is + * not a problem since these buffers will just get mapped when a write + * occurs. In case of a shrinking truncate, we will detect this later + * on due to the runlist being incomplete and if the page is being + * fully truncated, truncate will throw it away as soon as we unlock + * it so no need to worry what we do with it. + */ + iblock = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits); + read_lock_irqsave(&ni->size_lock, flags); + lblock = (ni->allocated_size + blocksize - 1) >> blocksize_bits; + init_size = ni->initialized_size; + i_size = i_size_read(vi); + read_unlock_irqrestore(&ni->size_lock, flags); + if (unlikely(init_size > i_size)) { + /* Race with shrinking truncate. */ + init_size = i_size; + } + zblock = (init_size + blocksize - 1) >> blocksize_bits; + + /* Loop through all the buffers in the page. */ + rl = NULL; + nr = i = 0; + do { + int err = 0; + + 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) { + 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; + } else if (!rl) + up_read(&ni->runlist.lock); + /* + * If buffer is outside the runlist, treat it as a + * hole. This can happen due to concurrent truncate + * for example. + */ + if (err == -ENOENT || lcn == LCN_ENOENT) { + err = 0; + goto handle_hole; + } + /* Hard error, zero out region. */ + if (!err) + err = -EIO; + 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 %i).", ni->mft_no, + ni->type, (unsigned long long)vcn, + vcn_ofs, is_retry ? " even after " + "retrying" : "", err); + } + /* + * 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: + zero_user(page, i * blocksize, blocksize); + if (likely(!err)) + 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; + struct inode *vi; + ntfs_inode *ni, *base_ni; + u8 *addr; + ntfs_attr_search_ctx *ctx; + MFT_RECORD *mrec; + unsigned long flags; + u32 attr_len; + int err = 0; + +retry_readpage: + 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)) { + zero_user(page, 0, PAGE_CACHE_SIZE); + ntfs_debug("Read outside i_size - truncated?"); + goto done; + } + /* + * 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(vi); + /* + * Only $DATA attributes can be encrypted and only unnamed $DATA + * attributes can be compressed. Index root can have the flags set but + * this means to create compressed/encrypted files, not that the + * attribute is compressed/encrypted. Note we need to check for + * AT_INDEX_ALLOCATION since this is the type of both directory and + * index inodes. + */ + if (ni->type != AT_INDEX_ALLOCATION) { + /* If attribute is encrypted, deny access, just like NT4. */ + if (NInoEncrypted(ni)) { + BUG_ON(ni->type != AT_DATA); + err = -EACCES; + goto err_out; + } + /* Compressed data streams are handled in compress.c. */ + if (NInoNonResident(ni) && NInoCompressed(ni)) { + BUG_ON(ni->type != AT_DATA); + BUG_ON(ni->name_len); + return ntfs_read_compressed_block(page); + } + } + /* NInoNonResident() == NInoIndexAllocPresent() */ + if (NInoNonResident(ni)) { + /* Normal, non-resident 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. Note the attribute can actually be marked compressed + * but if it is resident the actual data is not compressed so we are + * ok to ignore the compressed flag here. + */ + if (unlikely(page->index > 0)) { + zero_user(page, 0, PAGE_CACHE_SIZE); + 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; + } + /* + * If a parallel write made the attribute non-resident, drop the mft + * record and retry the readpage. + */ + if (unlikely(NInoNonResident(ni))) { + unmap_mft_record(base_ni); + goto retry_readpage; + } + 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); + read_lock_irqsave(&ni->size_lock, flags); + if (unlikely(attr_len > ni->initialized_size)) + attr_len = ni->initialized_size; + i_size = i_size_read(vi); + read_unlock_irqrestore(&ni->size_lock, flags); + if (unlikely(attr_len > i_size)) { + /* Race with shrinking truncate. */ + attr_len = i_size; + } + addr = kmap_atomic(page); + /* Copy the data to the page. */ + memcpy(addr, (u8*)ctx->attr + + le16_to_cpu(ctx->attr->data.resident.value_offset), + attr_len); + /* Zero the remainder of the page. */ + memset(addr + attr_len, 0, PAGE_CACHE_SIZE - attr_len); + flush_dcache_page(page); + kunmap_atomic(addr); +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; + s64 initialized_size; + loff_t i_size; + sector_t block, dblock, iblock; + struct inode *vi; + ntfs_inode *ni; + ntfs_volume *vol; + runlist_element *rl; + struct buffer_head *bh, *head; + unsigned long flags; + 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 = vol->sb->s_blocksize; + blocksize_bits = vol->sb->s_blocksize_bits; + if (!page_has_buffers(page)) { + BUG_ON(!PageUptodate(page)); + create_empty_buffers(page, blocksize, + (1 << BH_Uptodate) | (1 << BH_Dirty)); + if (unlikely(!page_has_buffers(page))) { + 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 buffers' dirty state as-is. + */ + redirty_page_for_writepage(wbc, page); + unlock_page(page); + return 0; + } + } + bh = head = page_buffers(page); + BUG_ON(!bh); + + /* NOTE: Different naming scheme to ntfs_read_block()! */ + + /* The first block in the page. */ + block = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits); + + read_lock_irqsave(&ni->size_lock, flags); + i_size = i_size_read(vi); + initialized_size = ni->initialized_size; + read_unlock_irqrestore(&ni->size_lock, flags); + + /* The first out of bounds block for the data size. */ + dblock = (i_size + blocksize - 1) >> blocksize_bits; + + /* The last (fully or partially) initialized block. */ + iblock = 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) && + (initialized_size < 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) { + u8 *kaddr; + unsigned long *bpos, *bend; + + /* Check if the buffer is zero. */ + kaddr = kmap_atomic(page); + bpos = (unsigned long *)(kaddr + bh_offset(bh)); + bend = (unsigned long *)((u8*)bpos + blocksize); + do { + if (unlikely(*bpos)) + break; + } while (likely(++bpos < bend)); + kunmap_atomic(kaddr); + if (bpos == bend) { + /* + * Buffer is zero and sparse, no need to write + * it. + */ + bh->b_blocknr = -1; + clear_buffer_dirty(bh); + continue; + } + // 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; + } else if (!rl) + up_read(&ni->runlist.lock); + /* + * If buffer is outside the runlist, truncate has cut it out + * of the runlist. Just clean and clear the buffer and set it + * uptodate so it can get discarded by the VM. + */ + if (err == -ENOENT || lcn == LCN_ENOENT) { + bh->b_blocknr = -1; + clear_buffer_dirty(bh); + zero_user(page, bh_offset(bh), blocksize); + set_buffer_uptodate(bh); + err = 0; + continue; + } + /* Failed to map the buffer, even after retrying. */ + if (!err) + err = -EIO; + 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 %i).", ni->mft_no, + ni->type, (unsigned long long)vcn, + vcn_ofs, is_retry ? " even after " + "retrying" : "", err); + 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() is not 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 { + 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. */ + + /* Submit the prepared buffers for i/o. */ + 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; + } + bh = next; + } while (bh != head); + unlock_page(page); + + /* 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 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; + struct buffer_head *bhs[MAX_BUF_PER_PAGE]; + runlist_element *rl; + int i, nr_locked_nis, nr_recs, nr_bhs, max_bhs, bhs_per_rec, err, err2; + unsigned bh_size, rec_size_bits; + bool sync, is_mft, page_is_dirty, rec_is_dirty; + unsigned char bh_size_bits; + + 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))); + bh_size = vol->sb->s_blocksize; + bh_size_bits = vol->sb->s_blocksize_bits; + max_bhs = PAGE_CACHE_SIZE / bh_size; + BUG_ON(!max_bhs); + BUG_ON(max_bhs > MAX_BUF_PER_PAGE); + + /* Were we called for sync purposes? */ + sync = (wbc->sync_mode == WB_SYNC_ALL); + + /* Make sure we have mapped buffers. */ + 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 = (i_size_read(vi) + 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); + set_buffer_uptodate(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; + + bh->b_bdev = vol->sb->s_bdev; + /* 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; + if (!rl) + up_read(&ni->runlist.lock); + } + /* 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).", + (long long)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 (!trylock_buffer(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. */ + mutex_lock(&tni->extent_lock); + if (tni->nr_extents >= 0) + base_tni = tni; + else { + base_tni = tni->ext.base_ntfs_ino; + BUG_ON(!base_tni); + } + mutex_unlock(&tni->extent_lock); + ntfs_debug("Unlocking %s inode 0x%lx.", + tni == base_tni ? "base" : "extent", + tni->mft_no); + mutex_unlock(&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 = page->mapping->host; + ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi); + char *addr; + ntfs_attr_search_ctx *ctx = NULL; + MFT_RECORD *m = NULL; + u32 attr_len; + int err; + +retry_writepage: + BUG_ON(!PageLocked(page)); + 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, PAGE_CACHE_SIZE); + unlock_page(page); + ntfs_debug("Write outside i_size - truncated?"); + return 0; + } + /* + * Only $DATA attributes can be encrypted and only unnamed $DATA + * attributes can be compressed. Index root can have the flags set but + * this means to create compressed/encrypted files, not that the + * attribute is compressed/encrypted. Note we need to check for + * AT_INDEX_ALLOCATION since this is the type of both directory and + * index inodes. + */ + if (ni->type != AT_INDEX_ALLOCATION) { + /* If file is encrypted, deny access, just like NT4. */ + if (NInoEncrypted(ni)) { + unlock_page(page); + BUG_ON(ni->type != AT_DATA); + ntfs_debug("Denying write access to encrypted file."); + return -EACCES; + } + /* Compressed data streams are handled in compress.c. */ + if (NInoNonResident(ni) && NInoCompressed(ni)) { + BUG_ON(ni->type != AT_DATA); + BUG_ON(ni->name_len); + // TODO: Implement and replace this 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 (NInoNonResident(ni) && NInoSparse(ni)) { + unlock_page(page); + ntfs_error(vi->i_sb, "Writing to sparse files is not " + "supported yet. Sorry."); + return -EOPNOTSUPP; + } + } + /* NInoNonResident() == NInoIndexAllocPresent() */ + if (NInoNonResident(ni)) { + /* 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; + zero_user_segment(page, ofs, PAGE_CACHE_SIZE); + } + /* Handle mst protected attributes. */ + if (NInoMstProtected(ni)) + return ntfs_write_mst_block(page, wbc); + /* Normal, non-resident data stream. */ + return ntfs_write_block(page, wbc); + } + /* + * Attribute is resident, implying it is not compressed, encrypted, 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. Note the attribute can actually be + * marked compressed but if it is resident the actual data is not + * compressed so we are ok to ignore the compressed flag here. + */ + 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; + } + /* + * If a parallel write made the attribute non-resident, drop the mft + * record and retry the writepage. + */ + if (unlikely(NInoNonResident(ni))) { + unmap_mft_record(base_ni); + goto retry_writepage; + } + 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); + attr_len = le32_to_cpu(ctx->attr->data.resident.value_length); + i_size = i_size_read(vi); + if (unlikely(attr_len > i_size)) { + /* Race with shrinking truncate or a failed truncate. */ + attr_len = i_size; + /* + * If the truncate failed, fix it up now. If a concurrent + * truncate, we do its job, so it does not have to do anything. + */ + err = ntfs_resident_attr_value_resize(ctx->mrec, ctx->attr, + attr_len); + /* Shrinking cannot fail. */ + BUG_ON(err); + } + addr = kmap_atomic(page); + /* Copy the data from the page to the mft record. */ + memcpy((u8*)ctx->attr + + le16_to_cpu(ctx->attr->data.resident.value_offset), + addr, attr_len); + /* Zero out of bounds area in the page cache page. */ + memset(addr + attr_len, 0, PAGE_CACHE_SIZE - attr_len); + kunmap_atomic(addr); + flush_dcache_page(page); + flush_dcache_mft_record_page(ctx->ntfs_ino); + /* We are done with the page. */ + end_page_writeback(page); + /* Finally, 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.", err); + SetPageError(page); + NVolSetErrors(ni->vol); + } + unlock_page(page); + if (ctx) + ntfs_attr_put_search_ctx(ctx); + if (m) + unmap_mft_record(base_ni); + return err; +} + +#endif /* NTFS_RW */ + +/** + * ntfs_bmap - map logical file block to physical device block + * @mapping: address space mapping to which the block to be mapped belongs + * @block: logical block to map to its physical device block + * + * For regular, non-resident files (i.e. not compressed and not encrypted), map + * the logical @block belonging to the file described by the address space + * mapping @mapping to its physical device block. + * + * The size of the block is equal to the @s_blocksize field of the super block + * of the mounted file system which is guaranteed to be smaller than or equal + * to the cluster size thus the block is guaranteed to fit entirely inside the + * cluster which means we do not need to care how many contiguous bytes are + * available after the beginning of the block. + * + * Return the physical device block if the mapping succeeded or 0 if the block + * is sparse or there was an error. + * + * Note: This is a problem if someone tries to run bmap() on $Boot system file + * as that really is in block zero but there is nothing we can do. bmap() is + * just broken in that respect (just like it cannot distinguish sparse from + * not available or error). + */ +static sector_t ntfs_bmap(struct address_space *mapping, sector_t block) +{ + s64 ofs, size; + loff_t i_size; + LCN lcn; + unsigned long blocksize, flags; + ntfs_inode *ni = NTFS_I(mapping->host); + ntfs_volume *vol = ni->vol; + unsigned delta; + unsigned char blocksize_bits, cluster_size_shift; + + ntfs_debug("Entering for mft_no 0x%lx, logical block 0x%llx.", + ni->mft_no, (unsigned long long)block); + if (ni->type != AT_DATA || !NInoNonResident(ni) || NInoEncrypted(ni)) { + ntfs_error(vol->sb, "BMAP does not make sense for %s " + "attributes, returning 0.", + (ni->type != AT_DATA) ? "non-data" : + (!NInoNonResident(ni) ? "resident" : + "encrypted")); + return 0; + } + /* None of these can happen. */ + BUG_ON(NInoCompressed(ni)); + BUG_ON(NInoMstProtected(ni)); + blocksize = vol->sb->s_blocksize; + blocksize_bits = vol->sb->s_blocksize_bits; + ofs = (s64)block << blocksize_bits; + read_lock_irqsave(&ni->size_lock, flags); + size = ni->initialized_size; + i_size = i_size_read(VFS_I(ni)); + read_unlock_irqrestore(&ni->size_lock, flags); + /* + * If the offset is outside the initialized size or the block straddles + * the initialized size then pretend it is a hole unless the + * initialized size equals the file size. + */ + if (unlikely(ofs >= size || (ofs + blocksize > size && size < i_size))) + goto hole; + cluster_size_shift = vol->cluster_size_bits; + down_read(&ni->runlist.lock); + lcn = ntfs_attr_vcn_to_lcn_nolock(ni, ofs >> cluster_size_shift, false); + up_read(&ni->runlist.lock); + if (unlikely(lcn < LCN_HOLE)) { + /* + * Step down to an integer to avoid gcc doing a long long + * comparision in the switch when we know @lcn is between + * LCN_HOLE and LCN_EIO (i.e. -1 to -5). + * + * Otherwise older gcc (at least on some architectures) will + * try to use __cmpdi2() which is of course not available in + * the kernel. + */ + switch ((int)lcn) { + case LCN_ENOENT: + /* + * If the offset is out of bounds then pretend it is a + * hole. + */ + goto hole; + case LCN_ENOMEM: + ntfs_error(vol->sb, "Not enough memory to complete " + "mapping for inode 0x%lx. " + "Returning 0.", ni->mft_no); + break; + default: + ntfs_error(vol->sb, "Failed to complete mapping for " + "inode 0x%lx. Run chkdsk. " + "Returning 0.", ni->mft_no); + break; + } + return 0; + } + if (lcn < 0) { + /* It is a hole. */ +hole: + ntfs_debug("Done (returning hole)."); + return 0; + } + /* + * The block is really allocated and fullfils all our criteria. + * Convert the cluster to units of block size and return the result. + */ + delta = ofs & vol->cluster_size_mask; + if (unlikely(sizeof(block) < sizeof(lcn))) { + block = lcn = ((lcn << cluster_size_shift) + delta) >> + blocksize_bits; + /* If the block number was truncated return 0. */ + if (unlikely(block != lcn)) { + ntfs_error(vol->sb, "Physical block 0x%llx is too " + "large to be returned, returning 0.", + (long long)lcn); + return 0; + } + } else + block = ((lcn << cluster_size_shift) + delta) >> + blocksize_bits; + ntfs_debug("Done (returning block 0x%llx).", (unsigned long long)lcn); + return block; +} + +/** + * ntfs_normal_aops - address space operations for normal inodes and attributes + * + * Note these are not used for compressed or mst protected inodes and + * attributes. + */ +const struct address_space_operations ntfs_normal_aops = { + .readpage = ntfs_readpage, +#ifdef NTFS_RW + .writepage = ntfs_writepage, + .set_page_dirty = __set_page_dirty_buffers, +#endif /* NTFS_RW */ + .bmap = ntfs_bmap, + .migratepage = buffer_migrate_page, + .is_partially_uptodate = block_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, +}; + +/** + * ntfs_compressed_aops - address space operations for compressed inodes + */ +const struct address_space_operations ntfs_compressed_aops = { + .readpage = ntfs_readpage, +#ifdef NTFS_RW + .writepage = ntfs_writepage, + .set_page_dirty = __set_page_dirty_buffers, +#endif /* NTFS_RW */ + .migratepage = buffer_migrate_page, + .is_partially_uptodate = block_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, +}; + +/** + * ntfs_mst_aops - general address space operations for mst protecteed inodes + * and attributes + */ +const struct address_space_operations ntfs_mst_aops = { + .readpage = ntfs_readpage, /* Fill page with data. */ +#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 */ + .migratepage = buffer_migrate_page, + .is_partially_uptodate = block_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, +}; + +#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 = VFS_I(ni)->i_sb->s_blocksize; + 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); + BUG_ON(!bh); + 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 */ |