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