bk pull http://linux-ntfs.bkbits.net/ntfs-2.5
Thanks! The 5th changeset, implementing write(2) based overwrites.
Best regards,
Anton
-- Anton Altaparmakov <aia21 at cantab.net> (replace at with @) Linux NTFS maintainer / IRC: #ntfs on irc.openprojects.net WWW: http://linux-ntfs.sf.net/, http://www-stu.christs.cam.ac.uk/~aia21/===================================================================
This will update the following files:
Documentation/filesystems/ntfs.txt | 5 fs/ntfs/ChangeLog | 37 + fs/ntfs/aops.c | 800 ++++++++++++++++++++++++++++++++++++- fs/ntfs/attrib.c | 5 fs/ntfs/file.c | 3 fs/ntfs/mft.c | 5 fs/ntfs/mft.h | 14 7 files changed, 847 insertions(+), 22 deletions(-)
through these ChangeSets:
<aia21@cantab.net> (02/08/20 1.486.1.2) NTFS: Initial implementation of write(2) based overwriting of existing files on ntfs. (Note: Resident files are not supported yet, so avoid writing to files smaller than 1kiB.)
diff -Nru a/Documentation/filesystems/ntfs.txt b/Documentation/filesystems/ntfs.txt --- a/Documentation/filesystems/ntfs.txt Tue Aug 20 23:58:06 2002 +++ b/Documentation/filesystems/ntfs.txt Tue Aug 20 23:58:06 2002 @@ -247,6 +247,11 @@ Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog. +2.1.0: + - Add configuration option for developmental write support. + - Initial implementation of file overwriting. (Writes to resident files + are not written out to disk yet, so avoid writing to files smaller + than about 1kiB.) 2.0.25: - Minor bugfixes in error code paths and small cleanups. 2.0.24: diff -Nru a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog --- a/fs/ntfs/ChangeLog Tue Aug 20 23:58:06 2002 +++ b/fs/ntfs/ChangeLog Tue Aug 20 23:58:06 2002 @@ -1,6 +1,43 @@ ToDo: - Find and fix bugs. - Enable NFS exporting of NTFS. + - Implement aops->set_page_dirty() in order to take control of buffer + dirtying. Not having it means if page_has_buffers(), all buffers + will be dirtied with the page. And if not they won't be. That is + fine for the moment but will break once we enable metadata updates. + - Implement sops->dirty_inode() to implement {a,m,c} time updates and + such things. + - Implement sops->write_inode(). + - In between ntfs_prepare/commit_write, need exclusion between + simultaneous file extensions. Need perhaps an NInoResizeUnderway() + flag which we can set in ntfs_prepare_write() and clear again in + ntfs_commit_write(). Just have to be careful in readpage/writepage, + as well as in truncate, that we play nice... We might need to have + a data_size field in the ntfs_inode to store the real attribute + length. Also need to be careful with initialized_size extention in + ntfs_prepare_write. Basically, just be _very_ careful in this code... + OTOH, perhaps i_sem, which is held accross generic_file_write is + sufficient for synchronisation here. We then just need to make sure + ntfs_readpage/writepage/truncate interoperate properly with us. + +2.1.0 - First steps towards write support: implement file overwrite. + + - Add configuration option for developmental write support with an + appropriately scary configuration help text. + - Initial implementation of fs/ntfs/aops.c::ntfs_writepage() and its + helper fs/ntfs/aops.c::ntfs_write_block(). This enables mmap(2) based + overwriting of existing files on ntfs. Note: Resident files are + only written into memory, and not written out to disk at present, so + avoid writing to files smaller than about 1kiB. + - Initial implementation of fs/ntfs/aops.c::ntfs_prepare_write(), its + helper fs/ntfs/aops.c::ntfs_prepare_nonresident_write() and their + counterparts, fs/ntfs/aops.c::ntfs_commit_write(), and + fs/ntfs/aops.c::ntfs_commit_nonresident_write(), respectively. Also, + add generic_file_write() to the ntfs file operations (fs/ntfs/file.c). + This enables write(2) based overwriting of existing files on ntfs. + Note: As with mmap(2) based overwriting, resident files are only + written into memory, and not written out to disk at present, so avoid + writing to files smaller than about 1kiB. 2.0.25 - Small bug fixes and cleanups. diff -Nru a/fs/ntfs/aops.c b/fs/ntfs/aops.c --- a/fs/ntfs/aops.c Tue Aug 20 23:58:06 2002 +++ b/fs/ntfs/aops.c Tue Aug 20 23:58:06 2002 @@ -462,12 +462,12 @@ { VCN vcn; LCN lcn; + sector_t block, dblock, iblock; struct inode *vi; ntfs_inode *ni; ntfs_volume *vol; run_list_element *rl; struct buffer_head *bh, *head; - sector_t block, dblock, iblock; unsigned int blocksize, vcn_ofs; int err; BOOL need_end_writeback; @@ -586,9 +586,12 @@ } /* * The current page straddles initialized size. Zero - * all non-uptodate buffers and set them uptodate. - * Note, there aren't any non-uptodate buffers if the - * page is uptodate. + * 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: @@ -605,6 +608,10 @@ "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. */ @@ -785,12 +792,11 @@ * * Return 0 on success and -errno on error. */ -int ntfs_writepage(struct page *page) +static int ntfs_writepage(struct page *page) { s64 attr_pos; struct inode *vi; ntfs_inode *ni, *base_ni; - ntfs_volume *vol; char *kaddr; attr_search_context *ctx; MFT_RECORD *m; @@ -810,7 +816,6 @@ } ni = NTFS_I(vi); - vol = ni->vol; if (NInoNonResident(ni)) { /* @@ -830,7 +835,7 @@ // TODO: Implement and replace this check with // return ntfs_write_compressed_block(page); unlock_page(page); - ntfs_error(vol->sb, "Writing to compressed " + ntfs_error(vi->i_sb, "Writing to compressed " "files is not supported yet. " "Sorry."); return -EOPNOTSUPP; @@ -838,7 +843,7 @@ // TODO: Implement and remove this check. if (NInoSparse(ni)) { unlock_page(page); - ntfs_error(vol->sb, "Writing to sparse files " + ntfs_error(vi->i_sb, "Writing to sparse files " "is not supported yet. Sorry."); return -EOPNOTSUPP; } @@ -857,7 +862,7 @@ // TODO: Implement and remove this check. if (NInoMstProtected(ni)) { unlock_page(page); - ntfs_error(vol->sb, "Writing to MST protected " + ntfs_error(vi->i_sb, "Writing to MST protected " "attributes is not supported yet. " "Sorry."); return -EOPNOTSUPP; @@ -889,7 +894,7 @@ else base_ni = ni->_INE(base_ntfs_ino); - /* Map, pin and lock the mft record. */ + /* Map, pin, and lock the mft record. */ m = map_mft_record(base_ni); if (unlikely(IS_ERR(m))) { err = PTR_ERR(m); @@ -915,14 +920,14 @@ attr_len = le32_to_cpu(ctx->attr->_ARA(value_length)); if (unlikely(vi->i_size != attr_len)) { - ntfs_error(vol->sb, "BUG()! i_size (0x%Lx) doesn't match " + ntfs_error(vi->i_sb, "BUG()! i_size (0x%Lx) doesn't match " "attr_len (0x%x). Aborting write.", vi->i_size, attr_len); err = -EIO; goto err_out; } if (unlikely(attr_pos >= attr_len)) { - ntfs_error(vol->sb, "BUG()! attr_pos (0x%Lx) > attr_len (0x%x)" + ntfs_error(vi->i_sb, "BUG()! attr_pos (0x%Lx) > attr_len (0x%x)" ". Aborting write.", attr_pos, attr_len); err = -EIO; goto err_out; @@ -953,6 +958,7 @@ /* Copy the data from the page to the mft record. */ memcpy((u8*)ctx->attr + le16_to_cpu(ctx->attr->_ARA(value_offset)) + attr_pos, kaddr, bytes); + flush_dcache_mft_record_page(ctx->ntfs_ino); #if 0 /* Zero out of bounds area. */ if (likely(bytes < PAGE_CACHE_SIZE)) { @@ -965,7 +971,7 @@ unlock_page(page); // TODO: Mark mft record dirty so it gets written back. - ntfs_error(vol->sb, "Writing to resident files is not supported yet. " + ntfs_error(vi->i_sb, "Writing to resident files is not supported yet. " "Wrote to memory only..."); put_attr_search_ctx(ctx); @@ -973,7 +979,7 @@ return 0; err_out: if (err == -ENOMEM) { - ntfs_warning(vol->sb, "Error allocating memory. Redirtying " + 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 @@ -985,7 +991,7 @@ __set_page_dirty_nobuffers(page); err = 0; } else { - ntfs_error(vol->sb, "Resident attribute write failed with " + ntfs_error(vi->i_sb, "Resident attribute write failed with " "error %i. Setting page error flag.", -err); SetPageError(page); } @@ -997,6 +1003,765 @@ 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; + run_list_element *rl; + struct buffer_head *bh, *head, *wait[2], **wait_bh = wait; + char *kaddr = page_address(page); + 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 %li, attribute type 0x%x, page index " + "0x%lx, from = %u, to = %u.", vi->i_ino, ni->type, + page->index, from, to); + + BUG_ON(!NInoNonResident(ni)); + BUG_ON(NInoMstProtected(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 = 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 accomodate 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->run_list.lock); + rl = ni->run_list.rl; + } + if (likely(rl != NULL)) { + /* Seek to element containing target vcn. */ + while (rl->length && rl[1].vcn <= vcn) + rl++; + lcn = vcn_to_lcn(rl, vcn); + } else + lcn = (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 run list, dropping + * lock for the duration. + */ + up_read(&ni->run_list.lock); + err = map_run_list(ni, vcn); + if (likely(!err)) + goto lock_retry_remap; + rl = NULL; + } + /* + * Failed to map the buffer, even after + * retrying. + */ + bh->b_blocknr = -1UL; + ntfs_error(vol->sb, "vcn_to_lcn(vcn = 0x%Lx) " + "failed with error code " + "0x%Lx%s.", (long long)vcn, + (long long)-lcn, is_retry ? + " even after retrying" : ""); + // FIXME: Depending on vol->on_errors, do + // something. + 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) + memset(kaddr + to, 0, block_end - to); + if (block_start < from) + memset(kaddr + block_start, 0, + from - block_start); + if (block_end > to || block_start < from) + flush_dcache_page(page); + 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->run_list.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)) { + clear_buffer_new(bh); + if (buffer_uptodate(bh)) + buffer_error(); + memset(kaddr + block_start, 0, bh->b_size); + 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->run_list.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 and kmap()ped so page_address() + * can simply be used. 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]. Can't do that due to + * ntfs specifics but can look at them for implementation guidancea. + * + * 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) +{ + struct inode *vi = page->mapping->host; + ntfs_inode *ni = NTFS_I(vi); + + ntfs_debug("Entering for inode %li, 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); + + 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; + } + } + + // TODO: Implement and remove this check. + if (NInoMstProtected(ni)) { + ntfs_error(vi->i_sb, "Writing to MST protected " + "attributes 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 + * mst protected. + */ + BUG_ON(page_has_buffers(page)); + + /* Do we need to resize the attribute? */ + if (((s64)page->index << PAGE_CACHE_SHIFT) + to > vi->i_size) { + // TODO: Implement resize... + ntfs_error(vi->i_sb, "Writing beyond the existing file size is " + "not supported yet. Sorry."); + return -EOPNOTSUPP; + } + + /* + * 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(). The reason for doing this + * is that we save one round of: + * map_mft_record(), get_attr_search_ctx(), lookup_attr(), + * kmap_atomic(), kunmap_atomic(), put_attr_search_ctx(), + * unmap_mft_record(). + * Which is obviously a very worthwhile save. + * + * Thus we just return success now... + */ + ntfs_debug("Done."); + return 0; +} + +/* + * NOTES: There is a disparity between the apparent need to extend the + * attribute in prepare write but to update i_size only in commit write. + * Need to make sure i_sem protection is sufficient. And if not will need to + * handle this in some way or another. + */ + +/** + * 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; + struct buffer_head *bh, *head; + unsigned int block_start, block_end, blocksize; + BOOL partial; + + vi = page->mapping->host; + + ntfs_debug("Entering for inode %li, 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 MST + // protected attributes for example. For compressed files, too... + // 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() at present. + + 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) { + 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 and kmap()ped so page_address() + * can simply be used. The source data has already been copied into the @page. + * + * 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. - We could still use this (obviously except for + * NInoMstProtected() attributes, where we will need to duplicate the core code + * because we need our own async_io completion handler) but we could just do + * the i_size update in prepare write, when we resize the attribute. Then + * we would avoid the i_size update and mark_inode_dirty() happening here. + * + * Can't 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 only + * need to map the mft record and find the attribute record in it only once. + */ +static int ntfs_commit_write(struct file *file, struct page *page, + unsigned from, unsigned to) +{ + s64 attr_pos; + struct inode *vi; + ntfs_inode *ni, *base_ni; + char *kaddr, *kattr; + attr_search_context *ctx; + MFT_RECORD *m; + u32 attr_len, bytes; + int err; + + vi = page->mapping->host; + ni = NTFS_I(vi); + + ntfs_debug("Entering for inode %li, attribute type 0x%x, page index " + "0x%lx, from = %u, to = %u.", vi->i_ino, ni->type, + page->index, from, to); + + 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)) { + // Should never get here! + 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); + // Should never get here! + 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)) { + // Should never get here! + ntfs_error(vi->i_sb, "Writing to sparse files " + "is not supported yet. Sorry."); + return -EOPNOTSUPP; + } + } + + // TODO: Implement and remove this check. + if (NInoMstProtected(ni)) { + // Should never get here! + ntfs_error(vi->i_sb, "Writing to MST protected " + "attributes is not supported yet. " + "Sorry."); + return -EOPNOTSUPP; + } + + /* Normal data stream. */ + return ntfs_commit_nonresident_write(page, from, to); + } + + /* + * Attribute is resident, implying it is not compressed, encrypted, or + * mst protected. + */ + + /* Do we need to resize the attribute? */ + if (((s64)page->index << PAGE_CACHE_SHIFT) + to > vi->i_size) { + // TODO: Implement resize... + // pos = ((s64)page->index << PAGE_CACHE_SHIFT) + to; + // vi->i_size = pos; + // mark_inode_dirty(vi); + // Should never get here! + ntfs_error(vi->i_sb, "Writing beyond the existing file size is " + "not supported yet. Sorry."); + return -EOPNOTSUPP; + } + + if (!NInoAttr(ni)) + base_ni = ni; + else + base_ni = ni->_INE(base_ntfs_ino); + + /* Map, pin, and lock the mft record. */ + m = map_mft_record(base_ni); + if (unlikely(IS_ERR(m))) { + err = PTR_ERR(m); + m = NULL; + ctx = NULL; + goto err_out; + } + ctx = get_attr_search_ctx(base_ni, m); + if (unlikely(!ctx)) { + err = -ENOMEM; + goto err_out; + } + if (unlikely(!lookup_attr(ni->type, ni->name, ni->name_len, + IGNORE_CASE, 0, NULL, 0, ctx))) { + err = -ENOENT; + goto err_out; + } + + /* Starting position of the page within the attribute value. */ + attr_pos = page->index << PAGE_CACHE_SHIFT; + + /* The total length of the attribute value. */ + attr_len = le32_to_cpu(ctx->attr->_ARA(value_length)); + + if (unlikely(vi->i_size != attr_len)) { + ntfs_error(vi->i_sb, "BUG()! i_size (0x%Lx) doesn't match " + "attr_len (0x%x). Aborting write.", vi->i_size, + attr_len); + err = -EIO; + goto err_out; + } + if (unlikely(attr_pos >= attr_len)) { + ntfs_error(vi->i_sb, "BUG()! attr_pos (0x%Lx) > attr_len (0x%x)" + ". Aborting write.", attr_pos, attr_len); + err = -EIO; + goto err_out; + } + + bytes = attr_len - attr_pos; + if (unlikely(bytes > PAGE_CACHE_SIZE)) + bytes = PAGE_CACHE_SIZE; + + /* + * Calculate the address of the attribute value corresponding to the + * beginning of the current data @page. + */ + kattr = (u8*)ctx->attr + le16_to_cpu(ctx->attr->_ARA(value_offset)) + + attr_pos; + + kaddr = kmap_atomic(page, KM_USER0); + + /* Copy the received data from the page to the mft record. */ + memcpy(kattr + from, kaddr + from, to - from); + flush_dcache_mft_record_page(ctx->ntfs_ino); + + if (!PageUptodate(page)) { + /* + * Bring the out of bounds area(s) uptodate by copying data + * from the mft record to the page. + */ + if (from > 0) + memcpy(kaddr, kattr, from); + if (to < bytes) + memcpy(kaddr + to, kattr + to, bytes - to); + + /* Zero the region outside the end of the attribute value. */ + if (likely(bytes < PAGE_CACHE_SIZE)) + memset(kaddr + bytes, 0, PAGE_CACHE_SIZE - bytes); + + /* + * 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); + + // TODO: Mark mft record dirty so it gets written back. + ntfs_error(vi->i_sb, "Writing to resident files is not supported yet. " + "Wrote to memory only..."); + + put_attr_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 + * buffer's 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 write failed with " + "error %i. Setting page error flag.", -err); + SetPageError(page); + } + if (ctx) + put_attr_search_ctx(ctx); + if (m) + unmap_mft_record(base_ni); + return err; +} + #endif /* NTFS_RW */ /** @@ -1008,6 +1773,9 @@ 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 }; diff -Nru a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c --- a/fs/ntfs/attrib.c Tue Aug 20 23:58:06 2002 +++ b/fs/ntfs/attrib.c Tue Aug 20 23:58:06 2002 @@ -1182,8 +1182,9 @@ else { register int rc; - rc = memcmp(val, (u8*)a +le16_to_cpu(a->_ARA(value_offset)), - min(val_len, le32_to_cpu(a->_ARA(value_length)))); + rc = memcmp(val, (u8*)a + le16_to_cpu( + a->_ARA(value_offset)), min(val_len, + le32_to_cpu(a->_ARA(value_length)))); /* * If @val collates before the current attribute's * value, there is no matching attribute. diff -Nru a/fs/ntfs/file.c b/fs/ntfs/file.c --- a/fs/ntfs/file.c Tue Aug 20 23:58:06 2002 +++ b/fs/ntfs/file.c Tue Aug 20 23:58:06 2002 @@ -51,6 +51,9 @@ struct file_operations ntfs_file_ops = { .llseek = generic_file_llseek, /* Seek inside file. */ .read = generic_file_read, /* Read from file. */ +#ifdef NTFS_RW + .write = generic_file_write, /* Write to a file. */ +#endif .mmap = generic_file_mmap, /* Mmap file. */ .sendfile = generic_file_sendfile,/* Zero-copy data send with the data source being on the diff -Nru a/fs/ntfs/mft.c b/fs/ntfs/mft.c --- a/fs/ntfs/mft.c Tue Aug 20 23:58:06 2002 +++ b/fs/ntfs/mft.c Tue Aug 20 23:58:06 2002 @@ -98,7 +98,7 @@ } /** - * From fs/ntfs/aops.c + * ntfs_readpage - external declaration, function is in fs/ntfs/aops.c */ extern int ntfs_readpage(struct file *, struct page *); @@ -109,12 +109,9 @@ * ntfs_map_page() in map_mft_record_page(). */ struct address_space_operations ntfs_mft_aops = { - .writepage = NULL, /* Write dirty page to disk. */ .readpage = ntfs_readpage, /* Fill page with data. */ .sync_page = block_sync_page, /* Currently, just unplugs the disk request queue. */ - .prepare_write = NULL, /* . */ - .commit_write = NULL, /* . */ }; /** diff -Nru a/fs/ntfs/mft.h b/fs/ntfs/mft.h --- a/fs/ntfs/mft.h Tue Aug 20 23:58:06 2002 +++ b/fs/ntfs/mft.h Tue Aug 20 23:58:06 2002 @@ -43,5 +43,19 @@ return; } +/* + * flush_dcache_mft_record_page - flush_dcache_page() for mft records + * @ni: ntfs inode structure of mft record + * + * Call flush_dcache_page() for the page in which an mft record resides. + * + * This must be called every time an mft record is modified, just after the + * modification. + */ +static inline void flush_dcache_mft_record_page(ntfs_inode *ni) +{ + flush_dcache_page(ni->page); +} + #endif /* _LINUX_NTFS_MFT_H */
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