diff options
Diffstat (limited to 'fs/ntfs/compress.c')
| -rw-r--r-- | fs/ntfs/compress.c | 950 |
1 files changed, 0 insertions, 950 deletions
diff --git a/fs/ntfs/compress.c b/fs/ntfs/compress.c deleted file mode 100644 index 761aaa0195..0000000000 --- a/fs/ntfs/compress.c +++ /dev/null @@ -1,950 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * compress.c - NTFS kernel compressed attributes handling. - * Part of the Linux-NTFS project. - * - * Copyright (c) 2001-2004 Anton Altaparmakov - * Copyright (c) 2002 Richard Russon - */ - -#include <linux/fs.h> -#include <linux/buffer_head.h> -#include <linux/blkdev.h> -#include <linux/vmalloc.h> -#include <linux/slab.h> - -#include "attrib.h" -#include "inode.h" -#include "debug.h" -#include "ntfs.h" - -/** - * ntfs_compression_constants - enum of constants used in the compression code - */ -typedef enum { - /* Token types and access mask. */ - NTFS_SYMBOL_TOKEN = 0, - NTFS_PHRASE_TOKEN = 1, - NTFS_TOKEN_MASK = 1, - - /* Compression sub-block constants. */ - NTFS_SB_SIZE_MASK = 0x0fff, - NTFS_SB_SIZE = 0x1000, - NTFS_SB_IS_COMPRESSED = 0x8000, - - /* - * The maximum compression block size is by definition 16 * the cluster - * size, with the maximum supported cluster size being 4kiB. Thus the - * maximum compression buffer size is 64kiB, so we use this when - * initializing the compression buffer. - */ - NTFS_MAX_CB_SIZE = 64 * 1024, -} ntfs_compression_constants; - -/* - * ntfs_compression_buffer - one buffer for the decompression engine - */ -static u8 *ntfs_compression_buffer; - -/* - * ntfs_cb_lock - spinlock which protects ntfs_compression_buffer - */ -static DEFINE_SPINLOCK(ntfs_cb_lock); - -/** - * allocate_compression_buffers - allocate the decompression buffers - * - * Caller has to hold the ntfs_lock mutex. - * - * Return 0 on success or -ENOMEM if the allocations failed. - */ -int allocate_compression_buffers(void) -{ - BUG_ON(ntfs_compression_buffer); - - ntfs_compression_buffer = vmalloc(NTFS_MAX_CB_SIZE); - if (!ntfs_compression_buffer) - return -ENOMEM; - return 0; -} - -/** - * free_compression_buffers - free the decompression buffers - * - * Caller has to hold the ntfs_lock mutex. - */ -void free_compression_buffers(void) -{ - BUG_ON(!ntfs_compression_buffer); - vfree(ntfs_compression_buffer); - ntfs_compression_buffer = NULL; -} - -/** - * zero_partial_compressed_page - zero out of bounds compressed page region - */ -static void zero_partial_compressed_page(struct page *page, - const s64 initialized_size) -{ - u8 *kp = page_address(page); - unsigned int kp_ofs; - - ntfs_debug("Zeroing page region outside initialized size."); - if (((s64)page->index << PAGE_SHIFT) >= initialized_size) { - clear_page(kp); - return; - } - kp_ofs = initialized_size & ~PAGE_MASK; - memset(kp + kp_ofs, 0, PAGE_SIZE - kp_ofs); - return; -} - -/** - * handle_bounds_compressed_page - test for&handle out of bounds compressed page - */ -static inline void handle_bounds_compressed_page(struct page *page, - const loff_t i_size, const s64 initialized_size) -{ - if ((page->index >= (initialized_size >> PAGE_SHIFT)) && - (initialized_size < i_size)) - zero_partial_compressed_page(page, initialized_size); - return; -} - -/** - * ntfs_decompress - decompress a compression block into an array of pages - * @dest_pages: destination array of pages - * @completed_pages: scratch space to track completed pages - * @dest_index: current index into @dest_pages (IN/OUT) - * @dest_ofs: current offset within @dest_pages[@dest_index] (IN/OUT) - * @dest_max_index: maximum index into @dest_pages (IN) - * @dest_max_ofs: maximum offset within @dest_pages[@dest_max_index] (IN) - * @xpage: the target page (-1 if none) (IN) - * @xpage_done: set to 1 if xpage was completed successfully (IN/OUT) - * @cb_start: compression block to decompress (IN) - * @cb_size: size of compression block @cb_start in bytes (IN) - * @i_size: file size when we started the read (IN) - * @initialized_size: initialized file size when we started the read (IN) - * - * The caller must have disabled preemption. ntfs_decompress() reenables it when - * the critical section is finished. - * - * This decompresses the compression block @cb_start into the array of - * destination pages @dest_pages starting at index @dest_index into @dest_pages - * and at offset @dest_pos into the page @dest_pages[@dest_index]. - * - * When the page @dest_pages[@xpage] is completed, @xpage_done is set to 1. - * If xpage is -1 or @xpage has not been completed, @xpage_done is not modified. - * - * @cb_start is a pointer to the compression block which needs decompressing - * and @cb_size is the size of @cb_start in bytes (8-64kiB). - * - * Return 0 if success or -EOVERFLOW on error in the compressed stream. - * @xpage_done indicates whether the target page (@dest_pages[@xpage]) was - * completed during the decompression of the compression block (@cb_start). - * - * Warning: This function *REQUIRES* PAGE_SIZE >= 4096 or it will blow up - * unpredicatbly! You have been warned! - * - * Note to hackers: This function may not sleep until it has finished accessing - * the compression block @cb_start as it is a per-CPU buffer. - */ -static int ntfs_decompress(struct page *dest_pages[], int completed_pages[], - int *dest_index, int *dest_ofs, const int dest_max_index, - const int dest_max_ofs, const int xpage, char *xpage_done, - u8 *const cb_start, const u32 cb_size, const loff_t i_size, - const s64 initialized_size) -{ - /* - * Pointers into the compressed data, i.e. the compression block (cb), - * and the therein contained sub-blocks (sb). - */ - u8 *cb_end = cb_start + cb_size; /* End of cb. */ - u8 *cb = cb_start; /* Current position in cb. */ - u8 *cb_sb_start; /* Beginning of the current sb in the cb. */ - u8 *cb_sb_end; /* End of current sb / beginning of next sb. */ - - /* Variables for uncompressed data / destination. */ - struct page *dp; /* Current destination page being worked on. */ - u8 *dp_addr; /* Current pointer into dp. */ - u8 *dp_sb_start; /* Start of current sub-block in dp. */ - u8 *dp_sb_end; /* End of current sb in dp (dp_sb_start + - NTFS_SB_SIZE). */ - u16 do_sb_start; /* @dest_ofs when starting this sub-block. */ - u16 do_sb_end; /* @dest_ofs of end of this sb (do_sb_start + - NTFS_SB_SIZE). */ - - /* Variables for tag and token parsing. */ - u8 tag; /* Current tag. */ - int token; /* Loop counter for the eight tokens in tag. */ - int nr_completed_pages = 0; - - /* Default error code. */ - int err = -EOVERFLOW; - - ntfs_debug("Entering, cb_size = 0x%x.", cb_size); -do_next_sb: - ntfs_debug("Beginning sub-block at offset = 0x%zx in the cb.", - cb - cb_start); - /* - * Have we reached the end of the compression block or the end of the - * decompressed data? The latter can happen for example if the current - * position in the compression block is one byte before its end so the - * first two checks do not detect it. - */ - if (cb == cb_end || !le16_to_cpup((le16*)cb) || - (*dest_index == dest_max_index && - *dest_ofs == dest_max_ofs)) { - int i; - - ntfs_debug("Completed. Returning success (0)."); - err = 0; -return_error: - /* We can sleep from now on, so we drop lock. */ - spin_unlock(&ntfs_cb_lock); - /* Second stage: finalize completed pages. */ - if (nr_completed_pages > 0) { - for (i = 0; i < nr_completed_pages; i++) { - int di = completed_pages[i]; - - dp = dest_pages[di]; - /* - * If we are outside the initialized size, zero - * the out of bounds page range. - */ - handle_bounds_compressed_page(dp, i_size, - initialized_size); - flush_dcache_page(dp); - kunmap(dp); - SetPageUptodate(dp); - unlock_page(dp); - if (di == xpage) - *xpage_done = 1; - else - put_page(dp); - dest_pages[di] = NULL; - } - } - return err; - } - - /* Setup offsets for the current sub-block destination. */ - do_sb_start = *dest_ofs; - do_sb_end = do_sb_start + NTFS_SB_SIZE; - - /* Check that we are still within allowed boundaries. */ - if (*dest_index == dest_max_index && do_sb_end > dest_max_ofs) - goto return_overflow; - - /* Does the minimum size of a compressed sb overflow valid range? */ - if (cb + 6 > cb_end) - goto return_overflow; - - /* Setup the current sub-block source pointers and validate range. */ - cb_sb_start = cb; - cb_sb_end = cb_sb_start + (le16_to_cpup((le16*)cb) & NTFS_SB_SIZE_MASK) - + 3; - if (cb_sb_end > cb_end) - goto return_overflow; - - /* Get the current destination page. */ - dp = dest_pages[*dest_index]; - if (!dp) { - /* No page present. Skip decompression of this sub-block. */ - cb = cb_sb_end; - - /* Advance destination position to next sub-block. */ - *dest_ofs = (*dest_ofs + NTFS_SB_SIZE) & ~PAGE_MASK; - if (!*dest_ofs && (++*dest_index > dest_max_index)) - goto return_overflow; - goto do_next_sb; - } - - /* We have a valid destination page. Setup the destination pointers. */ - dp_addr = (u8*)page_address(dp) + do_sb_start; - - /* Now, we are ready to process the current sub-block (sb). */ - if (!(le16_to_cpup((le16*)cb) & NTFS_SB_IS_COMPRESSED)) { - ntfs_debug("Found uncompressed sub-block."); - /* This sb is not compressed, just copy it into destination. */ - - /* Advance source position to first data byte. */ - cb += 2; - - /* An uncompressed sb must be full size. */ - if (cb_sb_end - cb != NTFS_SB_SIZE) - goto return_overflow; - - /* Copy the block and advance the source position. */ - memcpy(dp_addr, cb, NTFS_SB_SIZE); - cb += NTFS_SB_SIZE; - - /* Advance destination position to next sub-block. */ - *dest_ofs += NTFS_SB_SIZE; - if (!(*dest_ofs &= ~PAGE_MASK)) { -finalize_page: - /* - * First stage: add current page index to array of - * completed pages. - */ - completed_pages[nr_completed_pages++] = *dest_index; - if (++*dest_index > dest_max_index) - goto return_overflow; - } - goto do_next_sb; - } - ntfs_debug("Found compressed sub-block."); - /* This sb is compressed, decompress it into destination. */ - - /* Setup destination pointers. */ - dp_sb_start = dp_addr; - dp_sb_end = dp_sb_start + NTFS_SB_SIZE; - - /* Forward to the first tag in the sub-block. */ - cb += 2; -do_next_tag: - if (cb == cb_sb_end) { - /* Check if the decompressed sub-block was not full-length. */ - if (dp_addr < dp_sb_end) { - int nr_bytes = do_sb_end - *dest_ofs; - - ntfs_debug("Filling incomplete sub-block with " - "zeroes."); - /* Zero remainder and update destination position. */ - memset(dp_addr, 0, nr_bytes); - *dest_ofs += nr_bytes; - } - /* We have finished the current sub-block. */ - if (!(*dest_ofs &= ~PAGE_MASK)) - goto finalize_page; - goto do_next_sb; - } - - /* Check we are still in range. */ - if (cb > cb_sb_end || dp_addr > dp_sb_end) - goto return_overflow; - - /* Get the next tag and advance to first token. */ - tag = *cb++; - - /* Parse the eight tokens described by the tag. */ - for (token = 0; token < 8; token++, tag >>= 1) { - u16 lg, pt, length, max_non_overlap; - register u16 i; - u8 *dp_back_addr; - - /* Check if we are done / still in range. */ - if (cb >= cb_sb_end || dp_addr > dp_sb_end) - break; - - /* Determine token type and parse appropriately.*/ - if ((tag & NTFS_TOKEN_MASK) == NTFS_SYMBOL_TOKEN) { - /* - * We have a symbol token, copy the symbol across, and - * advance the source and destination positions. - */ - *dp_addr++ = *cb++; - ++*dest_ofs; - - /* Continue with the next token. */ - continue; - } - - /* - * We have a phrase token. Make sure it is not the first tag in - * the sb as this is illegal and would confuse the code below. - */ - if (dp_addr == dp_sb_start) - goto return_overflow; - - /* - * Determine the number of bytes to go back (p) and the number - * of bytes to copy (l). We use an optimized algorithm in which - * we first calculate log2(current destination position in sb), - * which allows determination of l and p in O(1) rather than - * O(n). We just need an arch-optimized log2() function now. - */ - lg = 0; - for (i = *dest_ofs - do_sb_start - 1; i >= 0x10; i >>= 1) - lg++; - - /* Get the phrase token into i. */ - pt = le16_to_cpup((le16*)cb); - - /* - * Calculate starting position of the byte sequence in - * the destination using the fact that p = (pt >> (12 - lg)) + 1 - * and make sure we don't go too far back. - */ - dp_back_addr = dp_addr - (pt >> (12 - lg)) - 1; - if (dp_back_addr < dp_sb_start) - goto return_overflow; - - /* Now calculate the length of the byte sequence. */ - length = (pt & (0xfff >> lg)) + 3; - - /* Advance destination position and verify it is in range. */ - *dest_ofs += length; - if (*dest_ofs > do_sb_end) - goto return_overflow; - - /* The number of non-overlapping bytes. */ - max_non_overlap = dp_addr - dp_back_addr; - - if (length <= max_non_overlap) { - /* The byte sequence doesn't overlap, just copy it. */ - memcpy(dp_addr, dp_back_addr, length); - - /* Advance destination pointer. */ - dp_addr += length; - } else { - /* - * The byte sequence does overlap, copy non-overlapping - * part and then do a slow byte by byte copy for the - * overlapping part. Also, advance the destination - * pointer. - */ - memcpy(dp_addr, dp_back_addr, max_non_overlap); - dp_addr += max_non_overlap; - dp_back_addr += max_non_overlap; - length -= max_non_overlap; - while (length--) - *dp_addr++ = *dp_back_addr++; - } - - /* Advance source position and continue with the next token. */ - cb += 2; - } - - /* No tokens left in the current tag. Continue with the next tag. */ - goto do_next_tag; - -return_overflow: - ntfs_error(NULL, "Failed. Returning -EOVERFLOW."); - goto return_error; -} - -/** - * ntfs_read_compressed_block - read a compressed block into the page cache - * @page: locked page in the compression block(s) we need to read - * - * When we are called the page has already been verified to be locked and the - * attribute is known to be non-resident, not encrypted, but compressed. - * - * 1. Determine which compression block(s) @page is in. - * 2. Get hold of all pages corresponding to this/these compression block(s). - * 3. Read the (first) compression block. - * 4. Decompress it into the corresponding pages. - * 5. Throw the compressed data away and proceed to 3. for the next compression - * block or return success if no more compression blocks left. - * - * Warning: We have to be careful what we do about existing pages. They might - * have been written to so that we would lose data if we were to just overwrite - * them with the out-of-date uncompressed data. - * - * FIXME: For PAGE_SIZE > cb_size we are not doing the Right Thing(TM) at - * the end of the file I think. We need to detect this case and zero the out - * of bounds remainder of the page in question and mark it as handled. At the - * moment we would just return -EIO on such a page. This bug will only become - * apparent if pages are above 8kiB and the NTFS volume only uses 512 byte - * clusters so is probably not going to be seen by anyone. Still this should - * be fixed. (AIA) - * - * FIXME: Again for PAGE_SIZE > cb_size we are screwing up both in - * handling sparse and compressed cbs. (AIA) - * - * FIXME: At the moment we don't do any zeroing out in the case that - * initialized_size is less than data_size. This should be safe because of the - * nature of the compression algorithm used. Just in case we check and output - * an error message in read inode if the two sizes are not equal for a - * compressed file. (AIA) - */ -int ntfs_read_compressed_block(struct page *page) -{ - loff_t i_size; - s64 initialized_size; - struct address_space *mapping = page->mapping; - ntfs_inode *ni = NTFS_I(mapping->host); - ntfs_volume *vol = ni->vol; - struct super_block *sb = vol->sb; - runlist_element *rl; - unsigned long flags, block_size = sb->s_blocksize; - unsigned char block_size_bits = sb->s_blocksize_bits; - u8 *cb, *cb_pos, *cb_end; - struct buffer_head **bhs; - unsigned long offset, index = page->index; - u32 cb_size = ni->itype.compressed.block_size; - u64 cb_size_mask = cb_size - 1UL; - VCN vcn; - LCN lcn; - /* The first wanted vcn (minimum alignment is PAGE_SIZE). */ - VCN start_vcn = (((s64)index << PAGE_SHIFT) & ~cb_size_mask) >> - vol->cluster_size_bits; - /* - * The first vcn after the last wanted vcn (minimum alignment is again - * PAGE_SIZE. - */ - VCN end_vcn = ((((s64)(index + 1UL) << PAGE_SHIFT) + cb_size - 1) - & ~cb_size_mask) >> vol->cluster_size_bits; - /* Number of compression blocks (cbs) in the wanted vcn range. */ - unsigned int nr_cbs = (end_vcn - start_vcn) << vol->cluster_size_bits - >> ni->itype.compressed.block_size_bits; - /* - * Number of pages required to store the uncompressed data from all - * compression blocks (cbs) overlapping @page. Due to alignment - * guarantees of start_vcn and end_vcn, no need to round up here. - */ - unsigned int nr_pages = (end_vcn - start_vcn) << - vol->cluster_size_bits >> PAGE_SHIFT; - unsigned int xpage, max_page, cur_page, cur_ofs, i; - unsigned int cb_clusters, cb_max_ofs; - int block, max_block, cb_max_page, bhs_size, nr_bhs, err = 0; - struct page **pages; - int *completed_pages; - unsigned char xpage_done = 0; - - ntfs_debug("Entering, page->index = 0x%lx, cb_size = 0x%x, nr_pages = " - "%i.", index, cb_size, nr_pages); - /* - * Bad things happen if we get here for anything that is not an - * unnamed $DATA attribute. - */ - BUG_ON(ni->type != AT_DATA); - BUG_ON(ni->name_len); - - pages = kmalloc_array(nr_pages, sizeof(struct page *), GFP_NOFS); - completed_pages = kmalloc_array(nr_pages + 1, sizeof(int), GFP_NOFS); - - /* Allocate memory to store the buffer heads we need. */ - bhs_size = cb_size / block_size * sizeof(struct buffer_head *); - bhs = kmalloc(bhs_size, GFP_NOFS); - - if (unlikely(!pages || !bhs || !completed_pages)) { - kfree(bhs); - kfree(pages); - kfree(completed_pages); - unlock_page(page); - ntfs_error(vol->sb, "Failed to allocate internal buffers."); - return -ENOMEM; - } - - /* - * We have already been given one page, this is the one we must do. - * Once again, the alignment guarantees keep it simple. - */ - offset = start_vcn << vol->cluster_size_bits >> PAGE_SHIFT; - xpage = index - offset; - pages[xpage] = page; - /* - * The remaining pages need to be allocated and inserted into the page - * cache, alignment guarantees keep all the below much simpler. (-8 - */ - read_lock_irqsave(&ni->size_lock, flags); - i_size = i_size_read(VFS_I(ni)); - initialized_size = ni->initialized_size; - read_unlock_irqrestore(&ni->size_lock, flags); - max_page = ((i_size + PAGE_SIZE - 1) >> PAGE_SHIFT) - - offset; - /* Is the page fully outside i_size? (truncate in progress) */ - if (xpage >= max_page) { - kfree(bhs); - kfree(pages); - kfree(completed_pages); - zero_user(page, 0, PAGE_SIZE); - ntfs_debug("Compressed read outside i_size - truncated?"); - SetPageUptodate(page); - unlock_page(page); - return 0; - } - if (nr_pages < max_page) - max_page = nr_pages; - for (i = 0; i < max_page; i++, offset++) { - if (i != xpage) - pages[i] = grab_cache_page_nowait(mapping, offset); - page = pages[i]; - if (page) { - /* - * We only (re)read the page if it isn't already read - * in and/or dirty or we would be losing data or at - * least wasting our time. - */ - if (!PageDirty(page) && (!PageUptodate(page) || - PageError(page))) { - ClearPageError(page); - kmap(page); - continue; - } - unlock_page(page); - put_page(page); - pages[i] = NULL; - } - } - - /* - * We have the runlist, and all the destination pages we need to fill. - * Now read the first compression block. - */ - cur_page = 0; - cur_ofs = 0; - cb_clusters = ni->itype.compressed.block_clusters; -do_next_cb: - nr_cbs--; - nr_bhs = 0; - - /* Read all cb buffer heads one cluster at a time. */ - rl = NULL; - for (vcn = start_vcn, start_vcn += cb_clusters; vcn < start_vcn; - vcn++) { - bool 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; - ntfs_debug("Reading vcn = 0x%llx, lcn = 0x%llx.", - (unsigned long long)vcn, - (unsigned long long)lcn); - if (lcn < 0) { - /* - * When we reach the first sparse cluster we have - * finished with the cb. - */ - if (lcn == LCN_HOLE) - break; - if (is_retry || lcn != LCN_RL_NOT_MAPPED) - goto rl_err; - is_retry = true; - /* - * Attempt to map runlist, dropping lock for the - * duration. - */ - up_read(&ni->runlist.lock); - if (!ntfs_map_runlist(ni, vcn)) - goto lock_retry_remap; - goto map_rl_err; - } - block = lcn << vol->cluster_size_bits >> block_size_bits; - /* Read the lcn from device in chunks of block_size bytes. */ - max_block = block + (vol->cluster_size >> block_size_bits); - do { - ntfs_debug("block = 0x%x.", block); - if (unlikely(!(bhs[nr_bhs] = sb_getblk(sb, block)))) - goto getblk_err; - nr_bhs++; - } while (++block < max_block); - } - - /* Release the lock if we took it. */ - if (rl) - up_read(&ni->runlist.lock); - - /* Setup and initiate io on all buffer heads. */ - for (i = 0; i < nr_bhs; i++) { - struct buffer_head *tbh = bhs[i]; - - if (!trylock_buffer(tbh)) - continue; - if (unlikely(buffer_uptodate(tbh))) { - unlock_buffer(tbh); - continue; - } - get_bh(tbh); - tbh->b_end_io = end_buffer_read_sync; - submit_bh(REQ_OP_READ, tbh); - } - - /* Wait for io completion on all buffer heads. */ - for (i = 0; i < nr_bhs; i++) { - struct buffer_head *tbh = bhs[i]; - - if (buffer_uptodate(tbh)) - continue; - wait_on_buffer(tbh); - /* - * We need an optimization barrier here, otherwise we start - * hitting the below fixup code when accessing a loopback - * mounted ntfs partition. This indicates either there is a - * race condition in the loop driver or, more likely, gcc - * overoptimises the code without the barrier and it doesn't - * do the Right Thing(TM). - */ - barrier(); - if (unlikely(!buffer_uptodate(tbh))) { - ntfs_warning(vol->sb, "Buffer is unlocked but not " - "uptodate! Unplugging the disk queue " - "and rescheduling."); - get_bh(tbh); - io_schedule(); - put_bh(tbh); - if (unlikely(!buffer_uptodate(tbh))) - goto read_err; - ntfs_warning(vol->sb, "Buffer is now uptodate. Good."); - } - } - - /* - * Get the compression buffer. We must not sleep any more - * until we are finished with it. - */ - spin_lock(&ntfs_cb_lock); - cb = ntfs_compression_buffer; - - BUG_ON(!cb); - - cb_pos = cb; - cb_end = cb + cb_size; - - /* Copy the buffer heads into the contiguous buffer. */ - for (i = 0; i < nr_bhs; i++) { - memcpy(cb_pos, bhs[i]->b_data, block_size); - cb_pos += block_size; - } - - /* Just a precaution. */ - if (cb_pos + 2 <= cb + cb_size) - *(u16*)cb_pos = 0; - - /* Reset cb_pos back to the beginning. */ - cb_pos = cb; - - /* We now have both source (if present) and destination. */ - ntfs_debug("Successfully read the compression block."); - - /* The last page and maximum offset within it for the current cb. */ - cb_max_page = (cur_page << PAGE_SHIFT) + cur_ofs + cb_size; - cb_max_ofs = cb_max_page & ~PAGE_MASK; - cb_max_page >>= PAGE_SHIFT; - - /* Catch end of file inside a compression block. */ - if (cb_max_page > max_page) - cb_max_page = max_page; - - if (vcn == start_vcn - cb_clusters) { - /* Sparse cb, zero out page range overlapping the cb. */ - ntfs_debug("Found sparse compression block."); - /* We can sleep from now on, so we drop lock. */ - spin_unlock(&ntfs_cb_lock); - if (cb_max_ofs) - cb_max_page--; - for (; cur_page < cb_max_page; cur_page++) { - page = pages[cur_page]; - if (page) { - if (likely(!cur_ofs)) - clear_page(page_address(page)); - else - memset(page_address(page) + cur_ofs, 0, - PAGE_SIZE - - cur_ofs); - flush_dcache_page(page); - kunmap(page); - SetPageUptodate(page); - unlock_page(page); - if (cur_page == xpage) - xpage_done = 1; - else - put_page(page); - pages[cur_page] = NULL; - } - cb_pos += PAGE_SIZE - cur_ofs; - cur_ofs = 0; - if (cb_pos >= cb_end) - break; - } - /* If we have a partial final page, deal with it now. */ - if (cb_max_ofs && cb_pos < cb_end) { - page = pages[cur_page]; - if (page) - memset(page_address(page) + cur_ofs, 0, - cb_max_ofs - cur_ofs); - /* - * No need to update cb_pos at this stage: - * cb_pos += cb_max_ofs - cur_ofs; - */ - cur_ofs = cb_max_ofs; - } - } else if (vcn == start_vcn) { - /* We can't sleep so we need two stages. */ - unsigned int cur2_page = cur_page; - unsigned int cur_ofs2 = cur_ofs; - u8 *cb_pos2 = cb_pos; - - ntfs_debug("Found uncompressed compression block."); - /* Uncompressed cb, copy it to the destination pages. */ - /* - * TODO: As a big optimization, we could detect this case - * before we read all the pages and use block_read_full_folio() - * on all full pages instead (we still have to treat partial - * pages especially but at least we are getting rid of the - * synchronous io for the majority of pages. - * Or if we choose not to do the read-ahead/-behind stuff, we - * could just return block_read_full_folio(pages[xpage]) as long - * as PAGE_SIZE <= cb_size. - */ - if (cb_max_ofs) - cb_max_page--; - /* First stage: copy data into destination pages. */ - for (; cur_page < cb_max_page; cur_page++) { - page = pages[cur_page]; - if (page) - memcpy(page_address(page) + cur_ofs, cb_pos, - PAGE_SIZE - cur_ofs); - cb_pos += PAGE_SIZE - cur_ofs; - cur_ofs = 0; - if (cb_pos >= cb_end) - break; - } - /* If we have a partial final page, deal with it now. */ - if (cb_max_ofs && cb_pos < cb_end) { - page = pages[cur_page]; - if (page) - memcpy(page_address(page) + cur_ofs, cb_pos, - cb_max_ofs - cur_ofs); - cb_pos += cb_max_ofs - cur_ofs; - cur_ofs = cb_max_ofs; - } - /* We can sleep from now on, so drop lock. */ - spin_unlock(&ntfs_cb_lock); - /* Second stage: finalize pages. */ - for (; cur2_page < cb_max_page; cur2_page++) { - page = pages[cur2_page]; - if (page) { - /* - * If we are outside the initialized size, zero - * the out of bounds page range. - */ - handle_bounds_compressed_page(page, i_size, - initialized_size); - flush_dcache_page(page); - kunmap(page); - SetPageUptodate(page); - unlock_page(page); - if (cur2_page == xpage) - xpage_done = 1; - else - put_page(page); - pages[cur2_page] = NULL; - } - cb_pos2 += PAGE_SIZE - cur_ofs2; - cur_ofs2 = 0; - if (cb_pos2 >= cb_end) - break; - } - } else { - /* Compressed cb, decompress it into the destination page(s). */ - unsigned int prev_cur_page = cur_page; - - ntfs_debug("Found compressed compression block."); - err = ntfs_decompress(pages, completed_pages, &cur_page, - &cur_ofs, cb_max_page, cb_max_ofs, xpage, - &xpage_done, cb_pos, cb_size - (cb_pos - cb), - i_size, initialized_size); - /* - * We can sleep from now on, lock already dropped by - * ntfs_decompress(). - */ - if (err) { - ntfs_error(vol->sb, "ntfs_decompress() failed in inode " - "0x%lx with error code %i. Skipping " - "this compression block.", - ni->mft_no, -err); - /* Release the unfinished pages. */ - for (; prev_cur_page < cur_page; prev_cur_page++) { - page = pages[prev_cur_page]; - if (page) { - flush_dcache_page(page); - kunmap(page); - unlock_page(page); - if (prev_cur_page != xpage) - put_page(page); - pages[prev_cur_page] = NULL; - } - } - } - } - - /* Release the buffer heads. */ - for (i = 0; i < nr_bhs; i++) - brelse(bhs[i]); - - /* Do we have more work to do? */ - if (nr_cbs) - goto do_next_cb; - - /* We no longer need the list of buffer heads. */ - kfree(bhs); - - /* Clean up if we have any pages left. Should never happen. */ - for (cur_page = 0; cur_page < max_page; cur_page++) { - page = pages[cur_page]; - if (page) { - ntfs_error(vol->sb, "Still have pages left! " - "Terminating them with extreme " - "prejudice. Inode 0x%lx, page index " - "0x%lx.", ni->mft_no, page->index); - flush_dcache_page(page); - kunmap(page); - unlock_page(page); - if (cur_page != xpage) - put_page(page); - pages[cur_page] = NULL; - } - } - - /* We no longer need the list of pages. */ - kfree(pages); - kfree(completed_pages); - - /* If we have completed the requested page, we return success. */ - if (likely(xpage_done)) - return 0; - - ntfs_debug("Failed. Returning error code %s.", err == -EOVERFLOW ? - "EOVERFLOW" : (!err ? "EIO" : "unknown error")); - return err < 0 ? err : -EIO; - -read_err: - ntfs_error(vol->sb, "IO error while reading compressed data."); - /* Release the buffer heads. */ - for (i = 0; i < nr_bhs; i++) - brelse(bhs[i]); - goto err_out; - -map_rl_err: - ntfs_error(vol->sb, "ntfs_map_runlist() failed. Cannot read " - "compression block."); - goto err_out; - -rl_err: - up_read(&ni->runlist.lock); - ntfs_error(vol->sb, "ntfs_rl_vcn_to_lcn() failed. Cannot read " - "compression block."); - goto err_out; - -getblk_err: - up_read(&ni->runlist.lock); - ntfs_error(vol->sb, "getblk() failed. Cannot read compression block."); - -err_out: - kfree(bhs); - for (i = cur_page; i < max_page; i++) { - page = pages[i]; - if (page) { - flush_dcache_page(page); - kunmap(page); - unlock_page(page); - if (i != xpage) - put_page(page); - } - } - kfree(pages); - kfree(completed_pages); - return -EIO; -} |