+++ /dev/null
-// 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;
-}
projects / linux-2.6-microblaze.git / blobdiff