return (n_err < 0) ? -EIO : 0;
}
-/* I really do not want to play with memory shortage right now, so
- to simplify the code, we are not going to write more than this much pages at
- a time. This still should considerably improve performance compared to 4k
- at a time case. This is 32 pages of 4k size. */
-#define REISERFS_WRITE_PAGES_AT_A_TIME (128 * 1024) / PAGE_CACHE_SIZE
-
-/* Allocates blocks for a file to fulfil write request.
- Maps all unmapped but prepared pages from the list.
- Updates metadata with newly allocated blocknumbers as needed */
-static int reiserfs_allocate_blocks_for_region(struct reiserfs_transaction_handle *th, struct inode *inode, /* Inode we work with */
- loff_t pos, /* Writing position */
- int num_pages, /* number of pages write going
- to touch */
- int write_bytes, /* amount of bytes to write */
- struct page **prepared_pages, /* array of
- prepared pages
- */
- int blocks_to_allocate /* Amount of blocks we
- need to allocate to
- fit the data into file
- */
- )
-{
- struct cpu_key key; // cpu key of item that we are going to deal with
- struct item_head *ih; // pointer to item head that we are going to deal with
- struct buffer_head *bh; // Buffer head that contains items that we are going to deal with
- __le32 *item; // pointer to item we are going to deal with
- INITIALIZE_PATH(path); // path to item, that we are going to deal with.
- b_blocknr_t *allocated_blocks; // Pointer to a place where allocated blocknumbers would be stored.
- reiserfs_blocknr_hint_t hint; // hint structure for block allocator.
- size_t res; // return value of various functions that we call.
- int curr_block; // current block used to keep track of unmapped blocks.
- int i; // loop counter
- int itempos; // position in item
- unsigned int from = (pos & (PAGE_CACHE_SIZE - 1)); // writing position in
- // first page
- unsigned int to = ((pos + write_bytes - 1) & (PAGE_CACHE_SIZE - 1)) + 1; /* last modified byte offset in last page */
- __u64 hole_size; // amount of blocks for a file hole, if it needed to be created.
- int modifying_this_item = 0; // Flag for items traversal code to keep track
- // of the fact that we already prepared
- // current block for journal
- int will_prealloc = 0;
- RFALSE(!blocks_to_allocate,
- "green-9004: tried to allocate zero blocks?");
-
- /* only preallocate if this is a small write */
- if (REISERFS_I(inode)->i_prealloc_count ||
- (!(write_bytes & (inode->i_sb->s_blocksize - 1)) &&
- blocks_to_allocate <
- REISERFS_SB(inode->i_sb)->s_alloc_options.preallocsize))
- will_prealloc =
- REISERFS_SB(inode->i_sb)->s_alloc_options.preallocsize;
-
- allocated_blocks = kmalloc((blocks_to_allocate + will_prealloc) *
- sizeof(b_blocknr_t), GFP_NOFS);
- if (!allocated_blocks)
- return -ENOMEM;
-
- /* First we compose a key to point at the writing position, we want to do
- that outside of any locking region. */
- make_cpu_key(&key, inode, pos + 1, TYPE_ANY, 3 /*key length */ );
-
- /* If we came here, it means we absolutely need to open a transaction,
- since we need to allocate some blocks */
- reiserfs_write_lock(inode->i_sb); // Journaling stuff and we need that.
- res = journal_begin(th, inode->i_sb, JOURNAL_PER_BALANCE_CNT * 3 + 1 + 2 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb)); // Wish I know if this number enough
- if (res)
- goto error_exit;
- reiserfs_update_inode_transaction(inode);
-
- /* Look for the in-tree position of our write, need path for block allocator */
- res = search_for_position_by_key(inode->i_sb, &key, &path);
- if (res == IO_ERROR) {
- res = -EIO;
- goto error_exit;
- }
-
- /* Allocate blocks */
- /* First fill in "hint" structure for block allocator */
- hint.th = th; // transaction handle.
- hint.path = &path; // Path, so that block allocator can determine packing locality or whatever it needs to determine.
- hint.inode = inode; // Inode is needed by block allocator too.
- hint.search_start = 0; // We have no hint on where to search free blocks for block allocator.
- hint.key = key.on_disk_key; // on disk key of file.
- hint.block = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); // Number of disk blocks this file occupies already.
- hint.formatted_node = 0; // We are allocating blocks for unformatted node.
- hint.preallocate = will_prealloc;
-
- /* Call block allocator to allocate blocks */
- res =
- reiserfs_allocate_blocknrs(&hint, allocated_blocks,
- blocks_to_allocate, blocks_to_allocate);
- if (res != CARRY_ON) {
- if (res == NO_DISK_SPACE) {
- /* We flush the transaction in case of no space. This way some
- blocks might become free */
- SB_JOURNAL(inode->i_sb)->j_must_wait = 1;
- res = restart_transaction(th, inode, &path);
- if (res)
- goto error_exit;
-
- /* We might have scheduled, so search again */
- res =
- search_for_position_by_key(inode->i_sb, &key,
- &path);
- if (res == IO_ERROR) {
- res = -EIO;
- goto error_exit;
- }
-
- /* update changed info for hint structure. */
- res =
- reiserfs_allocate_blocknrs(&hint, allocated_blocks,
- blocks_to_allocate,
- blocks_to_allocate);
- if (res != CARRY_ON) {
- res = res == QUOTA_EXCEEDED ? -EDQUOT : -ENOSPC;
- pathrelse(&path);
- goto error_exit;
- }
- } else {
- res = res == QUOTA_EXCEEDED ? -EDQUOT : -ENOSPC;
- pathrelse(&path);
- goto error_exit;
- }
- }
-#ifdef __BIG_ENDIAN
- // Too bad, I have not found any way to convert a given region from
- // cpu format to little endian format
- {
- int i;
- for (i = 0; i < blocks_to_allocate; i++)
- allocated_blocks[i] = cpu_to_le32(allocated_blocks[i]);
- }
-#endif
-
- /* Blocks allocating well might have scheduled and tree might have changed,
- let's search the tree again */
- /* find where in the tree our write should go */
- res = search_for_position_by_key(inode->i_sb, &key, &path);
- if (res == IO_ERROR) {
- res = -EIO;
- goto error_exit_free_blocks;
- }
-
- bh = get_last_bh(&path); // Get a bufferhead for last element in path.
- ih = get_ih(&path); // Get a pointer to last item head in path.
- item = get_item(&path); // Get a pointer to last item in path
-
- /* Let's see what we have found */
- if (res != POSITION_FOUND) { /* position not found, this means that we
- might need to append file with holes
- first */
- // Since we are writing past the file's end, we need to find out if
- // there is a hole that needs to be inserted before our writing
- // position, and how many blocks it is going to cover (we need to
- // populate pointers to file blocks representing the hole with zeros)
-
- {
- int item_offset = 1;
- /*
- * if ih is stat data, its offset is 0 and we don't want to
- * add 1 to pos in the hole_size calculation
- */
- if (is_statdata_le_ih(ih))
- item_offset = 0;
- hole_size = (pos + item_offset -
- (le_key_k_offset
- (get_inode_item_key_version(inode),
- &(ih->ih_key)) + op_bytes_number(ih,
- inode->
- i_sb->
- s_blocksize)))
- >> inode->i_sb->s_blocksize_bits;
- }
-
- if (hole_size > 0) {
- int to_paste = min_t(__u64, hole_size, MAX_ITEM_LEN(inode->i_sb->s_blocksize) / UNFM_P_SIZE); // How much data to insert first time.
- /* area filled with zeroes, to supply as list of zero blocknumbers
- We allocate it outside of loop just in case loop would spin for
- several iterations. */
- char *zeros = kzalloc(to_paste * UNFM_P_SIZE, GFP_ATOMIC); // We cannot insert more than MAX_ITEM_LEN bytes anyway.
- if (!zeros) {
- res = -ENOMEM;
- goto error_exit_free_blocks;
- }
- do {
- to_paste =
- min_t(__u64, hole_size,
- MAX_ITEM_LEN(inode->i_sb->
- s_blocksize) /
- UNFM_P_SIZE);
- if (is_indirect_le_ih(ih)) {
- /* Ok, there is existing indirect item already. Need to append it */
- /* Calculate position past inserted item */
- make_cpu_key(&key, inode,
- le_key_k_offset
- (get_inode_item_key_version
- (inode),
- &(ih->ih_key)) +
- op_bytes_number(ih,
- inode->
- i_sb->
- s_blocksize),
- TYPE_INDIRECT, 3);
- res =
- reiserfs_paste_into_item(th, &path,
- &key,
- inode,
- (char *)
- zeros,
- UNFM_P_SIZE
- *
- to_paste);
- if (res) {
- kfree(zeros);
- goto error_exit_free_blocks;
- }
- } else if (is_statdata_le_ih(ih)) {
- /* No existing item, create it */
- /* item head for new item */
- struct item_head ins_ih;
-
- /* create a key for our new item */
- make_cpu_key(&key, inode, 1,
- TYPE_INDIRECT, 3);
-
- /* Create new item head for our new item */
- make_le_item_head(&ins_ih, &key,
- key.version, 1,
- TYPE_INDIRECT,
- to_paste *
- UNFM_P_SIZE,
- 0 /* free space */ );
-
- /* Find where such item should live in the tree */
- res =
- search_item(inode->i_sb, &key,
- &path);
- if (res != ITEM_NOT_FOUND) {
- /* item should not exist, otherwise we have error */
- if (res != -ENOSPC) {
- reiserfs_warning(inode->
- i_sb,
- "green-9008: search_by_key (%K) returned %d",
- &key,
- res);
- }
- res = -EIO;
- kfree(zeros);
- goto error_exit_free_blocks;
- }
- res =
- reiserfs_insert_item(th, &path,
- &key, &ins_ih,
- inode,
- (char *)zeros);
- } else {
- reiserfs_panic(inode->i_sb,
- "green-9011: Unexpected key type %K\n",
- &key);
- }
- if (res) {
- kfree(zeros);
- goto error_exit_free_blocks;
- }
- /* Now we want to check if transaction is too full, and if it is
- we restart it. This will also free the path. */
- if (journal_transaction_should_end
- (th, th->t_blocks_allocated)) {
- inode->i_size = cpu_key_k_offset(&key) +
- (to_paste << inode->i_blkbits);
- res =
- restart_transaction(th, inode,
- &path);
- if (res) {
- pathrelse(&path);
- kfree(zeros);
- goto error_exit;
- }
- }
-
- /* Well, need to recalculate path and stuff */
- set_cpu_key_k_offset(&key,
- cpu_key_k_offset(&key) +
- (to_paste << inode->
- i_blkbits));
- res =
- search_for_position_by_key(inode->i_sb,
- &key, &path);
- if (res == IO_ERROR) {
- res = -EIO;
- kfree(zeros);
- goto error_exit_free_blocks;
- }
- bh = get_last_bh(&path);
- ih = get_ih(&path);
- item = get_item(&path);
- hole_size -= to_paste;
- } while (hole_size);
- kfree(zeros);
- }
- }
- // Go through existing indirect items first
- // replace all zeroes with blocknumbers from list
- // Note that if no corresponding item was found, by previous search,
- // it means there are no existing in-tree representation for file area
- // we are going to overwrite, so there is nothing to scan through for holes.
- for (curr_block = 0, itempos = path.pos_in_item;
- curr_block < blocks_to_allocate && res == POSITION_FOUND;) {
- retry:
-
- if (itempos >= ih_item_len(ih) / UNFM_P_SIZE) {
- /* We run out of data in this indirect item, let's look for another
- one. */
- /* First if we are already modifying current item, log it */
- if (modifying_this_item) {
- journal_mark_dirty(th, inode->i_sb, bh);
- modifying_this_item = 0;
- }
- /* Then set the key to look for a new indirect item (offset of old
- item is added to old item length */
- set_cpu_key_k_offset(&key,
- le_key_k_offset
- (get_inode_item_key_version(inode),
- &(ih->ih_key)) +
- op_bytes_number(ih,
- inode->i_sb->
- s_blocksize));
- /* Search ofor position of new key in the tree. */
- res =
- search_for_position_by_key(inode->i_sb, &key,
- &path);
- if (res == IO_ERROR) {
- res = -EIO;
- goto error_exit_free_blocks;
- }
- bh = get_last_bh(&path);
- ih = get_ih(&path);
- item = get_item(&path);
- itempos = path.pos_in_item;
- continue; // loop to check all kinds of conditions and so on.
- }
- /* Ok, we have correct position in item now, so let's see if it is
- representing file hole (blocknumber is zero) and fill it if needed */
- if (!item[itempos]) {
- /* Ok, a hole. Now we need to check if we already prepared this
- block to be journaled */
- while (!modifying_this_item) { // loop until succeed
- /* Well, this item is not journaled yet, so we must prepare
- it for journal first, before we can change it */
- struct item_head tmp_ih; // We copy item head of found item,
- // here to detect if fs changed under
- // us while we were preparing for
- // journal.
- int fs_gen; // We store fs generation here to find if someone
- // changes fs under our feet
-
- copy_item_head(&tmp_ih, ih); // Remember itemhead
- fs_gen = get_generation(inode->i_sb); // remember fs generation
- reiserfs_prepare_for_journal(inode->i_sb, bh, 1); // Prepare a buffer within which indirect item is stored for changing.
- if (fs_changed(fs_gen, inode->i_sb)
- && item_moved(&tmp_ih, &path)) {
- // Sigh, fs was changed under us, we need to look for new
- // location of item we are working with
-
- /* unmark prepaerd area as journaled and search for it's
- new position */
- reiserfs_restore_prepared_buffer(inode->
- i_sb,
- bh);
- res =
- search_for_position_by_key(inode->
- i_sb,
- &key,
- &path);
- if (res == IO_ERROR) {
- res = -EIO;
- goto error_exit_free_blocks;
- }
- bh = get_last_bh(&path);
- ih = get_ih(&path);
- item = get_item(&path);
- itempos = path.pos_in_item;
- goto retry;
- }
- modifying_this_item = 1;
- }
- item[itempos] = allocated_blocks[curr_block]; // Assign new block
- curr_block++;
- }
- itempos++;
- }
-
- if (modifying_this_item) { // We need to log last-accessed block, if it
- // was modified, but not logged yet.
- journal_mark_dirty(th, inode->i_sb, bh);
- }
-
- if (curr_block < blocks_to_allocate) {
- // Oh, well need to append to indirect item, or to create indirect item
- // if there weren't any
- if (is_indirect_le_ih(ih)) {
- // Existing indirect item - append. First calculate key for append
- // position. We do not need to recalculate path as it should
- // already point to correct place.
- make_cpu_key(&key, inode,
- le_key_k_offset(get_inode_item_key_version
- (inode),
- &(ih->ih_key)) +
- op_bytes_number(ih,
- inode->i_sb->s_blocksize),
- TYPE_INDIRECT, 3);
- res =
- reiserfs_paste_into_item(th, &path, &key, inode,
- (char *)(allocated_blocks +
- curr_block),
- UNFM_P_SIZE *
- (blocks_to_allocate -
- curr_block));
- if (res) {
- goto error_exit_free_blocks;
- }
- } else if (is_statdata_le_ih(ih)) {
- // Last found item was statdata. That means we need to create indirect item.
- struct item_head ins_ih; /* itemhead for new item */
-
- /* create a key for our new item */
- make_cpu_key(&key, inode, 1, TYPE_INDIRECT, 3); // Position one,
- // because that's
- // where first
- // indirect item
- // begins
- /* Create new item head for our new item */
- make_le_item_head(&ins_ih, &key, key.version, 1,
- TYPE_INDIRECT,
- (blocks_to_allocate -
- curr_block) * UNFM_P_SIZE,
- 0 /* free space */ );
- /* Find where such item should live in the tree */
- res = search_item(inode->i_sb, &key, &path);
- if (res != ITEM_NOT_FOUND) {
- /* Well, if we have found such item already, or some error
- occured, we need to warn user and return error */
- if (res != -ENOSPC) {
- reiserfs_warning(inode->i_sb,
- "green-9009: search_by_key (%K) "
- "returned %d", &key,
- res);
- }
- res = -EIO;
- goto error_exit_free_blocks;
- }
- /* Insert item into the tree with the data as its body */
- res =
- reiserfs_insert_item(th, &path, &key, &ins_ih,
- inode,
- (char *)(allocated_blocks +
- curr_block));
- } else {
- reiserfs_panic(inode->i_sb,
- "green-9010: unexpected item type for key %K\n",
- &key);
- }
- }
- // the caller is responsible for closing the transaction
- // unless we return an error, they are also responsible for logging
- // the inode.
- //
- pathrelse(&path);
- /*
- * cleanup prellocation from previous writes
- * if this is a partial block write
- */
- if (write_bytes & (inode->i_sb->s_blocksize - 1))
- reiserfs_discard_prealloc(th, inode);
- reiserfs_write_unlock(inode->i_sb);
-
- // go through all the pages/buffers and map the buffers to newly allocated
- // blocks (so that system knows where to write these pages later).
- curr_block = 0;
- for (i = 0; i < num_pages; i++) {
- struct page *page = prepared_pages[i]; //current page
- struct buffer_head *head = page_buffers(page); // first buffer for a page
- int block_start, block_end; // in-page offsets for buffers.
-
- if (!page_buffers(page))
- reiserfs_panic(inode->i_sb,
- "green-9005: No buffers for prepared page???");
-
- /* For each buffer in page */
- for (bh = head, block_start = 0; bh != head || !block_start;
- block_start = block_end, bh = bh->b_this_page) {
- if (!bh)
- reiserfs_panic(inode->i_sb,
- "green-9006: Allocated but absent buffer for a page?");
- block_end = block_start + inode->i_sb->s_blocksize;
- if (i == 0 && block_end <= from)
- /* if this buffer is before requested data to map, skip it */
- continue;
- if (i == num_pages - 1 && block_start >= to)
- /* If this buffer is after requested data to map, abort
- processing of current page */
- break;
-
- if (!buffer_mapped(bh)) { // Ok, unmapped buffer, need to map it
- map_bh(bh, inode->i_sb,
- le32_to_cpu(allocated_blocks
- [curr_block]));
- curr_block++;
- set_buffer_new(bh);
- }
- }
- }
-
- RFALSE(curr_block > blocks_to_allocate,
- "green-9007: Used too many blocks? weird");
-
- kfree(allocated_blocks);
- return 0;
-
-// Need to deal with transaction here.
- error_exit_free_blocks:
- pathrelse(&path);
- // free blocks
- for (i = 0; i < blocks_to_allocate; i++)
- reiserfs_free_block(th, inode, le32_to_cpu(allocated_blocks[i]),
- 1);
-
- error_exit:
- if (th->t_trans_id) {
- int err;
- // update any changes we made to blk count
- mark_inode_dirty(inode);
- err =
- journal_end(th, inode->i_sb,
- JOURNAL_PER_BALANCE_CNT * 3 + 1 +
- 2 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb));
- if (err)
- res = err;
- }
- reiserfs_write_unlock(inode->i_sb);
- kfree(allocated_blocks);
-
- return res;
-}
-
-/* Unlock pages prepared by reiserfs_prepare_file_region_for_write */
-static void reiserfs_unprepare_pages(struct page **prepared_pages, /* list of locked pages */
- size_t num_pages /* amount of pages */ )
-{
- int i; // loop counter
-
- for (i = 0; i < num_pages; i++) {
- struct page *page = prepared_pages[i];
-
- try_to_free_buffers(page);
- unlock_page(page);
- page_cache_release(page);
- }
-}
-
-/* This function will copy data from userspace to specified pages within
- supplied byte range */
-static int reiserfs_copy_from_user_to_file_region(loff_t pos, /* In-file position */
- int num_pages, /* Number of pages affected */
- int write_bytes, /* Amount of bytes to write */
- struct page **prepared_pages, /* pointer to
- array to
- prepared pages
- */
- const char __user * buf /* Pointer to user-supplied
- data */
- )
-{
- long page_fault = 0; // status of copy_from_user.
- int i; // loop counter.
- int offset; // offset in page
-
- for (i = 0, offset = (pos & (PAGE_CACHE_SIZE - 1)); i < num_pages;
- i++, offset = 0) {
- size_t count = min_t(size_t, PAGE_CACHE_SIZE - offset, write_bytes); // How much of bytes to write to this page
- struct page *page = prepared_pages[i]; // Current page we process.
-
- fault_in_pages_readable(buf, count);
-
- /* Copy data from userspace to the current page */
- kmap(page);
- page_fault = __copy_from_user(page_address(page) + offset, buf, count); // Copy the data.
- /* Flush processor's dcache for this page */
- flush_dcache_page(page);
- kunmap(page);
- buf += count;
- write_bytes -= count;
-
- if (page_fault)
- break; // Was there a fault? abort.
- }
-
- return page_fault ? -EFAULT : 0;
-}
-
/* taken fs/buffer.c:__block_commit_write */
int reiserfs_commit_page(struct inode *inode, struct page *page,
unsigned from, unsigned to)
return ret;
}
-/* Submit pages for write. This was separated from actual file copying
- because we might want to allocate block numbers in-between.
- This function assumes that caller will adjust file size to correct value. */
-static int reiserfs_submit_file_region_for_write(struct reiserfs_transaction_handle *th, struct inode *inode, loff_t pos, /* Writing position offset */
- size_t num_pages, /* Number of pages to write */
- size_t write_bytes, /* number of bytes to write */
- struct page **prepared_pages /* list of pages */
- )
-{
- int status; // return status of block_commit_write.
- int retval = 0; // Return value we are going to return.
- int i; // loop counter
- int offset; // Writing offset in page.
- int orig_write_bytes = write_bytes;
- int sd_update = 0;
-
- for (i = 0, offset = (pos & (PAGE_CACHE_SIZE - 1)); i < num_pages;
- i++, offset = 0) {
- int count = min_t(int, PAGE_CACHE_SIZE - offset, write_bytes); // How much of bytes to write to this page
- struct page *page = prepared_pages[i]; // Current page we process.
-
- status =
- reiserfs_commit_page(inode, page, offset, offset + count);
- if (status)
- retval = status; // To not overcomplicate matters We are going to
- // submit all the pages even if there was error.
- // we only remember error status to report it on
- // exit.
- write_bytes -= count;
- }
- /* now that we've gotten all the ordered buffers marked dirty,
- * we can safely update i_size and close any running transaction
- */
- if (pos + orig_write_bytes > inode->i_size) {
- inode->i_size = pos + orig_write_bytes; // Set new size
- /* If the file have grown so much that tail packing is no
- * longer possible, reset "need to pack" flag */
- if ((have_large_tails(inode->i_sb) &&
- inode->i_size > i_block_size(inode) * 4) ||
- (have_small_tails(inode->i_sb) &&
- inode->i_size > i_block_size(inode)))
- REISERFS_I(inode)->i_flags &= ~i_pack_on_close_mask;
- else if ((have_large_tails(inode->i_sb) &&
- inode->i_size < i_block_size(inode) * 4) ||
- (have_small_tails(inode->i_sb) &&
- inode->i_size < i_block_size(inode)))
- REISERFS_I(inode)->i_flags |= i_pack_on_close_mask;
-
- if (th->t_trans_id) {
- reiserfs_write_lock(inode->i_sb);
- // this sets the proper flags for O_SYNC to trigger a commit
- mark_inode_dirty(inode);
- reiserfs_write_unlock(inode->i_sb);
- } else {
- reiserfs_write_lock(inode->i_sb);
- reiserfs_update_inode_transaction(inode);
- mark_inode_dirty(inode);
- reiserfs_write_unlock(inode->i_sb);
- }
-
- sd_update = 1;
- }
- if (th->t_trans_id) {
- reiserfs_write_lock(inode->i_sb);
- if (!sd_update)
- mark_inode_dirty(inode);
- status = journal_end(th, th->t_super, th->t_blocks_allocated);
- if (status)
- retval = status;
- reiserfs_write_unlock(inode->i_sb);
- }
- th->t_trans_id = 0;
-
- /*
- * we have to unlock the pages after updating i_size, otherwise
- * we race with writepage
- */
- for (i = 0; i < num_pages; i++) {
- struct page *page = prepared_pages[i];
- unlock_page(page);
- mark_page_accessed(page);
- page_cache_release(page);
- }
- return retval;
-}
-
-/* Look if passed writing region is going to touch file's tail
- (if it is present). And if it is, convert the tail to unformatted node */
-static int reiserfs_check_for_tail_and_convert(struct inode *inode, /* inode to deal with */
- loff_t pos, /* Writing position */
- int write_bytes /* amount of bytes to write */
- )
-{
- INITIALIZE_PATH(path); // needed for search_for_position
- struct cpu_key key; // Key that would represent last touched writing byte.
- struct item_head *ih; // item header of found block;
- int res; // Return value of various functions we call.
- int cont_expand_offset; // We will put offset for generic_cont_expand here
- // This can be int just because tails are created
- // only for small files.
-
-/* this embodies a dependency on a particular tail policy */
- if (inode->i_size >= inode->i_sb->s_blocksize * 4) {
- /* such a big files do not have tails, so we won't bother ourselves
- to look for tails, simply return */
- return 0;
- }
-
- reiserfs_write_lock(inode->i_sb);
- /* find the item containing the last byte to be written, or if
- * writing past the end of the file then the last item of the
- * file (and then we check its type). */
- make_cpu_key(&key, inode, pos + write_bytes + 1, TYPE_ANY,
- 3 /*key length */ );
- res = search_for_position_by_key(inode->i_sb, &key, &path);
- if (res == IO_ERROR) {
- reiserfs_write_unlock(inode->i_sb);
- return -EIO;
- }
- ih = get_ih(&path);
- res = 0;
- if (is_direct_le_ih(ih)) {
- /* Ok, closest item is file tail (tails are stored in "direct"
- * items), so we need to unpack it. */
- /* To not overcomplicate matters, we just call generic_cont_expand
- which will in turn call other stuff and finally will boil down to
- reiserfs_get_block() that would do necessary conversion. */
- cont_expand_offset =
- le_key_k_offset(get_inode_item_key_version(inode),
- &(ih->ih_key));
- pathrelse(&path);
- res = generic_cont_expand(inode, cont_expand_offset);
- } else
- pathrelse(&path);
-
- reiserfs_write_unlock(inode->i_sb);
- return res;
-}
-
-/* This function locks pages starting from @pos for @inode.
- @num_pages pages are locked and stored in
- @prepared_pages array. Also buffers are allocated for these pages.
- First and last page of the region is read if it is overwritten only
- partially. If last page did not exist before write (file hole or file
- append), it is zeroed, then.
- Returns number of unallocated blocks that should be allocated to cover
- new file data.*/
-static int reiserfs_prepare_file_region_for_write(struct inode *inode
- /* Inode of the file */ ,
- loff_t pos, /* position in the file */
- size_t num_pages, /* number of pages to
- prepare */
- size_t write_bytes, /* Amount of bytes to be
- overwritten from
- @pos */
- struct page **prepared_pages /* pointer to array
- where to store
- prepared pages */
- )
-{
- int res = 0; // Return values of different functions we call.
- unsigned long index = pos >> PAGE_CACHE_SHIFT; // Offset in file in pages.
- int from = (pos & (PAGE_CACHE_SIZE - 1)); // Writing offset in first page
- int to = ((pos + write_bytes - 1) & (PAGE_CACHE_SIZE - 1)) + 1;
- /* offset of last modified byte in last
- page */
- struct address_space *mapping = inode->i_mapping; // Pages are mapped here.
- int i; // Simple counter
- int blocks = 0; /* Return value (blocks that should be allocated) */
- struct buffer_head *bh, *head; // Current bufferhead and first bufferhead
- // of a page.
- unsigned block_start, block_end; // Starting and ending offsets of current
- // buffer in the page.
- struct buffer_head *wait[2], **wait_bh = wait; // Buffers for page, if
- // Page appeared to be not up
- // to date. Note how we have
- // at most 2 buffers, this is
- // because we at most may
- // partially overwrite two
- // buffers for one page. One at // the beginning of write area
- // and one at the end.
- // Everything inthe middle gets // overwritten totally.
-
- struct cpu_key key; // cpu key of item that we are going to deal with
- struct item_head *ih = NULL; // pointer to item head that we are going to deal with
- struct buffer_head *itembuf = NULL; // Buffer head that contains items that we are going to deal with
- INITIALIZE_PATH(path); // path to item, that we are going to deal with.
- __le32 *item = NULL; // pointer to item we are going to deal with
- int item_pos = -1; /* Position in indirect item */
-
- if (num_pages < 1) {
- reiserfs_warning(inode->i_sb,
- "green-9001: reiserfs_prepare_file_region_for_write "
- "called with zero number of pages to process");
- return -EFAULT;
- }
-
- /* We have 2 loops for pages. In first loop we grab and lock the pages, so
- that nobody would touch these until we release the pages. Then
- we'd start to deal with mapping buffers to blocks. */
- for (i = 0; i < num_pages; i++) {
- prepared_pages[i] = grab_cache_page(mapping, index + i); // locks the page
- if (!prepared_pages[i]) {
- res = -ENOMEM;
- goto failed_page_grabbing;
- }
- if (!page_has_buffers(prepared_pages[i]))
- create_empty_buffers(prepared_pages[i],
- inode->i_sb->s_blocksize, 0);
- }
-
- /* Let's count amount of blocks for a case where all the blocks
- overwritten are new (we will substract already allocated blocks later) */
- if (num_pages > 2)
- /* These are full-overwritten pages so we count all the blocks in
- these pages are counted as needed to be allocated */
- blocks =
- (num_pages - 2) << (PAGE_CACHE_SHIFT - inode->i_blkbits);
-
- /* count blocks needed for first page (possibly partially written) */
- blocks += ((PAGE_CACHE_SIZE - from) >> inode->i_blkbits) + !!(from & (inode->i_sb->s_blocksize - 1)); /* roundup */
-
- /* Now we account for last page. If last page == first page (we
- overwrite only one page), we substract all the blocks past the
- last writing position in a page out of already calculated number
- of blocks */
- blocks += ((num_pages > 1) << (PAGE_CACHE_SHIFT - inode->i_blkbits)) -
- ((PAGE_CACHE_SIZE - to) >> inode->i_blkbits);
- /* Note how we do not roundup here since partial blocks still
- should be allocated */
-
- /* Now if all the write area lies past the file end, no point in
- maping blocks, since there is none, so we just zero out remaining
- parts of first and last pages in write area (if needed) */
- if ((pos & ~((loff_t) PAGE_CACHE_SIZE - 1)) > inode->i_size) {
- if (from != 0) /* First page needs to be partially zeroed */
- zero_user_page(prepared_pages[0], 0, from, KM_USER0);
-
- if (to != PAGE_CACHE_SIZE) /* Last page needs to be partially zeroed */
- zero_user_page(prepared_pages[num_pages-1], to,
- PAGE_CACHE_SIZE - to, KM_USER0);
-
- /* Since all blocks are new - use already calculated value */
- return blocks;
- }
-
- /* Well, since we write somewhere into the middle of a file, there is
- possibility we are writing over some already allocated blocks, so
- let's map these blocks and substract number of such blocks out of blocks
- we need to allocate (calculated above) */
- /* Mask write position to start on blocksize, we do it out of the
- loop for performance reasons */
- pos &= ~((loff_t) inode->i_sb->s_blocksize - 1);
- /* Set cpu key to the starting position in a file (on left block boundary) */
- make_cpu_key(&key, inode,
- 1 + ((pos) & ~((loff_t) inode->i_sb->s_blocksize - 1)),
- TYPE_ANY, 3 /*key length */ );
-
- reiserfs_write_lock(inode->i_sb); // We need that for at least search_by_key()
- for (i = 0; i < num_pages; i++) {
-
- head = page_buffers(prepared_pages[i]);
- /* For each buffer in the page */
- for (bh = head, block_start = 0; bh != head || !block_start;
- block_start = block_end, bh = bh->b_this_page) {
- if (!bh)
- reiserfs_panic(inode->i_sb,
- "green-9002: Allocated but absent buffer for a page?");
- /* Find where this buffer ends */
- block_end = block_start + inode->i_sb->s_blocksize;
- if (i == 0 && block_end <= from)
- /* if this buffer is before requested data to map, skip it */
- continue;
-
- if (i == num_pages - 1 && block_start >= to) {
- /* If this buffer is after requested data to map, abort
- processing of current page */
- break;
- }
-
- if (buffer_mapped(bh) && bh->b_blocknr != 0) {
- /* This is optimisation for a case where buffer is mapped
- and have blocknumber assigned. In case significant amount
- of such buffers are present, we may avoid some amount
- of search_by_key calls.
- Probably it would be possible to move parts of this code
- out of BKL, but I afraid that would overcomplicate code
- without any noticeable benefit.
- */
- item_pos++;
- /* Update the key */
- set_cpu_key_k_offset(&key,
- cpu_key_k_offset(&key) +
- inode->i_sb->s_blocksize);
- blocks--; // Decrease the amount of blocks that need to be
- // allocated
- continue; // Go to the next buffer
- }
-
- if (!itembuf || /* if first iteration */
- item_pos >= ih_item_len(ih) / UNFM_P_SIZE) { /* or if we progressed past the
- current unformatted_item */
- /* Try to find next item */
- res =
- search_for_position_by_key(inode->i_sb,
- &key, &path);
- /* Abort if no more items */
- if (res != POSITION_FOUND) {
- /* make sure later loops don't use this item */
- itembuf = NULL;
- item = NULL;
- break;
- }
-
- /* Update information about current indirect item */
- itembuf = get_last_bh(&path);
- ih = get_ih(&path);
- item = get_item(&path);
- item_pos = path.pos_in_item;
-
- RFALSE(!is_indirect_le_ih(ih),
- "green-9003: indirect item expected");
- }
-
- /* See if there is some block associated with the file
- at that position, map the buffer to this block */
- if (get_block_num(item, item_pos)) {
- map_bh(bh, inode->i_sb,
- get_block_num(item, item_pos));
- blocks--; // Decrease the amount of blocks that need to be
- // allocated
- }
- item_pos++;
- /* Update the key */
- set_cpu_key_k_offset(&key,
- cpu_key_k_offset(&key) +
- inode->i_sb->s_blocksize);
- }
- }
- pathrelse(&path); // Free the path
- reiserfs_write_unlock(inode->i_sb);
-
- /* Now zero out unmappend buffers for the first and last pages of
- write area or issue read requests if page is mapped. */
- /* First page, see if it is not uptodate */
- if (!PageUptodate(prepared_pages[0])) {
- head = page_buffers(prepared_pages[0]);
-
- /* For each buffer in page */
- for (bh = head, block_start = 0; bh != head || !block_start;
- block_start = block_end, bh = bh->b_this_page) {
-
- if (!bh)
- reiserfs_panic(inode->i_sb,
- "green-9002: Allocated but absent buffer for a page?");
- /* Find where this buffer ends */
- block_end = block_start + inode->i_sb->s_blocksize;
- if (block_end <= from)
- /* if this buffer is before requested data to map, skip it */
- continue;
- if (block_start < from) { /* Aha, our partial buffer */
- if (buffer_mapped(bh)) { /* If it is mapped, we need to
- issue READ request for it to
- not loose data */
- ll_rw_block(READ, 1, &bh);
- *wait_bh++ = bh;
- } else { /* Not mapped, zero it */
- zero_user_page(prepared_pages[0],
- block_start,
- from - block_start, KM_USER0);
- set_buffer_uptodate(bh);
- }
- }
- }
- }
-
- /* Last page, see if it is not uptodate, or if the last page is past the end of the file. */
- if (!PageUptodate(prepared_pages[num_pages - 1]) ||
- ((pos + write_bytes) >> PAGE_CACHE_SHIFT) >
- (inode->i_size >> PAGE_CACHE_SHIFT)) {
- head = page_buffers(prepared_pages[num_pages - 1]);
-
- /* for each buffer in page */
- for (bh = head, block_start = 0; bh != head || !block_start;
- block_start = block_end, bh = bh->b_this_page) {
-
- if (!bh)
- reiserfs_panic(inode->i_sb,
- "green-9002: Allocated but absent buffer for a page?");
- /* Find where this buffer ends */
- block_end = block_start + inode->i_sb->s_blocksize;
- if (block_start >= to)
- /* if this buffer is after requested data to map, skip it */
- break;
- if (block_end > to) { /* Aha, our partial buffer */
- if (buffer_mapped(bh)) { /* If it is mapped, we need to
- issue READ request for it to
- not loose data */
- ll_rw_block(READ, 1, &bh);
- *wait_bh++ = bh;
- } else { /* Not mapped, zero it */
- zero_user_page(prepared_pages[num_pages-1],
- to, block_end - to, KM_USER0);
- set_buffer_uptodate(bh);
- }
- }
- }
- }
-
- /* Wait for read requests we made to happen, if necessary */
- while (wait_bh > wait) {
- wait_on_buffer(*--wait_bh);
- if (!buffer_uptodate(*wait_bh)) {
- res = -EIO;
- goto failed_read;
- }
- }
-
- return blocks;
- failed_page_grabbing:
- num_pages = i;
- failed_read:
- reiserfs_unprepare_pages(prepared_pages, num_pages);
- return res;
-}
-
/* Write @count bytes at position @ppos in a file indicated by @file
from the buffer @buf.
* new current position before returning. */
)
{
- size_t already_written = 0; // Number of bytes already written to the file.
- loff_t pos; // Current position in the file.
- ssize_t res; // return value of various functions that we call.
- int err = 0;
struct inode *inode = file->f_path.dentry->d_inode; // Inode of the file that we are writing to.
/* To simplify coding at this time, we store
locked pages in array for now */
- struct page *prepared_pages[REISERFS_WRITE_PAGES_AT_A_TIME];
struct reiserfs_transaction_handle th;
th.t_trans_id = 0;
count = MAX_NON_LFS - (unsigned long)*ppos;
}
- if (file->f_flags & O_DIRECT)
- return do_sync_write(file, buf, count, ppos);
-
- if (unlikely((ssize_t) count < 0))
- return -EINVAL;
-
- if (unlikely(!access_ok(VERIFY_READ, buf, count)))
- return -EFAULT;
-
- mutex_lock(&inode->i_mutex); // locks the entire file for just us
-
- pos = *ppos;
-
- /* Check if we can write to specified region of file, file
- is not overly big and this kind of stuff. Adjust pos and
- count, if needed */
- res = generic_write_checks(file, &pos, &count, 0);
- if (res)
- goto out;
-
- if (count == 0)
- goto out;
-
- res = remove_suid(file->f_path.dentry);
- if (res)
- goto out;
-
- file_update_time(file);
-
- // Ok, we are done with all the checks.
-
- // Now we should start real work
-
- /* If we are going to write past the file's packed tail or if we are going
- to overwrite part of the tail, we need that tail to be converted into
- unformatted node */
- res = reiserfs_check_for_tail_and_convert(inode, pos, count);
- if (res)
- goto out;
-
- while (count > 0) {
- /* This is the main loop in which we running until some error occures
- or until we write all of the data. */
- size_t num_pages; /* amount of pages we are going to write this iteration */
- size_t write_bytes; /* amount of bytes to write during this iteration */
- size_t blocks_to_allocate; /* how much blocks we need to allocate for this iteration */
-
- /* (pos & (PAGE_CACHE_SIZE-1)) is an idiom for offset into a page of pos */
- num_pages = !!((pos + count) & (PAGE_CACHE_SIZE - 1)) + /* round up partial
- pages */
- ((count +
- (pos & (PAGE_CACHE_SIZE - 1))) >> PAGE_CACHE_SHIFT);
- /* convert size to amount of
- pages */
- reiserfs_write_lock(inode->i_sb);
- if (num_pages > REISERFS_WRITE_PAGES_AT_A_TIME
- || num_pages > reiserfs_can_fit_pages(inode->i_sb)) {
- /* If we were asked to write more data than we want to or if there
- is not that much space, then we shorten amount of data to write
- for this iteration. */
- num_pages =
- min_t(size_t, REISERFS_WRITE_PAGES_AT_A_TIME,
- reiserfs_can_fit_pages(inode->i_sb));
- /* Also we should not forget to set size in bytes accordingly */
- write_bytes = (num_pages << PAGE_CACHE_SHIFT) -
- (pos & (PAGE_CACHE_SIZE - 1));
- /* If position is not on the
- start of the page, we need
- to substract the offset
- within page */
- } else
- write_bytes = count;
-
- /* reserve the blocks to be allocated later, so that later on
- we still have the space to write the blocks to */
- reiserfs_claim_blocks_to_be_allocated(inode->i_sb,
- num_pages <<
- (PAGE_CACHE_SHIFT -
- inode->i_blkbits));
- reiserfs_write_unlock(inode->i_sb);
-
- if (!num_pages) { /* If we do not have enough space even for a single page... */
- if (pos >
- inode->i_size + inode->i_sb->s_blocksize -
- (pos & (inode->i_sb->s_blocksize - 1))) {
- res = -ENOSPC;
- break; // In case we are writing past the end of the last file block, break.
- }
- // Otherwise we are possibly overwriting the file, so
- // let's set write size to be equal or less than blocksize.
- // This way we get it correctly for file holes.
- // But overwriting files on absolutelly full volumes would not
- // be very efficient. Well, people are not supposed to fill
- // 100% of disk space anyway.
- write_bytes =
- min_t(size_t, count,
- inode->i_sb->s_blocksize -
- (pos & (inode->i_sb->s_blocksize - 1)));
- num_pages = 1;
- // No blocks were claimed before, so do it now.
- reiserfs_claim_blocks_to_be_allocated(inode->i_sb,
- 1 <<
- (PAGE_CACHE_SHIFT
- -
- inode->
- i_blkbits));
- }
-
- /* Prepare for writing into the region, read in all the
- partially overwritten pages, if needed. And lock the pages,
- so that nobody else can access these until we are done.
- We get number of actual blocks needed as a result. */
- res = reiserfs_prepare_file_region_for_write(inode, pos,
- num_pages,
- write_bytes,
- prepared_pages);
- if (res < 0) {
- reiserfs_release_claimed_blocks(inode->i_sb,
- num_pages <<
- (PAGE_CACHE_SHIFT -
- inode->i_blkbits));
- break;
- }
-
- blocks_to_allocate = res;
-
- /* First we correct our estimate of how many blocks we need */
- reiserfs_release_claimed_blocks(inode->i_sb,
- (num_pages <<
- (PAGE_CACHE_SHIFT -
- inode->i_sb->
- s_blocksize_bits)) -
- blocks_to_allocate);
-
- if (blocks_to_allocate > 0) { /*We only allocate blocks if we need to */
- /* Fill in all the possible holes and append the file if needed */
- res =
- reiserfs_allocate_blocks_for_region(&th, inode, pos,
- num_pages,
- write_bytes,
- prepared_pages,
- blocks_to_allocate);
- }
-
- /* well, we have allocated the blocks, so it is time to free
- the reservation we made earlier. */
- reiserfs_release_claimed_blocks(inode->i_sb,
- blocks_to_allocate);
- if (res) {
- reiserfs_unprepare_pages(prepared_pages, num_pages);
- break;
- }
-
-/* NOTE that allocating blocks and filling blocks can be done in reverse order
- and probably we would do that just to get rid of garbage in files after a
- crash */
-
- /* Copy data from user-supplied buffer to file's pages */
- res =
- reiserfs_copy_from_user_to_file_region(pos, num_pages,
- write_bytes,
- prepared_pages, buf);
- if (res) {
- reiserfs_unprepare_pages(prepared_pages, num_pages);
- break;
- }
-
- /* Send the pages to disk and unlock them. */
- res =
- reiserfs_submit_file_region_for_write(&th, inode, pos,
- num_pages,
- write_bytes,
- prepared_pages);
- if (res)
- break;
-
- already_written += write_bytes;
- buf += write_bytes;
- *ppos = pos += write_bytes;
- count -= write_bytes;
- balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
- }
-
- /* this is only true on error */
- if (th.t_trans_id) {
- reiserfs_write_lock(inode->i_sb);
- err = journal_end(&th, th.t_super, th.t_blocks_allocated);
- reiserfs_write_unlock(inode->i_sb);
- if (err) {
- res = err;
- goto out;
- }
- }
-
- if (likely(res >= 0) &&
- (unlikely((file->f_flags & O_SYNC) || IS_SYNC(inode))))
- res = generic_osync_inode(inode, file->f_mapping,
- OSYNC_METADATA | OSYNC_DATA);
-
- mutex_unlock(&inode->i_mutex);
- reiserfs_async_progress_wait(inode->i_sb);
- return (already_written != 0) ? already_written : res;
-
- out:
- mutex_unlock(&inode->i_mutex); // unlock the file on exit.
- return res;
+ return do_sync_write(file, buf, count, ppos);
}
const struct file_operations reiserfs_file_operations = {
projects / kernel.git / commitdiff