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1409 lines
52 KiB
1409 lines
52 KiB
/*
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* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
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*/
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#include <linux/time.h>
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#include <linux/reiserfs_fs.h>
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#include <linux/reiserfs_acl.h>
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#include <linux/reiserfs_xattr.h>
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#include <linux/smp_lock.h>
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#include <asm/uaccess.h>
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#include <linux/pagemap.h>
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#include <linux/swap.h>
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#include <linux/writeback.h>
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#include <linux/blkdev.h>
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#include <linux/buffer_head.h>
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#include <linux/quotaops.h>
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/*
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** We pack the tails of files on file close, not at the time they are written.
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** This implies an unnecessary copy of the tail and an unnecessary indirect item
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** insertion/balancing, for files that are written in one write.
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** It avoids unnecessary tail packings (balances) for files that are written in
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** multiple writes and are small enough to have tails.
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**
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** file_release is called by the VFS layer when the file is closed. If
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** this is the last open file descriptor, and the file
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** small enough to have a tail, and the tail is currently in an
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** unformatted node, the tail is converted back into a direct item.
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**
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** We use reiserfs_truncate_file to pack the tail, since it already has
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** all the conditions coded.
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*/
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static int reiserfs_file_release (struct inode * inode, struct file * filp)
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{
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struct reiserfs_transaction_handle th ;
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int err;
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int jbegin_failure = 0;
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if (!S_ISREG (inode->i_mode))
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BUG ();
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/* fast out for when nothing needs to be done */
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if ((atomic_read(&inode->i_count) > 1 ||
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!(REISERFS_I(inode)->i_flags & i_pack_on_close_mask) ||
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!tail_has_to_be_packed(inode)) &&
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REISERFS_I(inode)->i_prealloc_count <= 0) {
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return 0;
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}
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reiserfs_write_lock(inode->i_sb);
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down (&inode->i_sem);
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/* freeing preallocation only involves relogging blocks that
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* are already in the current transaction. preallocation gets
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* freed at the end of each transaction, so it is impossible for
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* us to log any additional blocks (including quota blocks)
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*/
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err = journal_begin(&th, inode->i_sb, 1);
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if (err) {
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/* uh oh, we can't allow the inode to go away while there
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* is still preallocation blocks pending. Try to join the
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* aborted transaction
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*/
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jbegin_failure = err;
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err = journal_join_abort(&th, inode->i_sb, 1);
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if (err) {
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/* hmpf, our choices here aren't good. We can pin the inode
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* which will disallow unmount from every happening, we can
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* do nothing, which will corrupt random memory on unmount,
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* or we can forcibly remove the file from the preallocation
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* list, which will leak blocks on disk. Lets pin the inode
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* and let the admin know what is going on.
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*/
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igrab(inode);
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reiserfs_warning(inode->i_sb, "pinning inode %lu because the "
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"preallocation can't be freed");
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goto out;
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}
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}
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reiserfs_update_inode_transaction(inode) ;
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#ifdef REISERFS_PREALLOCATE
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reiserfs_discard_prealloc (&th, inode);
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#endif
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err = journal_end(&th, inode->i_sb, 1);
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/* copy back the error code from journal_begin */
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if (!err)
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err = jbegin_failure;
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if (!err && atomic_read(&inode->i_count) <= 1 &&
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(REISERFS_I(inode)->i_flags & i_pack_on_close_mask) &&
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tail_has_to_be_packed (inode)) {
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/* if regular file is released by last holder and it has been
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appended (we append by unformatted node only) or its direct
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item(s) had to be converted, then it may have to be
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indirect2direct converted */
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err = reiserfs_truncate_file(inode, 0) ;
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}
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out:
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up (&inode->i_sem);
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reiserfs_write_unlock(inode->i_sb);
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return err;
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}
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static void reiserfs_vfs_truncate_file(struct inode *inode) {
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reiserfs_truncate_file(inode, 1) ;
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}
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/* Sync a reiserfs file. */
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/*
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* FIXME: sync_mapping_buffers() never has anything to sync. Can
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* be removed...
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*/
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static int reiserfs_sync_file(
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struct file * p_s_filp,
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struct dentry * p_s_dentry,
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int datasync
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) {
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struct inode * p_s_inode = p_s_dentry->d_inode;
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int n_err;
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int barrier_done;
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if (!S_ISREG(p_s_inode->i_mode))
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BUG ();
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n_err = sync_mapping_buffers(p_s_inode->i_mapping) ;
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reiserfs_write_lock(p_s_inode->i_sb);
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barrier_done = reiserfs_commit_for_inode(p_s_inode);
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reiserfs_write_unlock(p_s_inode->i_sb);
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if (barrier_done != 1)
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blkdev_issue_flush(p_s_inode->i_sb->s_bdev, NULL);
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if (barrier_done < 0)
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return barrier_done;
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return ( n_err < 0 ) ? -EIO : 0;
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}
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/* I really do not want to play with memory shortage right now, so
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to simplify the code, we are not going to write more than this much pages at
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a time. This still should considerably improve performance compared to 4k
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at a time case. This is 32 pages of 4k size. */
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#define REISERFS_WRITE_PAGES_AT_A_TIME (128 * 1024) / PAGE_CACHE_SIZE
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/* Allocates blocks for a file to fulfil write request.
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Maps all unmapped but prepared pages from the list.
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Updates metadata with newly allocated blocknumbers as needed */
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static int reiserfs_allocate_blocks_for_region(
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struct reiserfs_transaction_handle *th,
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struct inode *inode, /* Inode we work with */
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loff_t pos, /* Writing position */
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int num_pages, /* number of pages write going
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to touch */
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int write_bytes, /* amount of bytes to write */
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struct page **prepared_pages, /* array of
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prepared pages
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*/
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int blocks_to_allocate /* Amount of blocks we
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need to allocate to
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fit the data into file
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*/
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)
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{
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struct cpu_key key; // cpu key of item that we are going to deal with
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struct item_head *ih; // pointer to item head that we are going to deal with
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struct buffer_head *bh; // Buffer head that contains items that we are going to deal with
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__le32 * item; // pointer to item we are going to deal with
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INITIALIZE_PATH(path); // path to item, that we are going to deal with.
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b_blocknr_t *allocated_blocks; // Pointer to a place where allocated blocknumbers would be stored.
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reiserfs_blocknr_hint_t hint; // hint structure for block allocator.
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size_t res; // return value of various functions that we call.
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int curr_block; // current block used to keep track of unmapped blocks.
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int i; // loop counter
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int itempos; // position in item
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unsigned int from = (pos & (PAGE_CACHE_SIZE - 1)); // writing position in
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// first page
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unsigned int to = ((pos + write_bytes - 1) & (PAGE_CACHE_SIZE - 1)) + 1; /* last modified byte offset in last page */
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__u64 hole_size ; // amount of blocks for a file hole, if it needed to be created.
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int modifying_this_item = 0; // Flag for items traversal code to keep track
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// of the fact that we already prepared
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// current block for journal
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int will_prealloc = 0;
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RFALSE(!blocks_to_allocate, "green-9004: tried to allocate zero blocks?");
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/* only preallocate if this is a small write */
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if (REISERFS_I(inode)->i_prealloc_count ||
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(!(write_bytes & (inode->i_sb->s_blocksize -1)) &&
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blocks_to_allocate <
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REISERFS_SB(inode->i_sb)->s_alloc_options.preallocsize))
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will_prealloc = REISERFS_SB(inode->i_sb)->s_alloc_options.preallocsize;
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allocated_blocks = kmalloc((blocks_to_allocate + will_prealloc) *
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sizeof(b_blocknr_t), GFP_NOFS);
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/* First we compose a key to point at the writing position, we want to do
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that outside of any locking region. */
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make_cpu_key (&key, inode, pos+1, TYPE_ANY, 3/*key length*/);
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/* If we came here, it means we absolutely need to open a transaction,
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since we need to allocate some blocks */
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reiserfs_write_lock(inode->i_sb); // Journaling stuff and we need that.
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res = journal_begin(th, inode->i_sb, JOURNAL_PER_BALANCE_CNT * 3 + 1 + 2 * REISERFS_QUOTA_TRANS_BLOCKS); // Wish I know if this number enough
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if (res)
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goto error_exit;
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reiserfs_update_inode_transaction(inode) ;
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/* Look for the in-tree position of our write, need path for block allocator */
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res = search_for_position_by_key(inode->i_sb, &key, &path);
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if ( res == IO_ERROR ) {
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res = -EIO;
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goto error_exit;
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}
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/* Allocate blocks */
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/* First fill in "hint" structure for block allocator */
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hint.th = th; // transaction handle.
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hint.path = &path; // Path, so that block allocator can determine packing locality or whatever it needs to determine.
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hint.inode = inode; // Inode is needed by block allocator too.
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hint.search_start = 0; // We have no hint on where to search free blocks for block allocator.
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hint.key = key.on_disk_key; // on disk key of file.
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hint.block = inode->i_blocks>>(inode->i_sb->s_blocksize_bits-9); // Number of disk blocks this file occupies already.
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hint.formatted_node = 0; // We are allocating blocks for unformatted node.
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hint.preallocate = will_prealloc;
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/* Call block allocator to allocate blocks */
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res = reiserfs_allocate_blocknrs(&hint, allocated_blocks, blocks_to_allocate, blocks_to_allocate);
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if ( res != CARRY_ON ) {
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if ( res == NO_DISK_SPACE ) {
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/* We flush the transaction in case of no space. This way some
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blocks might become free */
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SB_JOURNAL(inode->i_sb)->j_must_wait = 1;
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res = restart_transaction(th, inode, &path);
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if (res)
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goto error_exit;
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/* We might have scheduled, so search again */
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res = search_for_position_by_key(inode->i_sb, &key, &path);
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if ( res == IO_ERROR ) {
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res = -EIO;
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goto error_exit;
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}
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/* update changed info for hint structure. */
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res = reiserfs_allocate_blocknrs(&hint, allocated_blocks, blocks_to_allocate, blocks_to_allocate);
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if ( res != CARRY_ON ) {
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res = -ENOSPC;
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pathrelse(&path);
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goto error_exit;
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}
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} else {
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res = -ENOSPC;
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pathrelse(&path);
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goto error_exit;
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}
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}
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#ifdef __BIG_ENDIAN
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// Too bad, I have not found any way to convert a given region from
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// cpu format to little endian format
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{
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int i;
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for ( i = 0; i < blocks_to_allocate ; i++)
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allocated_blocks[i]=cpu_to_le32(allocated_blocks[i]);
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}
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#endif
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/* Blocks allocating well might have scheduled and tree might have changed,
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let's search the tree again */
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/* find where in the tree our write should go */
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res = search_for_position_by_key(inode->i_sb, &key, &path);
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if ( res == IO_ERROR ) {
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res = -EIO;
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goto error_exit_free_blocks;
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}
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bh = get_last_bh( &path ); // Get a bufferhead for last element in path.
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ih = get_ih( &path ); // Get a pointer to last item head in path.
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item = get_item( &path ); // Get a pointer to last item in path
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/* Let's see what we have found */
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if ( res != POSITION_FOUND ) { /* position not found, this means that we
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might need to append file with holes
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first */
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// Since we are writing past the file's end, we need to find out if
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// there is a hole that needs to be inserted before our writing
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// position, and how many blocks it is going to cover (we need to
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// populate pointers to file blocks representing the hole with zeros)
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{
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int item_offset = 1;
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/*
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* if ih is stat data, its offset is 0 and we don't want to
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* add 1 to pos in the hole_size calculation
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*/
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if (is_statdata_le_ih(ih))
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item_offset = 0;
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hole_size = (pos + item_offset -
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(le_key_k_offset( get_inode_item_key_version(inode),
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&(ih->ih_key)) +
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op_bytes_number(ih, inode->i_sb->s_blocksize))) >>
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inode->i_sb->s_blocksize_bits;
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}
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if ( hole_size > 0 ) {
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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.
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/* area filled with zeroes, to supply as list of zero blocknumbers
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We allocate it outside of loop just in case loop would spin for
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several iterations. */
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char *zeros = kmalloc(to_paste*UNFM_P_SIZE, GFP_ATOMIC); // We cannot insert more than MAX_ITEM_LEN bytes anyway.
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if ( !zeros ) {
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res = -ENOMEM;
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goto error_exit_free_blocks;
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}
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memset ( zeros, 0, to_paste*UNFM_P_SIZE);
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do {
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to_paste = min_t(__u64, hole_size, MAX_ITEM_LEN(inode->i_sb->s_blocksize)/UNFM_P_SIZE );
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if ( is_indirect_le_ih(ih) ) {
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/* Ok, there is existing indirect item already. Need to append it */
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/* Calculate position past inserted item */
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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);
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res = reiserfs_paste_into_item( th, &path, &key, inode, (char *)zeros, UNFM_P_SIZE*to_paste);
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if ( res ) {
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kfree(zeros);
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goto error_exit_free_blocks;
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}
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} else if ( is_statdata_le_ih(ih) ) {
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/* No existing item, create it */
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/* item head for new item */
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struct item_head ins_ih;
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/* create a key for our new item */
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make_cpu_key( &key, inode, 1, TYPE_INDIRECT, 3);
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/* Create new item head for our new item */
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make_le_item_head (&ins_ih, &key, key.version, 1,
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TYPE_INDIRECT, to_paste*UNFM_P_SIZE,
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0 /* free space */);
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|
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/* Find where such item should live in the tree */
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res = search_item (inode->i_sb, &key, &path);
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if ( res != ITEM_NOT_FOUND ) {
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/* item should not exist, otherwise we have error */
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if ( res != -ENOSPC ) {
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reiserfs_warning (inode->i_sb,
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"green-9008: search_by_key (%K) returned %d",
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&key, res);
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}
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res = -EIO;
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kfree(zeros);
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goto error_exit_free_blocks;
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}
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res = reiserfs_insert_item( th, &path, &key, &ins_ih, inode, (char *)zeros);
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} else {
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reiserfs_panic(inode->i_sb, "green-9011: Unexpected key type %K\n", &key);
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}
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if ( res ) {
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kfree(zeros);
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goto error_exit_free_blocks;
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}
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/* Now we want to check if transaction is too full, and if it is
|
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we restart it. This will also free the path. */
|
|
if (journal_transaction_should_end(th, th->t_blocks_allocated)) {
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res = restart_transaction(th, inode, &path);
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if (res) {
|
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pathrelse (&path);
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kfree(zeros);
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goto error_exit;
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}
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}
|
|
|
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/* Well, need to recalculate path and stuff */
|
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set_cpu_key_k_offset( &key, cpu_key_k_offset(&key) + (to_paste << inode->i_blkbits));
|
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res = search_for_position_by_key(inode->i_sb, &key, &path);
|
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if ( res == IO_ERROR ) {
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res = -EIO;
|
|
kfree(zeros);
|
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goto error_exit_free_blocks;
|
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}
|
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bh=get_last_bh(&path);
|
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ih=get_ih(&path);
|
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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.
|
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for ( curr_block = 0, itempos = path.pos_in_item ; curr_block < blocks_to_allocate && res == POSITION_FOUND ; ) {
|
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retry:
|
|
|
|
if ( itempos >= ih_item_len(ih)/UNFM_P_SIZE ) {
|
|
/* We run out of data in this indirect item, let's look for another
|
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one. */
|
|
/* First if we are already modifying current item, log it */
|
|
if ( modifying_this_item ) {
|
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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) {
|
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res = -EIO;
|
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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
|
|
reiserfs_update_sd(th, inode);
|
|
err = journal_end(th, inode->i_sb, JOURNAL_PER_BALANCE_CNT * 3 + 1 + 2 * REISERFS_QUOTA_TRANS_BLOCKS);
|
|
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)
|
|
{
|
|
unsigned block_start, block_end;
|
|
int partial = 0;
|
|
unsigned blocksize;
|
|
struct buffer_head *bh, *head;
|
|
unsigned long i_size_index = inode->i_size >> PAGE_CACHE_SHIFT;
|
|
int new;
|
|
int logit = reiserfs_file_data_log(inode);
|
|
struct super_block *s = inode->i_sb;
|
|
int bh_per_page = PAGE_CACHE_SIZE / s->s_blocksize;
|
|
struct reiserfs_transaction_handle th;
|
|
int ret = 0;
|
|
|
|
th.t_trans_id = 0;
|
|
blocksize = 1 << inode->i_blkbits;
|
|
|
|
if (logit) {
|
|
reiserfs_write_lock(s);
|
|
ret = journal_begin(&th, s, bh_per_page + 1);
|
|
if (ret)
|
|
goto drop_write_lock;
|
|
reiserfs_update_inode_transaction(inode);
|
|
}
|
|
for(bh = head = page_buffers(page), block_start = 0;
|
|
bh != head || !block_start;
|
|
block_start=block_end, bh = bh->b_this_page)
|
|
{
|
|
|
|
new = buffer_new(bh);
|
|
clear_buffer_new(bh);
|
|
block_end = block_start + blocksize;
|
|
if (block_end <= from || block_start >= to) {
|
|
if (!buffer_uptodate(bh))
|
|
partial = 1;
|
|
} else {
|
|
set_buffer_uptodate(bh);
|
|
if (logit) {
|
|
reiserfs_prepare_for_journal(s, bh, 1);
|
|
journal_mark_dirty(&th, s, bh);
|
|
} else if (!buffer_dirty(bh)) {
|
|
mark_buffer_dirty(bh);
|
|
/* do data=ordered on any page past the end
|
|
* of file and any buffer marked BH_New.
|
|
*/
|
|
if (reiserfs_data_ordered(inode->i_sb) &&
|
|
(new || page->index >= i_size_index)) {
|
|
reiserfs_add_ordered_list(inode, bh);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (logit) {
|
|
ret = journal_end(&th, s, bh_per_page + 1);
|
|
drop_write_lock:
|
|
reiserfs_write_unlock(s);
|
|
}
|
|
/*
|
|
* If this is a partial write which happened to make all buffers
|
|
* uptodate then we can optimize away a bogus readpage() for
|
|
* the next read(). Here we 'discover' whether the page went
|
|
* uptodate as a result of this (potentially partial) write.
|
|
*/
|
|
if (!partial)
|
|
SetPageUptodate(page);
|
|
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);
|
|
reiserfs_update_sd(th, inode); // And update on-disk metadata
|
|
reiserfs_write_unlock(inode->i_sb);
|
|
} else
|
|
inode->i_sb->s_op->dirty_inode(inode);
|
|
|
|
sd_update = 1;
|
|
}
|
|
if (th->t_trans_id) {
|
|
reiserfs_write_lock(inode->i_sb);
|
|
if (!sd_update)
|
|
reiserfs_update_sd(th, 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 */
|
|
char *kaddr = kmap_atomic(prepared_pages[0], KM_USER0);
|
|
memset(kaddr, 0, from);
|
|
kunmap_atomic( kaddr, KM_USER0);
|
|
}
|
|
if ( to != PAGE_CACHE_SIZE ) { /* Last page needs to be partially zeroed */
|
|
char *kaddr = kmap_atomic(prepared_pages[num_pages-1], KM_USER0);
|
|
memset(kaddr+to, 0, PAGE_CACHE_SIZE - to);
|
|
kunmap_atomic( kaddr, 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 */
|
|
char *kaddr = kmap_atomic(prepared_pages[0], KM_USER0);
|
|
memset(kaddr+block_start, 0, from-block_start);
|
|
kunmap_atomic( kaddr, 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 */
|
|
char *kaddr = kmap_atomic(prepared_pages[num_pages-1], KM_USER0);
|
|
memset(kaddr+to, 0, block_end-to);
|
|
kunmap_atomic( kaddr, 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.
|
|
|
|
generic_file_write() is only appropriate for filesystems that are not seeking to optimize performance and want
|
|
something simple that works. It is not for serious use by general purpose filesystems, excepting the one that it was
|
|
written for (ext2/3). This is for several reasons:
|
|
|
|
* It has no understanding of any filesystem specific optimizations.
|
|
|
|
* It enters the filesystem repeatedly for each page that is written.
|
|
|
|
* It depends on reiserfs_get_block() function which if implemented by reiserfs performs costly search_by_key
|
|
* operation for each page it is supplied with. By contrast reiserfs_file_write() feeds as much as possible at a time
|
|
* to reiserfs which allows for fewer tree traversals.
|
|
|
|
* Each indirect pointer insertion takes a lot of cpu, because it involves memory moves inside of blocks.
|
|
|
|
* Asking the block allocation code for blocks one at a time is slightly less efficient.
|
|
|
|
All of these reasons for not using only generic file write were understood back when reiserfs was first miscoded to
|
|
use it, but we were in a hurry to make code freeze, and so it couldn't be revised then. This new code should make
|
|
things right finally.
|
|
|
|
Future Features: providing search_by_key with hints.
|
|
|
|
*/
|
|
static ssize_t reiserfs_file_write( struct file *file, /* the file we are going to write into */
|
|
const char __user *buf, /* pointer to user supplied data
|
|
(in userspace) */
|
|
size_t count, /* amount of bytes to write */
|
|
loff_t *ppos /* pointer to position in file that we start writing at. Should be updated to
|
|
* 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_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;
|
|
|
|
if ( file->f_flags & O_DIRECT) { // Direct IO needs treatment
|
|
ssize_t result, after_file_end = 0;
|
|
if ( (*ppos + count >= inode->i_size) || (file->f_flags & O_APPEND) ) {
|
|
/* If we are appending a file, we need to put this savelink in here.
|
|
If we will crash while doing direct io, finish_unfinished will
|
|
cut the garbage from the file end. */
|
|
reiserfs_write_lock(inode->i_sb);
|
|
err = journal_begin(&th, inode->i_sb, JOURNAL_PER_BALANCE_CNT );
|
|
if (err) {
|
|
reiserfs_write_unlock (inode->i_sb);
|
|
return err;
|
|
}
|
|
reiserfs_update_inode_transaction(inode);
|
|
add_save_link (&th, inode, 1 /* Truncate */);
|
|
after_file_end = 1;
|
|
err = journal_end(&th, inode->i_sb, JOURNAL_PER_BALANCE_CNT );
|
|
reiserfs_write_unlock(inode->i_sb);
|
|
if (err)
|
|
return err;
|
|
}
|
|
result = generic_file_write(file, buf, count, ppos);
|
|
|
|
if ( after_file_end ) { /* Now update i_size and remove the savelink */
|
|
struct reiserfs_transaction_handle th;
|
|
reiserfs_write_lock(inode->i_sb);
|
|
err = journal_begin(&th, inode->i_sb, 1);
|
|
if (err) {
|
|
reiserfs_write_unlock (inode->i_sb);
|
|
return err;
|
|
}
|
|
reiserfs_update_inode_transaction(inode);
|
|
reiserfs_update_sd(&th, inode);
|
|
err = journal_end(&th, inode->i_sb, 1);
|
|
if (err) {
|
|
reiserfs_write_unlock (inode->i_sb);
|
|
return err;
|
|
}
|
|
err = remove_save_link (inode, 1/* truncate */);
|
|
reiserfs_write_unlock(inode->i_sb);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
if ( unlikely((ssize_t) count < 0 ))
|
|
return -EINVAL;
|
|
|
|
if (unlikely(!access_ok(VERIFY_READ, buf, count)))
|
|
return -EFAULT;
|
|
|
|
down(&inode->i_sem); // 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_dentry);
|
|
if (res)
|
|
goto out;
|
|
|
|
inode_update_time(inode, 1); /* Both mtime and ctime */
|
|
|
|
// 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.*/
|
|
blocks_to_allocate = reiserfs_prepare_file_region_for_write(inode, pos, num_pages, write_bytes, prepared_pages);
|
|
if ( blocks_to_allocate < 0 ) {
|
|
res = blocks_to_allocate;
|
|
reiserfs_release_claimed_blocks(inode->i_sb, num_pages << (PAGE_CACHE_SHIFT - inode->i_blkbits));
|
|
break;
|
|
}
|
|
|
|
/* 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(inode->i_mapping);
|
|
}
|
|
|
|
/* 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 ((file->f_flags & O_SYNC) || IS_SYNC(inode))
|
|
res = generic_osync_inode(inode, file->f_mapping, OSYNC_METADATA|OSYNC_DATA);
|
|
|
|
up(&inode->i_sem);
|
|
reiserfs_async_progress_wait(inode->i_sb);
|
|
return (already_written != 0)?already_written:res;
|
|
|
|
out:
|
|
up(&inode->i_sem); // unlock the file on exit.
|
|
return res;
|
|
}
|
|
|
|
static ssize_t reiserfs_aio_write(struct kiocb *iocb, const char __user *buf,
|
|
size_t count, loff_t pos)
|
|
{
|
|
return generic_file_aio_write(iocb, buf, count, pos);
|
|
}
|
|
|
|
|
|
|
|
struct file_operations reiserfs_file_operations = {
|
|
.read = generic_file_read,
|
|
.write = reiserfs_file_write,
|
|
.ioctl = reiserfs_ioctl,
|
|
.mmap = generic_file_mmap,
|
|
.release = reiserfs_file_release,
|
|
.fsync = reiserfs_sync_file,
|
|
.sendfile = generic_file_sendfile,
|
|
.aio_read = generic_file_aio_read,
|
|
.aio_write = reiserfs_aio_write,
|
|
};
|
|
|
|
|
|
struct inode_operations reiserfs_file_inode_operations = {
|
|
.truncate = reiserfs_vfs_truncate_file,
|
|
.setattr = reiserfs_setattr,
|
|
.setxattr = reiserfs_setxattr,
|
|
.getxattr = reiserfs_getxattr,
|
|
.listxattr = reiserfs_listxattr,
|
|
.removexattr = reiserfs_removexattr,
|
|
.permission = reiserfs_permission,
|
|
};
|
|
|
|
|
|
|