1 files changed, 276 insertions, 0 deletions

diff --git a/fs/reiserfs/tail_conversion.c b/fs/reiserfs/tail_conversion.c
new file mode 100644
index 000000000000..6191909d5165
--- /dev/null
+++ b/fs/reiserfs/tail_conversion.c
@@ -0,0 +1,276 @@
+/*
+ * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details
+ */
+
+#include <linux/config.h>
+#include <linux/time.h>
+#include <linux/pagemap.h>
+#include <linux/buffer_head.h>
+#include <linux/reiserfs_fs.h>
+
+/* access to tail : when one is going to read tail it must make sure, that is not running.
+ direct2indirect and indirect2direct can not run concurrently */
+
+
+/* Converts direct items to an unformatted node. Panics if file has no
+   tail. -ENOSPC if no disk space for conversion */
+/* path points to first direct item of the file regarless of how many of
+   them are there */
+int direct2indirect (struct reiserfs_transaction_handle *th, struct inode * inode, 
+                     struct path * path, struct buffer_head * unbh,
+                     loff_t tail_offset)
+{
+    struct super_block * sb = inode->i_sb;
+    struct buffer_head *up_to_date_bh ;
+    struct item_head * p_le_ih = PATH_PITEM_HEAD (path);
+    unsigned long total_tail = 0 ;
+    struct cpu_key end_key;  /* Key to search for the last byte of the
+                                converted item. */
+    struct item_head ind_ih; /* new indirect item to be inserted or
+                                key of unfm pointer to be pasted */
+    int n_blk_size,
+      n_retval;   /* returned value for reiserfs_insert_item and clones */
+    unp_t unfm_ptr;  /* Handle on an unformatted node
+                                       that will be inserted in the
+                                       tree. */
+
+    BUG_ON (!th->t_trans_id);
+
+    REISERFS_SB(sb)->s_direct2indirect ++;
+
+    n_blk_size = sb->s_blocksize;
+
+    /* and key to search for append or insert pointer to the new
+       unformatted node. */
+    copy_item_head (&ind_ih, p_le_ih);
+    set_le_ih_k_offset (&ind_ih, tail_offset);
+    set_le_ih_k_type (&ind_ih, TYPE_INDIRECT);
+
+    /* Set the key to search for the place for new unfm pointer */
+    make_cpu_key (&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
+
+    // FIXME: we could avoid this 
+    if ( search_for_position_by_key (sb, &end_key, path) == POSITION_FOUND ) {
+        reiserfs_warning (sb, "PAP-14030: direct2indirect: "
+                        "pasted or inserted byte exists in the tree %K. "
+                        "Use fsck to repair.", &end_key);
+        pathrelse(path);
+        return -EIO;
+    }
+    
+    p_le_ih = PATH_PITEM_HEAD (path);
+
+    unfm_ptr = cpu_to_le32 (unbh->b_blocknr);
+    
+    if ( is_statdata_le_ih (p_le_ih) )  {
+        /* Insert new indirect item. */
+        set_ih_free_space (&ind_ih, 0); /* delete at nearest future */
+        put_ih_item_len( &ind_ih, UNFM_P_SIZE );
+        PATH_LAST_POSITION (path)++;
+        n_retval = reiserfs_insert_item (th, path, &end_key, &ind_ih, inode,
+                                         (char *)&unfm_ptr);
+    } else {
+        /* Paste into last indirect item of an object. */
+        n_retval = reiserfs_paste_into_item(th, path, &end_key, inode,
+                                            (char *)&unfm_ptr, UNFM_P_SIZE);
+    }
+    if ( n_retval ) {
+        return n_retval;
+    }
+
+    // note: from here there are two keys which have matching first
+    // three key components. They only differ by the fourth one.
+
+
+    /* Set the key to search for the direct items of the file */
+    make_cpu_key (&end_key, inode, max_reiserfs_offset (inode), TYPE_DIRECT, 4);
+
+    /* Move bytes from the direct items to the new unformatted node
+       and delete them. */
+    while (1)  {
+        int tail_size;
+
+        /* end_key.k_offset is set so, that we will always have found
+           last item of the file */
+        if ( search_for_position_by_key (sb, &end_key, path) == POSITION_FOUND )
+            reiserfs_panic (sb, "PAP-14050: direct2indirect: "
+                            "direct item (%K) not found", &end_key);
+        p_le_ih = PATH_PITEM_HEAD (path);
+        RFALSE( !is_direct_le_ih (p_le_ih),
+                "vs-14055: direct item expected(%K), found %h",
+                &end_key, p_le_ih);
+        tail_size = (le_ih_k_offset (p_le_ih) & (n_blk_size - 1))
+            + ih_item_len(p_le_ih) - 1;
+
+        /* we only send the unbh pointer if the buffer is not up to date.
+        ** this avoids overwriting good data from writepage() with old data
+        ** from the disk or buffer cache
+        ** Special case: unbh->b_page will be NULL if we are coming through
+        ** DIRECT_IO handler here.
+        */
+        if (!unbh->b_page || buffer_uptodate(unbh) || PageUptodate(unbh->b_page)) {
+            up_to_date_bh = NULL ;
+        } else {
+            up_to_date_bh = unbh ;
+        }
+        n_retval = reiserfs_delete_item (th, path, &end_key, inode, 
+                                         up_to_date_bh) ;
+
+        total_tail += n_retval ;
+        if (tail_size == n_retval)
+            // done: file does not have direct items anymore
+            break;
+
+    }
+    /* if we've copied bytes from disk into the page, we need to zero
+    ** out the unused part of the block (it was not up to date before)
+    */
+    if (up_to_date_bh) {
+        unsigned pgoff = (tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
+        char *kaddr=kmap_atomic(up_to_date_bh->b_page, KM_USER0);
+        memset(kaddr + pgoff, 0, n_blk_size - total_tail) ;
+        kunmap_atomic(kaddr, KM_USER0);
+    }
+
+    REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
+
+    return 0;
+}
+
+
+/* stolen from fs/buffer.c */
+void reiserfs_unmap_buffer(struct buffer_head *bh) {
+    lock_buffer(bh) ;
+    if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
+      BUG() ;
+    }
+    clear_buffer_dirty(bh) ;
+    /* Remove the buffer from whatever list it belongs to. We are mostly
+       interested in removing it from per-sb j_dirty_buffers list, to avoid
+        BUG() on attempt to write not mapped buffer */
+    if ( (!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
+        struct inode *inode = bh->b_page->mapping->host;
+        struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
+        spin_lock(&j->j_dirty_buffers_lock);
+        list_del_init(&bh->b_assoc_buffers);
+        reiserfs_free_jh(bh);
+        spin_unlock(&j->j_dirty_buffers_lock);
+    }
+    clear_buffer_mapped(bh) ;
+    clear_buffer_req(bh) ;
+    clear_buffer_new(bh);
+    bh->b_bdev = NULL;
+    unlock_buffer(bh) ;
+}
+
+/* this first locks inode (neither reads nor sync are permitted),
+   reads tail through page cache, insert direct item. When direct item
+   inserted successfully inode is left locked. Return value is always
+   what we expect from it (number of cut bytes). But when tail remains
+   in the unformatted node, we set mode to SKIP_BALANCING and unlock
+   inode */
+int indirect2direct (struct reiserfs_transaction_handle *th, 
+                     struct inode * p_s_inode,
+                     struct page *page, 
+                     struct path * p_s_path, /* path to the indirect item. */
+                     const struct cpu_key * p_s_item_key, /* Key to look for unformatted node pointer to be cut. */
+                     loff_t n_new_file_size, /* New file size. */
+                     char * p_c_mode)
+{
+    struct super_block * p_s_sb = p_s_inode->i_sb;
+    struct item_head      s_ih;
+    unsigned long n_block_size = p_s_sb->s_blocksize;
+    char * tail;
+    int tail_len, round_tail_len;
+    loff_t pos, pos1; /* position of first byte of the tail */
+    struct cpu_key key;
+
+    BUG_ON (!th->t_trans_id);
+
+    REISERFS_SB(p_s_sb)->s_indirect2direct ++;
+
+    *p_c_mode = M_SKIP_BALANCING;
+
+    /* store item head path points to. */
+    copy_item_head (&s_ih, PATH_PITEM_HEAD(p_s_path));
+
+    tail_len = (n_new_file_size & (n_block_size - 1));
+    if (get_inode_sd_version (p_s_inode) == STAT_DATA_V2)
+        round_tail_len = ROUND_UP (tail_len);
+    else
+        round_tail_len = tail_len;
+
+    pos = le_ih_k_offset (&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE - 1) * p_s_sb->s_blocksize;
+    pos1 = pos;
+
+    // we are protected by i_sem. The tail can not disapper, not
+    // append can be done either
+    // we are in truncate or packing tail in file_release
+
+    tail = (char *)kmap(page) ; /* this can schedule */
+
+    if (path_changed (&s_ih, p_s_path)) {
+        /* re-search indirect item */
+        if ( search_for_position_by_key (p_s_sb, p_s_item_key, p_s_path) == POSITION_NOT_FOUND )
+            reiserfs_panic(p_s_sb, "PAP-5520: indirect2direct: "
+                           "item to be converted %K does not exist", p_s_item_key);
+        copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
+#ifdef CONFIG_REISERFS_CHECK
+        pos = le_ih_k_offset (&s_ih) - 1 + 
+            (ih_item_len(&s_ih) / UNFM_P_SIZE - 1) * p_s_sb->s_blocksize;
+        if (pos != pos1)
+            reiserfs_panic (p_s_sb, "vs-5530: indirect2direct: "
+                            "tail position changed while we were reading it");
+#endif
+    }
+
+
+    /* Set direct item header to insert. */
+    make_le_item_head (&s_ih, NULL, get_inode_item_key_version (p_s_inode), pos1 + 1,
+                       TYPE_DIRECT, round_tail_len, 0xffff/*ih_free_space*/);
+
+    /* we want a pointer to the first byte of the tail in the page.
+    ** the page was locked and this part of the page was up to date when
+    ** indirect2direct was called, so we know the bytes are still valid
+    */
+    tail = tail + (pos & (PAGE_CACHE_SIZE - 1)) ;
+
+    PATH_LAST_POSITION(p_s_path)++;
+
+    key = *p_s_item_key;
+    set_cpu_key_k_type (&key, TYPE_DIRECT);
+    key.key_length = 4;
+    /* Insert tail as new direct item in the tree */
+    if ( reiserfs_insert_item(th, p_s_path, &key, &s_ih, p_s_inode,
+                              tail ? tail : NULL) < 0 ) {
+        /* No disk memory. So we can not convert last unformatted node
+           to the direct item.  In this case we used to adjust
+           indirect items's ih_free_space. Now ih_free_space is not
+           used, it would be ideal to write zeros to corresponding
+           unformatted node. For now i_size is considered as guard for
+           going out of file size */
+        kunmap(page) ;
+        return n_block_size - round_tail_len;
+    }
+    kunmap(page) ;
+
+    /* make sure to get the i_blocks changes from reiserfs_insert_item */
+    reiserfs_update_sd(th, p_s_inode);
+
+    // note: we have now the same as in above direct2indirect
+    // conversion: there are two keys which have matching first three
+    // key components. They only differ by the fouhth one.
+
+    /* We have inserted new direct item and must remove last
+       unformatted node. */
+    *p_c_mode = M_CUT;
+
+    /* we store position of first direct item in the in-core inode */
+    //mark_file_with_tail (p_s_inode, pos1 + 1);
+    REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1;
+
+    return n_block_size - round_tail_len;
+}
+
+
+