Btrfs: Cleanup and comment ordered-data.c
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Родитель
54641bd17d
Коммит
eb84ae039e
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@ -1343,7 +1343,7 @@ again:
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unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
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unlock_page(page);
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page_cache_release(page);
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btrfs_wait_ordered_extent(inode, ordered);
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btrfs_start_ordered_extent(inode, ordered, 1);
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btrfs_put_ordered_extent(ordered);
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goto again;
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}
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@ -2660,6 +2660,10 @@ static void btrfs_invalidatepage(struct page *page, unsigned long offset)
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ordered = btrfs_lookup_ordered_extent(page->mapping->host,
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page_offset(page));
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if (ordered) {
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/*
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* IO on this page will never be started, so we need
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* to account for any ordered extents now
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*/
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clear_extent_bit(tree, page_start, page_end,
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EXTENT_DIRTY | EXTENT_DELALLOC |
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EXTENT_LOCKED, 1, 0, GFP_NOFS);
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@ -2732,11 +2736,15 @@ again:
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lock_extent(io_tree, page_start, page_end, GFP_NOFS);
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set_page_extent_mapped(page);
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/*
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* we can't set the delalloc bits if there are pending ordered
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* extents. Drop our locks and wait for them to finish
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*/
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ordered = btrfs_lookup_ordered_extent(inode, page_start);
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if (ordered) {
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unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
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unlock_page(page);
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btrfs_wait_ordered_extent(inode, ordered);
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btrfs_start_ordered_extent(inode, ordered, 1);
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btrfs_put_ordered_extent(ordered);
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goto again;
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}
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@ -136,6 +136,19 @@ static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
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return ret;
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}
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/* allocate and add a new ordered_extent into the per-inode tree.
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* file_offset is the logical offset in the file
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*
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* start is the disk block number of an extent already reserved in the
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* extent allocation tree
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*
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* len is the length of the extent
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*
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* This also sets the EXTENT_ORDERED bit on the range in the inode.
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*
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* The tree is given a single reference on the ordered extent that was
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* inserted.
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*/
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int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
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u64 start, u64 len)
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{
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@ -152,7 +165,6 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
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entry->file_offset = file_offset;
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entry->start = start;
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entry->len = len;
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entry->inode = inode;
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/* one ref for the tree */
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atomic_set(&entry->refs, 1);
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init_waitqueue_head(&entry->wait);
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@ -167,12 +179,15 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
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set_extent_ordered(&BTRFS_I(inode)->io_tree, file_offset,
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entry_end(entry) - 1, GFP_NOFS);
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set_bit(BTRFS_ORDERED_START, &entry->flags);
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mutex_unlock(&tree->mutex);
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BUG_ON(node);
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return 0;
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}
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/*
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* Add a struct btrfs_ordered_sum into the list of checksums to be inserted
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* when an ordered extent is finished.
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*/
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int btrfs_add_ordered_sum(struct inode *inode, struct btrfs_ordered_sum *sum)
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{
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struct btrfs_ordered_inode_tree *tree;
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@ -182,29 +197,25 @@ int btrfs_add_ordered_sum(struct inode *inode, struct btrfs_ordered_sum *sum)
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tree = &BTRFS_I(inode)->ordered_tree;
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mutex_lock(&tree->mutex);
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node = tree_search(tree, sum->file_offset);
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if (!node) {
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search_fail:
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printk("add ordered sum failed to find a node for inode %lu offset %Lu\n", inode->i_ino, sum->file_offset);
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node = rb_first(&tree->tree);
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while(node) {
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entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
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printk("entry %Lu %Lu %Lu\n", entry->file_offset, entry->file_offset + entry->len, entry->start);
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node = rb_next(node);
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}
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BUG();
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}
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BUG_ON(!node);
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entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
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if (!offset_in_entry(entry, sum->file_offset)) {
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goto search_fail;
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}
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BUG_ON(!offset_in_entry(entry, sum->file_offset));
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list_add_tail(&sum->list, &entry->list);
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mutex_unlock(&tree->mutex);
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return 0;
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}
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/*
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* this is used to account for finished IO across a given range
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* of the file. The IO should not span ordered extents. If
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* a given ordered_extent is completely done, 1 is returned, otherwise
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* 0.
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*
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* test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
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* to make sure this function only returns 1 once for a given ordered extent.
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*/
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int btrfs_dec_test_ordered_pending(struct inode *inode,
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u64 file_offset, u64 io_size)
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{
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@ -233,9 +244,6 @@ int btrfs_dec_test_ordered_pending(struct inode *inode,
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ret = test_range_bit(io_tree, entry->file_offset,
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entry->file_offset + entry->len - 1,
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EXTENT_ORDERED, 0);
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if (!test_bit(BTRFS_ORDERED_START, &entry->flags)) {
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printk("inode %lu not ready yet for extent %Lu %Lu\n", inode->i_ino, entry->file_offset, entry_end(entry));
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}
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if (ret == 0)
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ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
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out:
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@ -243,6 +251,10 @@ out:
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return ret == 0;
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}
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/*
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* used to drop a reference on an ordered extent. This will free
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* the extent if the last reference is dropped
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*/
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int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
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{
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struct list_head *cur;
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@ -260,6 +272,10 @@ int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
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return 0;
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}
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/*
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* remove an ordered extent from the tree. No references are dropped
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* but, anyone waiting on this extent is woken up.
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*/
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int btrfs_remove_ordered_extent(struct inode *inode,
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struct btrfs_ordered_extent *entry)
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{
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@ -277,27 +293,25 @@ int btrfs_remove_ordered_extent(struct inode *inode,
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return 0;
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}
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void btrfs_wait_ordered_extent(struct inode *inode,
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struct btrfs_ordered_extent *entry)
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{
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u64 start = entry->file_offset;
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u64 end = start + entry->len - 1;
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
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do_sync_file_range(file, start, end, SYNC_FILE_RANGE_WRITE);
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#else
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do_sync_mapping_range(inode->i_mapping, start, end,
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SYNC_FILE_RANGE_WRITE);
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#endif
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wait_event(entry->wait,
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test_bit(BTRFS_ORDERED_COMPLETE, &entry->flags));
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}
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static void btrfs_start_ordered_extent(struct inode *inode,
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struct btrfs_ordered_extent *entry, int wait)
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/*
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* Used to start IO or wait for a given ordered extent to finish.
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*
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* If wait is one, this effectively waits on page writeback for all the pages
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* in the extent, and it waits on the io completion code to insert
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* metadata into the btree corresponding to the extent
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*/
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void btrfs_start_ordered_extent(struct inode *inode,
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struct btrfs_ordered_extent *entry,
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int wait)
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{
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u64 start = entry->file_offset;
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u64 end = start + entry->len - 1;
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/*
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* pages in the range can be dirty, clean or writeback. We
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* start IO on any dirty ones so the wait doesn't stall waiting
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* for pdflush to find them
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*/
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
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do_sync_file_range(file, start, end, SYNC_FILE_RANGE_WRITE);
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#else
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@ -309,6 +323,9 @@ static void btrfs_start_ordered_extent(struct inode *inode,
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&entry->flags));
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}
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/*
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* Used to wait on ordered extents across a large range of bytes.
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*/
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void btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
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{
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u64 end;
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@ -349,31 +366,11 @@ again:
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}
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}
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int btrfs_add_ordered_pending(struct inode *inode,
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struct btrfs_ordered_extent *ordered,
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u64 start, u64 len)
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{
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WARN_ON(1);
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return 0;
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#if 0
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int ret;
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struct btrfs_ordered_inode_tree *tree;
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struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
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tree = &BTRFS_I(inode)->ordered_tree;
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mutex_lock(&tree->mutex);
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if (test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags)) {
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ret = -EAGAIN;
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goto out;
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}
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set_extent_ordered(io_tree, start, start + len - 1, GFP_NOFS);
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ret = 0;
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out:
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mutex_unlock(&tree->mutex);
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return ret;
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#endif
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}
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/*
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* find an ordered extent corresponding to file_offset. return NULL if
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* nothing is found, otherwise take a reference on the extent and return it
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*/
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struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
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u64 file_offset)
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{
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@ -397,6 +394,10 @@ out:
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return entry;
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}
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/*
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* lookup and return any extent before 'file_offset'. NULL is returned
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* if none is found
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*/
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struct btrfs_ordered_extent *
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btrfs_lookup_first_ordered_extent(struct inode * inode, u64 file_offset)
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{
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@ -417,6 +418,10 @@ out:
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return entry;
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}
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/*
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* After an extent is done, call this to conditionally update the on disk
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* i_size. i_size is updated to cover any fully written part of the file.
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*/
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int btrfs_ordered_update_i_size(struct inode *inode,
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struct btrfs_ordered_extent *ordered)
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{
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@ -507,6 +512,11 @@ out:
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return 0;
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}
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/*
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* search the ordered extents for one corresponding to 'offset' and
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* try to find a checksum. This is used because we allow pages to
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* be reclaimed before their checksum is actually put into the btree
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*/
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int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u32 *sum)
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{
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struct btrfs_ordered_sum *ordered_sum;
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@ -19,12 +19,19 @@
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#ifndef __BTRFS_ORDERED_DATA__
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#define __BTRFS_ORDERED_DATA__
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/* one of these per inode */
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struct btrfs_ordered_inode_tree {
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struct mutex mutex;
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struct rb_root tree;
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struct rb_node *last;
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};
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/*
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* these are used to collect checksums done just before bios submission.
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* They are attached via a list into the ordered extent, and
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* checksum items are inserted into the tree after all the blocks in
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* the ordered extent are on disk
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*/
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struct btrfs_sector_sum {
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u64 offset;
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u32 sum;
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@ -34,27 +41,56 @@ struct btrfs_ordered_sum {
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u64 file_offset;
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u64 len;
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struct list_head list;
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/* last field is a variable length array of btrfs_sector_sums */
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struct btrfs_sector_sum sums;
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};
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/* bits for the flags field */
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/*
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* bits for the flags field:
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*
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* BTRFS_ORDERED_IO_DONE is set when all of the blocks are written.
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* It is used to make sure metadata is inserted into the tree only once
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* per extent.
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*
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* BTRFS_ORDERED_COMPLETE is set when the extent is removed from the
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* rbtree, just before waking any waiters. It is used to indicate the
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* IO is done and any metadata is inserted into the tree.
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*/
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#define BTRFS_ORDERED_IO_DONE 0 /* set when all the pages are written */
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#define BTRFS_ORDERED_COMPLETE 1 /* set when removed from the tree */
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#define BTRFS_ORDERED_START 2 /* set when tree setup */
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struct btrfs_ordered_extent {
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/* logical offset in the file */
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u64 file_offset;
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/* disk byte number */
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u64 start;
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/* length of the extent in bytes */
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u64 len;
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/* flags (described above) */
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unsigned long flags;
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/* reference count */
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atomic_t refs;
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/* list of checksums for insertion when the extent io is done */
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struct list_head list;
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struct inode *inode;
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/* used to wait for the BTRFS_ORDERED_COMPLETE bit */
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wait_queue_head_t wait;
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/* our friendly rbtree entry */
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struct rb_node rb_node;
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};
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/*
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* calculates the total size you need to allocate for an ordered sum
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* structure spanning 'bytes' in the file
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*/
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static inline int btrfs_ordered_sum_size(struct btrfs_root *root, u64 bytes)
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{
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unsigned long num_sectors = (bytes + root->sectorsize - 1) /
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@ -81,14 +117,11 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
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int btrfs_add_ordered_sum(struct inode *inode, struct btrfs_ordered_sum *sum);
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struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
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u64 file_offset);
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void btrfs_wait_ordered_extent(struct inode *inode,
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struct btrfs_ordered_extent *entry);
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void btrfs_start_ordered_extent(struct inode *inode,
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struct btrfs_ordered_extent *entry, int wait);
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void btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len);
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struct btrfs_ordered_extent *
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btrfs_lookup_first_ordered_extent(struct inode * inode, u64 file_offset);
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int btrfs_add_ordered_pending(struct inode *inode,
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struct btrfs_ordered_extent *ordered,
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u64 start, u64 len);
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int btrfs_ordered_update_i_size(struct inode *inode,
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struct btrfs_ordered_extent *ordered);
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int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u32 *sum);
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