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