Btrfs: O_DIRECT writes via buffered writes + invaldiate
This reworks the btrfs O_DIRECT write code a bit. It had always fallen
back to buffered IO and done an invalidate, but needed to be updated
for the data=ordered code. The invalidate wasn't actually removing pages
because they were still inside an ordered extent.
This also combines the O_DIRECT/O_SYNC paths where possible, and kicks
off IO in the main btrfs_file_write loop to keep the pipe down the the
disk full as we process long writes.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 3088a11..a03d1bb 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -905,6 +905,10 @@
struct page *pinned[2];
unsigned long first_index;
unsigned long last_index;
+ int will_write;
+
+ will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
+ (file->f_flags & O_DIRECT));
nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
PAGE_CACHE_SIZE / (sizeof(struct page *)));
@@ -1001,15 +1005,24 @@
if (ret)
goto out;
+ if (will_write) {
+ btrfs_fdatawrite_range(inode->i_mapping, pos,
+ pos + write_bytes - 1,
+ WB_SYNC_NONE);
+ } else {
+ balance_dirty_pages_ratelimited_nr(inode->i_mapping,
+ num_pages);
+ if (num_pages <
+ (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
+ btrfs_btree_balance_dirty(root, 1);
+ btrfs_throttle(root);
+ }
+
buf += write_bytes;
count -= write_bytes;
pos += write_bytes;
num_written += write_bytes;
- balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
- if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
- btrfs_btree_balance_dirty(root, 1);
- btrfs_throttle(root);
cond_resched();
}
out:
@@ -1023,36 +1036,29 @@
page_cache_release(pinned[1]);
*ppos = pos;
- if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+ if (num_written > 0 && will_write) {
struct btrfs_trans_handle *trans;
- err = btrfs_fdatawrite_range(inode->i_mapping, start_pos,
- start_pos + num_written -1,
- WB_SYNC_NONE);
- if (err < 0)
+ err = btrfs_wait_ordered_range(inode, start_pos, num_written);
+ if (err)
num_written = err;
- err = btrfs_wait_on_page_writeback_range(inode->i_mapping,
- start_pos, start_pos + num_written - 1);
- if (err < 0)
- num_written = err;
-
- trans = btrfs_start_transaction(root, 1);
- ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
- if (ret == 0) {
- btrfs_sync_log(trans, root);
- btrfs_end_transaction(trans, root);
- } else {
- btrfs_commit_transaction(trans, root);
+ if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
+ trans = btrfs_start_transaction(root, 1);
+ ret = btrfs_log_dentry_safe(trans, root,
+ file->f_dentry);
+ if (ret == 0) {
+ btrfs_sync_log(trans, root);
+ btrfs_end_transaction(trans, root);
+ } else {
+ btrfs_commit_transaction(trans, root);
+ }
}
- } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
- do_sync_mapping_range(inode->i_mapping, start_pos,
- start_pos + num_written - 1,
- SYNC_FILE_RANGE_WRITE |
- SYNC_FILE_RANGE_WAIT_AFTER);
- invalidate_mapping_pages(inode->i_mapping,
- start_pos >> PAGE_CACHE_SHIFT,
- (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
+ if (file->f_flags & O_DIRECT) {
+ invalidate_mapping_pages(inode->i_mapping,
+ start_pos >> PAGE_CACHE_SHIFT,
+ (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
+ }
}
current->backing_dev_info = NULL;
return num_written ? num_written : err;
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index dcc1730..2eb6cab 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -397,7 +397,7 @@
/*
* Used to wait on ordered extents across a large range of bytes.
*/
-void btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
+int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
{
u64 end;
u64 orig_end;
@@ -451,6 +451,7 @@
(unsigned long long)orig_end);
goto again;
}
+ return 0;
}
/*
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index fd45519..f50f887 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -135,7 +135,7 @@
u64 file_offset);
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);
+int 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_ordered_update_i_size(struct inode *inode,