@@ -8984,12 +8984,16 @@ static ssize_t btrfs_encoded_read_inline(
unsigned long ptr;
void *tmp;
ssize_t ret;
+ bool nowait = iocb->ki_flags & IOCB_NOWAIT;
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
+
+ path->nowait = !!nowait;
+
ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
extent_start, 0);
if (ret) {
@@ -9200,11 +9204,15 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
size_t count = iov_iter_count(iter);
u64 start, lockend;
struct extent_map *em;
+ bool nowait = iocb->ki_flags & IOCB_NOWAIT;
bool unlocked = false;
file_accessed(iocb->ki_filp);
- btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
+ ret = btrfs_inode_lock(inode,
+ BTRFS_ILOCK_SHARED | (nowait ? BTRFS_ILOCK_TRY : 0));
+ if (ret)
+ return ret;
if (iocb->ki_pos >= inode->vfs_inode.i_size) {
btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
@@ -9217,21 +9225,45 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter,
*/
lockend = start + BTRFS_MAX_UNCOMPRESSED - 1;
- for (;;) {
+ if (nowait) {
struct btrfs_ordered_extent *ordered;
- ret = btrfs_wait_ordered_range(inode, start,
- lockend - start + 1);
- if (ret)
+ if (filemap_range_needs_writeback(inode->vfs_inode.i_mapping,
+ start, lockend)) {
+ ret = -EAGAIN;
goto out_unlock_inode;
- lock_extent(io_tree, start, lockend, cached_state);
+ }
+
+ if (!try_lock_extent(io_tree, start, lockend, cached_state)) {
+ ret = -EAGAIN;
+ goto out_unlock_inode;
+ }
+
ordered = btrfs_lookup_ordered_range(inode, start,
lockend - start + 1);
- if (!ordered)
- break;
- btrfs_put_ordered_extent(ordered);
- unlock_extent(io_tree, start, lockend, cached_state);
- cond_resched();
+ if (ordered) {
+ btrfs_put_ordered_extent(ordered);
+ unlock_extent(io_tree, start, lockend, cached_state);
+ ret = -EAGAIN;
+ goto out_unlock_inode;
+ }
+ } else {
+ for (;;) {
+ struct btrfs_ordered_extent *ordered;
+
+ ret = btrfs_wait_ordered_range(inode, start,
+ lockend - start + 1);
+ if (ret)
+ goto out_unlock_inode;
+ lock_extent(io_tree, start, lockend, cached_state);
+ ordered = btrfs_lookup_ordered_range(inode, start,
+ lockend - start + 1);
+ if (!ordered)
+ break;
+ btrfs_put_ordered_extent(ordered);
+ unlock_extent(io_tree, start, lockend, cached_state);
+ cond_resched();
+ }
}
em = btrfs_get_extent(inode, NULL, start, lockend - start + 1);
Change btrfs_encoded_read so that it returns -EAGAIN rather than sleeps if IOCB_NOWAIT is set in iocb->ki_flags. Signed-off-by: Mark Harmstone <maharmstone@fb.com> --- fs/btrfs/inode.c | 54 ++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 11 deletions(-)