Implement unaligned read support for fuse.

diff --git a/cmd_fusemount.c b/cmd_fusemount.c
index 6460e7b9612a90778879090d09c40fdcf37b4c7b..059583c80ce313d57d766381d4ff99da7c054cf9 100644 (file)
--- a/cmd_fusemount.c
+++ b/cmd_fusemount.c
@@ -377,39 +377,25 @@ static void bcachefs_fuse_read_endio(struct bio *bio)
        closure_put(bio->bi_private);
 }
 
-static void bcachefs_fuse_read(fuse_req_t req, fuse_ino_t inum,
-                              size_t size, off_t offset,
-                              struct fuse_file_info *fi)
+static int read_aligned(struct bch_fs *c, fuse_ino_t inum, size_t aligned_size,
+                       off_t aligned_offset, void *buf)
 {
-       struct bch_fs *c = fuse_req_userdata(req);
-
-       if ((size|offset) & (block_bytes(c) - 1)) {
-               fuse_log(FUSE_LOG_DEBUG,
-                        "bcachefs_fuse_read: unaligned io not supported.\n");
-               fuse_reply_err(req, EINVAL);
-               return;
-       }
+       BUG_ON(aligned_size & (block_bytes(c) - 1));
+       BUG_ON(aligned_offset & (block_bytes(c) - 1));
 
        struct bch_io_opts io_opts;
-       if (get_inode_io_opts(c, inum, &io_opts)) {
-               fuse_reply_err(req, ENOENT);
-               return;
-       }
-
-       void *buf = aligned_alloc(max(PAGE_SIZE, size), size);
-       if (!buf) {
-               fuse_reply_err(req, ENOMEM);
-               return;
-       }
+       if (get_inode_io_opts(c, inum, &io_opts))
+               return -ENOENT;
 
-       struct bch_read_bio     rbio;
-       struct bio_vec          bv;
-       struct closure          cl;
+       struct bch_read_bio rbio;
+       struct bio_vec bv;
+       userbio_init(&rbio.bio, &bv, buf, aligned_size);
+       bio_set_op_attrs(&rbio.bio, REQ_OP_READ, REQ_SYNC);
+       rbio.bio.bi_iter.bi_sector      = aligned_offset >> 9;
 
+       struct closure cl;
        closure_init_stack(&cl);
-       userbio_init(&rbio.bio, &bv, buf, size);
-       bio_set_op_attrs(&rbio.bio, REQ_OP_READ, REQ_SYNC);
-       rbio.bio.bi_iter.bi_sector      = offset >> 9;
+
        closure_get(&cl);
        rbio.bio.bi_end_io              = bcachefs_fuse_read_endio;
        rbio.bio.bi_private             = &cl;
@@ -418,12 +404,37 @@ static void bcachefs_fuse_read(fuse_req_t req, fuse_ino_t inum,
 
        closure_sync(&cl);
 
-       if (likely(!rbio.bio.bi_status)) {
-               fuse_reply_buf(req, buf, size);
-       } else {
-               fuse_reply_err(req, -blk_status_to_errno(rbio.bio.bi_status));
+       return -blk_status_to_errno(rbio.bio.bi_status);
+}
+
+static void bcachefs_fuse_read(fuse_req_t req, fuse_ino_t inum,
+                              size_t size, off_t offset,
+                              struct fuse_file_info *fi)
+{
+       struct bch_fs *c = fuse_req_userdata(req);
+
+       /* Handle unaligned start and end */
+       /* TODO: align to block_bytes, sector size, or page size? */
+       BUG_ON(offset < 0);
+       off_t aligned_start = round_down(offset, block_bytes(c));
+       unsigned aligned_offset = offset - aligned_start;
+
+       off_t aligned_end = round_up(offset + size, block_bytes(c));
+       size_t aligned_size = aligned_end - aligned_start;
+
+       void *buf = aligned_alloc(PAGE_SIZE, aligned_size);
+       if (!buf) {
+               fuse_reply_err(req, ENOMEM);
+               return;
        }
 
+       int ret = read_aligned(c, inum, aligned_size, aligned_start, buf);
+
+       if (likely(!ret))
+               fuse_reply_buf(req, buf + aligned_offset, size);
+       else
+               fuse_reply_err(req, -ret);
+
        free(buf);
 }