Provide a splice_read stub for f2fs. This does some checks and tracing before proceeding and will switch from direct-I/O to buffered I/O if forced or if misaligned. It also updates the iostats after doing a buffered I/O.
[Note: I wonder if I should only do the tracing if I call filemap_splice_read() as direct_splice_read() will call f2fs_file_read_iter().] Signed-off-by: David Howells <[email protected]> cc: Christoph Hellwig <[email protected]> cc: Al Viro <[email protected]> cc: Jens Axboe <[email protected]> cc: Jaegeuk Kim <[email protected]> cc: Chao Yu <[email protected]> cc: [email protected] cc: [email protected] cc: [email protected] cc: [email protected] --- fs/f2fs/file.c | 68 ++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 60 insertions(+), 8 deletions(-) diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 5ac53d2627d2..3723387f4a87 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -4367,22 +4367,23 @@ static ssize_t f2fs_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) return ret; } -static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw) +static void f2fs_trace_rw_file_path(struct file *file, loff_t pos, size_t count, + int rw) { - struct inode *inode = file_inode(iocb->ki_filp); + struct inode *inode = file_inode(file); char *buf, *path; buf = f2fs_getname(F2FS_I_SB(inode)); if (!buf) return; - path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX); + path = dentry_path_raw(file_dentry(file), buf, PATH_MAX); if (IS_ERR(path)) goto free_buf; if (rw == WRITE) - trace_f2fs_datawrite_start(inode, iocb->ki_pos, count, + trace_f2fs_datawrite_start(inode, pos, count, current->pid, path, current->comm); else - trace_f2fs_dataread_start(inode, iocb->ki_pos, count, + trace_f2fs_dataread_start(inode, pos, count, current->pid, path, current->comm); free_buf: f2fs_putname(buf); @@ -4398,7 +4399,8 @@ static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) return -EOPNOTSUPP; if (trace_f2fs_dataread_start_enabled()) - f2fs_trace_rw_file_path(iocb, iov_iter_count(to), READ); + f2fs_trace_rw_file_path(iocb->ki_filp, iocb->ki_pos, + iov_iter_count(to), READ); if (f2fs_should_use_dio(inode, iocb, to)) { ret = f2fs_dio_read_iter(iocb, to); @@ -4413,6 +4415,55 @@ static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) return ret; } +static ssize_t f2fs_file_splice_read(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, + size_t len, unsigned int flags) +{ + struct inode *inode = file_inode(in); + const loff_t pos = *ppos; + ssize_t ret; + + if (!f2fs_is_compress_backend_ready(inode)) + return -EOPNOTSUPP; + + if (trace_f2fs_dataread_start_enabled()) + f2fs_trace_rw_file_path(in, pos, len, READ); + + if (in->f_flags & O_DIRECT) { + if (f2fs_force_buffered_io(inode, READ)) + goto buffered; + + /* + * Direct I/O not aligned to the disk's logical_block_size will + * be attempted, but will fail with -EINVAL. + * + * f2fs additionally requires that direct I/O be aligned to the + * filesystem block size, which is often a stricter + * requirement. However, f2fs traditionally falls back to + * buffered I/O on requests that are logical_block_size-aligned + * but not fs-block aligned. + * + * The below logic implements this behavior. + */ + if (!IS_ALIGNED(pos, i_blocksize(inode)) && + IS_ALIGNED(pos, bdev_logical_block_size(inode->i_sb->s_bdev))) + goto buffered; + ret = direct_splice_read(in, ppos, pipe, len, flags); + goto done; + } + +buffered: + ret = filemap_splice_read(in, ppos, pipe, len, flags); + if (ret > 0) + f2fs_update_iostat(F2FS_I_SB(inode), inode, + APP_BUFFERED_READ_IO, ret); + +done: + if (trace_f2fs_dataread_end_enabled()) + trace_f2fs_dataread_end(inode, pos, ret); + return ret; +} + static ssize_t f2fs_write_checks(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; @@ -4714,7 +4765,8 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) ret = preallocated; } else { if (trace_f2fs_datawrite_start_enabled()) - f2fs_trace_rw_file_path(iocb, orig_count, WRITE); + f2fs_trace_rw_file_path(iocb->ki_filp, iocb->ki_pos, + orig_count, WRITE); /* Do the actual write. */ ret = dio ? @@ -4919,7 +4971,7 @@ const struct file_operations f2fs_file_operations = { #ifdef CONFIG_COMPAT .compat_ioctl = f2fs_compat_ioctl, #endif - .splice_read = generic_file_splice_read, + .splice_read = f2fs_file_splice_read, .splice_write = iter_file_splice_write, .fadvise = f2fs_file_fadvise, }; _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
