| Message ID | 20180920211842.13721-3-longli@linuxonhyperv.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [V3,(resend),1/7] CIFS: pass page offsets on SMB1 read/write | expand |
чт, 20 сент. 2018 г. в 14:22, Long Li <longli@linuxonhyperv.com>: > > From: Long Li <longli@microsoft.com> > > With direct I/O read, we transfer the data directly from transport layer to > the user data buffer. > > Change in v3: add support for kernel AIO > > Signed-off-by: Long Li <longli@microsoft.com> > --- > fs/cifs/cifsfs.h | 1 + > fs/cifs/cifsglob.h | 5 ++ > fs/cifs/file.c | 210 +++++++++++++++++++++++++++++++++++++++++++++-------- > 3 files changed, 187 insertions(+), 29 deletions(-) > > diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h > index f047e87..ed5479c 100644 > --- a/fs/cifs/cifsfs.h > +++ b/fs/cifs/cifsfs.h > @@ -101,6 +101,7 @@ extern int cifs_open(struct inode *inode, struct file *file); > extern int cifs_close(struct inode *inode, struct file *file); > extern int cifs_closedir(struct inode *inode, struct file *file); > extern ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to); > +extern ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to); > extern ssize_t cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to); > extern ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from); > extern ssize_t cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from); > diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h > index 9dcaed0..2131fec 100644 > --- a/fs/cifs/cifsglob.h > +++ b/fs/cifs/cifsglob.h > @@ -1172,6 +1172,11 @@ struct cifs_aio_ctx { > unsigned int len; > unsigned int total_len; > bool should_dirty; > + /* > + * Indicates if this aio_ctx is for direct_io, > + * If yes, iter is a copy of the user passed iov_iter > + */ > + bool direct_io; > }; > > struct cifs_readdata; > diff --git a/fs/cifs/file.c b/fs/cifs/file.c > index 8d41ca7..6a939fa 100644 > --- a/fs/cifs/file.c > +++ b/fs/cifs/file.c > @@ -2965,7 +2965,6 @@ cifs_uncached_readdata_release(struct kref *refcount) > kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release); > for (i = 0; i < rdata->nr_pages; i++) { > put_page(rdata->pages[i]); > - rdata->pages[i] = NULL; why is this needed? > } > cifs_readdata_release(refcount); > } > @@ -3004,7 +3003,7 @@ cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter) > return remaining ? -EFAULT : 0; > } > > -static void collect_uncached_read_data(struct cifs_aio_ctx *ctx); > +static void collect_uncached_read_data(struct cifs_readdata *rdata, struct cifs_aio_ctx *ctx); > > static void > cifs_uncached_readv_complete(struct work_struct *work) > @@ -3013,7 +3012,7 @@ cifs_uncached_readv_complete(struct work_struct *work) > struct cifs_readdata, work); > > complete(&rdata->done); > - collect_uncached_read_data(rdata->ctx); > + collect_uncached_read_data(rdata, rdata->ctx); > /* the below call can possibly free the last ref to aio ctx */ > kref_put(&rdata->refcount, cifs_uncached_readdata_release); > } > @@ -3103,6 +3102,9 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, > int rc; > pid_t pid; > struct TCP_Server_Info *server; > + struct page **pagevec; > + size_t start; > + struct iov_iter direct_iov = ctx->iter; > > server = tlink_tcon(open_file->tlink)->ses->server; > > @@ -3111,6 +3113,9 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, > else > pid = current->tgid; > > + if (ctx->direct_io) > + iov_iter_advance(&direct_iov, offset - ctx->pos); > + > do { > rc = server->ops->wait_mtu_credits(server, cifs_sb->rsize, > &rsize, &credits); > @@ -3118,20 +3123,56 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, > break; > > cur_len = min_t(const size_t, len, rsize); > - npages = DIV_ROUND_UP(cur_len, PAGE_SIZE); > > - /* allocate a readdata struct */ > - rdata = cifs_readdata_alloc(npages, > + if (ctx->direct_io) { > + > + cur_len = iov_iter_get_pages_alloc( > + &direct_iov, &pagevec, > + cur_len, &start); > + if (cur_len < 0) { > + cifs_dbg(VFS, > + "couldn't get user pages (cur_len=%zd)" > + " iter type %d" > + " iov_offset %zd count %zd\n", > + cur_len, direct_iov.type, direct_iov.iov_offset, > + direct_iov.count); > + dump_stack(); > + break; > + } > + iov_iter_advance(&direct_iov, cur_len); > + > + rdata = cifs_readdata_direct_alloc( > + pagevec, cifs_uncached_readv_complete); > + if (!rdata) { > + add_credits_and_wake_if(server, credits, 0); > + rc = -ENOMEM; > + break; > + } > + > + npages = (cur_len + start + PAGE_SIZE-1) / PAGE_SIZE; > + rdata->page_offset = start; > + rdata->tailsz = npages > 1 ? > + cur_len-(PAGE_SIZE-start)-(npages-2)*PAGE_SIZE : > + cur_len; > + > + } else { > + > + npages = DIV_ROUND_UP(cur_len, PAGE_SIZE); > + /* allocate a readdata struct */ > + rdata = cifs_readdata_alloc(npages, > cifs_uncached_readv_complete); > - if (!rdata) { > - add_credits_and_wake_if(server, credits, 0); > - rc = -ENOMEM; > - break; > - } > + if (!rdata) { > + add_credits_and_wake_if(server, credits, 0); > + rc = -ENOMEM; > + break; > + } > > - rc = cifs_read_allocate_pages(rdata, npages); > - if (rc) > - goto error; > + rc = cifs_read_allocate_pages(rdata, npages); > + if (rc) > + goto error; > + > + rdata->tailsz = PAGE_SIZE; > + } > > rdata->cfile = cifsFileInfo_get(open_file); > rdata->nr_pages = npages; > @@ -3139,7 +3180,6 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, > rdata->bytes = cur_len; > rdata->pid = pid; > rdata->pagesz = PAGE_SIZE; > - rdata->tailsz = PAGE_SIZE; > rdata->read_into_pages = cifs_uncached_read_into_pages; > rdata->copy_into_pages = cifs_uncached_copy_into_pages; > rdata->credits = credits; > @@ -3153,13 +3193,17 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, > if (rc) { > add_credits_and_wake_if(server, rdata->credits, 0); > kref_put(&rdata->refcount, > - cifs_uncached_readdata_release); > - if (rc == -EAGAIN) > + cifs_uncached_readdata_release); > + if (rc == -EAGAIN) { > + iov_iter_revert(&direct_iov, cur_len); > continue; > + } > break; > } > > - list_add_tail(&rdata->list, rdata_list); > + /* Add to aio pending list if it's not there */ > + if (rdata_list) > + list_add_tail(&rdata->list, rdata_list); > offset += cur_len; > len -= cur_len; > } while (len > 0); > @@ -3168,7 +3212,7 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, > } > > static void > -collect_uncached_read_data(struct cifs_aio_ctx *ctx) > +collect_uncached_read_data(struct cifs_readdata *uncached_rdata, struct cifs_aio_ctx *ctx) Why do you need uncached_rdata argument? It doesn't seem you are using it in this function. > { > struct cifs_readdata *rdata, *tmp; > struct iov_iter *to = &ctx->iter; > @@ -3211,10 +3255,12 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) > * reading. > */ > if (got_bytes && got_bytes < rdata->bytes) { > - rc = cifs_readdata_to_iov(rdata, to); > + rc = 0; > + if (!ctx->direct_io) > + rc = cifs_readdata_to_iov(rdata, to); > if (rc) { > kref_put(&rdata->refcount, > - cifs_uncached_readdata_release); > + cifs_uncached_readdata_release); > continue; > } > } > @@ -3228,28 +3274,32 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) > list_splice(&tmp_list, &ctx->list); > > kref_put(&rdata->refcount, > - cifs_uncached_readdata_release); > + cifs_uncached_readdata_release); > goto again; > } else if (rdata->result) > rc = rdata->result; > - else > + else if (!ctx->direct_io) > rc = cifs_readdata_to_iov(rdata, to); > > /* if there was a short read -- discard anything left */ > if (rdata->got_bytes && rdata->got_bytes < rdata->bytes) > rc = -ENODATA; > + > + ctx->total_len += rdata->got_bytes; > } > list_del_init(&rdata->list); > kref_put(&rdata->refcount, cifs_uncached_readdata_release); > } > > - for (i = 0; i < ctx->npages; i++) { > - if (ctx->should_dirty) > - set_page_dirty(ctx->bv[i].bv_page); > - put_page(ctx->bv[i].bv_page); > - } > + if (!ctx->direct_io) { > + for (i = 0; i < ctx->npages; i++) { > + if (ctx->should_dirty) > + set_page_dirty(ctx->bv[i].bv_page); > + put_page(ctx->bv[i].bv_page); > + } > > - ctx->total_len = ctx->len - iov_iter_count(to); > + ctx->total_len = ctx->len - iov_iter_count(to); > + } > > cifs_stats_bytes_read(tcon, ctx->total_len); > > @@ -3267,6 +3317,108 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) > complete(&ctx->done); > } > > +ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to) > +{ > + size_t len; > + struct file *file; > + struct cifs_sb_info *cifs_sb; > + struct cifsFileInfo *cfile; > + struct cifs_tcon *tcon; > + ssize_t rc, total_read = 0; > + struct TCP_Server_Info *server; > + loff_t offset = iocb->ki_pos; > + pid_t pid; > + struct cifs_aio_ctx *ctx; > + > + /* > + * iov_iter_get_pages_alloc() doesn't work with ITER_KVEC, > + * fall back to data copy read path > + * this could be improved by getting pages directly in ITER_KVEC > + */ > + if (to->type & ITER_KVEC) { > + cifs_dbg(FYI, "use non-direct cifs_user_readv for kvec I/O\n"); > + return cifs_user_readv(iocb, to); > + } > + > + len = iov_iter_count(to); > + if (!len) > + return 0; > + > + file = iocb->ki_filp; > + cifs_sb = CIFS_FILE_SB(file); > + cfile = file->private_data; > + tcon = tlink_tcon(cfile->tlink); > + server = tcon->ses->server; > + > + if (!server->ops->async_readv) > + return -ENOSYS; > + > + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD) > + pid = cfile->pid; > + else > + pid = current->tgid; > + pid variable is not being used. > + if ((file->f_flags & O_ACCMODE) == O_WRONLY) > + cifs_dbg(FYI, "attempting read on write only file instance\n"); > + > + ctx = cifs_aio_ctx_alloc(); > + if (!ctx) > + return -ENOMEM; > + > + ctx->cfile = cifsFileInfo_get(cfile); > + > + if (!is_sync_kiocb(iocb)) > + ctx->iocb = iocb; > + > + if (to->type == ITER_IOVEC) > + ctx->should_dirty = true; > + > + ctx->pos = offset; > + ctx->direct_io = true; > + ctx->iter = *to; > + ctx->len = len; > + > + /* grab a lock here due to read response handlers can access ctx */ > + mutex_lock(&ctx->aio_mutex); > + > + rc = cifs_send_async_read(offset, len, cfile, cifs_sb, &ctx->list, ctx); > + > + /* if at least one read request send succeeded, then reset rc */ > + if (!list_empty(&ctx->list)) > + rc = 0; > + > + mutex_unlock(&ctx->aio_mutex); > + > + if (rc) { > + kref_put(&ctx->refcount, cifs_aio_ctx_release); > + return rc; > + } > + > + if (!is_sync_kiocb(iocb)) { > + kref_put(&ctx->refcount, cifs_aio_ctx_release); > + return -EIOCBQUEUED; > + } > + > + rc = wait_for_completion_killable(&ctx->done); > + if (rc) { > + mutex_lock(&ctx->aio_mutex); > + ctx->rc = rc = -EINTR; > + total_read = ctx->total_len; > + mutex_unlock(&ctx->aio_mutex); > + } else { > + rc = ctx->rc; > + total_read = ctx->total_len; > + } > + > + kref_put(&ctx->refcount, cifs_aio_ctx_release); > + > + if (total_read) { > + iocb->ki_pos += total_read; > + return total_read; > + } > + return rc; This function is almost identical to cifs_user_readv. Can the latter be refactored to avoid code duplication? > +} > + > ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to) > { > struct file *file = iocb->ki_filp; > -- > 2.7.4 >
> Subject: Re: [PATCH V3 (resend) 3/7] CIFS: Add support for direct I/O read > > чт, 20 сент. 2018 г. в 14:22, Long Li <longli@linuxonhyperv.com>: > > > > From: Long Li <longli@microsoft.com> > > > > With direct I/O read, we transfer the data directly from transport > > layer to the user data buffer. > > > > Change in v3: add support for kernel AIO > > > > Signed-off-by: Long Li <longli@microsoft.com> > > --- > > fs/cifs/cifsfs.h | 1 + > > fs/cifs/cifsglob.h | 5 ++ > > fs/cifs/file.c | 210 > +++++++++++++++++++++++++++++++++++++++++++++-------- > > 3 files changed, 187 insertions(+), 29 deletions(-) > > > > diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h index > > f047e87..ed5479c 100644 > > --- a/fs/cifs/cifsfs.h > > +++ b/fs/cifs/cifsfs.h > > @@ -101,6 +101,7 @@ extern int cifs_open(struct inode *inode, struct > > file *file); extern int cifs_close(struct inode *inode, struct file > > *file); extern int cifs_closedir(struct inode *inode, struct file > > *file); extern ssize_t cifs_user_readv(struct kiocb *iocb, struct > > iov_iter *to); > > +extern ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter > > +*to); > > extern ssize_t cifs_strict_readv(struct kiocb *iocb, struct iov_iter > > *to); extern ssize_t cifs_user_writev(struct kiocb *iocb, struct > > iov_iter *from); extern ssize_t cifs_strict_writev(struct kiocb > > *iocb, struct iov_iter *from); diff --git a/fs/cifs/cifsglob.h > > b/fs/cifs/cifsglob.h index 9dcaed0..2131fec 100644 > > --- a/fs/cifs/cifsglob.h > > +++ b/fs/cifs/cifsglob.h > > @@ -1172,6 +1172,11 @@ struct cifs_aio_ctx { > > unsigned int len; > > unsigned int total_len; > > bool should_dirty; > > + /* > > + * Indicates if this aio_ctx is for direct_io, > > + * If yes, iter is a copy of the user passed iov_iter > > + */ > > + bool direct_io; > > }; > > > > struct cifs_readdata; > > diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 8d41ca7..6a939fa > > 100644 > > --- a/fs/cifs/file.c > > +++ b/fs/cifs/file.c > > @@ -2965,7 +2965,6 @@ cifs_uncached_readdata_release(struct kref > *refcount) > > kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release); > > for (i = 0; i < rdata->nr_pages; i++) { > > put_page(rdata->pages[i]); > > - rdata->pages[i] = NULL; > > why is this needed? It is not needed. But there is no need to set pages[i] to NULL, so just remove this. > > > } > > cifs_readdata_release(refcount); } @@ -3004,7 +3003,7 @@ > > cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter) > > return remaining ? -EFAULT : 0; } > > > > -static void collect_uncached_read_data(struct cifs_aio_ctx *ctx); > > +static void collect_uncached_read_data(struct cifs_readdata *rdata, > > +struct cifs_aio_ctx *ctx); > > > > static void > > cifs_uncached_readv_complete(struct work_struct *work) @@ -3013,7 > > +3012,7 @@ cifs_uncached_readv_complete(struct work_struct *work) > > struct cifs_readdata, > > work); > > > > complete(&rdata->done); > > - collect_uncached_read_data(rdata->ctx); > > + collect_uncached_read_data(rdata, rdata->ctx); > > /* the below call can possibly free the last ref to aio ctx */ > > kref_put(&rdata->refcount, cifs_uncached_readdata_release); } > > @@ -3103,6 +3102,9 @@ cifs_send_async_read(loff_t offset, size_t len, > struct cifsFileInfo *open_file, > > int rc; > > pid_t pid; > > struct TCP_Server_Info *server; > > + struct page **pagevec; > > + size_t start; > > + struct iov_iter direct_iov = ctx->iter; > > > > server = tlink_tcon(open_file->tlink)->ses->server; > > > > @@ -3111,6 +3113,9 @@ cifs_send_async_read(loff_t offset, size_t len, > struct cifsFileInfo *open_file, > > else > > pid = current->tgid; > > > > + if (ctx->direct_io) > > + iov_iter_advance(&direct_iov, offset - ctx->pos); > > + > > do { > > rc = server->ops->wait_mtu_credits(server, cifs_sb->rsize, > > &rsize, &credits); > > @@ -3118,20 +3123,56 @@ cifs_send_async_read(loff_t offset, size_t len, > struct cifsFileInfo *open_file, > > break; > > > > cur_len = min_t(const size_t, len, rsize); > > - npages = DIV_ROUND_UP(cur_len, PAGE_SIZE); > > > > - /* allocate a readdata struct */ > > - rdata = cifs_readdata_alloc(npages, > > + if (ctx->direct_io) { > > + > > + cur_len = iov_iter_get_pages_alloc( > > + &direct_iov, &pagevec, > > + cur_len, &start); > > + if (cur_len < 0) { > > + cifs_dbg(VFS, > > + "couldn't get user pages (cur_len=%zd)" > > + " iter type %d" > > + " iov_offset %zd count %zd\n", > > + cur_len, direct_iov.type, direct_iov.iov_offset, > > + direct_iov.count); > > + dump_stack(); > > + break; > > + } > > + iov_iter_advance(&direct_iov, cur_len); > > + > > + rdata = cifs_readdata_direct_alloc( > > + pagevec, cifs_uncached_readv_complete); > > + if (!rdata) { > > + add_credits_and_wake_if(server, credits, 0); > > + rc = -ENOMEM; > > + break; > > + } > > + > > + npages = (cur_len + start + PAGE_SIZE-1) / PAGE_SIZE; > > + rdata->page_offset = start; > > + rdata->tailsz = npages > 1 ? > > + cur_len-(PAGE_SIZE-start)-(npages-2)*PAGE_SIZE : > > + cur_len; > > + > > + } else { > > + > > + npages = DIV_ROUND_UP(cur_len, PAGE_SIZE); > > + /* allocate a readdata struct */ > > + rdata = cifs_readdata_alloc(npages, > > cifs_uncached_readv_complete); > > - if (!rdata) { > > - add_credits_and_wake_if(server, credits, 0); > > - rc = -ENOMEM; > > - break; > > - } > > + if (!rdata) { > > + add_credits_and_wake_if(server, credits, 0); > > + rc = -ENOMEM; > > + break; > > + } > > > > - rc = cifs_read_allocate_pages(rdata, npages); > > - if (rc) > > - goto error; > > + rc = cifs_read_allocate_pages(rdata, npages); > > + if (rc) > > + goto error; > > + > > + rdata->tailsz = PAGE_SIZE; > > + } > > > > rdata->cfile = cifsFileInfo_get(open_file); > > rdata->nr_pages = npages; @@ -3139,7 +3180,6 @@ > > cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo > *open_file, > > rdata->bytes = cur_len; > > rdata->pid = pid; > > rdata->pagesz = PAGE_SIZE; > > - rdata->tailsz = PAGE_SIZE; > > rdata->read_into_pages = cifs_uncached_read_into_pages; > > rdata->copy_into_pages = cifs_uncached_copy_into_pages; > > rdata->credits = credits; @@ -3153,13 +3193,17 @@ > > cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo > *open_file, > > if (rc) { > > add_credits_and_wake_if(server, rdata->credits, 0); > > kref_put(&rdata->refcount, > > - cifs_uncached_readdata_release); > > - if (rc == -EAGAIN) > > + cifs_uncached_readdata_release); > > + if (rc == -EAGAIN) { > > + iov_iter_revert(&direct_iov, cur_len); > > continue; > > + } > > break; > > } > > > > - list_add_tail(&rdata->list, rdata_list); > > + /* Add to aio pending list if it's not there */ > > + if (rdata_list) > > + list_add_tail(&rdata->list, rdata_list); > > offset += cur_len; > > len -= cur_len; > > } while (len > 0); > > @@ -3168,7 +3212,7 @@ cifs_send_async_read(loff_t offset, size_t len, > > struct cifsFileInfo *open_file, } > > > > static void > > -collect_uncached_read_data(struct cifs_aio_ctx *ctx) > > +collect_uncached_read_data(struct cifs_readdata *uncached_rdata, > > +struct cifs_aio_ctx *ctx) > > Why do you need uncached_rdata argument? It doesn't seem you are using > it in this function. My bad. I will remove it. > > > { > > struct cifs_readdata *rdata, *tmp; > > struct iov_iter *to = &ctx->iter; @@ -3211,10 +3255,12 @@ > > collect_uncached_read_data(struct cifs_aio_ctx *ctx) > > * reading. > > */ > > if (got_bytes && got_bytes < rdata->bytes) { > > - rc = cifs_readdata_to_iov(rdata, to); > > + rc = 0; > > + if (!ctx->direct_io) > > + rc = > > + cifs_readdata_to_iov(rdata, to); > > if (rc) { > > kref_put(&rdata->refcount, > > - cifs_uncached_readdata_release); > > + > > + cifs_uncached_readdata_release); > > continue; > > } > > } > > @@ -3228,28 +3274,32 @@ collect_uncached_read_data(struct > cifs_aio_ctx *ctx) > > list_splice(&tmp_list, &ctx->list); > > > > kref_put(&rdata->refcount, > > - cifs_uncached_readdata_release); > > + > > + cifs_uncached_readdata_release); > > goto again; > > } else if (rdata->result) > > rc = rdata->result; > > - else > > + else if (!ctx->direct_io) > > rc = cifs_readdata_to_iov(rdata, to); > > > > /* if there was a short read -- discard anything left */ > > if (rdata->got_bytes && rdata->got_bytes < rdata->bytes) > > rc = -ENODATA; > > + > > + ctx->total_len += rdata->got_bytes; > > } > > list_del_init(&rdata->list); > > kref_put(&rdata->refcount, cifs_uncached_readdata_release); > > } > > > > - for (i = 0; i < ctx->npages; i++) { > > - if (ctx->should_dirty) > > - set_page_dirty(ctx->bv[i].bv_page); > > - put_page(ctx->bv[i].bv_page); > > - } > > + if (!ctx->direct_io) { > > + for (i = 0; i < ctx->npages; i++) { > > + if (ctx->should_dirty) > > + set_page_dirty(ctx->bv[i].bv_page); > > + put_page(ctx->bv[i].bv_page); > > + } > > > > - ctx->total_len = ctx->len - iov_iter_count(to); > > + ctx->total_len = ctx->len - iov_iter_count(to); > > + } > > > > cifs_stats_bytes_read(tcon, ctx->total_len); > > > > @@ -3267,6 +3317,108 @@ collect_uncached_read_data(struct > cifs_aio_ctx *ctx) > > complete(&ctx->done); > > } > > > > +ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to) { > > + size_t len; > > + struct file *file; > > + struct cifs_sb_info *cifs_sb; > > + struct cifsFileInfo *cfile; > > + struct cifs_tcon *tcon; > > + ssize_t rc, total_read = 0; > > + struct TCP_Server_Info *server; > > + loff_t offset = iocb->ki_pos; > > + pid_t pid; > > + struct cifs_aio_ctx *ctx; > > + > > + /* > > + * iov_iter_get_pages_alloc() doesn't work with ITER_KVEC, > > + * fall back to data copy read path > > + * this could be improved by getting pages directly in ITER_KVEC > > + */ > > + if (to->type & ITER_KVEC) { > > + cifs_dbg(FYI, "use non-direct cifs_user_readv for kvec I/O\n"); > > + return cifs_user_readv(iocb, to); > > + } > > + > > + len = iov_iter_count(to); > > + if (!len) > > + return 0; > > + > > + file = iocb->ki_filp; > > + cifs_sb = CIFS_FILE_SB(file); > > + cfile = file->private_data; > > + tcon = tlink_tcon(cfile->tlink); > > + server = tcon->ses->server; > > + > > + if (!server->ops->async_readv) > > + return -ENOSYS; > > + > > + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD) > > + pid = cfile->pid; > > + else > > + pid = current->tgid; > > + > > pid variable is not being used. I will remove it. > > > + if ((file->f_flags & O_ACCMODE) == O_WRONLY) > > + cifs_dbg(FYI, "attempting read on write only file > > + instance\n"); > > + > > + ctx = cifs_aio_ctx_alloc(); > > + if (!ctx) > > + return -ENOMEM; > > + > > + ctx->cfile = cifsFileInfo_get(cfile); > > + > > + if (!is_sync_kiocb(iocb)) > > + ctx->iocb = iocb; > > + > > + if (to->type == ITER_IOVEC) > > + ctx->should_dirty = true; > > + > > + ctx->pos = offset; > > + ctx->direct_io = true; > > + ctx->iter = *to; > > + ctx->len = len; > > + > > + /* grab a lock here due to read response handlers can access ctx */ > > + mutex_lock(&ctx->aio_mutex); > > + > > + rc = cifs_send_async_read(offset, len, cfile, cifs_sb, > > + &ctx->list, ctx); > > + > > + /* if at least one read request send succeeded, then reset rc */ > > + if (!list_empty(&ctx->list)) > > + rc = 0; > > + > > + mutex_unlock(&ctx->aio_mutex); > > + > > + if (rc) { > > + kref_put(&ctx->refcount, cifs_aio_ctx_release); > > + return rc; > > + } > > + > > + if (!is_sync_kiocb(iocb)) { > > + kref_put(&ctx->refcount, cifs_aio_ctx_release); > > + return -EIOCBQUEUED; > > + } > > + > > + rc = wait_for_completion_killable(&ctx->done); > > + if (rc) { > > + mutex_lock(&ctx->aio_mutex); > > + ctx->rc = rc = -EINTR; > > + total_read = ctx->total_len; > > + mutex_unlock(&ctx->aio_mutex); > > + } else { > > + rc = ctx->rc; > > + total_read = ctx->total_len; > > + } > > + > > + kref_put(&ctx->refcount, cifs_aio_ctx_release); > > + > > + if (total_read) { > > + iocb->ki_pos += total_read; > > + return total_read; > > + } > > + return rc; > > This function is almost identical to cifs_user_readv. Can the latter be > refactored to avoid code duplication? I was thinking about the same thing. I will merge them into one function. > > > +} > > + > > ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to) { > > struct file *file = iocb->ki_filp; > > -- > > 2.7.4 > >
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h index f047e87..ed5479c 100644 --- a/fs/cifs/cifsfs.h +++ b/fs/cifs/cifsfs.h @@ -101,6 +101,7 @@ extern int cifs_open(struct inode *inode, struct file *file); extern int cifs_close(struct inode *inode, struct file *file); extern int cifs_closedir(struct inode *inode, struct file *file); extern ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to); +extern ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to); extern ssize_t cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to); extern ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from); extern ssize_t cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from); diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 9dcaed0..2131fec 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1172,6 +1172,11 @@ struct cifs_aio_ctx { unsigned int len; unsigned int total_len; bool should_dirty; + /* + * Indicates if this aio_ctx is for direct_io, + * If yes, iter is a copy of the user passed iov_iter + */ + bool direct_io; }; struct cifs_readdata; diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 8d41ca7..6a939fa 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2965,7 +2965,6 @@ cifs_uncached_readdata_release(struct kref *refcount) kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release); for (i = 0; i < rdata->nr_pages; i++) { put_page(rdata->pages[i]); - rdata->pages[i] = NULL; } cifs_readdata_release(refcount); } @@ -3004,7 +3003,7 @@ cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter) return remaining ? -EFAULT : 0; } -static void collect_uncached_read_data(struct cifs_aio_ctx *ctx); +static void collect_uncached_read_data(struct cifs_readdata *rdata, struct cifs_aio_ctx *ctx); static void cifs_uncached_readv_complete(struct work_struct *work) @@ -3013,7 +3012,7 @@ cifs_uncached_readv_complete(struct work_struct *work) struct cifs_readdata, work); complete(&rdata->done); - collect_uncached_read_data(rdata->ctx); + collect_uncached_read_data(rdata, rdata->ctx); /* the below call can possibly free the last ref to aio ctx */ kref_put(&rdata->refcount, cifs_uncached_readdata_release); } @@ -3103,6 +3102,9 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, int rc; pid_t pid; struct TCP_Server_Info *server; + struct page **pagevec; + size_t start; + struct iov_iter direct_iov = ctx->iter; server = tlink_tcon(open_file->tlink)->ses->server; @@ -3111,6 +3113,9 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, else pid = current->tgid; + if (ctx->direct_io) + iov_iter_advance(&direct_iov, offset - ctx->pos); + do { rc = server->ops->wait_mtu_credits(server, cifs_sb->rsize, &rsize, &credits); @@ -3118,20 +3123,56 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, break; cur_len = min_t(const size_t, len, rsize); - npages = DIV_ROUND_UP(cur_len, PAGE_SIZE); - /* allocate a readdata struct */ - rdata = cifs_readdata_alloc(npages, + if (ctx->direct_io) { + + cur_len = iov_iter_get_pages_alloc( + &direct_iov, &pagevec, + cur_len, &start); + if (cur_len < 0) { + cifs_dbg(VFS, + "couldn't get user pages (cur_len=%zd)" + " iter type %d" + " iov_offset %zd count %zd\n", + cur_len, direct_iov.type, direct_iov.iov_offset, + direct_iov.count); + dump_stack(); + break; + } + iov_iter_advance(&direct_iov, cur_len); + + rdata = cifs_readdata_direct_alloc( + pagevec, cifs_uncached_readv_complete); + if (!rdata) { + add_credits_and_wake_if(server, credits, 0); + rc = -ENOMEM; + break; + } + + npages = (cur_len + start + PAGE_SIZE-1) / PAGE_SIZE; + rdata->page_offset = start; + rdata->tailsz = npages > 1 ? + cur_len-(PAGE_SIZE-start)-(npages-2)*PAGE_SIZE : + cur_len; + + } else { + + npages = DIV_ROUND_UP(cur_len, PAGE_SIZE); + /* allocate a readdata struct */ + rdata = cifs_readdata_alloc(npages, cifs_uncached_readv_complete); - if (!rdata) { - add_credits_and_wake_if(server, credits, 0); - rc = -ENOMEM; - break; - } + if (!rdata) { + add_credits_and_wake_if(server, credits, 0); + rc = -ENOMEM; + break; + } - rc = cifs_read_allocate_pages(rdata, npages); - if (rc) - goto error; + rc = cifs_read_allocate_pages(rdata, npages); + if (rc) + goto error; + + rdata->tailsz = PAGE_SIZE; + } rdata->cfile = cifsFileInfo_get(open_file); rdata->nr_pages = npages; @@ -3139,7 +3180,6 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, rdata->bytes = cur_len; rdata->pid = pid; rdata->pagesz = PAGE_SIZE; - rdata->tailsz = PAGE_SIZE; rdata->read_into_pages = cifs_uncached_read_into_pages; rdata->copy_into_pages = cifs_uncached_copy_into_pages; rdata->credits = credits; @@ -3153,13 +3193,17 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, if (rc) { add_credits_and_wake_if(server, rdata->credits, 0); kref_put(&rdata->refcount, - cifs_uncached_readdata_release); - if (rc == -EAGAIN) + cifs_uncached_readdata_release); + if (rc == -EAGAIN) { + iov_iter_revert(&direct_iov, cur_len); continue; + } break; } - list_add_tail(&rdata->list, rdata_list); + /* Add to aio pending list if it's not there */ + if (rdata_list) + list_add_tail(&rdata->list, rdata_list); offset += cur_len; len -= cur_len; } while (len > 0); @@ -3168,7 +3212,7 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file, } static void -collect_uncached_read_data(struct cifs_aio_ctx *ctx) +collect_uncached_read_data(struct cifs_readdata *uncached_rdata, struct cifs_aio_ctx *ctx) { struct cifs_readdata *rdata, *tmp; struct iov_iter *to = &ctx->iter; @@ -3211,10 +3255,12 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) * reading. */ if (got_bytes && got_bytes < rdata->bytes) { - rc = cifs_readdata_to_iov(rdata, to); + rc = 0; + if (!ctx->direct_io) + rc = cifs_readdata_to_iov(rdata, to); if (rc) { kref_put(&rdata->refcount, - cifs_uncached_readdata_release); + cifs_uncached_readdata_release); continue; } } @@ -3228,28 +3274,32 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) list_splice(&tmp_list, &ctx->list); kref_put(&rdata->refcount, - cifs_uncached_readdata_release); + cifs_uncached_readdata_release); goto again; } else if (rdata->result) rc = rdata->result; - else + else if (!ctx->direct_io) rc = cifs_readdata_to_iov(rdata, to); /* if there was a short read -- discard anything left */ if (rdata->got_bytes && rdata->got_bytes < rdata->bytes) rc = -ENODATA; + + ctx->total_len += rdata->got_bytes; } list_del_init(&rdata->list); kref_put(&rdata->refcount, cifs_uncached_readdata_release); } - for (i = 0; i < ctx->npages; i++) { - if (ctx->should_dirty) - set_page_dirty(ctx->bv[i].bv_page); - put_page(ctx->bv[i].bv_page); - } + if (!ctx->direct_io) { + for (i = 0; i < ctx->npages; i++) { + if (ctx->should_dirty) + set_page_dirty(ctx->bv[i].bv_page); + put_page(ctx->bv[i].bv_page); + } - ctx->total_len = ctx->len - iov_iter_count(to); + ctx->total_len = ctx->len - iov_iter_count(to); + } cifs_stats_bytes_read(tcon, ctx->total_len); @@ -3267,6 +3317,108 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx) complete(&ctx->done); } +ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to) +{ + size_t len; + struct file *file; + struct cifs_sb_info *cifs_sb; + struct cifsFileInfo *cfile; + struct cifs_tcon *tcon; + ssize_t rc, total_read = 0; + struct TCP_Server_Info *server; + loff_t offset = iocb->ki_pos; + pid_t pid; + struct cifs_aio_ctx *ctx; + + /* + * iov_iter_get_pages_alloc() doesn't work with ITER_KVEC, + * fall back to data copy read path + * this could be improved by getting pages directly in ITER_KVEC + */ + if (to->type & ITER_KVEC) { + cifs_dbg(FYI, "use non-direct cifs_user_readv for kvec I/O\n"); + return cifs_user_readv(iocb, to); + } + + len = iov_iter_count(to); + if (!len) + return 0; + + file = iocb->ki_filp; + cifs_sb = CIFS_FILE_SB(file); + cfile = file->private_data; + tcon = tlink_tcon(cfile->tlink); + server = tcon->ses->server; + + if (!server->ops->async_readv) + return -ENOSYS; + + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD) + pid = cfile->pid; + else + pid = current->tgid; + + if ((file->f_flags & O_ACCMODE) == O_WRONLY) + cifs_dbg(FYI, "attempting read on write only file instance\n"); + + ctx = cifs_aio_ctx_alloc(); + if (!ctx) + return -ENOMEM; + + ctx->cfile = cifsFileInfo_get(cfile); + + if (!is_sync_kiocb(iocb)) + ctx->iocb = iocb; + + if (to->type == ITER_IOVEC) + ctx->should_dirty = true; + + ctx->pos = offset; + ctx->direct_io = true; + ctx->iter = *to; + ctx->len = len; + + /* grab a lock here due to read response handlers can access ctx */ + mutex_lock(&ctx->aio_mutex); + + rc = cifs_send_async_read(offset, len, cfile, cifs_sb, &ctx->list, ctx); + + /* if at least one read request send succeeded, then reset rc */ + if (!list_empty(&ctx->list)) + rc = 0; + + mutex_unlock(&ctx->aio_mutex); + + if (rc) { + kref_put(&ctx->refcount, cifs_aio_ctx_release); + return rc; + } + + if (!is_sync_kiocb(iocb)) { + kref_put(&ctx->refcount, cifs_aio_ctx_release); + return -EIOCBQUEUED; + } + + rc = wait_for_completion_killable(&ctx->done); + if (rc) { + mutex_lock(&ctx->aio_mutex); + ctx->rc = rc = -EINTR; + total_read = ctx->total_len; + mutex_unlock(&ctx->aio_mutex); + } else { + rc = ctx->rc; + total_read = ctx->total_len; + } + + kref_put(&ctx->refcount, cifs_aio_ctx_release); + + if (total_read) { + iocb->ki_pos += total_read; + return total_read; + } + return rc; +} + ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to) { struct file *file = iocb->ki_filp;