Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs updates from Al Viro:
 "This the bunch that sat in -next + lock_parent() fix.  This is the
  minimal set; there's more pending stuff.

  In particular, I really hope to get acct.c fixes merged this cycle -
  we need that to deal sanely with delayed-mntput stuff.  In the next
  pile, hopefully - that series is fairly short and localized
  (kernel/acct.c, fs/super.c and fs/namespace.c).  In this pile: more
  iov_iter work.  Most of prereqs for ->splice_write with sane locking
  order are there and Kent's dio rewrite would also fit nicely on top of
  this pile"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits)
  lock_parent: don't step on stale ->d_parent of all-but-freed one
  kill generic_file_splice_write()
  ceph: switch to iter_file_splice_write()
  shmem: switch to iter_file_splice_write()
  nfs: switch to iter_splice_write_file()
  fs/splice.c: remove unneeded exports
  ocfs2: switch to iter_file_splice_write()
  ->splice_write() via ->write_iter()
  bio_vec-backed iov_iter
  optimize copy_page_{to,from}_iter()
  bury generic_file_aio_{read,write}
  lustre: get rid of messing with iovecs
  ceph: switch to ->write_iter()
  ceph_sync_direct_write: stop poking into iov_iter guts
  ceph_sync_read: stop poking into iov_iter guts
  new helper: copy_page_from_iter()
  fuse: switch to ->write_iter()
  btrfs: switch to ->write_iter()
  ocfs2: switch to ->write_iter()
  xfs: switch to ->write_iter()
  ...

3 files changed, 69 insertions, 98 deletions

diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index 13b691a8a7d2..966ace8b243f 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -94,8 +94,10 @@ static ssize_t cuse_read(struct file *file, char __user *buf, size_t count,
         loff_t pos = 0;
         struct iovec iov = { .iov_base = buf, .iov_len = count };
         struct fuse_io_priv io = { .async = 0, .file = file };
+        struct iov_iter ii;
+        iov_iter_init(&ii, READ, &iov, 1, count);
 
-        return fuse_direct_io(&io, &iov, 1, count, &pos, FUSE_DIO_CUSE);
+        return fuse_direct_io(&io, &ii, &pos, FUSE_DIO_CUSE);
 }
 
 static ssize_t cuse_write(struct file *file, const char __user *buf,
@@ -104,12 +106,14 @@ static ssize_t cuse_write(struct file *file, const char __user *buf,
         loff_t pos = 0;
         struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
         struct fuse_io_priv io = { .async = 0, .file = file };
+        struct iov_iter ii;
+        iov_iter_init(&ii, WRITE, &iov, 1, count);
 
         /*
          * No locking or generic_write_checks(), the server is
          * responsible for locking and sanity checks.
          */
-        return fuse_direct_io(&io, &iov, 1, count, &pos,
+        return fuse_direct_io(&io, &ii, &pos,
                               FUSE_DIO_WRITE | FUSE_DIO_CUSE);
 }
 
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 903cbc9cd6bd..6e16dad13e9b 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -933,8 +933,7 @@ out:
         return err;
 }
 
-static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
-                                  unsigned long nr_segs, loff_t pos)
+static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
         struct inode *inode = iocb->ki_filp->f_mapping->host;
         struct fuse_conn *fc = get_fuse_conn(inode);
@@ -945,14 +944,14 @@ static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
          * i_size is up to date).
          */
         if (fc->auto_inval_data ||
-            (pos + iov_length(iov, nr_segs) > i_size_read(inode))) {
+            (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
                 int err;
                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
                 if (err)
                         return err;
         }
 
-        return generic_file_aio_read(iocb, iov, nr_segs, pos);
+        return generic_file_read_iter(iocb, to);
 }
 
 static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
@@ -1181,19 +1180,17 @@ static ssize_t fuse_perform_write(struct file *file,
         return res > 0 ? res : err;
 }
 
-static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
-                                   unsigned long nr_segs, loff_t pos)
+static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
         struct file *file = iocb->ki_filp;
         struct address_space *mapping = file->f_mapping;
-        size_t count = 0;
-        size_t ocount = 0;
+        size_t count = iov_iter_count(from);
         ssize_t written = 0;
         ssize_t written_buffered = 0;
         struct inode *inode = mapping->host;
         ssize_t err;
-        struct iov_iter i;
         loff_t endbyte = 0;
+        loff_t pos = iocb->ki_pos;
 
         if (get_fuse_conn(inode)->writeback_cache) {
                 /* Update size (EOF optimization) and mode (SUID clearing) */
@@ -1201,17 +1198,9 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                 if (err)
                         return err;
 
-                return generic_file_aio_write(iocb, iov, nr_segs, pos);
+                return generic_file_write_iter(iocb, from);
         }
 
-        WARN_ON(iocb->ki_pos != pos);
-
-        ocount = 0;
-        err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
-        if (err)
-                return err;
-
-        count = ocount;
         mutex_lock(&inode->i_mutex);
 
         /* We can write back this queue in page reclaim */
@@ -1224,6 +1213,7 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         if (count == 0)
                 goto out;
 
+        iov_iter_truncate(from, count);
         err = file_remove_suid(file);
         if (err)
                 goto out;
@@ -1233,16 +1223,13 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                 goto out;
 
         if (file->f_flags & O_DIRECT) {
-                written = generic_file_direct_write(iocb, iov, &nr_segs, pos, 
-                                                    count, ocount);
-                if (written < 0 || written == count)
+                written = generic_file_direct_write(iocb, from, pos);
+                if (written < 0 || !iov_iter_count(from))
                         goto out;
 
                 pos += written;
-                count -= written;
 
-                iov_iter_init(&i, iov, nr_segs, count, written);
-                written_buffered = fuse_perform_write(file, mapping, &i, pos);
+                written_buffered = fuse_perform_write(file, mapping, from, pos);
                 if (written_buffered < 0) {
                         err = written_buffered;
                         goto out;
@@ -1261,8 +1248,7 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                 written += written_buffered;
                 iocb->ki_pos = pos + written_buffered;
         } else {
-                iov_iter_init(&i, iov, nr_segs, count, 0);
-                written = fuse_perform_write(file, mapping, &i, pos);
+                written = fuse_perform_write(file, mapping, from, pos);
                 if (written >= 0)
                         iocb->ki_pos = pos + written;
         }
@@ -1300,7 +1286,7 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
         size_t nbytes = 0;  /* # bytes already packed in req */
 
         /* Special case for kernel I/O: can copy directly into the buffer */
-        if (segment_eq(get_fs(), KERNEL_DS)) {
+        if (ii->type & ITER_KVEC) {
                 unsigned long user_addr = fuse_get_user_addr(ii);
                 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
 
@@ -1316,35 +1302,26 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 
         while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
                 unsigned npages;
-                unsigned long user_addr = fuse_get_user_addr(ii);
-                unsigned offset = user_addr & ~PAGE_MASK;
-                size_t frag_size = fuse_get_frag_size(ii, *nbytesp - nbytes);
-                int ret;
-
+                size_t start;
                 unsigned n = req->max_pages - req->num_pages;
-                frag_size = min_t(size_t, frag_size, n << PAGE_SHIFT);
-
-                npages = (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
-                npages = clamp(npages, 1U, n);
-
-                ret = get_user_pages_fast(user_addr, npages, !write,
-                                          &req->pages[req->num_pages]);
+                ssize_t ret = iov_iter_get_pages(ii,
+                                        &req->pages[req->num_pages],
+                                        n * PAGE_SIZE, &start);
                 if (ret < 0)
                         return ret;
 
-                npages = ret;
-                frag_size = min_t(size_t, frag_size,
-                                  (npages << PAGE_SHIFT) - offset);
-                iov_iter_advance(ii, frag_size);
+                iov_iter_advance(ii, ret);
+                nbytes += ret;
+
+                ret += start;
+                npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
 
-                req->page_descs[req->num_pages].offset = offset;
+                req->page_descs[req->num_pages].offset = start;
                 fuse_page_descs_length_init(req, req->num_pages, npages);
 
                 req->num_pages += npages;
                 req->page_descs[req->num_pages - 1].length -=
-                        (npages << PAGE_SHIFT) - offset - frag_size;
-
-                nbytes += frag_size;
+                        (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
         }
 
         if (write)
@@ -1359,24 +1336,11 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 
 static inline int fuse_iter_npages(const struct iov_iter *ii_p)
 {
-        struct iov_iter ii = *ii_p;
-        int npages = 0;
-
-        while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
-                unsigned long user_addr = fuse_get_user_addr(&ii);
-                unsigned offset = user_addr & ~PAGE_MASK;
-                size_t frag_size = iov_iter_single_seg_count(&ii);
-
-                npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
-                iov_iter_advance(&ii, frag_size);
-        }
-
-        return min(npages, FUSE_MAX_PAGES_PER_REQ);
+        return iov_iter_npages(ii_p, FUSE_MAX_PAGES_PER_REQ);
 }
 
-ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
-                       unsigned long nr_segs, size_t count, loff_t *ppos,
-                       int flags)
+ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
+                       loff_t *ppos, int flags)
 {
         int write = flags & FUSE_DIO_WRITE;
         int cuse = flags & FUSE_DIO_CUSE;
@@ -1386,18 +1350,16 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
         struct fuse_conn *fc = ff->fc;
         size_t nmax = write ? fc->max_write : fc->max_read;
         loff_t pos = *ppos;
+        size_t count = iov_iter_count(iter);
         pgoff_t idx_from = pos >> PAGE_CACHE_SHIFT;
         pgoff_t idx_to = (pos + count - 1) >> PAGE_CACHE_SHIFT;
         ssize_t res = 0;
         struct fuse_req *req;
-        struct iov_iter ii;
-
-        iov_iter_init(&ii, iov, nr_segs, count, 0);
 
         if (io->async)
-                req = fuse_get_req_for_background(fc, fuse_iter_npages(&ii));
+                req = fuse_get_req_for_background(fc, fuse_iter_npages(iter));
         else
-                req = fuse_get_req(fc, fuse_iter_npages(&ii));
+                req = fuse_get_req(fc, fuse_iter_npages(iter));
         if (IS_ERR(req))
                 return PTR_ERR(req);
 
@@ -1413,7 +1375,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
                 size_t nres;
                 fl_owner_t owner = current->files;
                 size_t nbytes = min(count, nmax);
-                int err = fuse_get_user_pages(req, &ii, &nbytes, write);
+                int err = fuse_get_user_pages(req, iter, &nbytes, write);
                 if (err) {
                         res = err;
                         break;
@@ -1443,9 +1405,9 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
                         fuse_put_request(fc, req);
                         if (io->async)
                                 req = fuse_get_req_for_background(fc,
-                                        fuse_iter_npages(&ii));
+                                        fuse_iter_npages(iter));
                         else
-                                req = fuse_get_req(fc, fuse_iter_npages(&ii));
+                                req = fuse_get_req(fc, fuse_iter_npages(iter));
                         if (IS_ERR(req))
                                 break;
                 }
@@ -1460,9 +1422,8 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
 EXPORT_SYMBOL_GPL(fuse_direct_io);
 
 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
-                                  const struct iovec *iov,
-                                  unsigned long nr_segs, loff_t *ppos,
-                                  size_t count)
+                                  struct iov_iter *iter,
+                                  loff_t *ppos)
 {
         ssize_t res;
         struct file *file = io->file;
@@ -1471,7 +1432,7 @@ static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
         if (is_bad_inode(inode))
                 return -EIO;
 
-        res = fuse_direct_io(io, iov, nr_segs, count, ppos, 0);
+        res = fuse_direct_io(io, iter, ppos, 0);
 
         fuse_invalidate_attr(inode);
 
@@ -1483,22 +1444,26 @@ static ssize_t fuse_direct_read(struct file *file, char __user *buf,
 {
         struct fuse_io_priv io = { .async = 0, .file = file };
         struct iovec iov = { .iov_base = buf, .iov_len = count };
-        return __fuse_direct_read(&io, &iov, 1, ppos, count);
+        struct iov_iter ii;
+        iov_iter_init(&ii, READ, &iov, 1, count);
+        return __fuse_direct_read(&io, &ii, ppos);
 }
 
 static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
-                                   const struct iovec *iov,
-                                   unsigned long nr_segs, loff_t *ppos)
+                                   struct iov_iter *iter,
+                                   loff_t *ppos)
 {
         struct file *file = io->file;
         struct inode *inode = file_inode(file);
-        size_t count = iov_length(iov, nr_segs);
+        size_t count = iov_iter_count(iter);
         ssize_t res;
 
+
         res = generic_write_checks(file, ppos, &count, 0);
-        if (!res)
-                res = fuse_direct_io(io, iov, nr_segs, count, ppos,
-                                     FUSE_DIO_WRITE);
+        if (!res) {
+                iov_iter_truncate(iter, count);
+                res = fuse_direct_io(io, iter, ppos, FUSE_DIO_WRITE);
+        }
 
         fuse_invalidate_attr(inode);
 
@@ -1512,13 +1477,15 @@ static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
         struct inode *inode = file_inode(file);
         ssize_t res;
         struct fuse_io_priv io = { .async = 0, .file = file };
+        struct iov_iter ii;
+        iov_iter_init(&ii, WRITE, &iov, 1, count);
 
         if (is_bad_inode(inode))
                 return -EIO;
 
         /* Don't allow parallel writes to the same file */
         mutex_lock(&inode->i_mutex);
-        res = __fuse_direct_write(&io, &iov, 1, ppos);
+        res = __fuse_direct_write(&io, &ii, ppos);
         if (res > 0)
                 fuse_write_update_size(inode, *ppos);
         mutex_unlock(&inode->i_mutex);
@@ -2372,7 +2339,7 @@ static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
         if (!bytes)
                 return 0;
 
-        iov_iter_init(&ii, iov, nr_segs, bytes, 0);
+        iov_iter_init(&ii, to_user ? READ : WRITE, iov, nr_segs, bytes);
 
         while (iov_iter_count(&ii)) {
                 struct page *page = pages[page_idx++];
@@ -2894,8 +2861,8 @@ static inline loff_t fuse_round_up(loff_t off)
 }
 
 static ssize_t
-fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-                        loff_t offset, unsigned long nr_segs)
+fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
+                        loff_t offset)
 {
         ssize_t ret = 0;
         struct file *file = iocb->ki_filp;
@@ -2904,7 +2871,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
         loff_t pos = 0;
         struct inode *inode;
         loff_t i_size;
-        size_t count = iov_length(iov, nr_segs);
+        size_t count = iov_iter_count(iter);
         struct fuse_io_priv *io;
 
         pos = offset;
@@ -2919,6 +2886,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
                 if (offset >= i_size)
                         return 0;
                 count = min_t(loff_t, count, fuse_round_up(i_size - offset));
+                iov_iter_truncate(iter, count);
         }
 
         io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
@@ -2948,9 +2916,9 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
                 io->async = false;
 
         if (rw == WRITE)
-                ret = __fuse_direct_write(io, iov, nr_segs, &pos);
+                ret = __fuse_direct_write(io, iter, &pos);
         else
-                ret = __fuse_direct_read(io, iov, nr_segs, &pos, count);
+                ret = __fuse_direct_read(io, iter, &pos);
 
         if (io->async) {
                 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
@@ -3061,10 +3029,10 @@ out:
 
 static const struct file_operations fuse_file_operations = {
         .llseek         = fuse_file_llseek,
-        .read           = do_sync_read,
-        .aio_read       = fuse_file_aio_read,
-        .write          = do_sync_write,
-        .aio_write      = fuse_file_aio_write,
+        .read           = new_sync_read,
+        .read_iter      = fuse_file_read_iter,
+        .write          = new_sync_write,
+        .write_iter     = fuse_file_write_iter,
         .mmap           = fuse_file_mmap,
         .open           = fuse_open,
         .flush          = fuse_flush,
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 7aa5c75e0de1..e8e47a6ab518 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -880,9 +880,8 @@ int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
 #define FUSE_DIO_CUSE  (1 << 1)
 
-ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
-                       unsigned long nr_segs, size_t count, loff_t *ppos,
-                       int flags);
+ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
+                       loff_t *ppos, int flags);
 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
                    unsigned int flags);
 long fuse_ioctl_common(struct file *file, unsigned int cmd,