1 files changed, 102 insertions, 64 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 29ff749ff4ca..79437c5eeb1e 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -46,32 +46,42 @@
 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
                                          int write_bytes,
                                          struct page **prepared_pages,
-                                         const char __user *buf)
+                                         struct iov_iter *i)
 {
-        long page_fault = 0;
-        int i;
+        size_t copied;
+        int pg = 0;
         int offset = pos & (PAGE_CACHE_SIZE - 1);
 
-        for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
+        while (write_bytes > 0) {
                 size_t count = min_t(size_t,
                                      PAGE_CACHE_SIZE - offset, write_bytes);
-                struct page *page = prepared_pages[i];
-                fault_in_pages_readable(buf, count);
+                struct page *page = prepared_pages[pg];
+again:
+                if (unlikely(iov_iter_fault_in_readable(i, count)))
+                        return -EFAULT;
 
                 /* Copy data from userspace to the current page */
-                kmap(page);
-                page_fault = __copy_from_user(page_address(page) + offset,
-                                              buf, count);
+                copied = iov_iter_copy_from_user(page, i, offset, count);
+
                 /* Flush processor's dcache for this page */
                 flush_dcache_page(page);
-                kunmap(page);
-                buf += count;
-                write_bytes -= count;
+                iov_iter_advance(i, copied);
+                write_bytes -= copied;
 
-                if (page_fault)
-                        break;
+                if (unlikely(copied == 0)) {
+                        count = min_t(size_t, PAGE_CACHE_SIZE - offset,
+                                      iov_iter_single_seg_count(i));
+                        goto again;
+                }
+
+                if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
+                        offset += copied;
+                } else {
+                        pg++;
+                        offset = 0;
+                }
         }
-        return page_fault ? -EFAULT : 0;
+        return 0;
 }
 
 /*
@@ -126,8 +136,7 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
         end_of_last_block = start_pos + num_bytes - 1;
         err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
                                         NULL);
-        if (err)
-                return err;
+        BUG_ON(err);
 
         for (i = 0; i < num_pages; i++) {
                 struct page *p = pages[i];
@@ -142,7 +151,7 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                  * at this time.
                  */
         }
-        return err;
+        return 0;
 }
 
 /*
@@ -823,45 +832,46 @@ again:
         return 0;
 }
 
-static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
-                                size_t count, loff_t *ppos)
+static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
+                                    const struct iovec *iov,
+                                    unsigned long nr_segs, loff_t pos)
 {
-        loff_t pos;
+        struct file *file = iocb->ki_filp;
+        struct inode *inode = fdentry(file)->d_inode;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct page *pinned[2];
+        struct page **pages = NULL;
+        struct iov_iter i;
+        loff_t *ppos = &iocb->ki_pos;
         loff_t start_pos;
         ssize_t num_written = 0;
         ssize_t err = 0;
+        size_t count;
+        size_t ocount;
         int ret = 0;
-        struct inode *inode = fdentry(file)->d_inode;
-        struct btrfs_root *root = BTRFS_I(inode)->root;
-        struct page **pages = NULL;
         int nrptrs;
-        struct page *pinned[2];
         unsigned long first_index;
         unsigned long last_index;
         int will_write;
+        int buffered = 0;
 
         will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) ||
                       (file->f_flags & O_DIRECT));
 
-        nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
-                     PAGE_CACHE_SIZE / (sizeof(struct page *)));
         pinned[0] = NULL;
         pinned[1] = NULL;
 
-        pos = *ppos;
         start_pos = pos;
 
         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
 
-        /* do the reserve before the mutex lock in case we have to do some
-         * flushing.  We wouldn't deadlock, but this is more polite.
-         */
-        err = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
-        if (err)
-                goto out_nolock;
-
         mutex_lock(&inode->i_mutex);
 
+        err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
+        if (err)
+                goto out;
+        count = ocount;
+
         current->backing_dev_info = inode->i_mapping->backing_dev_info;
         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
         if (err)
@@ -875,15 +885,53 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 goto out;
 
         file_update_time(file);
+        BTRFS_I(inode)->sequence++;
+
+        if (unlikely(file->f_flags & O_DIRECT)) {
+                num_written = generic_file_direct_write(iocb, iov, &nr_segs,
+                                                        pos, ppos, count,
+                                                        ocount);
+                /*
+                 * the generic O_DIRECT will update in-memory i_size after the
+                 * DIOs are done.  But our endio handlers that update the on
+                 * disk i_size never update past the in memory i_size.  So we
+                 * need one more update here to catch any additions to the
+                 * file
+                 */
+                if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
+                        btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
+                        mark_inode_dirty(inode);
+                }
 
+                if (num_written < 0) {
+                        ret = num_written;
+                        num_written = 0;
+                        goto out;
+                } else if (num_written == count) {
+                        /* pick up pos changes done by the generic code */
+                        pos = *ppos;
+                        goto out;
+                }
+                /*
+                 * We are going to do buffered for the rest of the range, so we
+                 * need to make sure to invalidate the buffered pages when we're
+                 * done.
+                 */
+                buffered = 1;
+                pos += num_written;
+        }
+
+        iov_iter_init(&i, iov, nr_segs, count, num_written);
+        nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) /
+                     PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
+                     (sizeof(struct page *)));
         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 
         /* generic_write_checks can change our pos */
         start_pos = pos;
 
-        BTRFS_I(inode)->sequence++;
         first_index = pos >> PAGE_CACHE_SHIFT;
-        last_index = (pos + count) >> PAGE_CACHE_SHIFT;
+        last_index = (pos + iov_iter_count(&i)) >> PAGE_CACHE_SHIFT;
 
         /*
          * there are lots of better ways to do this, but this code
@@ -900,7 +948,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                         unlock_page(pinned[0]);
                 }
         }
-        if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
+        if ((pos + iov_iter_count(&i)) & (PAGE_CACHE_SIZE - 1)) {
                 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
                 if (!PageUptodate(pinned[1])) {
                         ret = btrfs_readpage(NULL, pinned[1]);
@@ -911,10 +959,10 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 }
         }
 
-        while (count > 0) {
+        while (iov_iter_count(&i) > 0) {
                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
-                size_t write_bytes = min(count, nrptrs *
-                                        (size_t)PAGE_CACHE_SIZE -
+                size_t write_bytes = min(iov_iter_count(&i),
+                                         nrptrs * (size_t)PAGE_CACHE_SIZE -
                                          offset);
                 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
                                         PAGE_CACHE_SHIFT;
@@ -922,7 +970,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 WARN_ON(num_pages > nrptrs);
                 memset(pages, 0, sizeof(struct page *) * nrptrs);
 
-                ret = btrfs_check_data_free_space(root, inode, write_bytes);
+                ret = btrfs_delalloc_reserve_space(inode, write_bytes);
                 if (ret)
                         goto out;
 
@@ -930,26 +978,20 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                                     pos, first_index, last_index,
                                     write_bytes);
                 if (ret) {
-                        btrfs_free_reserved_data_space(root, inode,
-                                                       write_bytes);
+                        btrfs_delalloc_release_space(inode, write_bytes);
                         goto out;
                 }
 
                 ret = btrfs_copy_from_user(pos, num_pages,
-                                           write_bytes, pages, buf);
-                if (ret) {
-                        btrfs_free_reserved_data_space(root, inode,
-                                                       write_bytes);
-                        btrfs_drop_pages(pages, num_pages);
-                        goto out;
+                                           write_bytes, pages, &i);
+                if (ret == 0) {
+                        dirty_and_release_pages(NULL, root, file, pages,
+                                                num_pages, pos, write_bytes);
                 }
 
-                ret = dirty_and_release_pages(NULL, root, file, pages,
-                                              num_pages, pos, write_bytes);
                 btrfs_drop_pages(pages, num_pages);
                 if (ret) {
-                        btrfs_free_reserved_data_space(root, inode,
-                                                       write_bytes);
+                        btrfs_delalloc_release_space(inode, write_bytes);
                         goto out;
                 }
 
@@ -965,8 +1007,6 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                         btrfs_throttle(root);
                 }
 
-                buf += write_bytes;
-                count -= write_bytes;
                 pos += write_bytes;
                 num_written += write_bytes;
 
@@ -976,9 +1016,7 @@ out:
         mutex_unlock(&inode->i_mutex);
         if (ret)
                 err = ret;
-        btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
 
-out_nolock:
         kfree(pages);
         if (pinned[0])
                 page_cache_release(pinned[0]);
@@ -1008,7 +1046,7 @@ out_nolock:
                         num_written = err;
 
                 if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
-                        trans = btrfs_start_transaction(root, 1);
+                        trans = btrfs_start_transaction(root, 0);
                         ret = btrfs_log_dentry_safe(trans, root,
                                                     file->f_dentry);
                         if (ret == 0) {
@@ -1023,7 +1061,7 @@ out_nolock:
                                 btrfs_end_transaction(trans, root);
                         }
                 }
-                if (file->f_flags & O_DIRECT) {
+                if (file->f_flags & O_DIRECT && buffered) {
                         invalidate_mapping_pages(inode->i_mapping,
                               start_pos >> PAGE_CACHE_SHIFT,
                              (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
@@ -1104,9 +1142,9 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
         if (file && file->private_data)
                 btrfs_ioctl_trans_end(file);
 
-        trans = btrfs_start_transaction(root, 1);
-        if (!trans) {
-                ret = -ENOMEM;
+        trans = btrfs_start_transaction(root, 0);
+        if (IS_ERR(trans)) {
+                ret = PTR_ERR(trans);
                 goto out;
         }
 
@@ -1161,7 +1199,7 @@ const struct file_operations btrfs_file_operations = {
         .read           = do_sync_read,
         .aio_read       = generic_file_aio_read,
         .splice_read    = generic_file_splice_read,
-        .write          = btrfs_file_write,
+        .aio_write      = btrfs_file_aio_write,
         .mmap           = btrfs_file_mmap,
         .open           = generic_file_open,
         .release        = btrfs_release_file,