1 files changed, 180 insertions, 175 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 4d4975592668..f2a80e570a6c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -45,14 +45,14 @@
  * and be replaced with calls into generic code.
  */
 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
-                                         int write_bytes,
+                                         size_t write_bytes,
                                          struct page **prepared_pages,
                                          struct iov_iter *i)
 {
         size_t copied = 0;
+        size_t total_copied = 0;
         int pg = 0;
         int offset = pos & (PAGE_CACHE_SIZE - 1);
-        int total_copied = 0;
 
         while (write_bytes > 0) {
                 size_t count = min_t(size_t,
@@ -129,13 +129,12 @@ static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
  * this also makes the decision about creating an inline extent vs
  * doing real data extents, marking pages dirty and delalloc as required.
  */
-static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
-                                   struct btrfs_root *root,
-                                   struct file *file,
-                                   struct page **pages,
-                                   size_t num_pages,
-                                   loff_t pos,
-                                   size_t write_bytes)
+static noinline int dirty_and_release_pages(struct btrfs_root *root,
+                                            struct file *file,
+                                            struct page **pages,
+                                            size_t num_pages,
+                                            loff_t pos,
+                                            size_t write_bytes)
 {
         int err = 0;
         int i;
@@ -153,7 +152,8 @@ 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);
-        BUG_ON(err);
+        if (err)
+                return err;
 
         for (i = 0; i < num_pages; i++) {
                 struct page *p = pages[i];
@@ -896,127 +896,38 @@ fail:
 
 }
 
-static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
-                                    const struct iovec *iov,
-                                    unsigned long nr_segs, loff_t pos)
+static noinline ssize_t __btrfs_buffered_write(struct file *file,
+                                               struct iov_iter *i,
+                                               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 **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;
-        int nrptrs;
         unsigned long first_index;
         unsigned long last_index;
-        int will_write;
-        int buffered = 0;
-        int copied = 0;
-        int dirty_pages = 0;
-
-        will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) ||
-                      (file->f_flags & O_DIRECT));
-
-        start_pos = pos;
-
-        vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
-
-        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)
-                goto out;
-
-        if (count == 0)
-                goto out;
-
-        err = file_remove_suid(file);
-        if (err)
-                goto out;
-
-        /*
-         * If BTRFS flips readonly due to some impossible error
-         * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
-         * although we have opened a file as writable, we have
-         * to stop this write operation to ensure FS consistency.
-         */
-        if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
-                err = -EROFS;
-                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;
-        }
+        size_t num_written = 0;
+        int nrptrs;
+        int ret;
 
-        iov_iter_init(&i, iov, nr_segs, count, num_written);
-        nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) /
+        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);
-        if (!pages) {
-                ret = -ENOMEM;
-                goto out;
-        }
-
-        /* generic_write_checks can change our pos */
-        start_pos = pos;
+        if (!pages)
+                return -ENOMEM;
 
         first_index = pos >> PAGE_CACHE_SHIFT;
-        last_index = (pos + iov_iter_count(&i)) >> PAGE_CACHE_SHIFT;
+        last_index = (pos + iov_iter_count(i)) >> PAGE_CACHE_SHIFT;
 
-        while (iov_iter_count(&i) > 0) {
+        while (iov_iter_count(i) > 0) {
                 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
-                size_t write_bytes = min(iov_iter_count(&i),
+                size_t write_bytes = min(iov_iter_count(i),
                                          nrptrs * (size_t)PAGE_CACHE_SIZE -
                                          offset);
                 size_t num_pages = (write_bytes + offset +
                                     PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+                size_t dirty_pages;
+                size_t copied;
 
                 WARN_ON(num_pages > nrptrs);
                 memset(pages, 0, sizeof(struct page *) * nrptrs);
@@ -1025,15 +936,15 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
                  * Fault pages before locking them in prepare_pages
                  * to avoid recursive lock
                  */
-                if (unlikely(iov_iter_fault_in_readable(&i, write_bytes))) {
+                if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
                         ret = -EFAULT;
-                        goto out;
+                        break;
                 }
 
                 ret = btrfs_delalloc_reserve_space(inode,
                                         num_pages << PAGE_CACHE_SHIFT);
                 if (ret)
-                        goto out;
+                        break;
 
                 ret = prepare_pages(root, file, pages, num_pages,
                                     pos, first_index, last_index,
@@ -1041,11 +952,11 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
                 if (ret) {
                         btrfs_delalloc_release_space(inode,
                                         num_pages << PAGE_CACHE_SHIFT);
-                        goto out;
+                        break;
                 }
 
                 copied = btrfs_copy_from_user(pos, num_pages,
-                                           write_bytes, pages, &i);
+                                           write_bytes, pages, i);
 
                 /*
                  * if we have trouble faulting in the pages, fall
@@ -1061,6 +972,13 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
                                        PAGE_CACHE_SIZE - 1) >>
                                        PAGE_CACHE_SHIFT;
 
+                /*
+                 * If we had a short copy we need to release the excess delaloc
+                 * bytes we reserved.  We need to increment outstanding_extents
+                 * because btrfs_delalloc_release_space will decrement it, but
+                 * we still have an outstanding extent for the chunk we actually
+                 * managed to copy.
+                 */
                 if (num_pages > dirty_pages) {
                         if (copied > 0)
                                 atomic_inc(
@@ -1071,39 +989,157 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
                 }
 
                 if (copied > 0) {
-                        dirty_and_release_pages(NULL, root, file, pages,
-                                                dirty_pages, pos, copied);
+                        ret = dirty_and_release_pages(root, file, pages,
+                                                      dirty_pages, pos,
+                                                      copied);
+                        if (ret) {
+                                btrfs_delalloc_release_space(inode,
+                                        dirty_pages << PAGE_CACHE_SHIFT);
+                                btrfs_drop_pages(pages, num_pages);
+                                break;
+                        }
                 }
 
                 btrfs_drop_pages(pages, num_pages);
 
-                if (copied > 0) {
-                        if (will_write) {
-                                filemap_fdatawrite_range(inode->i_mapping, pos,
-                                                         pos + copied - 1);
-                        } else {
-                                balance_dirty_pages_ratelimited_nr(
-                                                        inode->i_mapping,
-                                                        dirty_pages);
-                                if (dirty_pages <
-                                (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
-                                        btrfs_btree_balance_dirty(root, 1);
-                                btrfs_throttle(root);
-                        }
-                }
+                cond_resched();
+
+                balance_dirty_pages_ratelimited_nr(inode->i_mapping,
+                                                   dirty_pages);
+                if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
+                        btrfs_btree_balance_dirty(root, 1);
+                btrfs_throttle(root);
 
                 pos += copied;
                 num_written += copied;
+        }
 
-                cond_resched();
+        kfree(pages);
+
+        return num_written ? num_written : ret;
+}
+
+static ssize_t __btrfs_direct_write(struct kiocb *iocb,
+                                    const struct iovec *iov,
+                                    unsigned long nr_segs, loff_t pos,
+                                    loff_t *ppos, size_t count, size_t ocount)
+{
+        struct file *file = iocb->ki_filp;
+        struct inode *inode = fdentry(file)->d_inode;
+        struct iov_iter i;
+        ssize_t written;
+        ssize_t written_buffered;
+        loff_t endbyte;
+        int err;
+
+        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 (written < 0 || written == count)
+                return written;
+
+        pos += written;
+        count -= written;
+        iov_iter_init(&i, iov, nr_segs, count, written);
+        written_buffered = __btrfs_buffered_write(file, &i, pos);
+        if (written_buffered < 0) {
+                err = written_buffered;
+                goto out;
+        }
+        endbyte = pos + written_buffered - 1;
+        err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
+        if (err)
+                goto out;
+        written += written_buffered;
+        *ppos = pos + written_buffered;
+        invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
+                                 endbyte >> PAGE_CACHE_SHIFT);
 out:
-        mutex_unlock(&inode->i_mutex);
-        if (ret)
-                err = ret;
+        return written ? written : err;
+}
 
-        kfree(pages);
-        *ppos = pos;
+static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
+                                    const struct iovec *iov,
+                                    unsigned long nr_segs, loff_t pos)
+{
+        struct file *file = iocb->ki_filp;
+        struct inode *inode = fdentry(file)->d_inode;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        loff_t *ppos = &iocb->ki_pos;
+        ssize_t num_written = 0;
+        ssize_t err = 0;
+        size_t count, ocount;
+
+        vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
+        mutex_lock(&inode->i_mutex);
+
+        err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
+        if (err) {
+                mutex_unlock(&inode->i_mutex);
+                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) {
+                mutex_unlock(&inode->i_mutex);
+                goto out;
+        }
+
+        if (count == 0) {
+                mutex_unlock(&inode->i_mutex);
+                goto out;
+        }
+
+        err = file_remove_suid(file);
+        if (err) {
+                mutex_unlock(&inode->i_mutex);
+                goto out;
+        }
+
+        /*
+         * If BTRFS flips readonly due to some impossible error
+         * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
+         * although we have opened a file as writable, we have
+         * to stop this write operation to ensure FS consistency.
+         */
+        if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+                mutex_unlock(&inode->i_mutex);
+                err = -EROFS;
+                goto out;
+        }
+
+        file_update_time(file);
+        BTRFS_I(inode)->sequence++;
+
+        if (unlikely(file->f_flags & O_DIRECT)) {
+                num_written = __btrfs_direct_write(iocb, iov, nr_segs,
+                                                   pos, ppos, count, ocount);
+        } else {
+                struct iov_iter i;
+
+                iov_iter_init(&i, iov, nr_segs, count, num_written);
+
+                num_written = __btrfs_buffered_write(file, &i, pos);
+                if (num_written > 0)
+                        *ppos = pos + num_written;
+        }
+
+        mutex_unlock(&inode->i_mutex);
 
         /*
          * we want to make sure fsync finds this change
@@ -1118,43 +1154,12 @@ out:
          * one running right now.
          */
         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
-
-        if (num_written > 0 && will_write) {
-                struct btrfs_trans_handle *trans;
-
-                err = btrfs_wait_ordered_range(inode, start_pos, num_written);
-                if (err)
+        if (num_written > 0 || num_written == -EIOCBQUEUED) {
+                err = generic_write_sync(file, pos, num_written);
+                if (err < 0 && num_written > 0)
                         num_written = err;
-
-                if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
-                        trans = btrfs_start_transaction(root, 0);
-                        if (IS_ERR(trans)) {
-                                num_written = PTR_ERR(trans);
-                                goto done;
-                        }
-                        mutex_lock(&inode->i_mutex);
-                        ret = btrfs_log_dentry_safe(trans, root,
-                                                    file->f_dentry);
-                        mutex_unlock(&inode->i_mutex);
-                        if (ret == 0) {
-                                ret = btrfs_sync_log(trans, root);
-                                if (ret == 0)
-                                        btrfs_end_transaction(trans, root);
-                                else
-                                        btrfs_commit_transaction(trans, root);
-                        } else if (ret != BTRFS_NO_LOG_SYNC) {
-                                btrfs_commit_transaction(trans, root);
-                        } else {
-                                btrfs_end_transaction(trans, root);
-                        }
-                }
-                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);
-                }
         }
-done:
+out:
         current->backing_dev_info = NULL;
         return num_written ? num_written : err;
 }