diff options
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/file.c | 92 |
1 files changed, 60 insertions, 32 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index c1faded5fca0..66836d85763b 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -48,30 +48,34 @@ static noinline int btrfs_copy_from_user(loff_t pos, int num_pages, struct page **prepared_pages, struct iov_iter *i) { - size_t copied; + size_t 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, PAGE_CACHE_SIZE - offset, write_bytes); 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 */ - copied = iov_iter_copy_from_user(page, i, offset, count); + /* + * Copy data from userspace to the current page + * + * Disable pagefault to avoid recursive lock since + * the pages are already locked + */ + pagefault_disable(); + copied = iov_iter_copy_from_user_atomic(page, i, offset, count); + pagefault_enable(); /* Flush processor's dcache for this page */ flush_dcache_page(page); iov_iter_advance(i, copied); write_bytes -= copied; + total_copied += copied; + /* Return to btrfs_file_aio_write to fault page */ if (unlikely(copied == 0)) { - count = min_t(size_t, PAGE_CACHE_SIZE - offset, - iov_iter_single_seg_count(i)); - goto again; + break; } if (unlikely(copied < PAGE_CACHE_SIZE - offset)) { @@ -81,7 +85,7 @@ again: offset = 0; } } - return 0; + return total_copied; } /* @@ -854,6 +858,8 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, 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)); @@ -970,7 +976,17 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, WARN_ON(num_pages > nrptrs); memset(pages, 0, sizeof(struct page *) * nrptrs); - ret = btrfs_delalloc_reserve_space(inode, write_bytes); + /* + * Fault pages before locking them in prepare_pages + * to avoid recursive lock + */ + if (unlikely(iov_iter_fault_in_readable(&i, write_bytes))) { + ret = -EFAULT; + goto out; + } + + ret = btrfs_delalloc_reserve_space(inode, + num_pages << PAGE_CACHE_SHIFT); if (ret) goto out; @@ -978,37 +994,49 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, pos, first_index, last_index, write_bytes); if (ret) { - btrfs_delalloc_release_space(inode, write_bytes); + btrfs_delalloc_release_space(inode, + num_pages << PAGE_CACHE_SHIFT); goto out; } - ret = btrfs_copy_from_user(pos, num_pages, + copied = btrfs_copy_from_user(pos, num_pages, write_bytes, pages, &i); - if (ret == 0) { + dirty_pages = (copied + PAGE_CACHE_SIZE - 1) >> + PAGE_CACHE_SHIFT; + + if (num_pages > dirty_pages) { + if (copied > 0) + atomic_inc( + &BTRFS_I(inode)->outstanding_extents); + btrfs_delalloc_release_space(inode, + (num_pages - dirty_pages) << + PAGE_CACHE_SHIFT); + } + + if (copied > 0) { dirty_and_release_pages(NULL, root, file, pages, - num_pages, pos, write_bytes); + dirty_pages, pos, copied); } btrfs_drop_pages(pages, num_pages); - if (ret) { - btrfs_delalloc_release_space(inode, write_bytes); - goto out; - } - if (will_write) { - filemap_fdatawrite_range(inode->i_mapping, pos, - pos + write_bytes - 1); - } else { - balance_dirty_pages_ratelimited_nr(inode->i_mapping, - num_pages); - if (num_pages < - (root->leafsize >> PAGE_CACHE_SHIFT) + 1) - btrfs_btree_balance_dirty(root, 1); - btrfs_throttle(root); + 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); + } } - pos += write_bytes; - num_written += write_bytes; + pos += copied; + num_written += copied; cond_resched(); } |