From: Andreas Gruenbacher agruenba@redhat.com
commit 6e5e41e2dc4e4413296d5a4af54ac92d7cd52317 upstream.
In gfs2_file_write_iter, for direct writes, the error checking in the buffered write fallback case is incomplete. This can cause inode write errors to go undetected. Fix and clean up gfs2_file_write_iter along the way.
Based on a proposed fix by Christoph Hellwig hch@lst.de.
Fixes: 967bcc91b044 ("gfs2: iomap direct I/O support") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/gfs2/file.c | 51 +++++++++++++++++++++------------------------------ 1 file changed, 21 insertions(+), 30 deletions(-)
--- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -780,7 +780,7 @@ static ssize_t gfs2_file_write_iter(stru struct file *file = iocb->ki_filp; struct inode *inode = file_inode(file); struct gfs2_inode *ip = GFS2_I(inode); - ssize_t written = 0, ret; + ssize_t ret;
ret = gfs2_rsqa_alloc(ip); if (ret) @@ -812,55 +812,46 @@ static ssize_t gfs2_file_write_iter(stru
if (iocb->ki_flags & IOCB_DIRECT) { struct address_space *mapping = file->f_mapping; - loff_t pos, endbyte; - ssize_t buffered; + ssize_t buffered, ret2;
- written = gfs2_file_direct_write(iocb, from); - if (written < 0 || !iov_iter_count(from)) + ret = gfs2_file_direct_write(iocb, from); + if (ret < 0 || !iov_iter_count(from)) goto out_unlock;
+ iocb->ki_flags |= IOCB_DSYNC; current->backing_dev_info = inode_to_bdi(inode); - ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops); + buffered = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops); current->backing_dev_info = NULL; - if (unlikely(ret < 0)) + if (unlikely(buffered <= 0)) goto out_unlock; - buffered = ret;
/* * We need to ensure that the page cache pages are written to * disk and invalidated to preserve the expected O_DIRECT - * semantics. + * semantics. If the writeback or invalidate fails, only report + * the direct I/O range as we don't know if the buffered pages + * made it to disk. */ - pos = iocb->ki_pos; - endbyte = pos + buffered - 1; - ret = filemap_write_and_wait_range(mapping, pos, endbyte); - if (!ret) { - iocb->ki_pos += buffered; - written += buffered; - invalidate_mapping_pages(mapping, - pos >> PAGE_SHIFT, - endbyte >> PAGE_SHIFT); - } else { - /* - * We don't know how much we wrote, so just return - * the number of bytes which were direct-written - */ - } + iocb->ki_pos += buffered; + ret2 = generic_write_sync(iocb, buffered); + invalidate_mapping_pages(mapping, + (iocb->ki_pos - buffered) >> PAGE_SHIFT, + (iocb->ki_pos - 1) >> PAGE_SHIFT); + if (!ret || ret2 > 0) + ret += ret2; } else { current->backing_dev_info = inode_to_bdi(inode); ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops); current->backing_dev_info = NULL; - if (likely(ret > 0)) + if (likely(ret > 0)) { iocb->ki_pos += ret; + ret = generic_write_sync(iocb, ret); + } }
out_unlock: inode_unlock(inode); - if (likely(ret > 0)) { - /* Handle various SYNC-type writes */ - ret = generic_write_sync(iocb, ret); - } - return written ? written : ret; + return ret; }
static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,