diff options
| -rw-r--r-- | fs/gfs2/aops.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c index 0bad69ed633..76251600cbe 100644 --- a/fs/gfs2/aops.c +++ b/fs/gfs2/aops.c @@ -999,6 +999,7 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; + struct address_space *mapping = inode->i_mapping; struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_holder gh; int rv; @@ -1019,6 +1020,35 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, if (rv != 1) goto out; /* dio not valid, fall back to buffered i/o */ + /* + * Now since we are holding a deferred (CW) lock at this point, you + * might be wondering why this is ever needed. There is a case however + * where we've granted a deferred local lock against a cached exclusive + * glock. That is ok provided all granted local locks are deferred, but + * it also means that it is possible to encounter pages which are + * cached and possibly also mapped. So here we check for that and sort + * them out ahead of the dio. The glock state machine will take care of + * everything else. + * + * If in fact the cached glock state (gl->gl_state) is deferred (CW) in + * the first place, mapping->nr_pages will always be zero. + */ + if (mapping->nrpages) { + loff_t lstart = offset & (PAGE_CACHE_SIZE - 1); + loff_t len = iov_length(iov, nr_segs); + loff_t end = PAGE_ALIGN(offset + len) - 1; + + rv = 0; + if (len == 0) + goto out; + if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags)) + unmap_shared_mapping_range(ip->i_inode.i_mapping, offset, len); + rv = filemap_write_and_wait_range(mapping, lstart, end); + if (rv) + return rv; + truncate_inode_pages_range(mapping, lstart, end); + } + rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, gfs2_get_block_direct, NULL, NULL, 0); |