Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752828AbaBCE03 (ORCPT ); Sun, 2 Feb 2014 23:26:29 -0500 Received: from mail.parknet.co.jp ([210.171.160.6]:50023 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752409AbaBCE01 (ORCPT ); Sun, 2 Feb 2014 23:26:27 -0500 From: OGAWA Hirofumi To: Namjae Jeon Cc: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Namjae Jeon , Amit Sahrawat Subject: Re: [PATCH v3 5/6] fat: permit to return phy block number by fibmap in fallocated region References: <1387953112-2828-1-git-send-email-linkinjeon@gmail.com> Date: Mon, 03 Feb 2014 13:26:21 +0900 In-Reply-To: <1387953112-2828-1-git-send-email-linkinjeon@gmail.com> (Namjae Jeon's message of "Wed, 25 Dec 2013 15:31:52 +0900") Message-ID: <87eh3kx1n6.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Namjae Jeon writes: > From: Namjae Jeon > > Make the fibmap call the return the proper physical block number for any > offset request in the fallocated range. > > Signed-off-by: Namjae Jeon > Signed-off-by: Amit Sahrawat > --- > fs/fat/cache.c | 13 ++++++++++--- > fs/fat/fat.h | 3 +++ > fs/fat/inode.c | 3 +++ > 3 files changed, 16 insertions(+), 3 deletions(-) > > diff --git a/fs/fat/cache.c b/fs/fat/cache.c > index a132666..d22c1a2 100644 > --- a/fs/fat/cache.c > +++ b/fs/fat/cache.c > @@ -325,19 +325,26 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys, > > last_block = (i_size_read(inode) + (blocksize - 1)) >> blocksize_bits; > if (sector >= last_block) { > - if (!create) > - return 0; > - > /* > * Both ->mmu_private and ->i_disksize can access > * on only allocation path. (caller must hold ->i_mutex) > */ > last_block = (MSDOS_I(inode)->i_disksize + (blocksize - 1)) > >> blocksize_bits; > + if (!create) { > + /* Map a block in fallocated region */ > + if (atomic_read(&MSDOS_I(inode)->beyond_isize)) > + if (sector < last_block) > + goto out_map_cluster; > + > + return 0; > + } > + > if (sector >= last_block) > return 0; > } > > +out_map_cluster: > cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits); > offset = sector & (sbi->sec_per_clus - 1); > cluster = fat_bmap_cluster(inode, cluster); > diff --git a/fs/fat/fat.h b/fs/fat/fat.h > index 7b5851f..b884276 100644 > --- a/fs/fat/fat.h > +++ b/fs/fat/fat.h > @@ -129,6 +129,9 @@ struct msdos_inode_info { > struct hlist_node i_dir_hash; /* hash by i_logstart */ > struct rw_semaphore truncate_lock; /* protect bmap against truncate */ > struct inode vfs_inode; > + > + /* for getting block number beyond file size in case of fallocate */ > + atomic_t beyond_isize; > }; > > struct fat_slot_info { > diff --git a/fs/fat/inode.c b/fs/fat/inode.c > index 3636617..1c3192b 100644 > --- a/fs/fat/inode.c > +++ b/fs/fat/inode.c > @@ -256,7 +256,10 @@ static sector_t _fat_bmap(struct address_space *mapping, sector_t block) > > /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ > down_read(&MSDOS_I(mapping->host)->truncate_lock); > + /* To get block number beyond file size in fallocated region */ > + atomic_set(&MSDOS_I(mapping->host)->beyond_isize, 1); > blocknr = generic_block_bmap(mapping, block, fat_get_block); > + atomic_set(&MSDOS_I(mapping->host)->beyond_isize, 0); > up_read(&MSDOS_I(mapping->host)->truncate_lock); This is racy. While user is using bmap, kernel can allocate new blocks. We should use another function for this. For example, something like fat_get_block_bmap() { [...] fat_get_block2(inode, iblock, &max_blocks, bh_result, create, bmap); [...] } blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap); -- OGAWA Hirofumi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/