From: "Darrick J. Wong" Subject: [PATCH 50/74] libext2fs: support allocating uninit blocks in bmap2() Date: Tue, 10 Dec 2013 17:23:53 -0800 Message-ID: <20131211012353.30655.82545.stgit@birch.djwong.org> References: <20131211011813.30655.39624.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: tytso@mit.edu, darrick.wong@oracle.com Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:27117 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751584Ab3LKBX7 (ORCPT ); Tue, 10 Dec 2013 20:23:59 -0500 In-Reply-To: <20131211011813.30655.39624.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: In order to support fallocate, we need to be able to have ext2fs_bmap2() allocate blocks and put them into uninitialized extents. There's a flag to do this in the extent code, but it's not exposed to the bmap2 interface, so plumb that in. Eventually fuse2fs or somebody will use it. Signed-off-by: Darrick J. Wong --- lib/ext2fs/bmap.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++-- lib/ext2fs/ext2fs.h | 1 + 2 files changed, 48 insertions(+), 2 deletions(-) diff --git a/lib/ext2fs/bmap.c b/lib/ext2fs/bmap.c index 3a18d76..ca89eb1 100644 --- a/lib/ext2fs/bmap.c +++ b/lib/ext2fs/bmap.c @@ -33,6 +33,32 @@ extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, #define inode_bmap(inode, nr) ((inode)->i_block[(nr)]) +static errcode_t zero_block(ext2_filsys fs, blk64_t blk) +{ + void *b; + errcode_t retval; + + if (io_channel_discard_zeroes_data(fs->io)) { + retval = io_channel_discard(fs->io, blk, 1); + if (retval == 0) + return 0; + } + + retval = ext2fs_get_memzero(fs->blocksize, &b); + if (retval) + return retval; + + memset(b, 0, fs->blocksize); + + retval = io_channel_write_blk64(fs->io, blk, 1, b); + if (retval) + goto out; + +out: + ext2fs_free_mem(&b); + return retval; +} + static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags, blk_t ind, char *block_buf, int *blocks_alloc, @@ -72,6 +98,11 @@ static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags, block_buf + fs->blocksize, &b); if (retval) return retval; + if (flags & BMAP_UNINIT) { + retval = zero_block(fs, b); + if (retval) + return retval; + } #ifdef WORDS_BIGENDIAN ((blk_t *) block_buf)[nr] = ext2fs_swab32(b); @@ -214,10 +245,13 @@ static errcode_t extent_bmap(ext2_filsys fs, ext2_ino_t ino, errcode_t retval = 0; blk64_t blk64 = 0; int alloc = 0; + int set_flags; + + set_flags = bmap_flags & BMAP_UNINIT ? EXT2_EXTENT_SET_BMAP_UNINIT : 0; if (bmap_flags & BMAP_SET) { retval = ext2fs_extent_set_bmap(handle, block, - *phys_blk, 0); + *phys_blk, set_flags); return retval; } retval = ext2fs_extent_goto(handle, block); @@ -254,7 +288,7 @@ got_block: alloc++; set_extent: retval = ext2fs_extent_set_bmap(handle, block, - blk64, 0); + blk64, set_flags); if (retval) return retval; /* Update inode after setting extent */ @@ -336,6 +370,12 @@ errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode, goto done; } + if ((bmap_flags & BMAP_SET) && (bmap_flags & BMAP_UNINIT)) { + retval = zero_block(fs, *phys_blk); + if (retval) + goto done; + } + if (block < EXT2_NDIR_BLOCKS) { if (bmap_flags & BMAP_SET) { b = *phys_blk; @@ -351,6 +391,11 @@ errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode, retval = ext2fs_alloc_block(fs, b, block_buf, &b); if (retval) goto done; + if (bmap_flags & BMAP_UNINIT) { + retval = zero_block(fs, b); + if (retval) + goto done; + } inode_bmap(inode, block) = b; blocks_alloc++; *phys_blk = b; diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h index da518df..316e6f5 100644 --- a/lib/ext2fs/ext2fs.h +++ b/lib/ext2fs/ext2fs.h @@ -525,6 +525,7 @@ typedef struct ext2_icount *ext2_icount_t; */ #define BMAP_ALLOC 0x0001 #define BMAP_SET 0x0002 +#define BMAP_UNINIT 0x0004 /* * Returned flags from ext2fs_bmap