[PATCH 2/2] libext2fs: support allocating uninit blocks in bmap2()

Darrick J. Wong
2014-05-08T00:14:55Z

Here's the second part, which for the most part is the old patch, but wired up
to use the bits in the other patch.

--D
---
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 <darrick.wong@oracle.com>
---
lib/ext2fs/bmap.c | 24 ++++++++++++++++++++++--
lib/ext2fs/ext2fs.h | 1 +
2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/lib/ext2fs/bmap.c b/lib/ext2fs/bmap.c
index c1d0e6f..a4dc8ef 100644
--- a/lib/ext2fs/bmap.c
+++ b/lib/ext2fs/bmap.c
@@ -72,6 +72,11 @@ 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 = ext2fs_zero_blocks2(fs, b, 1, NULL, NULL);
+ if (retval)
+ return retval;
+ }

#ifdef WORDS_BIGENDIAN
((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
@@ -214,10 +219,13 @@ 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 +262,7 @@ got_block:
alloc++;
set_extent:
retval = ext2fs_extent_set_bmap(handle, block,
- blk64, 0);
+ blk64, set_flags);
if (retval) {
ext2fs_block_alloc_stats2(fs, blk64, -1);
return retval;
@@ -345,6 +353,12 @@ 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 = ext2fs_zero_blocks2(fs, *phys_blk, 1, NULL, NULL);
+ if (retval)
+ goto done;
+ }
+
if (block < EXT2_NDIR_BLOCKS) {
if (bmap_flags & BMAP_SET) {
b = *phys_blk;
@@ -360,6 +374,12 @@ 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 = ext2fs_zero_blocks2(fs, b, 1, NULL,
+ NULL);
+ 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 599c972..819a14a 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -527,6 +527,7 @@ typedef struct ext2_icount *ext2_icount_t;
*/
#define BMAP_ALLOC 0x0001
#define BMAP_SET 0x0002
+#define BMAP_UNINIT 0x0004

/*
* Returned flags from ext2fs_bmap