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Message-ID: <20140501231407.31890.3876.stgit@birch.djwong.org> Date: Thu, 01 May 2014 16:14:07 -0700 From: "Darrick J. Wong" <darrick.wong@...cle.com> To: tytso@....edu, darrick.wong@...cle.com Cc: linux-ext4@...r.kernel.org Subject: [PATCH 16/37] libext2fs: support allocating uninit blocks in bmap2() 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@...cle.com> --- lib/ext2fs/bmap.c | 24 ++++++++++++++++++++++-- lib/ext2fs/ext2fs.h | 1 + lib/ext2fs/mkjournal.c | 17 +++++++++++++++++ 3 files changed, 40 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 diff --git a/lib/ext2fs/mkjournal.c b/lib/ext2fs/mkjournal.c index 884d9c0..ecc3912 100644 --- a/lib/ext2fs/mkjournal.c +++ b/lib/ext2fs/mkjournal.c @@ -174,6 +174,23 @@ errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, return ENOMEM; memset(buf, 0, fs->blocksize * STRIDE_LENGTH); } + + /* Try discard, if it zeroes data... */ + if (io_channel_discard_zeroes_data(fs->io)) { + memset(buf + fs->blocksize, 0, fs->blocksize); + retval = io_channel_discard(fs->io, blk, num); + if (retval) + goto skip_discard; + retval = io_channel_read_blk64(fs->io, blk, 1, buf); + if (retval) + goto skip_discard; + if (memcmp(buf, buf + fs->blocksize, fs->blocksize) == 0) + return 0; + /* Hah! Discard doesn't zero! */ + fs->io->flags &= ~CHANNEL_FLAGS_DISCARD_ZEROES; + } +skip_discard: + /* OK, do the write loop */ j=0; while (j < num) { -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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