On Mon, 30 Sep 2013, Darrick J. Wong wrote: > Date: Mon, 30 Sep 2013 18:27:34 -0700 > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > To: tytso@xxxxxxx, darrick.wong@xxxxxxxxxx > Cc: linux-ext4@xxxxxxxxxxxxxxx > Subject: [PATCH 08/31] libext2fs: Fix off-by-one error in file truncation > > When told to truncate a file, ext2fs_file_set_size2 should start with the first > block past the end of the file. The current calculation jumps one more block > ahead, with the result that it fails to hack off the last block. Adding > blocksize-1 and dividing is sufficient to find the last block. Looks good. Reviewed-by: Lukas Czerner <lczerner@xxxxxxxxxx> > > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > --- > lib/ext2fs/fileio.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > > diff --git a/lib/ext2fs/fileio.c b/lib/ext2fs/fileio.c > index ae5cbf1..d875630 100644 > --- a/lib/ext2fs/fileio.c > +++ b/lib/ext2fs/fileio.c > @@ -384,10 +384,10 @@ errcode_t ext2fs_file_set_size2(ext2_file_t file, ext2_off64_t size) > EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE); > > truncate_block = ((size + file->fs->blocksize - 1) >> > - EXT2_BLOCK_SIZE_BITS(file->fs->super)) + 1; > + EXT2_BLOCK_SIZE_BITS(file->fs->super)); > old_size = EXT2_I_SIZE(&file->inode); > old_truncate = ((old_size + file->fs->blocksize - 1) >> > - EXT2_BLOCK_SIZE_BITS(file->fs->super)) + 1; > + EXT2_BLOCK_SIZE_BITS(file->fs->super)); > > /* If we're writing a large file, set the large_file flag */ > if (LINUX_S_ISREG(file->inode.i_mode) && > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
