On Fri 22-05-15 10:35:21, Darrick J. Wong wrote:
> On Fri, May 22, 2015 at 01:28:54PM +0200, Jan Kara wrote:
...
> > diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> > index 28c46701da29..1e303d5d59ca 100644
> > --- a/lib/ext2fs/ext2fs.h
> > +++ b/lib/ext2fs/ext2fs.h
> > @@ -555,7 +555,8 @@ typedef struct ext2_icount *ext2_icount_t;
> > EXT2_FEATURE_COMPAT_RESIZE_INODE|\
> > EXT2_FEATURE_COMPAT_DIR_INDEX|\
> > EXT2_FEATURE_COMPAT_EXT_ATTR|\
> > - EXT4_FEATURE_COMPAT_SPARSE_SUPER2)
> > + EXT4_FEATURE_COMPAT_SPARSE_SUPER2|\
> > + EXT4_FEATURE_COMPAT_ORPHAN_FILE)
> >
> > #ifdef CONFIG_MMP
> > #define EXT4_LIB_INCOMPAT_MMP EXT4_FEATURE_INCOMPAT_MMP
> > @@ -589,7 +590,8 @@ typedef struct ext2_icount *ext2_icount_t;
> > EXT4_FEATURE_RO_COMPAT_BIGALLOC|\
> > EXT4_LIB_RO_COMPAT_QUOTA|\
> > EXT4_FEATURE_RO_COMPAT_METADATA_CSUM|\
> > - EXT4_FEATURE_RO_COMPAT_READONLY)
> > + EXT4_FEATURE_RO_COMPAT_READONLY|\
> > + EXT4_FEATURE_RO_COMPAT_ORPHAN_PRESENT)
> >
> > /*
> > * These features are only allowed if EXT2_FLAG_SOFTSUPP_FEATURES is passed
> > @@ -1512,6 +1514,19 @@ errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io);
> > errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io);
> > errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io);
> >
> > +/* orphan.c */
> > +/*
> > + * Minimum orphan file size (it must be at least 1 block and smaller one isn't
> > + * very useful).
> > + */
> > +#define EXT4_MIN_ORPHAN_FILE_SIZE 16384
>
> What about 64k block size? I guess it's fine not to use the whole block in
> this (non-default) configuration.
We round up file size to be a multiple of fs block size.
> > +struct mkorphan_info {
> > + char *buf;
> > + char *zerobuf;
> > + blk_t num_blocks;
> > + blk_t alloc_blocks;
> > + errcode_t err;
> > +};
> > +
> > +static int mkorphan_proc(ext2_filsys fs,
> > + blk64_t *blocknr,
> > + e2_blkcnt_t blockcnt,
> > + blk64_t ref_block EXT2FS_ATTR((unused)),
> > + int ref_offset EXT2FS_ATTR((unused)),
> > + void *priv_data)
> > +{
> > + struct mkorphan_info *oi = (struct mkorphan_info *)priv_data;
> > + blk64_t new_blk;
> > + errcode_t err;
> > +
> > + err = ext2fs_new_block2(fs, 0, 0, &new_blk);
>
> Hm. I think this breaks the cluster allocation rules, since this allocates
> a new block for every logical block inside a cluster.
Yes, I didn't think of cluster allocation. Frankly, I have just mirrored
what a code creating journal does. If this is wrong, then that code needs
fixing as well ;)
> Hopefully ext2fs_fallocate will land soon, then we can get rid of open-coding
> file block allocation like this. You'll still have to have the iterate3 loop
> to write out the appropriate block footer, but iirc the library call can be
> told to allocate written extents without zeroing the blocks, precisely for
> cases like these.
So should I wait for that or do you have any pointer to code which does
it correctly?
Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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