Re: [PATCH 1/3 v2] journal: use consts instead of 1024 and add helper for journal with 1k blocksize

[Azat Khuzhin <a3at.mail@gmail.com>]

On Tue, Jul 08, 2014 at 10:46:56PM -0600, Andreas Dilger wrote:
> The patch looks good, and you can add:
> 
> Reviewed-by: Andreas Dilger <adilger@dilger.ca>
> 
> One thing that could probably be fixed if this patch is refreshed,
> or in a precursor patch is to rename SUPERBLOCK_SIZE to be
> EXT2_SUPERBLOCK_SIZE since this avoids potential name clashes. 

I don't have any objections, but this change could break the
header-compatibily, no? (Since lib/ext2fs/ext2fs.h is public available).

Cheers, Azat.

> 
> Cheers, Andreas
> 
> > On Jul 8, 2014, at 21:56, Azat Khuzhin <a3at.mail@gmail.com> wrote:
> > 
> > Use EXT2_MIN_BLOCK_SIZE/JFS_MIN_JOURNAL_BLOCKS instead of hardcoded 1024
> > when it is okay, and also add a helper ext2fs_journal_sb_start() that
> > will return start of journal sb with special case for fs with 1k block
> > size.
> > 
> > Signed-off-by: Azat Khuzhin <a3at.mail@gmail.com>
> > ---
> > v2: mixxed htonl() (thanks to Andreas Dilger)
> > 
> > e2fsck/journal.c       |  5 ++---
> > lib/ext2fs/ext2fs.h    |  1 +
> > lib/ext2fs/mkjournal.c | 28 ++++++++++++++++------------
> > misc/tune2fs.c         |  6 +++---
> > 4 files changed, 22 insertions(+), 18 deletions(-)
> > 
> > diff --git a/e2fsck/journal.c b/e2fsck/journal.c
> > index a7b1150..5780be0 100644
> > --- a/e2fsck/journal.c
> > +++ b/e2fsck/journal.c
> > @@ -443,8 +443,7 @@ static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
> >    if (ext_journal) {
> >        blk64_t maxlen;
> > 
> > -        if (ctx->fs->blocksize == 1024)
> > -            start = 1;
> > +        start = ext2fs_journal_sb_start(ctx->fs->blocksize) - 1;
> >        bh = getblk(dev_journal, start, ctx->fs->blocksize);
> >        if (!bh) {
> >            retval = EXT2_ET_NO_MEMORY;
> > @@ -455,7 +454,7 @@ static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
> >            brelse(bh);
> >            goto errout;
> >        }
> > -        memcpy(&jsuper, start ? bh->b_data :  bh->b_data + 1024,
> > +        memcpy(&jsuper, start ? bh->b_data :  bh->b_data + EXT2_MIN_BLOCK_SIZE,
> >               sizeof(jsuper));
> >        brelse(bh);
> > #ifdef WORDS_BIGENDIAN
> > diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> > index 599c972..a759741 100644
> > --- a/lib/ext2fs/ext2fs.h
> > +++ b/lib/ext2fs/ext2fs.h
> > @@ -1498,6 +1498,7 @@ extern errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t num_blocks,
> > extern errcode_t ext2fs_add_journal_inode2(ext2_filsys fs, blk_t num_blocks,
> >                       blk64_t goal, int flags);
> > extern int ext2fs_default_journal_size(__u64 num_blocks);
> > +extern int ext2fs_journal_sb_start(int blocksize);
> > 
> > /* openfs.c */
> > extern errcode_t ext2fs_open(const char *name, int flags, int superblock,
> > diff --git a/lib/ext2fs/mkjournal.c b/lib/ext2fs/mkjournal.c
> > index 884d9c0..0ad674d 100644
> > --- a/lib/ext2fs/mkjournal.c
> > +++ b/lib/ext2fs/mkjournal.c
> > @@ -49,7 +49,7 @@ errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
> >    errcode_t        retval;
> >    journal_superblock_t    *jsb;
> > 
> > -    if (num_blocks < 1024)
> > +    if (num_blocks < JFS_MIN_JOURNAL_BLOCKS)
> >        return EXT2_ET_JOURNAL_TOO_SMALL;
> > 
> >    if ((retval = ext2fs_get_mem(fs->blocksize, &jsb)))
> > @@ -75,10 +75,7 @@ errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
> >    if (fs->super->s_feature_incompat &
> >        EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
> >        jsb->s_nr_users = 0;
> > -        if (fs->blocksize == 1024)
> > -            jsb->s_first = htonl(3);
> > -        else
> > -            jsb->s_first = htonl(2);
> > +        jsb->s_first = htonl(ext2fs_journal_sb_start(fs->blocksize) + 1);
> >    }
> > 
> >    *ret_jsb = (char *) jsb;
> > @@ -430,6 +427,13 @@ int ext2fs_default_journal_size(__u64 num_blocks)
> >    return 32768;
> > }
> > 
> > +int ext2fs_journal_sb_start(int blocksize)
> > +{
> > +    if (blocksize == EXT2_MIN_BLOCK_SIZE)
> > +        return 2;
> > +    return 1;
> > +}
> > +
> > /*
> >  * This function adds a journal device to a filesystem
> >  */
> > @@ -437,7 +441,7 @@ errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
> > {
> >    struct stat    st;
> >    errcode_t    retval;
> > -    char        buf[1024];
> > +    char        buf[SUPERBLOCK_SIZE];
> >    journal_superblock_t    *jsb;
> >    int        start;
> >    __u32        i, nr_users;
> > @@ -450,10 +454,9 @@ errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
> >        return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
> > 
> >    /* Get the journal superblock */
> > -    start = 1;
> > -    if (journal_dev->blocksize == 1024)
> > -        start++;
> > -    if ((retval = io_channel_read_blk64(journal_dev->io, start, -1024,
> > +    start = ext2fs_journal_sb_start(journal_dev->blocksize);
> > +    if ((retval = io_channel_read_blk64(journal_dev->io, start,
> > +                        -SUPERBLOCK_SIZE,
> >                        buf)))
> >        return retval;
> > 
> > @@ -479,7 +482,8 @@ errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
> >    }
> > 
> >    /* Writeback the journal superblock */
> > -    if ((retval = io_channel_write_blk64(journal_dev->io, start, -1024, buf)))
> > +    if ((retval = io_channel_write_blk64(journal_dev->io, start,
> > +                        -SUPERBLOCK_SIZE, buf)))
> >        return retval;
> > 
> >    fs->super->s_journal_inum = 0;
> > @@ -632,7 +636,7 @@ main(int argc, char **argv)
> >        exit(1);
> >    }
> > 
> > -    retval = ext2fs_add_journal_inode(fs, 1024, 0);
> > +    retval = ext2fs_add_journal_inode(fs, JFS_MIN_JOURNAL_BLOCKS, 0);
> >    if (retval) {
> >        com_err(argv[0], retval, "while adding journal to %s",
> >            device_name);
> > diff --git a/misc/tune2fs.c b/misc/tune2fs.c
> > index d95cc3d..0e7caf2 100644
> > --- a/misc/tune2fs.c
> > +++ b/misc/tune2fs.c
> > @@ -187,7 +187,7 @@ static int remove_journal_device(ext2_filsys fs)
> > {
> >    char        *journal_path;
> >    ext2_filsys    jfs;
> > -    char        buf[1024];
> > +    char        buf[SUPERBLOCK_SIZE];
> >    journal_superblock_t    *jsb;
> >    int        i, nr_users;
> >    errcode_t    retval;
> > @@ -230,7 +230,7 @@ static int remove_journal_device(ext2_filsys fs)
> >    }
> > 
> >    /* Get the journal superblock */
> > -    if ((retval = io_channel_read_blk64(jfs->io, 1, -1024, buf))) {
> > +    if ((retval = io_channel_read_blk64(jfs->io, 1, -SUPERBLOCK_SIZE, buf))) {
> >        com_err(program_name, retval, "%s",
> >            _("while reading journal superblock"));
> >        goto no_valid_journal;
> > @@ -261,7 +261,7 @@ static int remove_journal_device(ext2_filsys fs)
> >    jsb->s_nr_users = htonl(nr_users);
> > 
> >    /* Write back the journal superblock */
> > -    if ((retval = io_channel_write_blk64(jfs->io, 1, -1024, buf))) {
> > +    if ((retval = io_channel_write_blk64(jfs->io, 1, -SUPERBLOCK_SIZE, buf))) {
> >        com_err(program_name, retval,
> >            "while writing journal superblock.");
> >        goto no_valid_journal;
> > -- 
> > 2.0.0
> > 

-- 
Respectfully
Azat Khuzhin