On Wed, Jun 25, 2014 at 4:57 PM, Ivan Zhakov <ivan_at_visualsvn.com> wrote:
> On 21 June 2014 17:15, <stefan2_at_apache.org> wrote:
> > Author: stefan2
> > Date: Sat Jun 21 15:15:30 2014
> > New Revision: 1604421
> >
> > URL: http://svn.apache.org/r1604421
> > Log:
> > Append index data to the rev data file instead of using separate files.
> >
> > This gives unpacked FSFS format 7 similar I/O characteristics and disk
> > space usage as earlier formats. It also eliminates the need for retries
> > after a potential background pack run because each file is now always
> > consistent with itself (earlier, data or index files might already have
> > been deleted while the respective other was still valid). Overall,
> > most of this patch is removing code necessary to handle separate files.
> >
> > The new file format is simple:
> >
> > <rep data><l2p index><p2l index><footer><footer length>
> >
> > with the first three being identical what we had before. <footer length>
> > is a single byte giving the length of the preceding footer, so it's
> > easier to extract than the pre-f7 rev trailer and there is only one
> > per pack / rev file.
> >
> [..]
>
>
> >Modified: subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c
> >URL:
> http://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c?rev=1604421&r1=1604420&r2=1604421&view=diff
>
> >==============================================================================
> >--- subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c (original)
> >+++ subversion/trunk/subversion/libsvn_fs_fs/fs_fs.c Sat Jun 21 15:15:30
> 2014
> >@@ -1449,15 +1449,35 @@ write_revision_zero(svn_fs_t *fs)
> >+ SVN_ERR(svn_io_file_create_binary(path_revision_zero,
> >+ "PLAIN\nEND\nENDREP\n"
> >+ "id: 0.0.r0/2\n"
> >+ "type: dir\n"
> >+ "count: 0\n"
> >+ "text: 0 3 4 4 "
> >+ "2d2977d1c96f487abe4a1e202dd03b4e\n"
> >+ "cpath: /\n"
> >+ "\n\n"
> >+
> >+ /* L2P index */
> >+ "\0\x80\x40" /* rev 0, 8k entries per page */
> >+ "\1\1\1" /* 1 rev, 1 page, 1 page in 1st
> rev */
> >+ "\6\4" /* page size: bytes, count */
> >+ "\0\xd6\1\xb1\1\x21" /* phys offsets + 1 */
> >+
> >+ /* P2L index */
> >+ "\0\x6b" /* start rev, rev file size */
> >+ "\x80\x80\4\1\x1D" /* 64k pages, 1 page using 29
> bytes */
> >+ "\0" /* offset entry 0 page 1 */
> >+ /* len, item & type, rev,
> checksum */
> >+ "\x11\x34\0\xf5\xd6\x8c\x81\x06"
> >+ "\x59\x09\0\xc8\xfc\xf6\x81\x04"
> >+ "\1\x0d\0\x9d\x9e\xa9\x94\x0f"
> >+ "\x95\xff\3\x1b\0\0" /* last entry fills up 64k page
> */
> >+
> >+ /* Footer */
> >+ "107 121\7",
> >+ 107 + 14 + 38 + 7 + 1, fs->pool));
> This constant makes code unreadable, unmaintainable and very error prone.
>
How?
To make it more obvious that I intend to follow
the svn_io_file_create_binary interface, I added
some commentary explaining where the numbers
come from. But even just placing the sum (without
its elements) in there would be fine already.
Changing the rev 0 template has never been a fun
activity and wont become one in the foreseeable
future.
>
> > Modified: subversion/trunk/subversion/libsvn_fs_fs/rev_file.c
> > URL:
> http://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_fs_fs/rev_file.c?rev=1604421&r1=1604420&r2=1604421&view=diff
> >
> ==============================================================================
> > --- subversion/trunk/subversion/libsvn_fs_fs/rev_file.c (original)
> > +++ subversion/trunk/subversion/libsvn_fs_fs/rev_file.c Sat Jun 21
> 15:15:30 2014
> > @@ -23,6 +23,7 @@
> > #include "rev_file.h"
> > #include "fs_fs.h"
> > #include "index.h"
> > +#include "low_level.h"
> > #include "util.h"
> >
> > #include "../libsvn_fs/fs-loader.h"
> > @@ -46,6 +47,10 @@ init_revision_file(svn_fs_fs__revision_f
> > file->stream = NULL;
> > file->p2l_stream = NULL;
> > file->l2p_stream = NULL;
> > + file->block_size = ffd->block_size;
> > + file->l2p_offset = -1;
> > + file->p2l_offset = -1;
> > + file->footer_offset = -1;
> > file->pool = pool;
> > }
> >
> > @@ -127,14 +132,40 @@ svn_fs_fs__open_pack_or_rev_file(svn_fs_
> > }
> >
> > svn_error_t *
> > -svn_fs_fs__reopen_revision_file(svn_fs_fs__revision_file_t *file,
> > - svn_fs_t *fs,
> > - svn_revnum_t rev)
> > +svn_fs_fs__auto_read_footer(svn_fs_fs__revision_file_t *file)
> > {
> > - if (file->file)
> > - svn_fs_fs__close_revision_file(file);
> > + if (file->l2p_offset == -1)
> > + {
> > + apr_off_t filesize = 0;
> > + unsigned char footer_length;
> > + svn_stringbuf_t *footer;
> > +
> > + /* Determine file size. */
> > + SVN_ERR(svn_io_file_seek(file->file, APR_END, &filesize,
> file->pool));
> > +
> > + /* Read last byte (containing the length of the footer). */
> > + SVN_ERR(svn_io_file_aligned_seek(file->file, file->block_size,
> NULL,
> > + filesize - 1, file->pool));
> > + SVN_ERR(svn_io_file_read_full2(file->file, &footer_length,
> > + sizeof(footer_length), NULL, NULL,
> > + file->pool));
> > +
> > + /* Read footer. */
> > + footer = svn_stringbuf_create_ensure(footer_length, file->pool);
> > + SVN_ERR(svn_io_file_aligned_seek(file->file, file->block_size,
> NULL,
> > + filesize - 1 - footer_length,
> > + file->pool));
> > + SVN_ERR(svn_io_file_read_full2(file->file, footer->data,
> footer_length,
> > + &footer->len, NULL, file->pool));
> You're passing pointer to possible 32-bit value to function accepting
> pointer to 64-bit value. This will lead unpredictable results.
>
I assume you are referring to the &footer->len?
In that case, I think I'm passing an apr_size_t*
to an interface expecting an apr_size_t*.
What am I missing?
-- Stefan^2.
Received on 2014-06-25 17:25:27 CEST