Date: Thu, 14 Jan 2010 23:37:28 +0300 From: pluknet <pluknet@gmail.com> To: Ulf Lilleengen <lulf@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r202283 - in head/sys: conf fs/ext2fs gnu/fs/ext2fs gnu/fs/reiserfs modules/ext2fs Message-ID: <a31046fc1001141237r1c91390ajfec7a2796c28e112@mail.gmail.com> In-Reply-To: <201001141430.o0EEUssv057931@svn.freebsd.org> References: <201001141430.o0EEUssv057931@svn.freebsd.org>
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2010/1/14 Ulf Lilleengen <lulf@freebsd.org>: > Author: lulf > Date: Thu Jan 14 14:30:54 2010 > New Revision: 202283 > URL: http://svn.freebsd.org/changeset/base/202283 > Sorry for my late comment. Please, dedup those comments below (came from p4 165599). thanks! > /* > * Allocate a block in the file system. > - * > - * this takes the framework from ffs_alloc. To implement the > - * actual allocation, it calls ext2_new_block, the ported version > - * of the same Linux routine. > * > - * we note that this is always called in connection with ext2_blkpref > + * A preference may be optionally specified. If a preference is given > + * the following hierarchy is used to allocate a block: > + * 1) allocate the requested block. > + * 2) allocate a rotationally optimal block in the same cylinder. > + * 3) allocate a block in the same cylinder group. > + * 4) quadradically rehash into other cylinder groups, until an > + * available block is located. > + * If no block preference is given the following hierarchy is used > + * to allocate a block: > + * 1) allocate a block in the cylinder group that contains the > + * inode for the file. > + * 2) quadradically rehash into other cylinder groups, until an > + * available block is located. > * > - * preallocation is done as Linux does it > + * A preference may be optionally specified. If a preference is given > + * the following hierarchy is used to allocate a block: > + * 1) allocate the requested block. > + * 2) allocate a rotationally optimal block in the same cylinder. > + * 3) allocate a block in the same cylinder group. > + * 4) quadradically rehash into other cylinder groups, until an > + * available block is located. > + * If no block preference is given the following hierarchy is used > + * to allocate a block: > + * 1) allocate a block in the cylinder group that contains the > + * inode for the file. > + * 2) quadradically rehash into other cylinder groups, until an > + * available block is located. > */ -- wbr, pluknet
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