From: Jan Kara Subject: Re: [PATCH 13/19] tune2fs: Add support for changing number of reserved inodes Date: Wed, 26 Aug 2015 18:11:45 +0200 Message-ID: <20150826161145.GF14012@quack.suse.cz> References: <1438944689-24562-1-git-send-email-jack@suse.com> <1438944689-24562-14-git-send-email-jack@suse.com> <078D7EF7-202A-48A5-9B16-94C236853D8E@dilger.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , linux-ext4@vger.kernel.org, Ted Tso , "Darrick J. Wong" To: Andreas Dilger Return-path: Received: from mx2.suse.de ([195.135.220.15]:32783 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751690AbbHZQLu (ORCPT ); Wed, 26 Aug 2015 12:11:50 -0400 Content-Disposition: inline In-Reply-To: <078D7EF7-202A-48A5-9B16-94C236853D8E@dilger.ca> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri 07-08-15 12:58:49, Andreas Dilger wrote: > On Aug 7, 2015, at 4:51 AM, Jan Kara wrote: > > > > Signed-off-by: Jan Kara > > --- > > misc/tune2fs.8.in | 5 +++ > > misc/tune2fs.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 107 insertions(+) > > > > diff --git a/misc/tune2fs.8.in b/misc/tune2fs.8.in > > index 4373fc49b255..922705329112 100644 > > --- a/misc/tune2fs.8.in > > +++ b/misc/tune2fs.8.in > > @@ -236,6 +236,11 @@ program. > > This superblock setting is only honored in 2.6.35+ kernels; > > and not at all by the ext2 and ext3 file system drivers. > > .TP > > +.BI reserved_inodes= number_of_reserved_inodes > > +Set the number of inodes reserved for system files. This number must be > > +at least 10. Currently 10 is enough but future features may require additional > > +reserved inodes. Reserving more inodes requires full file system scan so it > > +can take a long time. > > .B test_fs > > Set a flag in the filesystem superblock indicating that it may be > > mounted using experimental kernel code, such as the ext4dev filesystem. > > diff --git a/misc/tune2fs.c b/misc/tune2fs.c > > index d6bfad3374d1..d6e75fe00814 100644 > > --- a/misc/tune2fs.c > > +++ b/misc/tune2fs.c > > @@ -92,6 +92,7 @@ static char *features_cmd; > > static char *mntopts_cmd; > > static int stride, stripe_width; > > static int stride_set, stripe_width_set; > > +static unsigned long new_first_ino; > > static char *extended_cmd; > > static unsigned long new_inode_size; > > static char *ext_mount_opts; > > @@ -2298,6 +2299,34 @@ static int parse_extended_opts(ext2_filsys fs, const char *opts) > > continue; > > } > > ext_mount_opts = strdup(arg); > > + } else if (!strcmp(token, "reserved_inodes")) { > > + if (!arg) { > > + r_usage++; > > + continue; > > + } > > + new_first_ino = strtoul(arg, &p, 0); > > + if (*p) { > > + fprintf(stderr, > > + _("Invalid number of reserved inodes " > > + "%s\n"), > > + arg); > > + r_usage++; > > + continue; > > + } > > + /* Ino 0 is invalid so bump by 1... */ > > + new_first_ino++; > > + if (new_first_ino < EXT2_GOOD_OLD_FIRST_INO) { > > + fprintf(stderr, > > + _("Too few reserved inodes " > > + "%s (must be at least %u)\n"), > > + arg, EXT2_GOOD_OLD_FIRST_INO - 1); > > + r_usage++; > > + continue; > > + } > > + /* > > + * Here should go further feature tests to disallow > > + * admin to free used system inode > > + */ > > Not only should this check that the new_first_ino isn't shrinking too > small to cover in-use special inodes, it should also verify that it > isn't growing to cover in-use normal inodes (e.g. lost+found). > > I guess one option might be to reserve "12" for the lost+found inode, > since virtually all filesystems have it this way (though not all), > and it would also help e2fsck in the future if it didn't need to > allocate some other inode for lost+found in case of corruption. We do take care to move any normal inodes that are in the way. So this isn't an issue... That's why I had to refactor all the resize code after all... Honza > > Cheers, Andreas > > > } else > > r_usage++; > > } > > @@ -2312,6 +2341,7 @@ static int parse_extended_opts(ext2_filsys fs, const char *opts) > > "\tmount_opts=\n" > > "\tstride=\n" > > "\tstripe_width=\n" > > + "\treserved_inodes=\n" > > "\ttest_fs\n" > > "\t^test_fs\n")); > > free(buf); > > @@ -2986,6 +3016,75 @@ fs_update_journal_user(struct ext2_super_block *sb, __u8 old_uuid[UUID_SIZE]) > > return 0; > > } > > > > +/* Zero range of inodes and mark them as free / used */ > > +static errcode_t zero_inodes_range(ext2_filsys fs, ext2_ino_t start, > > + ext2_ino_t end, int inuse) > > +{ > > + char *inode; > > + int length = EXT2_INODE_SIZE(fs->super); > > + ext2_ino_t ino; > > + errcode_t retval; > > + > > + retval = ext2fs_get_memzero(length, &inode); > > + if (retval) > > + return retval; > > + > > + for (ino = start; ino <= end; ino++) { > > + ext2fs_inode_alloc_stats(fs, ino, inuse); > > + retval = ext2fs_write_inode_full(fs, ino, > > + (struct ext2_inode *)inode, > > + length); > > + if (retval) > > + break; > > + } > > + ext2fs_free_mem(inode); > > + > > + return retval; > > +} > > + > > +static errcode_t update_reserved_inodes(ext2_filsys fs) > > +{ > > + errcode_t retval = 0; > > + ext2fs_inode_bitmap imap; > > + ext2_ino_t ino, first_ino = fs->super->s_first_ino; > > + > > + if (new_first_ino == first_ino) > > + return 0; > > + > > + /* Group descriptors will need writing as well */ > > + fs->flags &= ~EXT2_FLAG_SUPER_ONLY; > > + > > + /* Freeing reserved inodes is easy */ > > + if (new_first_ino < first_ino) { > > + retval = zero_inodes_range(fs, new_first_ino, first_ino - 1, > > + -1); > > + if (retval) > > + return retval; > > + goto out; > > + } > > + > > + retval = ext2fs_allocate_inode_bitmap(fs, "inodes to move", &imap); > > + if (retval) > > + return retval; > > + > > + for (ino = fs->super->s_first_ino; ino < new_first_ino; ino++) > > + ext2fs_mark_inode_bitmap2(imap, ino); > > + > > + retval = ext2fs_move_inodes(fs, imap); > > + ext2fs_free_inode_bitmap(imap); > > + if (retval) > > + return retval; > > + > > + retval = zero_inodes_range(fs, first_ino, new_first_ino - 1, +1); > > + if (retval) > > + return retval; > > +out: > > + fs->super->s_first_ino = new_first_ino; > > + ext2fs_mark_super_dirty(fs); > > + > > + return 0; > > +} > > + > > int main(int argc, char **argv) > > { > > errcode_t retval; > > @@ -3404,6 +3503,9 @@ retry_open: > > if (feature_64bit) > > convert_64bit(&fs, feature_64bit); > > > > + if (new_first_ino) > > + update_reserved_inodes(fs); > > + > > if (rewrite_checksums) > > rewrite_metadata_checksums(fs); > > > > -- > > 2.1.4 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > Cheers, Andreas > > > > > > -- Jan Kara SUSE Labs, CR