linux-kernel - RE: [PATCH v2 05/13] exfat: add file operations

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Date:   Thu, 21 Nov 2019 10:42:13 +0900
From:   "Namjae Jeon" <namjae.jeon@...sung.com>
To:     "'Nikolay Borisov'" <nborisov@...e.com>
Cc:     <gregkh@...uxfoundation.org>, <valdis.kletnieks@...edu>,
        <hch@....de>, <linkinjeon@...il.com>, <Markus.Elfring@....de>,
        <sj1557.seo@...sung.com>, <linux-kernel@...r.kernel.org>,
        <linux-fsdevel@...r.kernel.org>
Subject: RE: [PATCH v2 05/13] exfat: add file operations


> > +static int exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode
> *inode)
> > +{
> > +	mode_t allow_utime = sbi->options.allow_utime;
> > +
> > +	if (!uid_eq(current_fsuid(), inode->i_uid)) {
> > +		if (in_group_p(inode->i_gid))
> > +			allow_utime >>= 3;
> > +		if (allow_utime & MAY_WRITE)
> > +			return 1;
> > +	}
> > +
> > +	/* use a default check */
> > +	return 0;
> 
> this function can be made to return bool.
Okay.
> 
> > +}
> > +
> 
> <snip>
> 
> > +/* resize the file length */
> > +int __exfat_truncate(struct inode *inode, loff_t new_size)
> > +{
> > +	unsigned int num_clusters_new, num_clusters_phys;
> > +	unsigned int last_clu = FREE_CLUSTER;
> > +	struct exfat_chain clu;
> > +	struct exfat_timestamp tm;
> > +	struct exfat_dentry *ep, *ep2;
> > +	struct super_block *sb = inode->i_sb;
> > +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> > +	struct exfat_inode_info *ei = EXFAT_I(inode);
> > +	struct exfat_entry_set_cache *es = NULL;
> > +	int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0;
> > +
> > +	/* check if the given file ID is opened */
> > +	if (ei->type != TYPE_FILE && ei->type != TYPE_DIR)
> > +		return -EPERM;
> > +
> > +	exfat_set_vol_flags(sb, VOL_DIRTY);
> > +
> > +	num_clusters_new = EXFAT_B_TO_CLU_ROUND_UP(i_size_read(inode), sbi);
> > +	num_clusters_phys =
> > +		EXFAT_B_TO_CLU_ROUND_UP(EXFAT_I(inode)->i_size_ondisk, sbi);
> > +
> > +	exfat_chain_set(&clu, ei->start_clu, num_clusters_phys, ei->flags);
> > +
> > +	if (new_size > 0) {
> > +		/*
> > +		 * Truncate FAT chain num_clusters after the first cluster
> > +		 * num_clusters = min(new, phys);
> > +		 */
> > +		unsigned int num_clusters =
> > +			min(num_clusters_new, num_clusters_phys);
> > +
> > +		/*
> > +		 * Follow FAT chain
> > +		 * (defensive coding - works fine even with corrupted FAT table
> > +		 */
> > +		if (clu.flags == 0x03) {
> 
> That 0x03 is magic constant, better define actual flags and check
> clu.flag == (FLAG1|FLAG2)
Okay, Will fix it on v4.

Thanks for your review!