On Aug 16, 2017, at 9:41 AM, Jan Kara <jack@xxxxxxx> wrote:
>
> Push down acquisition of dqio_sem into ->read_file_info() callback. This
> is for consistency with other operations and it also allows us to get
> rid of an ugliness in OCFS2.
Always nice to get rid of workarounds like this (which I admit I've had to
do similar things in the past as well).
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
One minor cleanup suggestion below, but probably for a later patch.
> Signed-off-by: Jan Kara <jack@xxxxxxx>
>
> diff --git a/fs/quota/quota_v2.c b/fs/quota/quota_v2.c
> index 5e47012d2f57..373d7cfea5b0 100644
> --- a/fs/quota/quota_v2.c
> +++ b/fs/quota/quota_v2.c
> @@ -90,29 +90,38 @@ static int v2_read_file_info(struct super_block *sb, int type)
> {
> struct v2_disk_dqinfo dinfo;
> struct v2_disk_dqheader dqhead;
> - struct mem_dqinfo *info = sb_dqinfo(sb, type);
> + struct quota_info *dqopt = sb_dqopt(sb);
> + struct mem_dqinfo *info = &dqopt->info[type];
> struct qtree_mem_dqinfo *qinfo;
> ssize_t size;
> unsigned int version;
> + int ret;
>
> - if (!v2_read_header(sb, type, &dqhead))
> - return -1;
> + down_read(&dqopt->dqio_sem);
> + if (!v2_read_header(sb, type, &dqhead)) {
> + ret = -1;
This is a bit strange to return -1 here, but -ENOMEM below. The various
->quota_read() methods return -EIO or other proper error codes, so it
makes sense to return those back from v2_read_header() and onward here.
> + goto out;
> + }
> version = le32_to_cpu(dqhead.dqh_version);
> if ((info->dqi_fmt_id == QFMT_VFS_V0 && version != 0) ||
> - (info->dqi_fmt_id == QFMT_VFS_V1 && version != 1))
> - return -1;
> + (info->dqi_fmt_id == QFMT_VFS_V1 && version != 1)) {
> + ret = -1;
This could be -EINVAL or -EIO or similar.
> + goto out;
> + }
>
> size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
> sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
> if (size != sizeof(struct v2_disk_dqinfo)) {
> quota_error(sb, "Can't read info structure");
> - return -1;
> + ret = -1;
> + goto out;
->quota_read() is returning a proper error code, except in the case of
short reads, which could be converted to -EIO or similar.
> }
> info->dqi_priv = kmalloc(sizeof(struct qtree_mem_dqinfo), GFP_NOFS);
> if (!info->dqi_priv) {
> printk(KERN_WARNING
> "Not enough memory for quota information structure.\n");
> - return -ENOMEM;
> + ret = -ENOMEM;
> + goto out;
> }
> qinfo = info->dqi_priv;
> if (version == 0) {
> @@ -147,7 +156,10 @@ static int v2_read_file_info(struct super_block *sb, int type)
> qinfo->dqi_entry_size = sizeof(struct v2r1_disk_dqblk);
> qinfo->dqi_ops = &v2r1_qtree_ops;
> }
> - return 0;
> + ret = 0;
> +out:
> + up_read(&dqopt->dqio_sem);
> + return ret;
> }
>
> /* Write information header to quota file */
> --
> 2.12.3
>
Cheers, Andreas
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