Re: [PATCH v22 11/16] xfs: Add xfs_attr_set_deferred and xfs_attr_remove_deferred

Allison Henderson
2021-08-02T08:33:42Z

On 7/30/21 7:58 AM, Chandan Babu R wrote:
> On 27 Jul 2021 at 11:50, Allison Henderson wrote:
>> From: Allison Collins <allison.henderson@oracle.com>
>>
>> These routines set up and queue a new deferred attribute operations.
>> These functions are meant to be called by any routine needing to
>> initiate a deferred attribute operation as opposed to the existing
>> inline operations. New helper function xfs_attr_item_init also added.
>>
>> Finally enable delayed attributes in xfs_attr_set and xfs_attr_remove.
>
> Apart from the issues pointed out by Darrick, the remaining changes seem to be
> fine.
Alrighty! Thanks!

Allison

>
>>
>> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
>> ---
>> fs/xfs/libxfs/xfs_attr.c | 70 +++++++++++++++++++++++++++++++++++++++++++++---
>> fs/xfs/libxfs/xfs_attr.h | 2 ++
>> fs/xfs/xfs_log.c | 41 ++++++++++++++++++++++++++++
>> fs/xfs/xfs_log.h | 1 +
>> 4 files changed, 111 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>> index eee219c6..c447c21 100644
>> --- a/fs/xfs/libxfs/xfs_attr.c
>> +++ b/fs/xfs/libxfs/xfs_attr.c
>> @@ -25,6 +25,8 @@
>> #include "xfs_trans_space.h"
>> #include "xfs_trace.h"
>> #include "xfs_attr_item.h"
>> +#include "xfs_attr.h"
>> +#include "xfs_log.h"
>>
>> /*
>> * xfs_attr.c
>> @@ -779,13 +781,19 @@ xfs_attr_set(
>> rmt_blks = xfs_attr3_rmt_blocks(mp, XFS_XATTR_SIZE_MAX);
>> }
>>
>> + if (xfs_hasdelattr(mp)) {
>> + error = xfs_attr_use_log_assist(mp);
>> + if (error)
>> + return error;
>> + }
>> +
>> /*
>> * Root fork attributes can use reserved data blocks for this
>> * operation if necessary
>> */
>> error = xfs_trans_alloc_inode(dp, &tres, total, 0, rsvd, &args->trans);
>> if (error)
>> - return error;
>> + goto drop_incompat;
>>
>> if (args->value || xfs_inode_hasattr(dp)) {
>> error = xfs_iext_count_may_overflow(dp, XFS_ATTR_FORK,
>> @@ -803,9 +811,10 @@ xfs_attr_set(
>> if (error != -ENOATTR && error != -EEXIST)
>> goto out_trans_cancel;
>>
>> - error = xfs_attr_set_args(args);
>> + error = xfs_attr_set_deferred(args);
>> if (error)
>> goto out_trans_cancel;
>> +
>> /* shortform attribute has already been committed */
>> if (!args->trans)
>> goto out_unlock;
>> @@ -814,7 +823,7 @@ xfs_attr_set(
>> if (error != -EEXIST)
>> goto out_trans_cancel;
>>
>> - error = xfs_attr_remove_args(args);
>> + error = xfs_attr_remove_deferred(args);
>> if (error)
>> goto out_trans_cancel;
>> }
>> @@ -836,6 +845,9 @@ xfs_attr_set(
>> error = xfs_trans_commit(args->trans);
>> out_unlock:
>> xfs_iunlock(dp, XFS_ILOCK_EXCL);
>> +drop_incompat:
>> + if (xfs_hasdelattr(mp))
>> + xlog_drop_incompat_feat(mp->m_log);
>> return error;
>>
>> out_trans_cancel:
>> @@ -844,6 +856,58 @@ xfs_attr_set(
>> goto out_unlock;
>> }
>>
>> +STATIC int
>> +xfs_attr_item_init(
>> + struct xfs_da_args *args,
>> + unsigned int op_flags, /* op flag (set or remove) */
>> + struct xfs_attr_item **attr) /* new xfs_attr_item */
>> +{
>> +
>> + struct xfs_attr_item *new;
>> +
>> + new = kmem_zalloc(sizeof(struct xfs_attr_item), KM_NOFS);
>> + new->xattri_op_flags = op_flags;
>> + new->xattri_dac.da_args = args;
>> +
>> + *attr = new;
>> + return 0;
>> +}
>> +
>> +/* Sets an attribute for an inode as a deferred operation */
>> +int
>> +xfs_attr_set_deferred(
>> + struct xfs_da_args *args)
>> +{
>> + struct xfs_attr_item *new;
>> + int error = 0;
>> +
>> + error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
>> + if (error)
>> + return error;
>> +
>> + xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
>> +
>> + return 0;
>> +}
>> +
>> +/* Removes an attribute for an inode as a deferred operation */
>> +int
>> +xfs_attr_remove_deferred(
>> + struct xfs_da_args *args)
>> +{
>> +
>> + struct xfs_attr_item *new;
>> + int error;
>> +
>> + error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REMOVE, &new);
>> + if (error)
>> + return error;
>> +
>> + xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
>> +
>> + return 0;
>> +}
>> +
>> /*========================================================================
>> * External routines when attribute list is inside the inode
>> *========================================================================*/
>> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
>> index 463b2be..72b0ea5 100644
>> --- a/fs/xfs/libxfs/xfs_attr.h
>> +++ b/fs/xfs/libxfs/xfs_attr.h
>> @@ -527,5 +527,7 @@ bool xfs_attr_namecheck(const void *name, size_t length);
>> void xfs_delattr_context_init(struct xfs_delattr_context *dac,
>> struct xfs_da_args *args);
>> int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
>> +int xfs_attr_set_deferred(struct xfs_da_args *args);
>> +int xfs_attr_remove_deferred(struct xfs_da_args *args);
>>
>> #endif /* __XFS_ATTR_H__ */
>> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
>> index 7c593d9..216de6c 100644
>> --- a/fs/xfs/xfs_log.c
>> +++ b/fs/xfs/xfs_log.c
>> @@ -3948,3 +3948,44 @@ xlog_drop_incompat_feat(
>> {
>> up_read(&log->l_incompat_users);
>> }
>> +
>> +/*
>> + * Get permission to use log-assisted atomic exchange of file extents.
>> + *
>> + * Callers must not be running any transactions or hold any inode locks, and
>> + * they must release the permission by calling xlog_drop_incompat_feat
>> + * when they're done.
>> + */
>> +int
>> +xfs_attr_use_log_assist(
>> + struct xfs_mount *mp)
>> +{
>> + int error = 0;
>> +
>> + /*
>> + * Protect ourselves from an idle log clearing the logged xattrs log
>> + * incompat feature bit.
>> + */
>> + xlog_use_incompat_feat(mp->m_log);
>> +
>> + /*
>> + * If log-assisted xattrs are already enabled, the caller can use the
>> + * log assisted swap functions with the log-incompat reference we got.
>> + */
>> + if (xfs_sb_version_hasdelattr(&mp->m_sb))
>> + return 0;
>> +
>> + /* Enable log-assisted xattrs. */
>> + xfs_warn_once(mp,
>> +"EXPERIMENTAL logged extended attributes feature added. Use at your own risk!");
>> +
>> + error = xfs_add_incompat_log_feature(mp,
>> + XFS_SB_FEAT_INCOMPAT_LOG_DELATTR);
>> + if (error)
>> + goto drop_incompat;
>> +
>> + return 0;
>> +drop_incompat:
>> + xlog_drop_incompat_feat(mp->m_log);
>> + return error;
>> +}
>> diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
>> index b274fb9..1e461671 100644
>> --- a/fs/xfs/xfs_log.h
>> +++ b/fs/xfs/xfs_log.h
>> @@ -144,5 +144,6 @@ xfs_lsn_t xlog_grant_push_threshold(struct xlog *log, int need_bytes);
>>
>> void xlog_use_incompat_feat(struct xlog *log);
>> void xlog_drop_incompat_feat(struct xlog *log);
>> +int xfs_attr_use_log_assist(struct xfs_mount *mp);
>>
>> #endif /* __XFS_LOG_H__ */
>
>
> --
> chandan
>