Re: [PATCH v15 16/22] xfs: Set up infastructure for deferred attribute operations

From: Allison Henderson <allison.henderson@oracle.com>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH v15 16/22] xfs: Set up infastructure for deferred attribute operations
Date: Tue, 2 Mar 2021 00:13:23 -0700	[thread overview]
Message-ID: <83053a19-3ac0-ff9a-60ef-30a2a513325a@oracle.com> (raw)
In-Reply-To: <88ef7647-5898-888e-e4f0-0a115835759b@oracle.com>

On 2/26/21 5:56 PM, Allison Henderson wrote:
> 
> 
> On 2/25/21 9:58 PM, Darrick J. Wong wrote:
>> On Thu, Feb 18, 2021 at 09:53:42AM -0700, Allison Henderson wrote:
>>> Currently attributes are modified directly across one or more
>>> transactions. But they are not logged or replayed in the event of an
>>> error. The goal of delayed attributes is to enable logging and replaying
>>> of attribute operations using the existing delayed operations
>>> infrastructure.  This will later enable the attributes to become part of
>>> larger multi part operations that also must first be recorded to the
>>> log.  This is mostly of interest in the scheme of parent pointers which
>>> would need to maintain an attribute containing parent inode information
>>> any time an inode is moved, created, or removed.  Parent pointers would
>>> then be of interest to any feature that would need to quickly derive an
>>> inode path from the mount point. Online scrub, nfs lookups and fs grow
>>> or shrink operations are all features that could take advantage of this.
>>>
>>> This patch adds two new log item types for setting or removing
>>> attributes as deferred operations.  The xfs_attri_log_item logs an
>>> intent to set or remove an attribute.  The corresponding
>>> xfs_attrd_log_item holds a reference to the xfs_attri_log_item and is
>>> freed once the transaction is done.  Both log items use a generic
>>> xfs_attr_log_format structure that contains the attribute name, value,
>>> flags, inode, and an op_flag that indicates if the operations is a set
>>> or remove.
>>>
>>> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>>
>> I saw a 36K patch and thought "Jeez!  This should be broken up!"
>>
>> Then I looked at atomic extent swap (which does add its log item code
>> gradually) and decided that maybe you just don't want to explode the
>> patchset from 22 to 30.  That sounds (kind of) reasonable.
>>
>> (...and by 'kind of', I probably mean that if I end up taking everything
>> up to this patch for 5.13 then this part really ought to get broken up a
>> bit for a future submission.  But let's wait until the end of this
>> review to decide that...)
> 
> Yes, I've thought about falling back into a "Delay ready" sub series 
> again.  It think the focus right now is the state machine and getting 
> everyone on board with that, so I think it's reasonable to delay this 
> part for now.  Since really the statemachine is a bit of a pre-req for 
> this.
> 
> Allison
I'm sorry, I didnt see you had more feed back.  Comments below...
>>
>>> ---
>>>   fs/xfs/Makefile                 |   1 +
>>>   fs/xfs/libxfs/xfs_attr.c        |   7 +-
>>>   fs/xfs/libxfs/xfs_attr.h        |  31 ++
>>>   fs/xfs/libxfs/xfs_defer.c       |   1 +
>>>   fs/xfs/libxfs/xfs_defer.h       |   3 +
>>>   fs/xfs/libxfs/xfs_log_format.h  |  44 ++-
>>>   fs/xfs/libxfs/xfs_log_recover.h |   2 +
>>>   fs/xfs/scrub/common.c           |   2 +
>>>   fs/xfs/xfs_acl.c                |   2 +
>>>   fs/xfs/xfs_attr_item.c          | 828 
>>> ++++++++++++++++++++++++++++++++++++++++
>>>   fs/xfs/xfs_attr_item.h          |  52 +++
>>>   fs/xfs/xfs_attr_list.c          |   1 +
>>>   fs/xfs/xfs_ioctl.c              |   2 +
>>>   fs/xfs/xfs_ioctl32.c            |   2 +
>>>   fs/xfs/xfs_iops.c               |   2 +
>>>   fs/xfs/xfs_log.c                |   4 +
>>>   fs/xfs/xfs_log_recover.c        |   2 +
>>>   fs/xfs/xfs_ondisk.h             |   2 +
>>>   fs/xfs/xfs_xattr.c              |   1 +
>>>   19 files changed, 984 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
>>> index 04611a1..b056cfc 100644
>>> --- a/fs/xfs/Makefile
>>> +++ b/fs/xfs/Makefile
>>> @@ -102,6 +102,7 @@ xfs-y                += xfs_log.o \
>>>                      xfs_buf_item_recover.o \
>>>                      xfs_dquot_item_recover.o \
>>>                      xfs_extfree_item.o \
>>> +                   xfs_attr_item.o \
>>>                      xfs_icreate_item.o \
>>>                      xfs_inode_item.o \
>>>                      xfs_inode_item_recover.o \
>>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>>> index 2b8e481..e4c1b4b 100644
>>> --- a/fs/xfs/libxfs/xfs_attr.c
>>> +++ b/fs/xfs/libxfs/xfs_attr.c
>>> @@ -24,6 +24,7 @@
>>>   #include "xfs_quota.h"
>>>   #include "xfs_trans_space.h"
>>>   #include "xfs_trace.h"
>>> +#include "xfs_attr_item.h"
>>>   /*
>>>    * xfs_attr.c
>>> @@ -61,8 +62,8 @@ STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
>>>                    struct xfs_da_state **state);
>>>   STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
>>>   STATIC int xfs_attr_refillstate(xfs_da_state_t *state);
>>> -STATIC int xfs_attr_set_iter(struct xfs_delattr_context *dac,
>>> -                 struct xfs_buf **leaf_bp);
>>> +int xfs_attr_set_iter(struct xfs_delattr_context *dac,
>>> +              struct xfs_buf **leaf_bp);
>>>   int
>>>   xfs_inode_hasattr(
>>> @@ -144,7 +145,7 @@ xfs_attr_get(
>>>   /*
>>>    * Calculate how many blocks we need for the new attribute,
>>>    */
>>> -STATIC int
>>> +int
>>>   xfs_attr_calc_size(
>>>       struct xfs_da_args    *args,
>>>       int            *local)
>>> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
>>> index 603887e..ee79763 100644
>>> --- a/fs/xfs/libxfs/xfs_attr.h
>>> +++ b/fs/xfs/libxfs/xfs_attr.h
>>> @@ -28,6 +28,11 @@ struct xfs_attr_list_context;
>>>    */
>>>   #define    ATTR_MAX_VALUELEN    (64*1024)    /* max length of a 
>>> value */
>>> +static inline bool xfs_hasdelattr(struct xfs_mount *mp)
>>> +{
>>> +    return false;
>>> +}
>>> +
>>>   /*
>>>    * Kernel-internal version of the attrlist cursor.
>>>    */
>>> @@ -390,6 +395,7 @@ enum xfs_delattr_state {
>>>    */
>>>   #define XFS_DAC_DEFER_FINISH        0x01 /* finish the transaction */
>>>   #define XFS_DAC_LEAF_ADDNAME_INIT    0x02 /* xfs_attr_leaf_addname 
>>> init*/
>>> +#define XFS_DAC_DELAYED_OP_INIT        0x04 /* delayed operations 
>>> init*/
>>>   /*
>>>    * Context used for keeping track of delayed attribute operations
>>> @@ -397,6 +403,11 @@ enum xfs_delattr_state {
>>>   struct xfs_delattr_context {
>>>       struct xfs_da_args      *da_args;
>>> +    /*
>>> +     * Used by xfs_attr_set to hold a leaf buffer across a 
>>> transaction roll
>>> +     */
>>> +    struct xfs_buf        *leaf_bp;
>>> +
>>>       /* Used in xfs_attr_rmtval_set_blk to roll through allocating 
>>> blocks */
>>>       struct xfs_bmbt_irec    map;
>>>       xfs_dablk_t        lblkno;
>>> @@ -410,6 +421,23 @@ struct xfs_delattr_context {
>>>       enum xfs_delattr_state  dela_state;
>>>   };
>>> +/*
>>> + * List of attrs to commit later.
>>> + */
>>> +struct xfs_attr_item {
>>> +    struct xfs_delattr_context    xattri_dac;
>>> +
>>> +    /*
>>> +     * Indicates if the attr operation is a set or a remove
>>> +     * XFS_ATTR_OP_FLAGS_{SET,REMOVE}
>>> +     */
>>> +    uint32_t            xattri_op_flags;
>>> +
>>> +    /* used to log this item to an intent */
>>> +    struct list_head        xattri_list;
>>> +};
>>> +
>>> +
>>>   
>>> /*======================================================================== 
>>>
>>>    * Function prototypes for the kernel.
>>>    
>>> *========================================================================*/ 
>>>
>>> @@ -425,11 +453,14 @@ int xfs_attr_get_ilocked(struct xfs_da_args 
>>> *args);
>>>   int xfs_attr_get(struct xfs_da_args *args);
>>>   int xfs_attr_set(struct xfs_da_args *args);
>>>   int xfs_attr_set_args(struct xfs_da_args *args);
>>> +int xfs_attr_set_iter(struct xfs_delattr_context *dac,
>>> +              struct xfs_buf **leaf_bp);
>>>   int xfs_has_attr(struct xfs_da_args *args);
>>>   int xfs_attr_remove_args(struct xfs_da_args *args);
>>>   int xfs_attr_remove_iter(struct xfs_delattr_context *dac);
>>>   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);
>>>   #endif    /* __XFS_ATTR_H__ */
>>> diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
>>> index eff4a12..e9caff7 100644
>>> --- a/fs/xfs/libxfs/xfs_defer.c
>>> +++ b/fs/xfs/libxfs/xfs_defer.c
>>> @@ -178,6 +178,7 @@ static const struct xfs_defer_op_type 
>>> *defer_op_types[] = {
>>>       [XFS_DEFER_OPS_TYPE_RMAP]    = &xfs_rmap_update_defer_type,
>>>       [XFS_DEFER_OPS_TYPE_FREE]    = &xfs_extent_free_defer_type,
>>>       [XFS_DEFER_OPS_TYPE_AGFL_FREE]    = &xfs_agfl_free_defer_type,
>>> +    [XFS_DEFER_OPS_TYPE_ATTR]    = &xfs_attr_defer_type,
>>>   };
>>>   static void
>>> diff --git a/fs/xfs/libxfs/xfs_defer.h b/fs/xfs/libxfs/xfs_defer.h
>>> index 05472f7..72a5789 100644
>>> --- a/fs/xfs/libxfs/xfs_defer.h
>>> +++ b/fs/xfs/libxfs/xfs_defer.h
>>> @@ -19,6 +19,7 @@ enum xfs_defer_ops_type {
>>>       XFS_DEFER_OPS_TYPE_RMAP,
>>>       XFS_DEFER_OPS_TYPE_FREE,
>>>       XFS_DEFER_OPS_TYPE_AGFL_FREE,
>>> +    XFS_DEFER_OPS_TYPE_ATTR,
>>>       XFS_DEFER_OPS_TYPE_MAX,
>>>   };
>>> @@ -63,6 +64,8 @@ extern const struct xfs_defer_op_type 
>>> xfs_refcount_update_defer_type;
>>>   extern const struct xfs_defer_op_type xfs_rmap_update_defer_type;
>>>   extern const struct xfs_defer_op_type xfs_extent_free_defer_type;
>>>   extern const struct xfs_defer_op_type xfs_agfl_free_defer_type;
>>> +extern const struct xfs_defer_op_type xfs_attr_defer_type;
>>> +
>>>   /*
>>>    * This structure enables a dfops user to detach the chain of deferred
>>> diff --git a/fs/xfs/libxfs/xfs_log_format.h 
>>> b/fs/xfs/libxfs/xfs_log_format.h
>>> index 8bd00da..19963b6 100644
>>> --- a/fs/xfs/libxfs/xfs_log_format.h
>>> +++ b/fs/xfs/libxfs/xfs_log_format.h
>>> @@ -117,7 +117,12 @@ struct xfs_unmount_log_format {
>>>   #define XLOG_REG_TYPE_CUD_FORMAT    24
>>>   #define XLOG_REG_TYPE_BUI_FORMAT    25
>>>   #define XLOG_REG_TYPE_BUD_FORMAT    26
>>> -#define XLOG_REG_TYPE_MAX        26
>>> +#define XLOG_REG_TYPE_ATTRI_FORMAT    27
>>> +#define XLOG_REG_TYPE_ATTRD_FORMAT    28
>>> +#define XLOG_REG_TYPE_ATTR_NAME    29
>>> +#define XLOG_REG_TYPE_ATTR_VALUE    30
>>> +#define XLOG_REG_TYPE_MAX        30
>>> +
>>>   /*
>>>    * Flags to log operation header
>>> @@ -240,6 +245,8 @@ typedef struct xfs_trans_header {
>>>   #define    XFS_LI_CUD        0x1243
>>>   #define    XFS_LI_BUI        0x1244    /* bmbt update intent */
>>>   #define    XFS_LI_BUD        0x1245
>>> +#define    XFS_LI_ATTRI        0x1246  /* attr set/remove intent*/
>>> +#define    XFS_LI_ATTRD        0x1247  /* attr set/remove done */
>>>   #define XFS_LI_TYPE_DESC \
>>>       { XFS_LI_EFI,        "XFS_LI_EFI" }, \
>>> @@ -255,7 +262,9 @@ typedef struct xfs_trans_header {
>>>       { XFS_LI_CUI,        "XFS_LI_CUI" }, \
>>>       { XFS_LI_CUD,        "XFS_LI_CUD" }, \
>>>       { XFS_LI_BUI,        "XFS_LI_BUI" }, \
>>> -    { XFS_LI_BUD,        "XFS_LI_BUD" }
>>> +    { XFS_LI_BUD,        "XFS_LI_BUD" }, \
>>> +    { XFS_LI_ATTRI,        "XFS_LI_ATTRI" }, \
>>> +    { XFS_LI_ATTRD,        "XFS_LI_ATTRD" }
>>>   /*
>>>    * Inode Log Item Format definitions.
>>> @@ -863,4 +872,35 @@ struct xfs_icreate_log {
>>>       __be32        icl_gen;    /* inode generation number to use */
>>>   };
>>> +/*
>>> + * Flags for deferred attribute operations.
>>> + * Upper bits are flags, lower byte is type code
>>> + */
>>> +#define XFS_ATTR_OP_FLAGS_SET        1    /* Set the attribute */
>>> +#define XFS_ATTR_OP_FLAGS_REMOVE    2    /* Remove the attribute */
>>> +#define XFS_ATTR_OP_FLAGS_TYPE_MASK    0x0FF    /* Flags type mask */
>>> +
>>> +/*
>>> + * This is the structure used to lay out an attr log item in the
>>> + * log.
>>> + */
>>> +struct xfs_attri_log_format {
>>> +    uint16_t    alfi_type;    /* attri log item type */
>>> +    uint16_t    alfi_size;    /* size of this item */
>>> +    uint32_t    __pad;        /* pad to 64 bit aligned */
>>> +    uint64_t    alfi_id;    /* attri identifier */
>>> +    uint64_t    alfi_ino;    /* the inode for this attr operation */
>>> +    uint32_t    alfi_op_flags;    /* marks the op as a set or remove */
>>> +    uint32_t    alfi_name_len;    /* attr name length */
>>> +    uint32_t    alfi_value_len;    /* attr value length */
>>> +    uint32_t    alfi_attr_flags;/* attr flags */
>>> +};
>>> +
>>> +struct xfs_attrd_log_format {
>>> +    uint16_t    alfd_type;    /* attrd log item type */
>>> +    uint16_t    alfd_size;    /* size of this item */
>>> +    uint32_t    __pad;        /* pad to 64 bit aligned */
>>> +    uint64_t    alfd_alf_id;    /* id of corresponding attri */
>>> +};
>>> +
>>>   #endif /* __XFS_LOG_FORMAT_H__ */
>>> diff --git a/fs/xfs/libxfs/xfs_log_recover.h 
>>> b/fs/xfs/libxfs/xfs_log_recover.h
>>> index 3cca2bf..b6e5514 100644
>>> --- a/fs/xfs/libxfs/xfs_log_recover.h
>>> +++ b/fs/xfs/libxfs/xfs_log_recover.h
>>> @@ -72,6 +72,8 @@ extern const struct xlog_recover_item_ops 
>>> xlog_rui_item_ops;
>>>   extern const struct xlog_recover_item_ops xlog_rud_item_ops;
>>>   extern const struct xlog_recover_item_ops xlog_cui_item_ops;
>>>   extern const struct xlog_recover_item_ops xlog_cud_item_ops;
>>> +extern const struct xlog_recover_item_ops xlog_attri_item_ops;
>>> +extern const struct xlog_recover_item_ops xlog_attrd_item_ops;
>>>   /*
>>>    * Macros, structures, prototypes for internal log manager use.
>>> diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
>>> index 53456f3..ac35121 100644
>>> --- a/fs/xfs/scrub/common.c
>>> +++ b/fs/xfs/scrub/common.c
>>> @@ -24,6 +24,8 @@
>>>   #include "xfs_rmap_btree.h"
>>>   #include "xfs_log.h"
>>>   #include "xfs_trans_priv.h"
>>> +#include "xfs_da_format.h"
>>> +#include "xfs_da_btree.h"
>>>   #include "xfs_attr.h"
>>>   #include "xfs_reflink.h"
>>>   #include "scrub/scrub.h"
>>> diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
>>> index 779cb73..79f7bd2 100644
>>> --- a/fs/xfs/xfs_acl.c
>>> +++ b/fs/xfs/xfs_acl.c
>>> @@ -10,6 +10,8 @@
>>>   #include "xfs_trans_resv.h"
>>>   #include "xfs_mount.h"
>>>   #include "xfs_inode.h"
>>> +#include "xfs_da_format.h"
>>> +#include "xfs_da_btree.h"
>>>   #include "xfs_attr.h"
>>>   #include "xfs_trace.h"
>>>   #include "xfs_error.h"
>>> diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
>>> new file mode 100644
>>> index 0000000..8c8f72d
>>> --- /dev/null
>>> +++ b/fs/xfs/xfs_attr_item.c
>>> @@ -0,0 +1,828 @@
>>> +// SPDX-License-Identifier: GPL-2.0-or-later
>>> +/*
>>> + * Copyright (C) 2021 Oracle.  All Rights Reserved.
>>> + * Author: Allison Collins <allison.henderson@oracle.com>
>>> + */
>>> +
>>> +#include "xfs.h"
>>> +#include "xfs_fs.h"
>>> +#include "xfs_format.h"
>>> +#include "xfs_log_format.h"
>>> +#include "xfs_trans_resv.h"
>>> +#include "xfs_bit.h"
>>> +#include "xfs_shared.h"
>>> +#include "xfs_mount.h"
>>> +#include "xfs_defer.h"
>>> +#include "xfs_da_format.h"
>>> +#include "xfs_log_format.h"
>>> +#include "xfs_trans.h"
>>> +#include "xfs_bmap.h"
>>> +#include "xfs_bmap_btree.h"
>>> +#include "xfs_trans_priv.h"
>>> +#include "xfs_buf_item.h"
>>> +#include "xfs_attr_item.h"
>>> +#include "xfs_log.h"
>>> +#include "xfs_btree.h"
>>> +#include "xfs_rmap.h"
>>> +#include "xfs_inode.h"
>>> +#include "xfs_icache.h"
>>> +#include "xfs_da_format.h"
>>> +#include "xfs_da_btree.h"
>>> +#include "xfs_attr.h"
>>> +#include "xfs_shared.h"
>>> +#include "xfs_attr_item.h"
>>> +#include "xfs_alloc.h"
>>> +#include "xfs_bmap.h"
>>> +#include "xfs_trace.h"
>>> +#include "libxfs/xfs_da_format.h"
>>> +#include "xfs_inode.h"
>>> +#include "xfs_quota.h"
>>> +#include "xfs_trans_space.h"
>>> +#include "xfs_log_priv.h"
>>> +#include "xfs_log_recover.h"
>>> +
>>> +static const struct xfs_item_ops xfs_attri_item_ops;
>>> +static const struct xfs_item_ops xfs_attrd_item_ops;
>>> +
>>> +/* iovec length must be 32-bit aligned */
>>> +static inline size_t ATTR_NVEC_SIZE(size_t size)
>>> +{
>>> +    return size == sizeof(int32_t) ? size :
>>> +           sizeof(int32_t) + round_up(size, sizeof(int32_t));
>>> +}
>>> +
>>> +static inline struct xfs_attri_log_item *ATTRI_ITEM(struct 
>>> xfs_log_item *lip)
>>> +{
>>> +    return container_of(lip, struct xfs_attri_log_item, attri_item);
>>> +}
>>> +
>>> +STATIC void
>>> +xfs_attri_item_free(
>>> +    struct xfs_attri_log_item    *attrip)
>>> +{
>>> +    kmem_free(attrip->attri_item.li_lv_shadow);
>>> +    kmem_free(attrip);
>>> +}
>>> +
>>> +/*
>>> + * Freeing the attrip requires that we remove it from the AIL if it 
>>> has already
>>> + * been placed there. However, the ATTRI may not yet have been 
>>> placed in the
>>> + * AIL when called by xfs_attri_release() from ATTRD processing due 
>>> to the
>>> + * ordering of committed vs unpin operations in bulk insert 
>>> operations. Hence
>>> + * the reference count to ensure only the last caller frees the ATTRI.
>>> + */
>>> +STATIC void
>>> +xfs_attri_release(
>>> +    struct xfs_attri_log_item    *attrip)
>>> +{
>>> +    ASSERT(atomic_read(&attrip->attri_refcount) > 0);
>>> +    if (atomic_dec_and_test(&attrip->attri_refcount)) {
>>> +        xfs_trans_ail_delete(&attrip->attri_item,
>>> +                     SHUTDOWN_LOG_IO_ERROR);
>>> +        xfs_attri_item_free(attrip);
>>> +    }
>>> +}
>>> +
>>> +STATIC void
>>> +xfs_attri_item_size(
>>> +    struct xfs_log_item    *lip,
>>> +    int            *nvecs,
>>> +    int            *nbytes)
>>> +{
>>> +    struct xfs_attri_log_item       *attrip = ATTRI_ITEM(lip);
>>> +
>>> +    *nvecs += 1;
>>> +    *nbytes += sizeof(struct xfs_attri_log_format);
>>> +
>>> +    /* Attr set and remove operations require a name */
>>> +    ASSERT(attrip->attri_name_len > 0);
>>> +
>>> +    *nvecs += 1;
>>> +    *nbytes += ATTR_NVEC_SIZE(attrip->attri_name_len);
>>> +
>>> +    /*
>>> +     * Set ops can accept a value of 0 len to clear an attr value.  
>>> Remove
>>> +     * ops do not need a value at all.  So only account for the value
>>> +     * when it is needed.
>>> +     */
>>> +    if (attrip->attri_value_len > 0) {
>>> +        *nvecs += 1;
>>> +        *nbytes += ATTR_NVEC_SIZE(attrip->attri_value_len);
>>> +    }
>>> +}
>>> +
>>> +/*
>>> + * This is called to fill in the log iovecs for the given attri log
>>> + * item. We use  1 iovec for the attri_format_item, 1 for the name, and
>>> + * another for the value if it is present
>>> + */
>>> +STATIC void
>>> +xfs_attri_item_format(
>>> +    struct xfs_log_item    *lip,
>>> +    struct xfs_log_vec    *lv)
>>> +{
>>> +    struct xfs_attri_log_item    *attrip = ATTRI_ITEM(lip);
>>> +    struct xfs_log_iovec        *vecp = NULL;
>>> +
>>> +    attrip->attri_format.alfi_type = XFS_LI_ATTRI;
>>> +    attrip->attri_format.alfi_size = 1;
>>> +
>>> +    /*
>>> +     * This size accounting must be done before copying the attrip 
>>> into the
>>> +     * iovec.  If we do it after, the wrong size will be recorded to 
>>> the log
>>> +     * and we trip across assertion checks for bad region sizes 
>>> later during
>>> +     * the log recovery.
>>> +     */
>>> +
>>> +    ASSERT(attrip->attri_name_len > 0);
>>> +    attrip->attri_format.alfi_size++;
>>> +
>>> +    if (attrip->attri_value_len > 0)
>>> +        attrip->attri_format.alfi_size++;
>>> +
>>> +    xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ATTRI_FORMAT,
>>> +            &attrip->attri_format,
>>> +            sizeof(struct xfs_attri_log_format));
>>> +    xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ATTR_NAME,
>>> +            attrip->attri_name,
>>> +            ATTR_NVEC_SIZE(attrip->attri_name_len));
>>> +    if (attrip->attri_value_len > 0)
>>> +        xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ATTR_VALUE,
>>> +                attrip->attri_value,
>>> +                ATTR_NVEC_SIZE(attrip->attri_value_len));
>>> +}
>>> +
>>> +/*
>>> + * The unpin operation is the last place an ATTRI is manipulated in 
>>> the log. It
>>> + * is either inserted in the AIL or aborted in the event of a log 
>>> I/O error. In
>>> + * either case, the ATTRI transaction has been successfully 
>>> committed to make
>>> + * it this far. Therefore, we expect whoever committed the ATTRI to 
>>> either
>>> + * construct and commit the ATTRD or drop the ATTRD's reference in 
>>> the event of
>>> + * error. Simply drop the log's ATTRI reference now that the log is 
>>> done with
>>> + * it.
>>> + */
>>> +STATIC void
>>> +xfs_attri_item_unpin(
>>> +    struct xfs_log_item    *lip,
>>> +    int            remove)
>>> +{
>>> +    xfs_attri_release(ATTRI_ITEM(lip));
>>> +}
>>> +
>>> +
>>> +STATIC void
>>> +xfs_attri_item_release(
>>> +    struct xfs_log_item    *lip)
>>> +{
>>> +    xfs_attri_release(ATTRI_ITEM(lip));
>>> +}
>>> +
>>> +/*
>>> + * Allocate and initialize an attri item.  Caller may allocate an 
>>> additional
>>> + * trailing buffer of the specified size
>>> + */
>>> +STATIC struct xfs_attri_log_item *
>>> +xfs_attri_init(
>>> +    struct xfs_mount        *mp,
>>> +    int                buffer_size)
>>> +
>>> +{
>>> +    struct xfs_attri_log_item    *attrip;
>>> +    uint                size;
>>> +
>>> +    size = sizeof(struct xfs_attri_log_item) + buffer_size;
>>> +    attrip = kmem_alloc_large(size, KM_ZERO);
>>> +    if (attrip == NULL)
>>> +        return NULL;
>>> +
>>> +    xfs_log_item_init(mp, &attrip->attri_item, XFS_LI_ATTRI,
>>> +              &xfs_attri_item_ops);
>>> +    attrip->attri_format.alfi_id = (uintptr_t)(void *)attrip;
>>> +    atomic_set(&attrip->attri_refcount, 2);
>>> +
>>> +    return attrip;
>>> +}
>>> +
>>> +/*
>>> + * Copy an attr format buffer from the given buf, and into the 
>>> destination attr
>>> + * format structure.
>>> + */
>>> +STATIC int
>>> +xfs_attri_copy_format(
>>> +    struct xfs_log_iovec        *buf,
>>> +    struct xfs_attri_log_format    *dst_attr_fmt)
>>> +{
>>> +    struct xfs_attri_log_format    *src_attr_fmt = buf->i_addr;
>>> +    uint                len;
>>> +
>>> +    len = sizeof(struct xfs_attri_log_format);
>>> +    if (buf->i_len != len)
>>> +        return -EFSCORRUPTED;
>>> +
>>> +    memcpy((char *)dst_attr_fmt, (char *)src_attr_fmt, len);
>>> +    return 0;
>>> +}
>>> +
>>> +static inline struct xfs_attrd_log_item *ATTRD_ITEM(struct 
>>> xfs_log_item *lip)
>>> +{
>>> +    return container_of(lip, struct xfs_attrd_log_item, attrd_item);
>>> +}
>>> +
>>> +STATIC void
>>> +xfs_attrd_item_free(struct xfs_attrd_log_item *attrdp)
>>> +{
>>> +    kmem_free(attrdp->attrd_item.li_lv_shadow);
>>> +    kmem_free(attrdp);
>>> +}
>>> +
>>> +STATIC void
>>> +xfs_attrd_item_size(
>>> +    struct xfs_log_item        *lip,
>>> +    int                *nvecs,
>>> +    int                *nbytes)
>>> +{
>>> +    *nvecs += 1;
>>> +    *nbytes += sizeof(struct xfs_attrd_log_format);
>>> +}
>>> +
>>> +/*
>>> + * This is called to fill in the log iovecs for the given attrd log 
>>> item. We use
>>> + * only 1 iovec for the attrd_format, and we point that at the 
>>> attr_log_format
>>> + * structure embedded in the attrd item.
>>> + */
>>> +STATIC void
>>> +xfs_attrd_item_format(
>>> +    struct xfs_log_item    *lip,
>>> +    struct xfs_log_vec    *lv)
>>> +{
>>> +    struct xfs_attrd_log_item    *attrdp = ATTRD_ITEM(lip);
>>> +    struct xfs_log_iovec        *vecp = NULL;
>>> +
>>> +    attrdp->attrd_format.alfd_type = XFS_LI_ATTRD;
>>> +    attrdp->attrd_format.alfd_size = 1;
>>> +
>>> +    xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ATTRD_FORMAT,
>>> +            &attrdp->attrd_format,
>>> +            sizeof(struct xfs_attrd_log_format));
>>> +}
>>> +
>>> +/*
>>> + * The ATTRD is either committed or aborted if the transaction is 
>>> cancelled. If
>>> + * the transaction is cancelled, drop our reference to the ATTRI and 
>>> free the
>>> + * ATTRD.
>>> + */
>>> +STATIC void
>>> +xfs_attrd_item_release(
>>> +    struct xfs_log_item        *lip)
>>> +{
>>> +    struct xfs_attrd_log_item    *attrdp = ATTRD_ITEM(lip);
>>> +
>>> +    xfs_attri_release(attrdp->attrd_attrip);
>>> +    xfs_attrd_item_free(attrdp);
>>> +}
>>> +
>>> +/*
>>> + * Performs one step of an attribute update intent and marks the 
>>> attrd item
>>> + * dirty..  An attr operation may be a set or a remove.  Note that the
>>> + * transaction is marked dirty regardless of whether the operation 
>>> succeeds or
>>> + * fails to support the ATTRI/ATTRD lifecycle rules.
>>> + */
>>> +int
>>> +xfs_trans_attr(
>>
>> xfs_attri_finish_update() ?
Well, while this is more descriptive, I think it's a bit of an 
anti-pattern.  xfs_trans_attr sort of fit with the existing scheme that 
the other delayed ops did.  Like xfs_trans_free_extent, 
xfs_trans_log_finish_refcount_update or 
xfs_trans_log_finish_bmap_update.  I guess I just noticed the pattern of 
a xfs_trans_* getting called by it's corresponding xfs_*_finish_item. 
So I figured xfs_trans_attr would be consistent?  I suppose if 
consistency is not a concern though, xfs_attri_finish_update is 
appropriate as long as everyone else is ok with it.

>>
>>> +    struct xfs_delattr_context    *dac,
>>> +    struct xfs_attrd_log_item    *attrdp,
>>> +    struct xfs_buf            **leaf_bp,
>>> +    uint32_t            op_flags)
>>> +{
>>> +    struct xfs_da_args        *args = dac->da_args;
>>> +    int                error;
>>> +
>>> +    error = xfs_qm_dqattach_locked(args->dp, 0);
>>> +    if (error)
>>> +        return error;
>>> +
>>> +    switch (op_flags) {
>>> +    case XFS_ATTR_OP_FLAGS_SET:
>>> +        args->op_flags |= XFS_DA_OP_ADDNAME;
>>> +        error = xfs_attr_set_iter(dac, leaf_bp);
>>> +        break;
>>> +    case XFS_ATTR_OP_FLAGS_REMOVE:
>>> +        ASSERT(XFS_IFORK_Q(args->dp));
>>> +        error = xfs_attr_remove_iter(dac);
>>> +        break;
>>> +    default:
>>> +        error = -EFSCORRUPTED;
>>> +        break;
>>> +    }
>>> +
>>> +    /*
>>> +     * Mark the transaction dirty, even on error. This ensures the
>>> +     * transaction is aborted, which:
>>> +     *
>>> +     * 1.) releases the ATTRI and frees the ATTRD
>>> +     * 2.) shuts down the filesystem
>>> +     */
>>> +    args->trans->t_flags |= XFS_TRANS_DIRTY;
>>> +
>>> +    /*
>>> +     * attr intent/done items are null when delayed attributes are 
>>> disabled
>>> +     */
>>> +    if (attrdp)
>>> +        set_bit(XFS_LI_DIRTY, &attrdp->attrd_item.li_flags);
>>> +
>>> +    return error;
>>> +}
>>> +
>>> +/* Log an attr to the intent item. */
>>> +STATIC void
>>> +xfs_attr_log_item(
>>> +    struct xfs_trans        *tp,
>>> +    struct xfs_attri_log_item    *attrip,
>>> +    struct xfs_attr_item        *attr)
>>> +{
>>> +    struct xfs_attri_log_format    *attrp;
>>> +
>>> +    tp->t_flags |= XFS_TRANS_DIRTY;
>>> +    set_bit(XFS_LI_DIRTY, &attrip->attri_item.li_flags);
>>> +
>>> +    /*
>>> +     * At this point the xfs_attr_item has been constructed, and we've
>>> +     * created the log intent. Fill in the attri log item and log 
>>> format
>>> +     * structure with fields from this xfs_attr_item
>>> +     */
>>> +    attrp = &attrip->attri_format;
>>> +    attrp->alfi_ino = attr->xattri_dac.da_args->dp->i_ino;
>>> +    attrp->alfi_op_flags = attr->xattri_op_flags;
>>> +    attrp->alfi_value_len = attr->xattri_dac.da_args->valuelen;
>>> +    attrp->alfi_name_len = attr->xattri_dac.da_args->namelen;
>>> +    attrp->alfi_attr_flags = attr->xattri_dac.da_args->attr_filter;
>>> +
>>> +    attrip->attri_name = (void *)attr->xattri_dac.da_args->name;
>>> +    attrip->attri_value = attr->xattri_dac.da_args->value;
>>> +    attrip->attri_name_len = attr->xattri_dac.da_args->namelen;
>>> +    attrip->attri_value_len = attr->xattri_dac.da_args->valuelen;
>>> +}
>>> +
>>> +/* Get an ATTRI. */
>>> +static struct xfs_log_item *
>>> +xfs_attr_create_intent(
>>> +    struct xfs_trans        *tp,
>>> +    struct list_head        *items,
>>> +    unsigned int            count,
>>> +    bool                sort)
>>> +{
>>> +    struct xfs_mount        *mp = tp->t_mountp;
>>> +    struct xfs_attri_log_item    *attrip;
>>> +    struct xfs_attr_item        *attr;
>>> +
>>> +    ASSERT(count == 1);
>>> +
>>> +    if (!xfs_hasdelattr(mp))
>>> +        return NULL;
>>> +
>>> +    attrip = xfs_attri_init(mp, 0);
>>> +    if (attrip == NULL)
>>> +        return NULL;
>>> +
>>> +    xfs_trans_add_item(tp, &attrip->attri_item);
>>> +    list_for_each_entry(attr, items, xattri_list)
>>> +        xfs_attr_log_item(tp, attrip, attr);
>>> +    return &attrip->attri_item;
>>> +}
>>> +
>>> +/* Process an attr. */
>>> +STATIC int
>>> +xfs_attr_finish_item(
>>> +    struct xfs_trans        *tp,
>>> +    struct xfs_log_item        *done,
>>> +    struct list_head        *item,
>>> +    struct xfs_btree_cur        **state)
>>> +{
>>> +    struct xfs_attr_item        *attr;
>>> +    struct xfs_attrd_log_item    *done_item = NULL;
>>> +    int                error;
>>> +    struct xfs_delattr_context    *dac;
>>> +
>>> +    attr = container_of(item, struct xfs_attr_item, xattri_list);
>>> +    dac = &attr->xattri_dac;
>>> +    if (done)
>>> +        done_item = ATTRD_ITEM(done);
>>> +
>>> +    /*
>>> +     * Corner case that can happen during a recovery.  Because the 
>>> first
>>> +     * iteration of a multi part delay op happens in 
>>> xfs_attri_item_recover
>>> +     * to maintain the order of the log replay items.  But the new
>>> +     * transactions do not automatically rejoin during a recovery as 
>>> they do
>>> +     * in a standard delay op, so we need to catch this here and 
>>> rejoin the
>>> +     * leaf to the new transaction
>>> +     */
>>> +    if (attr->xattri_dac.leaf_bp &&
>>> +        attr->xattri_dac.leaf_bp->b_transp != tp) {
>>> +        xfs_trans_bjoin(tp, attr->xattri_dac.leaf_bp);
>>> +        xfs_trans_bhold(tp, attr->xattri_dac.leaf_bp);
>>> +    }
>>> +
>>> +    /*
>>> +     * Always reset trans after EAGAIN cycle
>>> +     * since the transaction is new
>>> +     */
>>> +    dac->da_args->trans = tp;
>>> +
>>> +    error = xfs_trans_attr(dac, done_item, &dac->leaf_bp,
>>> +                   attr->xattri_op_flags);
>>> +    if (error != -EAGAIN)
>>> +        kmem_free(attr);
>>> +
>>> +    return error;
>>> +}
>>> +
>>> +/* Abort all pending ATTRs. */
>>> +STATIC void
>>> +xfs_attr_abort_intent(
>>> +    struct xfs_log_item        *intent)
>>> +{
>>> +    xfs_attri_release(ATTRI_ITEM(intent));
>>> +}
>>> +
>>> +/* Cancel an attr */
>>> +STATIC void
>>> +xfs_attr_cancel_item(
>>> +    struct list_head        *item)
>>> +{
>>> +    struct xfs_attr_item        *attr;
>>> +
>>> +    attr = container_of(item, struct xfs_attr_item, xattri_list);
>>> +    kmem_free(attr);
>>> +}
>>> +
>>> +STATIC xfs_lsn_t
>>> +xfs_attri_item_committed(
>>> +    struct xfs_log_item        *lip,
>>> +    xfs_lsn_t            lsn)
>>> +{
>>> +    struct xfs_attri_log_item    *attrip;
>>> +    /*
>>> +     * The attrip refers to xfs_attr_item memory to log the name and 
>>> value
>>> +     * with the intent item. This already occurred when the intent was
>>> +     * committed so these fields are no longer accessed. Clear them 
>>> out of
>>   +     * caution since we're about to free the xfs_attr_item.
>>> +     */
>>> +    attrip = ATTRI_ITEM(lip);
>>> +    attrip->attri_name = NULL;
>>> +    attrip->attri_value = NULL;
>>> +
>>> +    /*
>>> +     * The ATTRI is logged only once and cannot be moved in the log, so
>>> +     * simply return the lsn at which it's been logged.
>>> +     */
>>> +    return lsn;
>>> +}
>>> +
>>> +STATIC bool
>>> +xfs_attri_item_match(
>>> +    struct xfs_log_item    *lip,
>>> +    uint64_t        intent_id)
>>> +{
>>> +    return ATTRI_ITEM(lip)->attri_format.alfi_id == intent_id;
>>> +}
>>> +
>>> +/*
>>> + * This routine is called to allocate an "attr free done" log item.
>>> + */
>>> +struct xfs_attrd_log_item *
>>> +xfs_trans_get_attrd(struct xfs_trans        *tp,
>>> +          struct xfs_attri_log_item    *attrip)
>>> +{
>>> +    struct xfs_attrd_log_item        *attrdp;
>>> +    uint                    size;
>>> +
>>> +    ASSERT(tp != NULL);
>>> +
>>> +    size = sizeof(struct xfs_attrd_log_item);
>>> +    attrdp = kmem_zalloc(size, 0);
>>> +
>>> +    xfs_log_item_init(tp->t_mountp, &attrdp->attrd_item, XFS_LI_ATTRD,
>>> +              &xfs_attrd_item_ops);
>>> +    attrdp->attrd_attrip = attrip;
>>> +    attrdp->attrd_format.alfd_alf_id = attrip->attri_format.alfi_id;
>>> +
>>> +    xfs_trans_add_item(tp, &attrdp->attrd_item);
>>> +    return attrdp;
>>> +}
>>> +
>>> +static const struct xfs_item_ops xfs_attrd_item_ops = {
>>> +    .flags        = XFS_ITEM_RELEASE_WHEN_COMMITTED,
>>> +    .iop_size    = xfs_attrd_item_size,
>>> +    .iop_format    = xfs_attrd_item_format,
>>> +    .iop_release    = xfs_attrd_item_release,
>>> +};
>>> +
>>> +
>>> +/* Get an ATTRD so we can process all the attrs. */
>>> +static struct xfs_log_item *
>>> +xfs_attr_create_done(
>>> +    struct xfs_trans        *tp,
>>> +    struct xfs_log_item        *intent,
>>> +    unsigned int            count)
>>> +{
>>> +    if (!intent)
>>> +        return NULL;
>>> +
>>> +    return &xfs_trans_get_attrd(tp, ATTRI_ITEM(intent))->attrd_item;
>>> +}
>>> +
>>> +const struct xfs_defer_op_type xfs_attr_defer_type = {
>>> +    .max_items    = 1,
>>> +    .create_intent    = xfs_attr_create_intent,
>>> +    .abort_intent    = xfs_attr_abort_intent,
>>> +    .create_done    = xfs_attr_create_done,
>>> +    .finish_item    = xfs_attr_finish_item,
>>> +    .cancel_item    = xfs_attr_cancel_item,
>>> +};
>>> +
>>> +/*
>>> + * Process an attr intent item that was recovered from the log.  We 
>>> need to
>>> + * delete the attr that it describes.
>>> + */
>>> +STATIC int
>>> +xfs_attri_item_recover(
>>> +    struct xfs_log_item        *lip,
>>> +    struct list_head        *capture_list)
>>> +{
>>> +    struct xfs_attri_log_item    *attrip = ATTRI_ITEM(lip);
>>> +    struct xfs_attr_item        *new_attr;
>>> +    struct xfs_mount        *mp = lip->li_mountp;
>>> +    struct xfs_inode        *ip;
>>> +    struct xfs_da_args        args;
>>> +    struct xfs_da_args        *new_args;
>>> +    struct xfs_trans_res        tres;
>>> +    bool                rsvd;
>>> +    struct xfs_attri_log_format    *attrp;
>>> +    int                error;
>>> +    int                total;
>>> +    int                local;
>>> +    struct xfs_attrd_log_item    *done_item = NULL;
>>> +    struct xfs_attr_item        attr = {
>>> +        .xattri_op_flags    = attrip->attri_format.alfi_op_flags,
>>> +        .xattri_dac.da_args    = &args,
>>> +    };
>>> +
>>> +    /*
>>> +     * First check the validity of the attr described by the ATTRI.  
>>> If any
>>> +     * are bad, then assume that all are bad and just toss the ATTRI.
>>> +     */
>>> +    attrp = &attrip->attri_format;
>>> +    if (!(attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_SET ||
>>> +          attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_REMOVE) ||
>>> +        (attrp->alfi_value_len > XATTR_SIZE_MAX) ||
>>> +        (attrp->alfi_name_len > XATTR_NAME_MAX) ||
>>> +        (attrp->alfi_name_len == 0) ||
>>> +        xfs_verify_ino(mp, attrp->alfi_ino) == false ||
>>
>> Please put this validation logic in a separate predicate.
>>
>> It probably ought to ensure that there aren't illegal characters in the
>> attr name too.
Sure, will do

>>
>>> +        !xfs_hasdelattr(mp)) {
>>
>> Weird nit: If you mount with -o delattr, crash, and remount without that
>> mount option, we'll report that as a corruption error.
>>
>> Not sure what we want to do about that, it's a rough edge but it's also
>> an experimental feature.
Oh i see.  Yeah, this is a corner case where we sort of need the 
incompat flag to do that correctly.

>>
>>> +        return -EFSCORRUPTED;
>>> +    }
>>> +
>>> +    error = xfs_iget(mp, 0, attrp->alfi_ino, 0, 0, &ip);
>>> +    if (error)
>>> +        return error;
>>> +
>>> +    if (VFS_I(ip)->i_nlink == 0)
>>> +        xfs_iflags_set(ip, XFS_IRECOVERY);
>>
>>> +
>>> +    memset(&args, 0, sizeof(struct xfs_da_args));
>>> +    args.dp = ip;
>>> +    args.geo = mp->m_attr_geo;
>>> +    args.op_flags = attrp->alfi_op_flags;
>>> +    args.whichfork = XFS_ATTR_FORK;
>>> +    args.name = attrip->attri_name;
>>> +    args.namelen = attrp->alfi_name_len;
>>> +    args.hashval = xfs_da_hashname(args.name, args.namelen);
>>> +    args.attr_filter = attrp->alfi_attr_flags;
>>> +
>>> +    if (attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_SET) {
>>> +        args.value = attrip->attri_value;
>>> +        args.valuelen = attrp->alfi_value_len;
>>> +        args.total = xfs_attr_calc_size(&args, &local);
>>> +
>>> +        tres.tr_logres = M_RES(mp)->tr_attrsetm.tr_logres +
>>> +                 M_RES(mp)->tr_attrsetrt.tr_logres *
>>> +                    args.total;
>>> +        tres.tr_logcount = XFS_ATTRSET_LOG_COUNT;
>>> +        tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
>>> +        total = args.total;
>>> +    } else {
>>> +        tres = M_RES(mp)->tr_attrrm;
>>> +        total = XFS_ATTRRM_SPACE_RES(mp);
>>> +    }
>>
>> Isn't there already code in xfs_attr.c that does this?
Mmm, I think in a previous version it did because we had to unpack the 
intent into the args to kick off the underlying attr operation.  But 
then we sort of submerged the args into dac and and the attr item, so 
now it doenst unpack, it just passes the attr item through.  But this 
case in the recover is different because now we have to reconstruct the 
attr item from a replayed log item.  Does that make sense?  Or am I 
missing something?

>>
>>> +    error = xfs_trans_alloc(mp, &tres, total, 0,
>>> +                rsvd ? XFS_TRANS_RESERVE : 0, &args.trans);
>>> +    if (error)
>>> +        return error;
>>> +
>>> +    done_item = xfs_trans_get_attrd(args.trans, attrip);
>>> +
>>> +    xfs_ilock(ip, XFS_ILOCK_EXCL);
>>> +    xfs_trans_ijoin(args.trans, ip, 0);
>>> +
>>> +    error = xfs_trans_attr(&attr.xattri_dac, done_item,
>>> +                   &attr.xattri_dac.leaf_bp, attrp->alfi_op_flags);
>>> +    if (error == -EAGAIN) {
>>> +        /*
>>> +         * There's more work to do, so make a new xfs_attr_item and add
>>> +         * it to this transaction.  We dont use xfs_attr_item_init here
>>> +         * because we need the info stored in the current attr to
>>> +         * continue with this multi-part operation.  So, alloc space
>>> +         * for it and the args and copy everything there.
>>> +         */
>>> +        new_attr = kmem_zalloc(sizeof(struct xfs_attr_item) +
>>> +                       sizeof(struct xfs_da_args), KM_NOFS);
>>> +        new_args = (struct xfs_da_args *)((char *)new_attr +
>>> +               sizeof(struct xfs_attr_item));
>>> +
>>> +        memcpy(new_args, &args, sizeof(struct xfs_da_args));
>>> +        memcpy(new_attr, &attr, sizeof(struct xfs_attr_item));
>>> +
>>> +        new_attr->xattri_dac.da_args = new_args;
>>> +        memset(&new_attr->xattri_list, 0, sizeof(struct list_head));
>>> +
>>> +        xfs_defer_add(args.trans, XFS_DEFER_OPS_TYPE_ATTR,
>>> +                  &new_attr->xattri_list);
>>> +
>>> +        /* Do not send -EAGAIN back to caller */
>>> +        error = 0;
>>> +    } else if (error) {
>>> +        xfs_trans_cancel(args.trans);
>>> +        goto out;
>>> +    }
>>> +
>>> +    xfs_defer_ops_capture_and_commit(args.trans, ip, capture_list);
>>> +
>>> +out:
>>> +    xfs_iunlock(ip, XFS_ILOCK_EXCL);
>>> +    xfs_irele(ip);
>>> +    return error;
>>> +}
>>> +
>>> +/* Relog an intent item to push the log tail forward. */
>>> +static struct xfs_log_item *
>>> +xfs_attri_item_relog(
>>> +    struct xfs_log_item        *intent,
>>> +    struct xfs_trans        *tp)
>>> +{
>>> +    struct xfs_attrd_log_item    *attrdp;
>>> +    struct xfs_attri_log_item    *old_attrip;
>>> +    struct xfs_attri_log_item    *new_attrip;
>>> +    struct xfs_attri_log_format    *new_attrp;
>>> +    struct xfs_attri_log_format    *old_attrp;
>>> +    int                buffer_size;
>>> +
>>> +    old_attrip = ATTRI_ITEM(intent);
>>> +    old_attrp = &old_attrip->attri_format;
>>> +    buffer_size = old_attrp->alfi_value_len + old_attrp->alfi_name_len;
>>> +
>>> +    tp->t_flags |= XFS_TRANS_DIRTY;
>>> +    attrdp = xfs_trans_get_attrd(tp, old_attrip);
>>> +    set_bit(XFS_LI_DIRTY, &attrdp->attrd_item.li_flags);
>>> +
>>> +    new_attrip = xfs_attri_init(tp->t_mountp, buffer_size);
>>> +    new_attrp = &new_attrip->attri_format;
>>> +
>>> +    new_attrp->alfi_ino = old_attrp->alfi_ino;
>>> +    new_attrp->alfi_op_flags = old_attrp->alfi_op_flags;
>>> +    new_attrp->alfi_value_len = old_attrp->alfi_value_len;
>>> +    new_attrp->alfi_name_len = old_attrp->alfi_name_len;
>>> +    new_attrp->alfi_attr_flags = old_attrp->alfi_attr_flags;
>>> +
>>> +    new_attrip->attri_name_len = old_attrip->attri_name_len;
>>> +    new_attrip->attri_name = ((char *)new_attrip) +
>>> +                 sizeof(struct xfs_attri_log_item);
>>> +    memcpy(new_attrip->attri_name, old_attrip->attri_name,
>>> +        new_attrip->attri_name_len);
>>> +
>>> +    new_attrip->attri_value_len = old_attrip->attri_value_len;
>>> +    if (new_attrip->attri_value_len > 0) {
>>> +        new_attrip->attri_value = new_attrip->attri_name +
>>> +                      new_attrip->attri_name_len;
>>> +
>>> +        memcpy(new_attrip->attri_value, old_attrip->attri_value,
>>> +               new_attrip->attri_value_len);
>>> +    }
>>> +
>>> +    xfs_trans_add_item(tp, &new_attrip->attri_item);
>>> +    set_bit(XFS_LI_DIRTY, &new_attrip->attri_item.li_flags);
>>> +
>>> +    return &new_attrip->attri_item;
>>> +}
>>> +
>>> +static const struct xfs_item_ops xfs_attri_item_ops = {
>>> +    .iop_size    = xfs_attri_item_size,
>>> +    .iop_format    = xfs_attri_item_format,
>>> +    .iop_unpin    = xfs_attri_item_unpin,
>>> +    .iop_committed    = xfs_attri_item_committed,
>>> +    .iop_release    = xfs_attri_item_release,
>>> +    .iop_recover    = xfs_attri_item_recover,
>>> +    .iop_match    = xfs_attri_item_match,
>>> +    .iop_relog    = xfs_attri_item_relog,
>>> +};
>>> +
>>> +
>>> +
>>> +STATIC int
>>> +xlog_recover_attri_commit_pass2(
>>> +    struct xlog                     *log,
>>> +    struct list_head        *buffer_list,
>>> +    struct xlog_recover_item        *item,
>>> +    xfs_lsn_t                       lsn)
>>> +{
>>> +    int                             error;
>>> +    struct xfs_mount                *mp = log->l_mp;
>>> +    struct xfs_attri_log_item       *attrip;
>>> +    struct xfs_attri_log_format     *attri_formatp;
>>> +    char                *name = NULL;
>>> +    char                *value = NULL;
>>> +    int                region = 0;
>>> +    int                buffer_size;
>>> +
>>> +    attri_formatp = item->ri_buf[region].i_addr;
>>> +
>>> +    /* Validate xfs_attri_log_format */
>>> +    if (attri_formatp->__pad != 0 || attri_formatp->alfi_name_len == 
>>> 0 ||
>>> +        (attri_formatp->alfi_op_flags == XFS_ATTR_OP_FLAGS_REMOVE &&
>>> +        attri_formatp->alfi_value_len != 0))
>>> +        return -EFSCORRUPTED;
>>
>> Might be worth an XFS_ERROR_REPORT here since this is evidence of incore
>> memory corruption, right?
Sure, will add

>>
>>> +
>>> +    buffer_size = attri_formatp->alfi_name_len +
>>> +              attri_formatp->alfi_value_len;
>>> +
>>> +    attrip = xfs_attri_init(mp, buffer_size);
>>> +    if (attrip == NULL)
>>> +        return -ENOMEM;
>>> +
>>> +    error = xfs_attri_copy_format(&item->ri_buf[region],
>>> +                      &attrip->attri_format);
>>> +    if (error) {
>>> +        xfs_attri_item_free(attrip);
>>> +        return error;
>>> +    }
>>> +
>>> +    attrip->attri_name_len = attri_formatp->alfi_name_len;
>>> +    attrip->attri_value_len = attri_formatp->alfi_value_len;
>>> +    region++;
>>> +    name = ((char *)attrip) + sizeof(struct xfs_attri_log_item);
>>> +    memcpy(name, item->ri_buf[region].i_addr, attrip->attri_name_len);
>>> +    attrip->attri_name = name;
>>> +
>>> +    if (attrip->attri_value_len > 0) {
>>> +        region++;
>>> +        value = ((char *)attrip) + sizeof(struct xfs_attri_log_item) +
>>> +            attrip->attri_name_len;
>>> +        memcpy(value, item->ri_buf[region].i_addr,
>>> +            attrip->attri_value_len);
>>> +        attrip->attri_value = value;
>>> +    }
>>> +
>>> +    /*
>>> +     * The ATTRI has two references. One for the ATTRD and one for 
>>> ATTRI to
>>> +     * ensure it makes it into the AIL. Insert the ATTRI into the AIL
>>> +     * directly and drop the ATTRI reference. Note that
>>> +     * xfs_trans_ail_update() drops the AIL lock.
>>> +     */
>>> +    xfs_trans_ail_insert(log->l_ailp, &attrip->attri_item, lsn);
>>> +    xfs_attri_release(attrip);
>>> +    return 0;
>>> +}
>>> +
>>> +const struct xlog_recover_item_ops xlog_attri_item_ops = {
>>> +    .item_type    = XFS_LI_ATTRI,
>>> +    .commit_pass2    = xlog_recover_attri_commit_pass2,
>>> +};
>>> +
>>> +/*
>>> + * This routine is called when an ATTRD format structure is found in 
>>> a committed
>>> + * transaction in the log. Its purpose is to cancel the 
>>> corresponding ATTRI if
>>> + * it was still in the log. To do this it searches the AIL for the 
>>> ATTRI with
>>> + * an id equal to that in the ATTRD format structure. If we find it 
>>> we drop
>>> + * the ATTRD reference, which removes the ATTRI from the AIL and 
>>> frees it.
>>> + */
>>> +STATIC int
>>> +xlog_recover_attrd_commit_pass2(
>>> +    struct xlog            *log,
>>> +    struct list_head        *buffer_list,
>>> +    struct xlog_recover_item    *item,
>>> +    xfs_lsn_t            lsn)
>>> +{
>>> +    struct xfs_attrd_log_format    *attrd_formatp;
>>> +
>>> +    attrd_formatp = item->ri_buf[0].i_addr;
>>> +    ASSERT((item->ri_buf[0].i_len ==
>>> +                (sizeof(struct xfs_attrd_log_format))));
>>> +
>>> +    xlog_recover_release_intent(log, XFS_LI_ATTRI,
>>> +                    attrd_formatp->alfd_alf_id);
>>> +    return 0;
>>> +}
>>> +
>>> +const struct xlog_recover_item_ops xlog_attrd_item_ops = {
>>> +    .item_type    = XFS_LI_ATTRD,
>>> +    .commit_pass2    = xlog_recover_attrd_commit_pass2,
>>> +};
>>> diff --git a/fs/xfs/xfs_attr_item.h b/fs/xfs/xfs_attr_item.h
>>> new file mode 100644
>>> index 0000000..27c6bae
>>> --- /dev/null
>>> +++ b/fs/xfs/xfs_attr_item.h
>>> @@ -0,0 +1,52 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-or-later
>>> + *
>>> + * Copyright (C) 2019 Oracle.  All Rights Reserved.
>>> + * Author: Allison Collins <allison.henderson@oracle.com>
>>> + */
>>> +#ifndef    __XFS_ATTR_ITEM_H__
>>> +#define    __XFS_ATTR_ITEM_H__
>>> +
>>> +/* kernel only ATTRI/ATTRD definitions */
>>> +
>>> +struct xfs_mount;
>>> +struct kmem_zone;
>>> +
>>> +/*
>>> + * Define ATTR flag bits. Manipulated by set/clear/test_bit operators.
>>> + */
>>> +#define    XFS_ATTRI_RECOVERED    1
>>> +
>>> +
>>> +/*
>>> + * This is the "attr intention" log item.  It is used to log the 
>>> fact that some
>>
>> Well, it's the incore state tracking for attr intent log items... :)
>>
>> Aside from the nits I 've pointed out so far, this looks more or less ok
>> to me.
>>
>> --------------
>>
>> Ok, so here we are at the end.  Looking at my own atomic extent swap
>> series, I broke this up into two pieces -- one to create the barebones
>> log item (with dummy implementations); and a second one to create the
>> defer ops code and connect it to the log item.
>>
>> Oh, heh.  The first patch is 16K and the second one is 47K.
>>
>> That might be a good way to break *this* patch into smaller parts, if
>> nothing else -- concentrate on getting the log parts working, then
>> connect the new state machine to defer ops and log items.
Sure, I can break up this patch in a similar way

>>
>> That said, as this series gets longer and longer I find it really more
>> difficult to go through the whole series one by one vs. just diffing the
>> whole branch and reviewing that.
That's fine, it's that's easier for you, I could probably figure out in 
what patch the line of code you are commenting on would affect.  As 
noted in the call earlier today, I try to help reviewers in the cover 
letter by listing off which patches have changed since the last 
revision, and which havnt.  That way you dont have to grind through 
things that havnt changed.  Though I'm not sure if folks really use the 
cover letter :-)

>>
>> <shrug> I don't really have a definitive answer for which is better.
>> The xattr code is very complex, and I struggle even combining both of my
>> usual strategies and attacking review from both ends.
I actually think it's very reasonable to just focus on patches 11 and 
12?  Or maybe just the diff of the branch up to 12 if that's easier for 
you.  Because if there's something about 11 or 12 that people want to 
change, it generally implies some change to the underlying refactoring. 
  So it seems a bit wasteful to keep re-reviewing the refactoring if the 
end result has some gripe about it.  If everyone is happy about how the 
refactoring ends up, then it makes sense to go back and review the 
implementation details.

To be clear, it's certaintly not that I dont appreciate the reviews, but 
I understand it's an exhausting thing to grind through, and I try to be 
mindful of that.  The only reason I dont push out the entire extended 
set is because its a 40 patch monster that's not reasonable for anyone 
to review right now, and I dont want people to think that I'm asking for 
that at this time.  So I just sort of send the links out so that people 
can see where it's meant to go.  For similar reasons, I've thought about 
reducing the visible window of patches to reduce reviewer burnout. So 
dont feel like you have to flog yourself through all 22, I think 12 is 
also reasonable cap off.

>>
>> By the way, have you been stress testing the xattr code with all this
>> stuff applied?  At some point it becomes easier to pull this in and fix
>> up the breakage than it is to review 22 slice-n-dice patches every cycle.
>>
No, I've been testing with the attr group, and then a  few tests I came 
up with to replay the journal and also parent pointers.  I can toss in 
some stress tests too and make sure nothing turns up.

Thank you for the reviews, I know it's a lot
Allison

>> --D
>>
>>> + * attribute operations need to be processed.  An operation is 
>>> currently either
>>> + * a set or remove.  Set or remove operations are described by the 
>>> xfs_attr_item
>>> + * which may be logged to this intent.
>>> + *
>>> + * During a normal attr operation, name and value point to the name 
>>> and value
>>> + * feilds of the calling functions xfs_da_args.  During a recovery, 
>>> the name
>>> + * and value buffers are copied from the log, and stored in a 
>>> trailing buffer
>>> + * attached to the xfs_attr_item until they are committed.  They are 
>>> freed when
>>> + * the xfs_attr_item itself is freed when the work is done.
>>> + */
>>> +struct xfs_attri_log_item {
>>> +    struct xfs_log_item        attri_item;
>>> +    atomic_t            attri_refcount;
>>> +    int                attri_name_len;
>>> +    int                attri_value_len;
>>> +    void                *attri_name;
>>> +    void                *attri_value;
>>> +    struct xfs_attri_log_format    attri_format;
>>> +};
>>> +
>>> +/*
>>> + * This is the "attr done" log item.  It is used to log the fact 
>>> that some attrs
>>> + * earlier mentioned in an attri item have been freed.
>>> + */
>>> +struct xfs_attrd_log_item {
>>> +    struct xfs_attri_log_item    *attrd_attrip;
>>> +    struct xfs_log_item        attrd_item;
>>> +    struct xfs_attrd_log_format    attrd_format;
>>> +};
>>> +
>>> +#endif    /* __XFS_ATTR_ITEM_H__ */
>>> diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c
>>> index 8f8837f..d7787a5 100644
>>> --- a/fs/xfs/xfs_attr_list.c
>>> +++ b/fs/xfs/xfs_attr_list.c
>>> @@ -15,6 +15,7 @@
>>>   #include "xfs_inode.h"
>>>   #include "xfs_trans.h"
>>>   #include "xfs_bmap.h"
>>> +#include "xfs_da_btree.h"
>>>   #include "xfs_attr.h"
>>>   #include "xfs_attr_sf.h"
>>>   #include "xfs_attr_leaf.h"
>>> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
>>> index 248083e..6682936 100644
>>> --- a/fs/xfs/xfs_ioctl.c
>>> +++ b/fs/xfs/xfs_ioctl.c
>>> @@ -15,6 +15,8 @@
>>>   #include "xfs_iwalk.h"
>>>   #include "xfs_itable.h"
>>>   #include "xfs_error.h"
>>> +#include "xfs_da_format.h"
>>> +#include "xfs_da_btree.h"
>>>   #include "xfs_attr.h"
>>>   #include "xfs_bmap.h"
>>>   #include "xfs_bmap_util.h"
>>> diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
>>> index c1771e7..62e1534 100644
>>> --- a/fs/xfs/xfs_ioctl32.c
>>> +++ b/fs/xfs/xfs_ioctl32.c
>>> @@ -17,6 +17,8 @@
>>>   #include "xfs_itable.h"
>>>   #include "xfs_fsops.h"
>>>   #include "xfs_rtalloc.h"
>>> +#include "xfs_da_format.h"
>>> +#include "xfs_da_btree.h"
>>>   #include "xfs_attr.h"
>>>   #include "xfs_ioctl.h"
>>>   #include "xfs_ioctl32.h"
>>> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
>>> index 00369502f..ce04721 100644
>>> --- a/fs/xfs/xfs_iops.c
>>> +++ b/fs/xfs/xfs_iops.c
>>> @@ -13,6 +13,8 @@
>>>   #include "xfs_inode.h"
>>>   #include "xfs_acl.h"
>>>   #include "xfs_quota.h"
>>> +#include "xfs_da_format.h"
>>> +#include "xfs_da_btree.h"
>>>   #include "xfs_attr.h"
>>>   #include "xfs_trans.h"
>>>   #include "xfs_trace.h"
>>> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
>>> index 0604183..290e57b 100644
>>> --- a/fs/xfs/xfs_log.c
>>> +++ b/fs/xfs/xfs_log.c
>>> @@ -2070,6 +2070,10 @@ xlog_print_tic_res(
>>>           REG_TYPE_STR(CUD_FORMAT, "cud_format"),
>>>           REG_TYPE_STR(BUI_FORMAT, "bui_format"),
>>>           REG_TYPE_STR(BUD_FORMAT, "bud_format"),
>>> +        REG_TYPE_STR(ATTRI_FORMAT, "attri_format"),
>>> +        REG_TYPE_STR(ATTRD_FORMAT, "attrd_format"),
>>> +        REG_TYPE_STR(ATTR_NAME, "attr_name"),
>>> +        REG_TYPE_STR(ATTR_VALUE, "attr_value"),
>>>       };
>>>       BUILD_BUG_ON(ARRAY_SIZE(res_type_str) != XLOG_REG_TYPE_MAX + 1);
>>>   #undef REG_TYPE_STR
>>> diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
>>> index 295a5c6..c0821b6 100644
>>> --- a/fs/xfs/xfs_log_recover.c
>>> +++ b/fs/xfs/xfs_log_recover.c
>>> @@ -1775,6 +1775,8 @@ static const struct xlog_recover_item_ops 
>>> *xlog_recover_item_ops[] = {
>>>       &xlog_cud_item_ops,
>>>       &xlog_bui_item_ops,
>>>       &xlog_bud_item_ops,
>>> +    &xlog_attri_item_ops,
>>> +    &xlog_attrd_item_ops,
>>>   };
>>>   static const struct xlog_recover_item_ops *
>>> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
>>> index 0aa87c21..bc9c25e 100644
>>> --- a/fs/xfs/xfs_ondisk.h
>>> +++ b/fs/xfs/xfs_ondisk.h
>>> @@ -132,6 +132,8 @@ xfs_check_ondisk_structs(void)
>>>       XFS_CHECK_STRUCT_SIZE(struct xfs_inode_log_format,    56);
>>>       XFS_CHECK_STRUCT_SIZE(struct xfs_qoff_logformat,    20);
>>>       XFS_CHECK_STRUCT_SIZE(struct xfs_trans_header,        16);
>>> +    XFS_CHECK_STRUCT_SIZE(struct xfs_attri_log_format,    40);
>>> +    XFS_CHECK_STRUCT_SIZE(struct xfs_attrd_log_format,    16);
>>>       /*
>>>        * The v5 superblock format extended several v4 header 
>>> structures with
>>> diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
>>> index bca48b3..9b0c790 100644
>>> --- a/fs/xfs/xfs_xattr.c
>>> +++ b/fs/xfs/xfs_xattr.c
>>> @@ -10,6 +10,7 @@
>>>   #include "xfs_log_format.h"
>>>   #include "xfs_da_format.h"
>>>   #include "xfs_inode.h"
>>> +#include "xfs_da_btree.h"
>>>   #include "xfs_attr.h"
>>>   #include "xfs_acl.h"
>>>   #include "xfs_da_btree.h"
>>> -- 
>>> 2.7.4
>>>