Re: [PATCH v6 16/16] xfs: Add delay ready attr set routines

Allison Collins
2020-01-22T16:58:36Z

On 1/21/20 5:12 PM, Darrick J. Wong wrote:
> On Sat, Jan 18, 2020 at 03:50:35PM -0700, Allison Collins wrote:
>> This patch modifies the attr set routines to be delay ready. This means
>> they no longer roll or commit transactions, but instead return -EAGAIN
>> to have the calling routine roll and refresh the transaction. In this
>> series, xfs_attr_set_args has become xfs_attr_set_iter, which uses a
>> state machine like switch to keep track of where it was when EAGAIN was
>> returned.
>>
>> Part of xfs_attr_leaf_addname has been factored out into a new helper
>> function xfs_attr_leaf_try_add to allow transaction cycling between the
>> two routines.
>>
>> Two new helper functions have been added: xfs_attr_rmtval_set_init and
>> xfs_attr_rmtval_set_blk. They provide a subset of logic similar to
>> xfs_attr_rmtval_set, but they store the current block in the delay attr
>> context to allow the caller to roll the transaction between allocations.
>> This helps to simplify and consolidate code used by
>> xfs_attr_leaf_addname and xfs_attr_node_addname
>>
>> Finally, xfs_attr_set_args has become a simple loop to refresh the
>> transaction until the operation is completed.
>>
>> Signed-off-by: Allison Collins <allison.henderson@oracle.com>
>> ---
>> fs/xfs/libxfs/xfs_attr.c | 347 +++++++++++++++++++++++++---------------
>> fs/xfs/libxfs/xfs_attr.h | 1 +
>> fs/xfs/libxfs/xfs_attr_remote.c | 67 +++++++-
>> fs/xfs/libxfs/xfs_attr_remote.h | 4 +
>> fs/xfs/libxfs/xfs_da_btree.h | 13 ++
>> 5 files changed, 301 insertions(+), 131 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>> index 92929ad..02a7f55 100644
>> --- a/fs/xfs/libxfs/xfs_attr.c
>> +++ b/fs/xfs/libxfs/xfs_attr.c
>> @@ -58,6 +58,7 @@ 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_leaf_try_add(struct xfs_da_args *args, struct xfs_buf *bp);
>>
>>
>> STATIC int
>> @@ -259,9 +260,86 @@ int
>> xfs_attr_set_args(
>> struct xfs_da_args *args)
>> {
>> + int error = 0;
>> + int err2 = 0;
>> + struct xfs_buf *leaf_bp = NULL;
>> +
>> + do {
>> + error = xfs_attr_set_iter(args, &leaf_bp);
>> + if (error && error != -EAGAIN)
>> + goto out;
>> +
>> + if (args->dac.flags & XFS_DAC_FINISH_TRANS) {
>> + args->dac.flags &= ~XFS_DAC_FINISH_TRANS;
>> +
>> + err2 = xfs_defer_finish(&args->trans);
>> + if (err2) {
>> + error = err2;
>> + goto out;
>> + }
>> + }
>> +
>> + err2 = xfs_trans_roll_inode(&args->trans, args->dp);
>> + if (err2) {
>> + error = err2;
>> + goto out;
>> + }
>> +
>> + if (leaf_bp) {
>> + xfs_trans_bjoin(args->trans, leaf_bp);
>> + xfs_trans_bhold(args->trans, leaf_bp);
>> + }
>> +
>> + } while (error == -EAGAIN);
>> +
>> +out:
>> + return error;
>> +}
>> +
>> +/*
>> + * Set the attribute specified in @args.
>> + * This routine is meant to function as a delayed operation, and may return
>> + * -EAGAIN when the transaction needs to be rolled. Calling functions will need
>> + * to handle this, and recall the function until a successful error code is
>> + * returned.
>> + */
>> +int
>> +xfs_attr_set_iter(
>> + struct xfs_da_args *args,
>> + struct xfs_buf **leaf_bp)
>> +{
>> struct xfs_inode *dp = args->dp;
>> - struct xfs_buf *leaf_bp = NULL;
>> - int error, error2 = 0;
>> + int error = 0;
>> + int sf_size;
>> +
>> + /* State machine switch */
>> + switch (args->dac.dela_state) {
>> + case XFS_DAS_SF_TO_LEAF:
>> + goto sf_to_leaf;
>> + case XFS_DAS_ALLOC_LEAF:
>> + case XFS_DAS_FLIP_LFLAG:
>> + case XFS_DAS_FOUND_LBLK:
>> + goto leaf;
>> + case XFS_DAS_FOUND_NBLK:
>> + case XFS_DAS_FLIP_NFLAG:
>> + case XFS_DAS_ALLOC_NODE:
>> + case XFS_DAS_LEAF_TO_NODE:
>> + goto node;
>> + default:
>
> Er... do these need to ASSERT on invalid states? e.g. if somehow we end
> up with XFS_DAS_RM_SHRINK, we ought to blow up loudly, right?
>
>
>> + break;
>> + }
>> +
>> + /*
>> + * New inodes may not have an attribute fork yet. So set the attribute
>> + * fork appropriately
>> + */
>> + if (XFS_IFORK_Q((args->dp)) == 0) {
>> + sf_size = sizeof(struct xfs_attr_sf_hdr) +
>> + XFS_ATTR_SF_ENTSIZE_BYNAME(args->name.len, args->valuelen);
>> + xfs_bmap_set_attrforkoff(args->dp, sf_size, NULL);
>> + args->dp->i_afp = kmem_zone_zalloc(xfs_ifork_zone, 0);
>> + args->dp->i_afp->if_flags = XFS_IFEXTENTS;
>> + }
>>
>> /*
>> * If the attribute list is non-existent or a shortform list, proceed to
>> @@ -272,22 +350,20 @@ xfs_attr_set_args(
>> (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
>> dp->i_d.di_anextents == 0)))
>> goto sf_to_leaf;
>> -
>> /*
>> * Try to add the attr to the attribute list in the inode.
>> */
>> error = xfs_attr_try_sf_addname(dp, args);
>> - if (error != -ENOSPC) {
>> - error2 = xfs_trans_commit(args->trans);
>> - args->trans = NULL;
>> - return error ? error : error2;
>
> Where does this commit go?
>
>> - }
>> +
>> + /* Should only be 0, -EEXIST or ENOSPC */
>> + if (error != -ENOSPC)
>> + return error;
>>
>> /*
>> * It won't fit in the shortform, transform to a leaf block.
>> * GROT: another possible req'mt for a double-split btree op.
>> */
>> - error = xfs_attr_shortform_to_leaf(args, &leaf_bp);
>> + error = xfs_attr_shortform_to_leaf(args, leaf_bp);
>> if (error)
>> return error;
>>
>> @@ -295,42 +371,47 @@ xfs_attr_set_args(
>> * Prevent the leaf buffer from being unlocked so that a
>> * concurrent AIL push cannot grab the half-baked leaf
>> * buffer and run into problems with the write verifier.
>> - * Once we're done rolling the transaction we can release
>> - * the hold and add the attr to the leaf.
>> */
>> - xfs_trans_bhold(args->trans, leaf_bp);
>> - error = xfs_defer_finish(&args->trans);
>> - xfs_trans_bhold_release(args->trans, leaf_bp);
>> - if (error) {
>> - xfs_trans_brelse(args->trans, leaf_bp);
>> - return error;
>> - }
>> + xfs_trans_bhold(args->trans, *leaf_bp);
>> + args->dac.flags |= XFS_DAC_FINISH_TRANS;
>> + args->dac.dela_state = XFS_DAS_SF_TO_LEAF;
>> + return -EAGAIN;
>>
>> sf_to_leaf:
>>
>> - if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
>> - error = xfs_attr_leaf_addname(args);
>> - if (error != -ENOSPC)
>> - return error;
>> -
>> - /*
>> - * Commit that transaction so that the node_addname()
>> - * call can manage its own transactions.
>> - */
>> - error = xfs_defer_finish(&args->trans);
>> - if (error)
>> - return error;
>> + /*
>> + * After a shortform to leaf conversion, we need to hold the leaf and
>> + * cylce out the transaction. When we get back, we need to release
>> + * the leaf.
>> + */
>> + if (*leaf_bp != NULL) {
>> + xfs_trans_brelse(args->trans, *leaf_bp);
>> + *leaf_bp = NULL;
>> + }
>>
>> - /*
>> - * Commit the current trans (including the inode) and
>> - * start a new one.
>> - */
>> - error = xfs_trans_roll_inode(&args->trans, dp);
>> - if (error)
>> + if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
>> + error = xfs_attr_leaf_try_add(args, *leaf_bp);
>> + switch (error) {
>> + case -ENOSPC:
>> + args->dac.flags |= XFS_DAC_FINISH_TRANS;
>> + args->dac.dela_state = XFS_DAS_LEAF_TO_NODE;
>> + return -EAGAIN;
>> + case 0:
>> + args->dac.dela_state = XFS_DAS_FOUND_LBLK;
>> + return -EAGAIN;
>> + default:
>> return error;
>> -
>> + }
>> +leaf:
>> + error = xfs_attr_leaf_addname(args);
>> + if (error == -ENOSPC) {
>> + args->dac.dela_state = XFS_DAS_LEAF_TO_NODE;
>> + return -EAGAIN;
>> + }
>> + return error;
>> }
>> -
>> + args->dac.dela_state = XFS_DAS_LEAF_TO_NODE;
>> +node:
>> error = xfs_attr_node_addname(args);
>> return error;
>> }
>> @@ -759,27 +840,28 @@ xfs_attr_leaf_try_add(
>> *
>> * This leaf block cannot have a "remote" value, we only call this routine
>> * if bmap_one_block() says there is only one block (ie: no remote blks).
>> + *
>> + * This routine is meant to function as a delayed operation, and may return
>> + * -EAGAIN when the transaction needs to be rolled. Calling functions will need
>> + * to handle this, and recall the function until a successful error code is
>> + * returned.
>> */
>> STATIC int
>> xfs_attr_leaf_addname(struct xfs_da_args *args)
>> {
>> - int error, forkoff;
>> struct xfs_buf *bp = NULL;
>> + int error, forkoff;
>> struct xfs_inode *dp = args->dp;
>>
>> - trace_xfs_attr_leaf_addname(args);
>> -
>> - error = xfs_attr_leaf_try_add(args, bp);
>> - if (error)
>> - return error;
>> -
>> - /*
>> - * Commit the transaction that added the attr name so that
>> - * later routines can manage their own transactions.
>> - */
>> - error = xfs_trans_roll_inode(&args->trans, dp);
>> - if (error)
>> - return error;
>> + /* State machine switch */
>> + switch (args->dac.dela_state) {
>> + case XFS_DAS_FLIP_LFLAG:
>> + goto flip_flag;
>> + case XFS_DAS_ALLOC_LEAF:
>> + goto alloc_leaf;
>> + default:
>> + break;
>> + }
>>
>> /*
>> * If there was an out-of-line value, allocate the blocks we
>> @@ -788,7 +870,28 @@ xfs_attr_leaf_addname(struct xfs_da_args *args)
>> * maximum size of a transaction and/or hit a deadlock.
>> */
>> if (args->rmtblkno > 0) {
>> - error = xfs_attr_rmtval_set(args);
>> +
>> + /* Open coded xfs_attr_rmtval_set without trans handling */
>> + error = xfs_attr_rmtval_set_init(args);
>> + if (error)
>> + return error;
>> +
>> + /*
>> + * Roll through the "value", allocating blocks on disk as
>> + * required.
>> + */
>> +alloc_leaf:
>> + while (args->dac.blkcnt > 0) {
>> + error = xfs_attr_rmtval_set_blk(args);
>> + if (error)
>> + return error;
>> +
>> + args->dac.flags |= XFS_DAC_FINISH_TRANS;
>> + args->dac.dela_state = XFS_DAS_ALLOC_LEAF;
>> + return -EAGAIN;
>> + }
>> +
>> + error = xfs_attr_rmtval_set_value(args);
>> if (error)
>> return error;
>> }
>> @@ -807,13 +910,10 @@ xfs_attr_leaf_addname(struct xfs_da_args *args)
>> error = xfs_attr3_leaf_flipflags(args);
>> if (error)
>> return error;
>> - /*
>> - * Commit the flag value change and start the next trans in
>> - * series.
>> - */
>> - error = xfs_trans_roll_inode(&args->trans, args->dp);
>> - if (error)
>> - return error;
>> +
>> + args->dac.dela_state = XFS_DAS_FLIP_LFLAG;
>> + return -EAGAIN;
>> +flip_flag:
>>
>> /*
>> * Dismantle the "old" attribute/value pair by removing
>> @@ -844,34 +944,17 @@ xfs_attr_leaf_addname(struct xfs_da_args *args)
>> /*
>> * If the result is small enough, shrink it all into the inode.
>> */
>> - if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
>> + forkoff = xfs_attr_shortform_allfit(bp, dp);
>> + if (forkoff)
>> error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
>> - /* bp is gone due to xfs_da_shrink_inode */
>> - if (error)
>> - return error;
>> - error = xfs_defer_finish(&args->trans);
>> - if (error)
>> - return error;
>> - }
>>
>> - /*
>> - * Commit the remove and start the next trans in series.
>> - */
>> - error = xfs_trans_roll_inode(&args->trans, dp);
>> + args->dac.flags |= XFS_DAC_FINISH_TRANS;
>>
>> } else if (args->rmtblkno > 0) {
>> /*
>> * Added a "remote" value, just clear the incomplete flag.
>> */
>> error = xfs_attr3_leaf_clearflag(args);
>> - if (error)
>> - return error;
>> -
>> - /*
>> - * Commit the flag value change and start the next trans in
>> - * series.
>> - */
>> - error = xfs_trans_roll_inode(&args->trans, args->dp);
>> }
>> return error;
>> }
>> @@ -1020,16 +1103,22 @@ xfs_attr_node_hasname(
>> *
>> * "Remote" attribute values confuse the issue and atomic rename operations
>> * add a whole extra layer of confusion on top of that.
>> + *
>> + * This routine is meant to function as a delayed operation, and may return
>> + * -EAGAIN when the transaction needs to be rolled. Calling functions will need
>> + * to handle this, and recall the function until a successful error code is
>> + *returned.
>> */
>> STATIC int
>> xfs_attr_node_addname(
>> struct xfs_da_args *args)
>> {
>> - struct xfs_da_state *state;
>> + struct xfs_da_state *state = NULL;
>> struct xfs_da_state_blk *blk;
>> struct xfs_inode *dp;
>> struct xfs_mount *mp;
>> - int retval, error;
>> + int retval = 0;
>> + int error = 0;
>>
>> trace_xfs_attr_node_addname(args);
>>
>> @@ -1038,7 +1127,19 @@ xfs_attr_node_addname(
>> */
>> dp = args->dp;
>> mp = dp->i_mount;
>> -restart:
>> +
>> + /* State machine switch */
>> + switch (args->dac.dela_state) {
>> + case XFS_DAS_FLIP_NFLAG:
>> + goto flip_flag;
>> + case XFS_DAS_FOUND_NBLK:
>> + goto found_nblk;
>> + case XFS_DAS_ALLOC_NODE:
>> + goto alloc_node;
>> + default:
>> + break;
>> + }
>> +
>> /*
>> * Search to see if name already exists, and get back a pointer
>> * to where it should go.
>> @@ -1088,19 +1189,13 @@ xfs_attr_node_addname(
>> error = xfs_attr3_leaf_to_node(args);
>> if (error)
>> goto out;
>> - error = xfs_defer_finish(&args->trans);
>> - if (error)
>> - goto out;
>>
>> /*
>> - * Commit the node conversion and start the next
>> - * trans in the chain.
>> + * Restart routine from the top. No need to set the
>> + * state
>

I think I missed responding to this comment in my last email:

> *OH*, dela_state == 0 does not mean "do not use delayed attrs", we're
> switching /all/ users to delayed attrs. Urk.

Not quite. While both inline and delayed operations go through this
same dance of EAGAIN ping pong, it's not a delayed operation until we
package it into an intent and log it. And then the intent pops back out
during defer finish, and the ping pong starts from
xfs_defer_finish_noroll instead of xfs_attr_set_iter.

We still need to support in line operations for older versions that do
not support the attr log item. Later when we get into delayed attrs, we
use a feature bit to control this, and toggle as needed.

Hope that helps!

>
>> */
>> - error = xfs_trans_roll_inode(&args->trans, dp);
>> - if (error)
>> - goto out;
>> -
>> - goto restart;
>> + args->dac.flags |= XFS_DAC_FINISH_TRANS;
>> + return -EAGAIN;
>> }
>>
>> /*
>> @@ -1112,9 +1207,7 @@ xfs_attr_node_addname(
>> error = xfs_da3_split(state);
>> if (error)
>> goto out;
>> - error = xfs_defer_finish(&args->trans);
>> - if (error)
>> - goto out;
>> + args->dac.flags |= XFS_DAC_FINISH_TRANS;
>> } else {
>> /*
>> * Addition succeeded, update Btree hashvals.
>> @@ -1129,13 +1222,9 @@ xfs_attr_node_addname(
>> xfs_da_state_free(state);
>> state = NULL;
>>
>> - /*
>> - * Commit the leaf addition or btree split and start the next
>> - * trans in the chain.
>> - */
>> - error = xfs_trans_roll_inode(&args->trans, dp);
>> - if (error)
>> - goto out;
>> + args->dac.dela_state = XFS_DAS_FOUND_NBLK;
>> + return -EAGAIN;
>> +found_nblk:
>>
>> /*
>> * If there was an out-of-line value, allocate the blocks we
>> @@ -1144,7 +1233,27 @@ xfs_attr_node_addname(
>> * maximum size of a transaction and/or hit a deadlock.
>> */
>> if (args->rmtblkno > 0) {
>> - error = xfs_attr_rmtval_set(args);
>> + /* Open coded xfs_attr_rmtval_set without trans handling */
>> + error = xfs_attr_rmtval_set_init(args);
>> + if (error)
>> + return error;
>> +
>> + /*
>> + * Roll through the "value", allocating blocks on disk as
>> + * required.
>> + */
>> +alloc_node:
>> + while (args->dac.blkcnt > 0) {
>> + error = xfs_attr_rmtval_set_blk(args);
>> + if (error)
>> + return error;
>> +
>> + args->dac.flags |= XFS_DAC_FINISH_TRANS;
>> + args->dac.dela_state = XFS_DAS_ALLOC_NODE;
>> + return -EAGAIN;
>> + }
>> +
>> + error = xfs_attr_rmtval_set_value(args);
>> if (error)
>> return error;
>> }
>> @@ -1167,10 +1276,9 @@ xfs_attr_node_addname(
>> * Commit the flag value change and start the next trans in
>> * series
>> */
>> - error = xfs_trans_roll_inode(&args->trans, args->dp);
>> - if (error)
>> - goto out;
>> -
>> + args->dac.dela_state = XFS_DAS_FLIP_NFLAG;
>> + return -EAGAIN;
>> +flip_flag:
>> /*
>> * Dismantle the "old" attribute/value pair by removing
>> * a "remote" value (if it exists).
>> @@ -1199,7 +1307,6 @@ xfs_attr_node_addname(
>> error = xfs_da3_node_lookup_int(state, &retval);
>> if (error)
>> goto out;
>> -
>> /*
>> * Remove the name and update the hashvals in the tree.
>> */
>> @@ -1207,7 +1314,6 @@ xfs_attr_node_addname(
>> ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
>> error = xfs_attr3_leaf_remove(blk->bp, args);
>> xfs_da3_fixhashpath(state, &state->path);
>> -
>> /*
>> * Check to see if the tree needs to be collapsed.
>> */
>> @@ -1215,18 +1321,9 @@ xfs_attr_node_addname(
>> error = xfs_da3_join(state);
>> if (error)
>> goto out;
>> - error = xfs_defer_finish(&args->trans);
>> - if (error)
>> - goto out;
>> - }
>> -
>> - /*
>> - * Commit and start the next trans in the chain.
>> - */
>> - error = xfs_trans_roll_inode(&args->trans, dp);
>> - if (error)
>> - goto out;
>>
>> + args->dac.flags |= XFS_DAC_FINISH_TRANS;
>> + }
>> } else if (args->rmtblkno > 0) {
>> /*
>> * Added a "remote" value, just clear the incomplete flag.
>> @@ -1234,14 +1331,6 @@ xfs_attr_node_addname(
>> error = xfs_attr3_leaf_clearflag(args);
>> if (error)
>> goto out;
>> -
>> - /*
>> - * Commit the flag value change and start the next trans in
>> - * series.
>> - */
>> - error = xfs_trans_roll_inode(&args->trans, args->dp);
>> - if (error)
>> - goto out;
>> }
>> retval = error = 0;
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
>> index ea873a5..f450d8c 100644
>> --- a/fs/xfs/libxfs/xfs_attr.h
>> +++ b/fs/xfs/libxfs/xfs_attr.h
>> @@ -152,6 +152,7 @@ int xfs_attr_get(struct xfs_inode *ip, struct xfs_name *name,
>> int xfs_attr_set(struct xfs_inode *dp, struct xfs_name *name,
>> unsigned char *value, int valuelen, int flags);
>> int xfs_attr_set_args(struct xfs_da_args *args);
>> +int xfs_attr_set_iter(struct xfs_da_args *args, struct xfs_buf **leaf_bp);
>> int xfs_attr_remove(struct xfs_inode *dp, struct xfs_name *name, int flags);
>> int xfs_has_attr(struct xfs_da_args *args);
>> int xfs_attr_remove_args(struct xfs_da_args *args);
>> diff --git a/fs/xfs/libxfs/xfs_attr_remote.c b/fs/xfs/libxfs/xfs_attr_remote.c
>> index f2ee0b8..ad4f14a 100644
>> --- a/fs/xfs/libxfs/xfs_attr_remote.c
>> +++ b/fs/xfs/libxfs/xfs_attr_remote.c
>> @@ -428,7 +428,7 @@ xfs_attr_rmtval_get(
>> * Find a "hole" in the attribute address space large enough for us to drop the
>> * new attribute's value into
>> */
>> -STATIC int
>> +int
>> xfs_attr_rmt_find_hole(
>> struct xfs_da_args *args)
>> {
>> @@ -455,7 +455,7 @@ xfs_attr_rmt_find_hole(
>> return 0;
>> }
>>
>> -STATIC int
>> +int
>> xfs_attr_rmtval_set_value(
>> struct xfs_da_args *args)
>> {
>> @@ -588,6 +588,69 @@ xfs_attr_rmtval_set(
>> }
>>
>> /*
>> + * Find a hole for the attr and store it in the delayed attr context. This
>> + * initializes the context to roll through allocating an attr extent for a
>> + * delayed attr operation
>> + */
>> +int
>> +xfs_attr_rmtval_set_init(
>> + struct xfs_da_args *args)
>> +{
>> + struct xfs_bmbt_irec *map = &args->dac.map;
>> + int error;
>> +
>> + args->dac.lblkno = 0;
>> + args->dac.lfileoff = 0;
>> + args->dac.blkcnt = 0;
>> + args->rmtblkcnt = 0;
>> + args->rmtblkno = 0;
>> + memset(map, 0, sizeof(struct xfs_bmbt_irec));
>> +
>> + error = xfs_attr_rmt_find_hole(args);
>> + if (error)
>> + return error;
>> +
>> + args->dac.blkcnt = args->rmtblkcnt;
>> + args->dac.lblkno = args->rmtblkno;
>> +
>> + return error;
>> +}
>> +
>> +/*
>> + * Write one block of the value associated with an attribute into the
>> + * out-of-line buffer that we have defined for it. This is similar to a subset
>> + * of xfs_attr_rmtval_set, but records the current block to the delayed attr
>> + * context, and leaves transaction handling to the caller.
>> + */
>> +int
>> +xfs_attr_rmtval_set_blk(
>> + struct xfs_da_args *args)
>> +{
>> + struct xfs_inode *dp = args->dp;
>> + struct xfs_bmbt_irec *map = &args->dac.map;
>> + int nmap;
>> + int error;
>> +
>> + nmap = 1;
>> + error = xfs_bmapi_write(args->trans, dp,
>> + (xfs_fileoff_t)args->dac.lblkno,
>> + args->dac.blkcnt, XFS_BMAPI_ATTRFORK,
>> + args->total, map, &nmap);
>> + if (error)
>> + return error;
>> +
>> + ASSERT(nmap == 1);
>> + ASSERT((map->br_startblock != DELAYSTARTBLOCK) &&
>> + (map->br_startblock != HOLESTARTBLOCK));
>> +
>> + /* roll attribute extent map forwards */
>> + args->dac.lblkno += map->br_blockcount;
>> + args->dac.blkcnt -= map->br_blockcount;
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> * Remove the value associated with an attribute by deleting the
>> * out-of-line buffer that it is stored on.
>> */
>> diff --git a/fs/xfs/libxfs/xfs_attr_remote.h b/fs/xfs/libxfs/xfs_attr_remote.h
>> index 7ab3770..ab03519 100644
>> --- a/fs/xfs/libxfs/xfs_attr_remote.h
>> +++ b/fs/xfs/libxfs/xfs_attr_remote.h
>> @@ -13,4 +13,8 @@ int xfs_attr_rmtval_set(struct xfs_da_args *args);
>> int xfs_attr_rmtval_remove(struct xfs_da_args *args);
>> int xfs_attr_rmtval_invalidate(struct xfs_da_args *args);
>> int xfs_attr_rmtval_unmap(struct xfs_da_args *args);
>> +int xfs_attr_rmt_find_hole(struct xfs_da_args *args);
>> +int xfs_attr_rmtval_set_value(struct xfs_da_args *args);
>> +int xfs_attr_rmtval_set_blk(struct xfs_da_args *args);
>> +int xfs_attr_rmtval_set_init(struct xfs_da_args *args);
>> #endif /* __XFS_ATTR_REMOTE_H__ */
>> diff --git a/fs/xfs/libxfs/xfs_da_btree.h b/fs/xfs/libxfs/xfs_da_btree.h
>> index 7fc87da..9943062 100644
>> --- a/fs/xfs/libxfs/xfs_da_btree.h
>> +++ b/fs/xfs/libxfs/xfs_da_btree.h
>> @@ -55,6 +55,14 @@ enum xfs_dacmp {
>> enum xfs_delattr_state {
>> XFS_DAS_RM_SHRINK = 1, /* We are shrinking the tree */
>> XFS_DAS_RM_NODE_BLKS = 2, /* We are removing node blocks */
>> + XFS_DAS_SF_TO_LEAF = 3, /* Converted short form to leaf */
>> + XFS_DAS_FOUND_LBLK = 4, /* We found leaf blk for attr */
>> + XFS_DAS_LEAF_TO_NODE = 5, /* Converted leaf to node */
>> + XFS_DAS_FOUND_NBLK = 6, /* We found node blk for attr */
>> + XFS_DAS_ALLOC_LEAF = 7, /* We are allocating leaf blocks */
>> + XFS_DAS_FLIP_LFLAG = 8, /* Flipped leaf INCOMPLETE attr flag */
>> + XFS_DAS_ALLOC_NODE = 9, /* We are allocating node blocks */
>> + XFS_DAS_FLIP_NFLAG = 10,/* Flipped node INCOMPLETE attr flag */
>
> We've definitely reached the point where a state diagram would be
> helpful. Can you go from any of the RM_ states to the ones that you've
> just added?
>
> The new state machine code in last two patches would be a lot easier to
> review if I could look down from above instead of up from the XFS_DAS
> values and goto labels. I /think/ it looks sane, but I'm only 20%
> confident of that statement.
>
> --D
>
>> };
>>
>> /*
>> @@ -66,8 +74,13 @@ enum xfs_delattr_state {
>> * Context used for keeping track of delayed attribute operations
>> */
>> struct xfs_delattr_context {
>> + struct xfs_bmbt_irec map;
>> + struct xfs_buf *leaf_bp;
>> + xfs_fileoff_t lfileoff;
>> struct xfs_da_state *da_state;
>> struct xfs_da_state_blk *blk;
>> + xfs_dablk_t lblkno;
>> + int blkcnt;
>> int flags;
>> enum xfs_delattr_state dela_state;
>> };
>> --
>> 2.7.4
>>