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

Darrick J. Wong
2020-01-22T00:12:44Z

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

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

> */
> - 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
>