[PATCH 15/17] xfs: remove xfs_attri_remove_iter

Dave Chinner
2022-05-06T09:46:17Z

xfs_attri_remove_iter is not used anymore, so remove it and all the
infrastructure it uses and is needed to drive it. THe
xfs_attr_refillstate() function now throws an unused warning, so
isolate the xfs_attr_fillstate()/xfs_attr_refillstate() code pair
with an #if 0 and a comment explaining why we want to keep this code
and restore the optimisation it provides in the near future.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
---
fs/xfs/libxfs/xfs_attr.c | 431 ++++++++++++---------------------------
1 file changed, 135 insertions(+), 296 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index e2067aead818..c326fb2f5417 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -64,8 +64,6 @@ STATIC int xfs_attr_node_addname_find_attr(struct xfs_attr_item *attr);
STATIC int xfs_attr_node_remove_attr(struct xfs_attr_item *attr);
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_node_removename(struct xfs_da_args *args,
struct xfs_da_state *state);

@@ -100,6 +98,123 @@ xfs_attr_is_leaf(
return imap.br_startoff == 0 && imap.br_blockcount == 1;
}

+/*
+ * XXX (dchinner): name path state saving and refilling is an optimisation to
+ * avoid needing to look up name entries after rolling transactions removing
+ * remote xattr blocks between the name entry lookup and name entry removal.
+ * This optimisation got sidelined when combining the set and remove state
+ * machines, but the code has been left in place because it is worthwhile to
+ * restore the optimisation once the combined state machine paths have settled.
+ *
+ * This comment is a public service announcement to remind Future Dave that he
+ * still needs to restore this code to working order.
+ */
+#if 0
+/*
+ * Fill in the disk block numbers in the state structure for the buffers
+ * that are attached to the state structure.
+ * This is done so that we can quickly reattach ourselves to those buffers
+ * after some set of transaction commits have released these buffers.
+ */
+static int
+xfs_attr_fillstate(xfs_da_state_t *state)
+{
+ xfs_da_state_path_t *path;
+ xfs_da_state_blk_t *blk;
+ int level;
+
+ trace_xfs_attr_fillstate(state->args);
+
+ /*
+ * Roll down the "path" in the state structure, storing the on-disk
+ * block number for those buffers in the "path".
+ */
+ path = &state->path;
+ ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
+ for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
+ if (blk->bp) {
+ blk->disk_blkno = xfs_buf_daddr(blk->bp);
+ blk->bp = NULL;
+ } else {
+ blk->disk_blkno = 0;
+ }
+ }
+
+ /*
+ * Roll down the "altpath" in the state structure, storing the on-disk
+ * block number for those buffers in the "altpath".
+ */
+ path = &state->altpath;
+ ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
+ for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
+ if (blk->bp) {
+ blk->disk_blkno = xfs_buf_daddr(blk->bp);
+ blk->bp = NULL;
+ } else {
+ blk->disk_blkno = 0;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Reattach the buffers to the state structure based on the disk block
+ * numbers stored in the state structure.
+ * This is done after some set of transaction commits have released those
+ * buffers from our grip.
+ */
+static int
+xfs_attr_refillstate(xfs_da_state_t *state)
+{
+ xfs_da_state_path_t *path;
+ xfs_da_state_blk_t *blk;
+ int level, error;
+
+ trace_xfs_attr_refillstate(state->args);
+
+ /*
+ * Roll down the "path" in the state structure, storing the on-disk
+ * block number for those buffers in the "path".
+ */
+ path = &state->path;
+ ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
+ for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
+ if (blk->disk_blkno) {
+ error = xfs_da3_node_read_mapped(state->args->trans,
+ state->args->dp, blk->disk_blkno,
+ &blk->bp, XFS_ATTR_FORK);
+ if (error)
+ return error;
+ } else {
+ blk->bp = NULL;
+ }
+ }
+
+ /*
+ * Roll down the "altpath" in the state structure, storing the on-disk
+ * block number for those buffers in the "altpath".
+ */
+ path = &state->altpath;
+ ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
+ for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
+ if (blk->disk_blkno) {
+ error = xfs_da3_node_read_mapped(state->args->trans,
+ state->args->dp, blk->disk_blkno,
+ &blk->bp, XFS_ATTR_FORK);
+ if (error)
+ return error;
+ } else {
+ blk->bp = NULL;
+ }
+ }
+
+ return 0;
+}
+#else
+static int xfs_attr_fillstate(xfs_da_state_t *state) { return 0; }
+#endif
+
/*========================================================================
* Overall external interface routines.
*========================================================================*/
@@ -1339,6 +1454,24 @@ xfs_attr_node_try_addname(
return error;
}

+static int
+xfs_attr_node_removename(
+ struct xfs_da_args *args,
+ struct xfs_da_state *state)
+{
+ struct xfs_da_state_blk *blk;
+ int retval;
+
+ /*
+ * Remove the name and update the hashvals in the tree.
+ */
+ blk = &state->path.blk[state->path.active-1];
+ ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
+ retval = xfs_attr3_leaf_remove(blk->bp, args);
+ xfs_da3_fixhashpath(state, &state->path);
+
+ return retval;
+}

static int
xfs_attr_node_remove_attr(
@@ -1381,300 +1514,6 @@ xfs_attr_node_remove_attr(
return retval;
}

-/*
- * Shrink an attribute from leaf to shortform
- */
-STATIC int
-xfs_attr_node_shrink(
- struct xfs_da_args *args,
- struct xfs_da_state *state)
-{
- struct xfs_inode *dp = args->dp;
- int error, forkoff;
- struct xfs_buf *bp;
-
- /*
- * Have to get rid of the copy of this dabuf in the state.
- */
- ASSERT(state->path.active == 1);
- ASSERT(state->path.blk[0].bp);
- state->path.blk[0].bp = NULL;
-
- error = xfs_attr3_leaf_read(args->trans, args->dp, 0, &bp);
- if (error)
- return error;
-
- 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 */
- } else
- xfs_trans_brelse(args->trans, bp);
-
- return error;
-}
-
-STATIC int
-xfs_attr_node_removename(
- struct xfs_da_args *args,
- struct xfs_da_state *state)
-{
- struct xfs_da_state_blk *blk;
- int retval;
-
- /*
- * Remove the name and update the hashvals in the tree.
- */
- blk = &state->path.blk[state->path.active-1];
- ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
- retval = xfs_attr3_leaf_remove(blk->bp, args);
- xfs_da3_fixhashpath(state, &state->path);
-
- return retval;
-}
-
-/*
- * Remove the attribute specified in @args.
- *
- * This will involve walking down the Btree, and may involve joining
- * leaf nodes and even joining intermediate nodes up to and including
- * the root node (a special case of an intermediate node).
- *
- * This routine is meant to function as either an in-line or delayed operation,
- * and may return -EAGAIN when the transaction needs to be rolled. Calling
- * functions will need to handle this, and call the function until a
- * successful error code is returned.
- */
-int
-xfs_attr_remove_iter(
- struct xfs_attr_item *attr)
-{
- struct xfs_da_args *args = attr->xattri_da_args;
- struct xfs_da_state *state = attr->xattri_da_state;
- int retval, error = 0;
- struct xfs_inode *dp = args->dp;
-
- trace_xfs_attr_node_removename(args);
-
- switch (attr->xattri_dela_state) {
- case XFS_DAS_UNINIT:
- if (!xfs_inode_hasattr(dp))
- return -ENOATTR;
-
- /*
- * Shortform or leaf formats don't require transaction rolls and
- * thus state transitions. Call the right helper and return.
- */
- if (dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL)
- return xfs_attr_sf_removename(args);
-
- if (xfs_attr_is_leaf(dp))
- return xfs_attr_leaf_removename(args);
-
- /*
- * Node format may require transaction rolls. Set up the
- * state context and fall into the state machine.
- */
- if (!attr->xattri_da_state) {
- error = xfs_attr_node_removename_setup(attr);
- if (error)
- return error;
- state = attr->xattri_da_state;
- }
-
- fallthrough;
- case XFS_DAS_RMTBLK:
- attr->xattri_dela_state = XFS_DAS_RMTBLK;
-
- /*
- * If there is an out-of-line value, de-allocate the blocks.
- * This is done before we remove the attribute so that we don't
- * overflow the maximum size of a transaction and/or hit a
- * deadlock.
- */
- if (args->rmtblkno > 0) {
- /*
- * May return -EAGAIN. Roll and repeat until all remote
- * blocks are removed.
- */
- error = xfs_attr_rmtval_remove(attr);
- if (error == -EAGAIN) {
- trace_xfs_attr_remove_iter_return(
- attr->xattri_dela_state, args->dp);
- return error;
- } else if (error) {
- goto out;
- }
-
- /*
- * Refill the state structure with buffers (the prior
- * calls released our buffers) and close out this
- * transaction before proceeding.
- */
- ASSERT(args->rmtblkno == 0);
- error = xfs_attr_refillstate(state);
- if (error)
- goto out;
-
- attr->xattri_dela_state = XFS_DAS_RM_NAME;
- trace_xfs_attr_remove_iter_return(
- attr->xattri_dela_state, args->dp);
- return -EAGAIN;
- }
-
- fallthrough;
- case XFS_DAS_RM_NAME:
- /*
- * If we came here fresh from a transaction roll, reattach all
- * the buffers to the current transaction.
- */
- if (attr->xattri_dela_state == XFS_DAS_RM_NAME) {
- error = xfs_attr_refillstate(state);
- if (error)
- goto out;
- }
-
- retval = xfs_attr_node_removename(args, state);
-
- /*
- * Check to see if the tree needs to be collapsed. If so, roll
- * the transacton and fall into the shrink state.
- */
- if (retval && (state->path.active > 1)) {
- error = xfs_da3_join(state);
- if (error)
- goto out;
-
- attr->xattri_dela_state = XFS_DAS_RM_SHRINK;
- trace_xfs_attr_remove_iter_return(
- attr->xattri_dela_state, args->dp);
- return -EAGAIN;
- }
-
- fallthrough;
- case XFS_DAS_RM_SHRINK:
- /*
- * If the result is small enough, push it all into the inode.
- * This is our final state so it's safe to return a dirty
- * transaction.
- */
- if (xfs_attr_is_leaf(dp))
- error = xfs_attr_node_shrink(args, state);
- ASSERT(error != -EAGAIN);
- break;
- default:
- ASSERT(0);
- error = -EINVAL;
- goto out;
- }
-out:
- if (state)
- xfs_da_state_free(state);
- return error;
-}
-
-/*
- * Fill in the disk block numbers in the state structure for the buffers
- * that are attached to the state structure.
- * This is done so that we can quickly reattach ourselves to those buffers
- * after some set of transaction commits have released these buffers.
- */
-STATIC int
-xfs_attr_fillstate(xfs_da_state_t *state)
-{
- xfs_da_state_path_t *path;
- xfs_da_state_blk_t *blk;
- int level;
-
- trace_xfs_attr_fillstate(state->args);
-
- /*
- * Roll down the "path" in the state structure, storing the on-disk
- * block number for those buffers in the "path".
- */
- path = &state->path;
- ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
- for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
- if (blk->bp) {
- blk->disk_blkno = xfs_buf_daddr(blk->bp);
- blk->bp = NULL;
- } else {
- blk->disk_blkno = 0;
- }
- }
-
- /*
- * Roll down the "altpath" in the state structure, storing the on-disk
- * block number for those buffers in the "altpath".
- */
- path = &state->altpath;
- ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
- for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
- if (blk->bp) {
- blk->disk_blkno = xfs_buf_daddr(blk->bp);
- blk->bp = NULL;
- } else {
- blk->disk_blkno = 0;
- }
- }
-
- return 0;
-}
-
-/*
- * Reattach the buffers to the state structure based on the disk block
- * numbers stored in the state structure.
- * This is done after some set of transaction commits have released those
- * buffers from our grip.
- */
-STATIC int
-xfs_attr_refillstate(xfs_da_state_t *state)
-{
- xfs_da_state_path_t *path;
- xfs_da_state_blk_t *blk;
- int level, error;
-
- trace_xfs_attr_refillstate(state->args);
-
- /*
- * Roll down the "path" in the state structure, storing the on-disk
- * block number for those buffers in the "path".
- */
- path = &state->path;
- ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
- for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
- if (blk->disk_blkno) {
- error = xfs_da3_node_read_mapped(state->args->trans,
- state->args->dp, blk->disk_blkno,
- &blk->bp, XFS_ATTR_FORK);
- if (error)
- return error;
- } else {
- blk->bp = NULL;
- }
- }
-
- /*
- * Roll down the "altpath" in the state structure, storing the on-disk
- * block number for those buffers in the "altpath".
- */
- path = &state->altpath;
- ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
- for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
- if (blk->disk_blkno) {
- error = xfs_da3_node_read_mapped(state->args->trans,
- state->args->dp, blk->disk_blkno,
- &blk->bp, XFS_ATTR_FORK);
- if (error)
- return error;
- } else {
- blk->bp = NULL;
- }
- }
-
- return 0;
-}
-
/*
* Retrieve the attribute data from a node attribute list.
*
--
2.35.1