[PATCH v5 14/14] xfs: Add delay ready attr set routines

Allison Collins
2019-12-12T04:15:37Z

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. xfs_attr_set_args consists of 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 | 440 +++++++++++++++++++++++++++----------------
fs/xfs/libxfs/xfs_attr.h | 1 +
fs/xfs/libxfs/xfs_da_btree.h | 13 ++
3 files changed, 293 insertions(+), 161 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 726b75e..90daa9e 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
@@ -228,96 +229,166 @@ 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;
+
+ 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:
+ break;
+ }

/*
- * If the attribute list is non-existent or a shortform list,
- * upgrade it to a single-leaf-block attribute list.
+ * New inodes may not have an attribute fork yet. So set the attribute
+ * fork appropriately
*/
- if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL ||
+ 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
+ * upgrade it to a single-leaf-block attribute list. Otherwise jump
+ * straight to leaf handling
+ */
+ if (!(dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL ||
(dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
- dp->i_d.di_anextents == 0)) {
+ dp->i_d.di_anextents == 0)))
+ goto sf_to_leaf;

- /*
- * Build initial attribute list (if required).
- */
- if (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS)
- xfs_attr_shortform_create(args);
+ /*
+ * Build initial attribute list (if required).
+ */
+ if (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS)
+ xfs_attr_shortform_create(args);
+
+ /*
+ * Try to add the attr to the attribute list in the inode.
+ */
+ error = xfs_attr_shortform_addname(args);

+ /* Should only be 0, -EEXIST or ENOSPC */
+ if (error != -ENOSPC) {
/*
- * Try to add the attr to the attribute list in the inode.
+ * Commit the shortform mods, and we're done.
+ * NOTE: this is also the error path (EEXIST, etc).
*/
+ if (!error && (args->name.type & ATTR_KERNOTIME) == 0)
+ xfs_trans_ichgtime(args->trans, dp,
+ XFS_ICHGTIME_CHG);

- error = xfs_attr_shortform_addname(args);
+ if (dp->i_mount->m_flags & XFS_MOUNT_WSYNC)
+ xfs_trans_set_sync(args->trans);

- /* Should only be 0, -EEXIST or ENOSPC */
- if (error != -ENOSPC) {
- /*
- * Commit the shortform mods, and we're done.
- * NOTE: this is also the error path (EEXIST, etc).
- */
- if (!error && (args->name.type & ATTR_KERNOTIME) == 0)
- xfs_trans_ichgtime(args->trans, dp,
- XFS_ICHGTIME_CHG);
+ return error;
+ }

- if (dp->i_mount->m_flags & XFS_MOUNT_WSYNC)
- xfs_trans_set_sync(args->trans);
+ /*
+ * 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);
+ if (error)
+ return error;

- error2 = xfs_trans_commit(args->trans);
- args->trans = NULL;
- return error ? error : error2;
- }
+ /*
+ * 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.
+ */

+ xfs_trans_bhold(args->trans, *leaf_bp);
+ args->dac.dela_state = XFS_DAS_SF_TO_LEAF;
+ return -EAGAIN;

- /*
- * 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);
- if (error)
- return error;
+sf_to_leaf:

- /*
- * 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;
- }
+ /*
+ * 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;
}

if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
- error = xfs_attr_leaf_addname(args);
- if (error == 0 || error != -ENOSPC)
- return 0;
-
- /*
- * Commit that transaction so that the node_addname()
- * call can manage its own transactions.
- */
- error = xfs_defer_finish(&args->trans);
- if (error)
- return error;
-
- /*
- * Commit the current trans (including the inode) and
- * start a new one.
- */
- error = xfs_trans_roll_inode(&args->trans, dp);
- if (error)
+ error = xfs_attr_leaf_try_add(args, *leaf_bp);
+ switch (error) {
+ case -ENOSPC:
+ 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;
}
@@ -740,27 +811,29 @@ 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, nmap;
struct xfs_inode *dp = args->dp;
+ struct xfs_bmbt_irec *map = &args->dac.map;

- 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
@@ -769,7 +842,49 @@ 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 */
+
+ args->dac.lfileoff = 0;
+ args->dac.lblkno = 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;
+
+ /*
+ * Roll through the "value", allocating blocks on disk as
+ * required.
+ */
+alloc_leaf:
+ while (args->dac.blkcnt > 0) {
+ 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;
+
+ args->dac.dela_state = XFS_DAS_ALLOC_LEAF;
+ return -EAGAIN;
+ }
+
+ error = xfs_attr_rmtval_set_value(args);
if (error)
return error;
}
@@ -788,13 +903,10 @@ 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
@@ -825,34 +937,15 @@ 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);

} 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;
}
@@ -995,16 +1088,24 @@ 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;
+ int nmap;
+ struct xfs_bmbt_irec *map = &args->dac.map;

trace_xfs_attr_node_addname(args);

@@ -1013,7 +1114,19 @@ 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.
@@ -1063,19 +1176,12 @@ 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
*/
- error = xfs_trans_roll_inode(&args->trans, dp);
- if (error)
- goto out;
-
- goto restart;
+ return -EAGAIN;
}

/*
@@ -1087,9 +1193,6 @@ xfs_attr_node_addname(
error = xfs_da3_split(state);
if (error)
goto out;
- error = xfs_defer_finish(&args->trans);
- if (error)
- goto out;
} else {
/*
* Addition succeeded, update Btree hashvals.
@@ -1104,13 +1207,9 @@ 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
@@ -1119,7 +1218,48 @@ 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 */
+ 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;
+ /*
+ * Roll through the "value", allocating blocks on disk as
+ * required.
+ */
+alloc_node:
+ while (args->dac.blkcnt > 0) {
+ 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;
+
+ args->dac.dela_state = XFS_DAS_ALLOC_NODE;
+ return -EAGAIN;
+ }
+
+ error = xfs_attr_rmtval_set_value(args);
if (error)
return error;
}
@@ -1142,10 +1282,9 @@ 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).
@@ -1174,7 +1313,6 @@ 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.
*/
@@ -1182,7 +1320,6 @@ 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.
*/
@@ -1190,18 +1327,7 @@ 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;
-
} else if (args->rmtblkno > 0) {
/*
* Added a "remote" value, just clear the incomplete flag.
@@ -1209,14 +1335,6 @@ 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 f6ac571..0ba80c9 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -149,6 +149,7 @@ 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_da_btree.h b/fs/xfs/libxfs/xfs_da_btree.h
index 137ec29..69b510a 100644
--- a/fs/xfs/libxfs/xfs_da_btree.h
+++ b/fs/xfs/libxfs/xfs_da_btree.h
@@ -53,14 +53,27 @@ enum xfs_delattr_state {
XFS_DAS_RM_INVALIDATE = 1, /* We are invalidating blocks */
XFS_DAS_RM_SHRINK = 2, /* We are shrinking the tree */
XFS_DAS_RM_NODE_BLKS = 3,/* We are removing node blocks */
+ XFS_DAS_SF_TO_LEAF = 4, /* Converted short form to leaf */
+ XFS_DAS_FOUND_LBLK = 5, /* We found leaf blk for attr */
+ XFS_DAS_LEAF_TO_NODE = 6, /* Converted leaf to node */
+ XFS_DAS_FOUND_NBLK = 7, /* We found node blk for attr */
+ XFS_DAS_ALLOC_LEAF = 8, /* We are allocating leaf blocks */
+ XFS_DAS_FLIP_LFLAG = 9, /* Flipped leaf INCOMPLETE attr flag */
+ XFS_DAS_ALLOC_NODE = 10,/* We are allocating node blocks */
+ XFS_DAS_FLIP_NFLAG = 11,/* Flipped node INCOMPLETE attr flag */
};

/*
* 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;
enum xfs_delattr_state dela_state;
};

--
2.7.4