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.
Below is a state machine diagram for attr set operations. The XFS_DAS_* states
indicate places where the function would return -EAGAIN, and then immediately
resume from after being recalled by the calling function. States marked as a
"subroutine state" indicate that they belong to a subroutine, and so the calling
function needs to pass them back to that subroutine to allow it to finish where it
left off. But they otherwise do not have a role in the calling function other
than just passing through.
xfs_attr_set_iter()
│
v
need to upgrade
from sf to leaf? ──n─â”
│ │
y │
│ │
V │
XFS_DAS_ADD_LEAF │
│ │
v │
┌──────n── fork has <──────┘
│ only 1 blk?
│ │
│ y
│ │
│ v
│ xfs_attr_leaf_try_add()
│ │
│ v
│ had enough
├──────n── space?
│ │
│ y
│ │
│ v
│ XFS_DAS_FOUND_LBLK ──â”
│ │
│ XFS_DAS_FLIP_LFLAG ──┤
│ (subroutine state) │
│ │
│ XFS_DAS_ALLOC_LEAF ──┤
│ (subroutine state) │
│ └─>xfs_attr_leaf_addname()
│ │
│ v
│ ┌─────n── need to
│ │ alloc blks?
│ │ │
│ │ y
│ │ │
│ │ v
│ │ ┌─>XFS_DAS_ALLOC_LEAF
│ │ │ │
│ │ │ v
│ │ └──y── need to alloc
│ │ more blocks?
│ │ │
│ │ n
│ │ │
│ │ v
│ │ was this
│ └────────> a rename? ──n─â”
│ │ │
│ y │
│ │ │
│ v │
│ flip incomplete │
│ flag │
│ │ │
│ v │
│ ┌─>XFS_DAS_FLIP_LFLAG │
│ │ │ │
│ │ v │
│ │ remove │
│ │ old name │
│ │ │ │
│ │ v │
│ └────y── more to │
│ remove │
│ │ │
│ n │
│ │ │
│ v │
│ done <──────┘
└────> XFS_DAS_LEAF_TO_NODE ─â”
│
XFS_DAS_FOUND_NBLK ──┤
(subroutine state) │
│
XFS_DAS_ALLOC_NODE ──┤
(subroutine state) │
│
XFS_DAS_FLIP_NFLAG ──┤
(subroutine state) │
│
└─>xfs_attr_node_addname()
│
v
find space to store
attr. Split if needed
│
v
XFS_DAS_FOUND_NBLK
│
v
┌─────n── need to
│ alloc blks?
│ │
│ y
│ │
│ v
│ ┌─>XFS_DAS_ALLOC_NODE
│ │ │
│ │ v
│ └──y── need to alloc
│ more blocks?
│ │
│ n
│ │
│ v
│ was this
└────────> a rename? ──n─â”
│ │
y │
│ │
v │
flip incomplete │
flag │
│ │
v │
┌─>XFS_DAS_FLIP_NFLAG │
│ │ │
│ v │
│ remove │
│ old name │
│ │ │
│ v │
└────y── more to │
remove │
│ │
n │
│ │
v │
done <──────┘
Signed-off-by: Allison Collins <allison.henderson@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_attr.c | 368 ++++++++++++++++++++++++++--------------
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, 319 insertions(+), 134 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index cd3a3f7..4b788f2 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_ADD_LEAF:
+ goto add_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;
+ }
+
+ /*
+ * 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,
@@ -275,17 +353,16 @@ xfs_attr_set_args(
* 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;
- }
+
+ /* 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;
@@ -293,41 +370,48 @@ 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_ADD_LEAF;
+ return -EAGAIN;
}
- if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
- error = xfs_attr_leaf_addname(args);
- if (error != -ENOSPC)
- return error;
+add_leaf:
- /*
- * 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;
}
@@ -766,28 +850,29 @@ 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;
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
@@ -796,7 +881,28 @@ xfs_attr_leaf_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_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;
}
@@ -815,13 +921,6 @@ xfs_attr_leaf_addname(
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;
/*
* Dismantle the "old" attribute/value pair by removing
@@ -832,8 +931,17 @@ xfs_attr_leaf_addname(
args->rmtblkno = args->rmtblkno2;
args->rmtblkcnt = args->rmtblkcnt2;
args->rmtvaluelen = args->rmtvaluelen2;
+
+ args->dac.dela_state = XFS_DAS_FLIP_LFLAG;
+ return -EAGAIN;
+flip_flag:
if (args->rmtblkno) {
- error = xfs_attr_rmtval_remove(args);
+ error = xfs_attr_rmtval_unmap(args);
+
+ /*
+ * if (error == -EAGAIN), we will repeat this until
+ * args->rmtblkno is zero
+ */
if (error)
return error;
}
