On 12/13/19 10:30 AM, Brian Foster wrote:
On Wed, Dec 11, 2019 at 09:15:12PM -0700, Allison Collins wrote:
This patch modifies the attr remove 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_remove_args has become
xfs_attr_remove_iter, which uses a sort of state machine like switch
to keep track of where it was when EAGAIN was returned.
xfs_attr_node_removename has also been modified to use the switch,
and a new version of xfs_attr_remove_args consists of a simple loop
to refresh the transaction until the operation is completed.
This patch also adds a new struct xfs_delattr_context, which we will
use to keep track of the current state of an attribute operation.
The new xfs_delattr_state enum is used to track various operations
that are in progress so that we know not to repeat them, and resume
where we left off before EAGAIN was returned to cycle out the
transaction. Other members take the place of local variables that
need to retain their values across multiple function recalls.
Signed-off-by: Allison Collins <allison.henderson@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_attr.c | 127 ++++++++++++++++++++++++++++++++++++-------
fs/xfs/libxfs/xfs_attr.h | 1 +
fs/xfs/libxfs/xfs_da_btree.h | 16 ++++++
fs/xfs/scrub/common.c | 2 +
fs/xfs/xfs_acl.c | 2 +
fs/xfs/xfs_attr_list.c | 1 +
fs/xfs/xfs_ioctl.c | 2 +
fs/xfs/xfs_ioctl32.c | 2 +
fs/xfs/xfs_iops.c | 2 +
fs/xfs/xfs_xattr.c | 1 +
10 files changed, 137 insertions(+), 19 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index b5a5c84..726b75e 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
...
@@ -1206,12 +1249,29 @@ xfs_attr_node_removename(
struct xfs_buf *bp;
int retval, error, forkoff;
struct xfs_inode *dp = args->dp;
+ int done = 0;
trace_xfs_attr_node_removename(args);
+ state = args->dac.da_state;
+ blk = args->dac.blk;
+
+ /* State machine switch */
+ switch (args->dac.dela_state) {
+ case XFS_DAS_RM_NODE_BLKS:
+ goto rm_node_blks;
+ case XFS_DAS_RM_INVALIDATE:
+ goto rm_invalidate;
+ case XFS_DAS_RM_SHRINK:
+ goto rm_shrink;
+ default:
+ break;
+ }
I think this function could use at least a couple more prepatory
refactoring patches before we introduce the state machine...
error = xfs_attr_node_hasname(args, &state);
if (error != -EEXIST)
goto out;
+ else
+ error = 0;
/*
* If there is an out-of-line value, de-allocate the blocks.
@@ -1221,6 +1281,14 @@ xfs_attr_node_removename(
blk = &state->path.blk[ state->path.active-1 ];
ASSERT(blk->bp != NULL);
ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
+
+ /*
+ * Store blk and state in the context incase we need to cycle out the
+ * transaction
+ */
+ args->dac.blk = blk;
+ args->dac.da_state = state;
+
if (args->rmtblkno > 0) {
/*
* Fill in disk block numbers in the state structure
@@ -1239,13 +1307,40 @@ xfs_attr_node_removename(
if (error)
goto out;
- error = xfs_trans_roll_inode(&args->trans, args->dp);
- if (error)
- goto out;
+ args->dac.dela_state = XFS_DAS_RM_INVALIDATE;
+ return -EAGAIN;
+ }
The entire (args->rmtblkno > 0) branch above could be reduced into a
helper function. BTW, does it matter whether the invalidate occurs
before or after this particular transaction roll? It looks to me it just
makes in-core changes. I'm wondering if we could just fold that in as
well and eliminate that state entirely.
I assumed the reason for the roll here was the invalidate? But I
suppose if we only have in-core changes maybe it's not needed. I'll see
if I can remove this state, and tuck the above logic into a helper.
+
+rm_invalidate:
+ args->dac.dela_state = XFS_DAS_RM_INVALIDATE;
- error = xfs_attr_rmtval_remove(args);
+ if (args->rmtblkno > 0) {
+ error = xfs_attr_rmtval_invalidate(args);
if (error)
goto out;
+ }
+
+rm_node_blks:
+
+ args->dac.dela_state = XFS_DAS_RM_NODE_BLKS;
+ if (args->rmtblkno > 0) {
+ /*
+ * Unmap value blocks for this attr. This is similar to
+ * xfs_attr_rmtval_remove, but open coded here to return EAGAIN
+ * for new transactions
+ */
+ while (!done && !error) {
+ error = xfs_bunmapi(args->trans, args->dp,
+ args->rmtblkno, args->rmtblkcnt,
+ XFS_BMAPI_ATTRFORK, 1, &done);
+ if (error)
+ return error;
+
+ if (!done) {
+ args->dac.dela_state = XFS_DAS_RM_NODE_BLKS;
+ return -EAGAIN;
+ }
+ }
The above could use the helper function treatment as well. E.g.,
something like xfs_attr_rmtval_unmap() that has a *done param this
function can check to determine whether to return -EAGAIN or proceed.
Sure, will do
/*
* Refill the state structure with buffers, the prior calls
@@ -1271,17 +1366,14 @@ xfs_attr_node_removename(
error = xfs_da3_join(state);
if (error)
goto out;
- error = xfs_defer_finish(&args->trans);
- if (error)
- goto out;
Hmm.. I think we might want to lift the xfs_defer_finish() call up into
the iter() function rather than just drop it. Otherwise this changes
behavior in that the transaction roll doesn't complete pending deferred
operations.
Ok, I'll tack that on then
- /*
- * Commit the Btree join operation and start a new trans.
- */
- error = xfs_trans_roll_inode(&args->trans, dp);
- if (error)
- goto out;
+
+ args->dac.dela_state = XFS_DAS_RM_SHRINK;
+ return -EAGAIN;
}
+rm_shrink:
+ args->dac.dela_state = XFS_DAS_RM_SHRINK;
+
/*
* If the result is small enough, push it all into the inode.
*/
@@ -1302,9 +1394,6 @@ xfs_attr_node_removename(
/* bp is gone due to xfs_da_shrink_inode */
if (error)
goto out;
- error = xfs_defer_finish(&args->trans);
- if (error)
- goto out;
} else
xfs_trans_brelse(args->trans, bp);
}
Same deal here (and same fundamental comment for the next patch)..
create a xfs_attr_node_shrink() or some such helper to make functions
that handle state smaller and easier to follow once the state bits are
introduced.
Brian
Ok then, sounds good. Thanks again for all the reviews, I know it's
been a lot! I'll get all this stuff updated in the next version.
Allison
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index 3b5dad4..f6ac571 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -152,6 +152,7 @@ int xfs_attr_set_args(struct xfs_da_args *args);
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);
+int xfs_attr_remove_iter(struct xfs_da_args *args);
int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
int flags, struct attrlist_cursor_kern *cursor);
bool xfs_attr_namecheck(const void *name, size_t length);
diff --git a/fs/xfs/libxfs/xfs_da_btree.h b/fs/xfs/libxfs/xfs_da_btree.h
index 580fb72..137ec29 100644
--- a/fs/xfs/libxfs/xfs_da_btree.h
+++ b/fs/xfs/libxfs/xfs_da_btree.h
@@ -49,10 +49,26 @@ enum xfs_dacmp {
XFS_CMP_CASE /* names are same but differ in case */
};
+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 */
+};
+
+/*
+ * Context used for keeping track of delayed attribute operations
+ */
+struct xfs_delattr_context {
+ struct xfs_da_state *da_state;
+ struct xfs_da_state_blk *blk;
+ enum xfs_delattr_state dela_state;
+};
+
/*
* Structure to ease passing around component names.
*/
typedef struct xfs_da_args {
+ struct xfs_delattr_context dac;/* context used for delay attr ops */
struct xfs_da_geometry *geo; /* da block geometry */
struct xfs_name name; /* name, length and argument flags*/
uint8_t filetype; /* filetype of inode for directories */
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index 1887605..9a649d1 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -24,6 +24,8 @@
#include "xfs_rmap_btree.h"
#include "xfs_log.h"
#include "xfs_trans_priv.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_reflink.h"
#include "scrub/scrub.h"
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 7b0e5b7..573e47e 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -10,6 +10,8 @@
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include "xfs_error.h"
diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c
index d37743b..881b9a4 100644
--- a/fs/xfs/xfs_attr_list.c
+++ b/fs/xfs/xfs_attr_list.c
@@ -12,6 +12,7 @@
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 4fc8698..a31753f 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -15,6 +15,8 @@
#include "xfs_iwalk.h"
#include "xfs_itable.h"
#include "xfs_error.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index c4c4f09..4b693e3 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -17,6 +17,8 @@
#include "xfs_itable.h"
#include "xfs_fsops.h"
#include "xfs_rtalloc.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_ioctl.h"
#include "xfs_ioctl32.h"
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index e85bbf5..a2d299f 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -13,6 +13,8 @@
#include "xfs_inode.h"
#include "xfs_acl.h"
#include "xfs_quota.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_trans.h"
#include "xfs_trace.h"
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index 5623682..8bdb972 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -10,6 +10,7 @@
#include "xfs_log_format.h"
#include "xfs_da_format.h"
#include "xfs_inode.h"
+#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_acl.h"
--
2.7.4
