From 94da54d582e6866a9613514b59f326456e88446d Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 4 Dec 2023 12:13:26 -0800 Subject: xfs: document what LARP means Christoph requested a blurb somewhere explaining exactly what LARP means. I don't know of a good place other than the source code (debug knobs aren't covered in Documentation/), so here it is. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/xfs_sysfs.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c index a3c6b1548723..871f16a4a5d8 100644 --- a/fs/xfs/xfs_sysfs.c +++ b/fs/xfs/xfs_sysfs.c @@ -229,6 +229,15 @@ pwork_threads_show( } XFS_SYSFS_ATTR_RW(pwork_threads); +/* + * The "LARP" (Logged extended Attribute Recovery Persistence) debugging knob + * sets the XFS_DA_OP_LOGGED flag on all xfs_attr_set operations performed on + * V5 filesystems. As a result, the intermediate progress of all setxattr and + * removexattr operations are tracked via the log and can be restarted during + * recovery. This is useful for testing xattr recovery prior to merging of the + * parent pointer feature which requires it to maintain consistency, and may be + * enabled for userspace xattrs in the future. + */ static ssize_t larp_store( struct kobject *kobject, -- cgit From 9c07bca793b4ff9f0b7871e2a928a1b28b8fa4e3 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 4 Dec 2023 12:21:06 -0800 Subject: xfs: elide ->create_done calls for unlogged deferred work Extended attribute updates use the deferred work machinery to manage state across a chain of smaller transactions. All previous deferred work users have employed log intent items and log done items to manage restarting of interrupted operations, which means that ->create_intent sets dfp_intent to a log intent item and ->create_done uses that item to create a log intent done item. However, xattrs have used the INCOMPLETE flag to deal with the lack of recovery support for an interrupted transaction chain. Log items are optional if the xattr update caller didn't set XFS_DA_OP_LOGGED to require a restartable sequence. In other words, ->create_intent can return NULL to say that there's no log intent item. If that's the case, no log intent done item should be created. Clean up xfs_defer_create_done not to do this, so that the ->create_done functions don't have to check for non-null dfp_intent themselves. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/libxfs/xfs_defer.c | 4 ++++ fs/xfs/xfs_attr_item.c | 3 --- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c index 54a6be06e6cd..06e890b44c52 100644 --- a/fs/xfs/libxfs/xfs_defer.c +++ b/fs/xfs/libxfs/xfs_defer.c @@ -201,6 +201,10 @@ xfs_defer_create_done( const struct xfs_defer_op_type *ops = defer_op_types[dfp->dfp_type]; struct xfs_log_item *lip; + /* If there is no log intent item, there can be no log done item. */ + if (!dfp->dfp_intent) + return; + /* * Mark the transaction dirty, even on error. This ensures the * transaction is aborted, which: diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c index 988d395a48ad..39f2c5a46179 100644 --- a/fs/xfs/xfs_attr_item.c +++ b/fs/xfs/xfs_attr_item.c @@ -740,9 +740,6 @@ xfs_attr_create_done( struct xfs_attri_log_item *attrip; struct xfs_attrd_log_item *attrdp; - if (!intent) - return NULL; - attrip = ATTRI_ITEM(intent); attrdp = kmem_cache_zalloc(xfs_attrd_cache, GFP_NOFS | __GFP_NOFAIL); -- cgit