64 lines
2.2 KiB
Diff
64 lines
2.2 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Alex Zhuravlev <alexey.zhuravlev@intel.com>
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Date: Mon, 8 Jan 2018 10:57:47 -0800
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Subject: [PATCH] Use zap_count instead of cached z_size for unlink
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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As a performance optimization Lustre does not strictly update
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the SA_ZPL_SIZE when adding/removing from non-directory entries.
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This results in entries which cannot be removed through the ZPL
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layer even though the ZAP is empty and safe to remove.
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Resolve this issue by checking the zap_count() directly instead
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on relying on the cached SA_ZPL_SIZE. Micro-benchmarks show no
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significant performance impact due to the additional overhead
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of using zap_count().
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Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
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Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
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Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
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Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
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Closes #7019
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(cherry picked from commit 129e3e8dc32673809d1d3523a0e773567e281a4a)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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module/zfs/zfs_dir.c | 16 +++++++++++++++-
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1 file changed, 15 insertions(+), 1 deletion(-)
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diff --git a/module/zfs/zfs_dir.c b/module/zfs/zfs_dir.c
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index c6ee30291..9a8bbccd9 100644
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--- a/module/zfs/zfs_dir.c
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+++ b/module/zfs/zfs_dir.c
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@@ -977,11 +977,25 @@ zfs_link_destroy(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag,
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* Indicate whether the directory is empty. Works with or without z_lock
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* held, but can only be consider a hint in the latter case. Returns true
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* if only "." and ".." remain and there's no work in progress.
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+ *
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+ * The internal ZAP size, rather than zp->z_size, needs to be checked since
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+ * some consumers (Lustre) do not strictly maintain an accurate SA_ZPL_SIZE.
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*/
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boolean_t
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zfs_dirempty(znode_t *dzp)
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{
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- return (dzp->z_size == 2 && dzp->z_dirlocks == 0);
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+ zfsvfs_t *zfsvfs = ZTOZSB(dzp);
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+ uint64_t count;
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+ int error;
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+
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+ if (dzp->z_dirlocks != NULL)
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+ return (B_FALSE);
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+
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+ error = zap_count(zfsvfs->z_os, dzp->z_id, &count);
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+ if (error != 0 || count != 0)
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+ return (B_FALSE);
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+
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+ return (B_TRUE);
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}
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int
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--
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2.14.2
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