144 lines
5.8 KiB
Diff
144 lines
5.8 KiB
Diff
From cf13847a6341b7519ed0dc51e3b9ecf12444a3e4 Mon Sep 17 00:00:00 2001
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From: Kotresh HR <khiremat@redhat.com>
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Date: Mon, 29 Jul 2019 16:22:10 +0530
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Subject: [PATCH 267/276] posix/ctime: Fix race during lookup ctime xattr heal
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Problem:
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Ctime heals the ctime xattr ("trusted.glusterfs.mdata") in lookup
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if it's not present. In a multi client scenario, there is a race
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which results in updating the ctime xattr to older value.
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e.g. Let c1 and c2 be two clients and file1 be the file which
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doesn't have the ctime xattr. Let the ctime of file1 be t1.
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(from backend, ctime heals time attributes from backend when not present).
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Now following operations are done on mount
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c1 -> ls -l /mnt/file1 | c2 -> ls -l /mnt/file1;echo "append" >> /mnt/file1;
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The race is that the both c1 and c2 didn't fetch the ctime xattr in lookup,
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so both of them tries to heal ctime to time 't1'. If c2 wins the race and
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appends the file before c1 heals it, it sets the time to 't1' and updates
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it to 't2' (because of append). Now c1 proceeds to heal and sets it to 't1'
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which is incorrect.
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Solution:
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Compare the times during heal and only update the larger time. This is the
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general approach used in ctime feature but got missed with healing legacy
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files.
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> upstream patch : https://review.gluster.org/#/c/glusterfs/+/23131/
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>fixes: bz#1734299
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>Change-Id: I930bda192c64c3d49d0aed431ce23d3bc57e51b7
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>Signed-off-by: Kotresh HR <khiremat@redhat.com>
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BUG: 1734305
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Change-Id: I930bda192c64c3d49d0aed431ce23d3bc57e51b7
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Signed-off-by: Kotresh HR <khiremat@redhat.com>
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Reviewed-on: https://code.engineering.redhat.com/gerrit/177866
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Tested-by: RHGS Build Bot <nigelb@redhat.com>
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Reviewed-by: Sunil Kumar Heggodu Gopala Acharya <sheggodu@redhat.com>
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---
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xlators/storage/posix/src/posix-metadata.c | 76 +++++++++++++++++++++++-------
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1 file changed, 58 insertions(+), 18 deletions(-)
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diff --git a/xlators/storage/posix/src/posix-metadata.c b/xlators/storage/posix/src/posix-metadata.c
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index 647c0bb..57791fa 100644
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--- a/xlators/storage/posix/src/posix-metadata.c
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+++ b/xlators/storage/posix/src/posix-metadata.c
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@@ -344,33 +344,73 @@ posix_set_mdata_xattr_legacy_files(xlator_t *this, inode_t *inode,
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struct mdata_iatt *mdata_iatt, int *op_errno)
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{
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posix_mdata_t *mdata = NULL;
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+ posix_mdata_t imdata = {
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+ 0,
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+ };
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int ret = 0;
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+ gf_boolean_t mdata_already_set = _gf_false;
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GF_VALIDATE_OR_GOTO("posix", this, out);
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GF_VALIDATE_OR_GOTO(this->name, inode, out);
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LOCK(&inode->lock);
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{
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- mdata = GF_CALLOC(1, sizeof(posix_mdata_t), gf_posix_mt_mdata_attr);
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- if (!mdata) {
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- gf_msg(this->name, GF_LOG_ERROR, ENOMEM, P_MSG_NOMEM,
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- "Could not allocate mdata. gfid: %s",
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- uuid_utoa(inode->gfid));
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- ret = -1;
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- *op_errno = ENOMEM;
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- goto unlock;
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- }
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+ ret = __inode_ctx_get1(inode, this, (uint64_t *)&mdata);
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+ if (ret == 0 && mdata) {
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+ mdata_already_set = _gf_true;
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+ } else if (ret == -1 || !mdata) {
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+ mdata = GF_CALLOC(1, sizeof(posix_mdata_t), gf_posix_mt_mdata_attr);
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+ if (!mdata) {
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+ gf_msg(this->name, GF_LOG_ERROR, ENOMEM, P_MSG_NOMEM,
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+ "Could not allocate mdata. gfid: %s",
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+ uuid_utoa(inode->gfid));
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+ ret = -1;
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+ *op_errno = ENOMEM;
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+ goto unlock;
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+ }
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+
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+ ret = posix_fetch_mdata_xattr(this, NULL, -1, inode, (void *)mdata,
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+ op_errno);
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+ if (ret == 0) {
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+ /* Got mdata from disk. This is a race, another client
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+ * has healed the xattr during lookup. So set it in inode
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+ * ctx */
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+ __inode_ctx_set1(inode, this, (uint64_t *)&mdata);
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+ mdata_already_set = _gf_true;
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+ } else {
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+ *op_errno = 0;
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+ mdata->version = 1;
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+ mdata->flags = 0;
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+ mdata->ctime.tv_sec = mdata_iatt->ia_ctime;
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+ mdata->ctime.tv_nsec = mdata_iatt->ia_ctime_nsec;
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+ mdata->atime.tv_sec = mdata_iatt->ia_atime;
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+ mdata->atime.tv_nsec = mdata_iatt->ia_atime_nsec;
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+ mdata->mtime.tv_sec = mdata_iatt->ia_mtime;
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+ mdata->mtime.tv_nsec = mdata_iatt->ia_mtime_nsec;
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- mdata->version = 1;
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- mdata->flags = 0;
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- mdata->ctime.tv_sec = mdata_iatt->ia_ctime;
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- mdata->ctime.tv_nsec = mdata_iatt->ia_ctime_nsec;
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- mdata->atime.tv_sec = mdata_iatt->ia_atime;
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- mdata->atime.tv_nsec = mdata_iatt->ia_atime_nsec;
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- mdata->mtime.tv_sec = mdata_iatt->ia_mtime;
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- mdata->mtime.tv_nsec = mdata_iatt->ia_mtime_nsec;
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+ __inode_ctx_set1(inode, this, (uint64_t *)&mdata);
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+ }
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+ }
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- __inode_ctx_set1(inode, this, (uint64_t *)&mdata);
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+ if (mdata_already_set) {
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+ /* Compare and update the larger time */
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+ imdata.ctime.tv_sec = mdata_iatt->ia_ctime;
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+ imdata.ctime.tv_nsec = mdata_iatt->ia_ctime_nsec;
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+ imdata.atime.tv_sec = mdata_iatt->ia_atime;
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+ imdata.atime.tv_nsec = mdata_iatt->ia_atime_nsec;
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+ imdata.mtime.tv_sec = mdata_iatt->ia_mtime;
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+ imdata.mtime.tv_nsec = mdata_iatt->ia_mtime_nsec;
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+
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+ if (posix_compare_timespec(&imdata.ctime, &mdata->ctime) > 0) {
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+ mdata->ctime = imdata.ctime;
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+ }
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+ if (posix_compare_timespec(&imdata.mtime, &mdata->mtime) > 0) {
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+ mdata->mtime = imdata.mtime;
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+ }
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+ if (posix_compare_timespec(&imdata.atime, &mdata->atime) > 0) {
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+ mdata->atime = imdata.atime;
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+ }
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+ }
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ret = posix_store_mdata_xattr(this, NULL, -1, inode, mdata);
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if (ret) {
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--
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1.8.3.1
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