summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorKotresh HR <khiremat@redhat.com>2019-07-29 16:22:10 +0530
committerhari gowtham <hari.gowtham005@gmail.com>2019-08-07 05:07:56 +0000
commitaa45fcc1384ea6120d582cdad35b1d610e6437af (patch)
treef6df4f4976bd99b8c657bd7e001b8241c831ed13
parent05f9dc24e13df9f993438ee9b98b7a1052cf8b12 (diff)
posix/ctime: Fix race during lookup ctime xattr heal
Problem: Ctime heals the ctime xattr ("trusted.glusterfs.mdata") in lookup if it's not present. In a multi client scenario, there is a race which results in updating the ctime xattr to older value. e.g. Let c1 and c2 be two clients and file1 be the file which doesn't have the ctime xattr. Let the ctime of file1 be t1. (from backend, ctime heals time attributes from backend when not present). Now following operations are done on mount c1 -> ls -l /mnt/file1 | c2 -> ls -l /mnt/file1;echo "append" >> /mnt/file1; The race is that the both c1 and c2 didn't fetch the ctime xattr in lookup, so both of them tries to heal ctime to time 't1'. If c2 wins the race and appends the file before c1 heals it, it sets the time to 't1' and updates it to 't2' (because of append). Now c1 proceeds to heal and sets it to 't1' which is incorrect. Solution: Compare the times during heal and only update the larger time. This is the general approach used in ctime feature but got missed with healing legacy files. Backport of: > Patch: https://review.gluster.org/23131 > BUG: 1734299 > Change-Id: I930bda192c64c3d49d0aed431ce23d3bc57e51b7 > Signed-off-by: Kotresh HR <khiremat@redhat.com> fixes: bz#1737745 Change-Id: I930bda192c64c3d49d0aed431ce23d3bc57e51b7 Signed-off-by: Kotresh HR <khiremat@redhat.com>
-rw-r--r--xlators/storage/posix/src/posix-metadata.c76
1 files changed, 58 insertions, 18 deletions
diff --git a/xlators/storage/posix/src/posix-metadata.c b/xlators/storage/posix/src/posix-metadata.c
index 647c0bb..57791fa 100644
--- a/xlators/storage/posix/src/posix-metadata.c
+++ b/xlators/storage/posix/src/posix-metadata.c
@@ -344,33 +344,73 @@ posix_set_mdata_xattr_legacy_files(xlator_t *this, inode_t *inode,
struct mdata_iatt *mdata_iatt, int *op_errno)
{
posix_mdata_t *mdata = NULL;
+ posix_mdata_t imdata = {
+ 0,
+ };
int ret = 0;
+ gf_boolean_t mdata_already_set = _gf_false;
GF_VALIDATE_OR_GOTO("posix", this, out);
GF_VALIDATE_OR_GOTO(this->name, inode, out);
LOCK(&inode->lock);
{
- mdata = GF_CALLOC(1, sizeof(posix_mdata_t), gf_posix_mt_mdata_attr);
- if (!mdata) {
- gf_msg(this->name, GF_LOG_ERROR, ENOMEM, P_MSG_NOMEM,
- "Could not allocate mdata. gfid: %s",
- uuid_utoa(inode->gfid));
- ret = -1;
- *op_errno = ENOMEM;
- goto unlock;
- }
+ ret = __inode_ctx_get1(inode, this, (uint64_t *)&mdata);
+ if (ret == 0 && mdata) {
+ mdata_already_set = _gf_true;
+ } else if (ret == -1 || !mdata) {
+ mdata = GF_CALLOC(1, sizeof(posix_mdata_t), gf_posix_mt_mdata_attr);
+ if (!mdata) {
+ gf_msg(this->name, GF_LOG_ERROR, ENOMEM, P_MSG_NOMEM,
+ "Could not allocate mdata. gfid: %s",
+ uuid_utoa(inode->gfid));
+ ret = -1;
+ *op_errno = ENOMEM;
+ goto unlock;
+ }
+
+ ret = posix_fetch_mdata_xattr(this, NULL, -1, inode, (void *)mdata,
+ op_errno);
+ if (ret == 0) {
+ /* Got mdata from disk. This is a race, another client
+ * has healed the xattr during lookup. So set it in inode
+ * ctx */
+ __inode_ctx_set1(inode, this, (uint64_t *)&mdata);
+ mdata_already_set = _gf_true;
+ } else {
+ *op_errno = 0;
+ mdata->version = 1;
+ mdata->flags = 0;
+ mdata->ctime.tv_sec = mdata_iatt->ia_ctime;
+ mdata->ctime.tv_nsec = mdata_iatt->ia_ctime_nsec;
+ mdata->atime.tv_sec = mdata_iatt->ia_atime;
+ mdata->atime.tv_nsec = mdata_iatt->ia_atime_nsec;
+ mdata->mtime.tv_sec = mdata_iatt->ia_mtime;
+ mdata->mtime.tv_nsec = mdata_iatt->ia_mtime_nsec;
- mdata->version = 1;
- mdata->flags = 0;
- mdata->ctime.tv_sec = mdata_iatt->ia_ctime;
- mdata->ctime.tv_nsec = mdata_iatt->ia_ctime_nsec;
- mdata->atime.tv_sec = mdata_iatt->ia_atime;
- mdata->atime.tv_nsec = mdata_iatt->ia_atime_nsec;
- mdata->mtime.tv_sec = mdata_iatt->ia_mtime;
- mdata->mtime.tv_nsec = mdata_iatt->ia_mtime_nsec;
+ __inode_ctx_set1(inode, this, (uint64_t *)&mdata);
+ }
+ }
- __inode_ctx_set1(inode, this, (uint64_t *)&mdata);
+ if (mdata_already_set) {
+ /* Compare and update the larger time */
+ imdata.ctime.tv_sec = mdata_iatt->ia_ctime;
+ imdata.ctime.tv_nsec = mdata_iatt->ia_ctime_nsec;
+ imdata.atime.tv_sec = mdata_iatt->ia_atime;
+ imdata.atime.tv_nsec = mdata_iatt->ia_atime_nsec;
+ imdata.mtime.tv_sec = mdata_iatt->ia_mtime;
+ imdata.mtime.tv_nsec = mdata_iatt->ia_mtime_nsec;
+
+ if (posix_compare_timespec(&imdata.ctime, &mdata->ctime) > 0) {
+ mdata->ctime = imdata.ctime;
+ }
+ if (posix_compare_timespec(&imdata.mtime, &mdata->mtime) > 0) {
+ mdata->mtime = imdata.mtime;
+ }
+ if (posix_compare_timespec(&imdata.atime, &mdata->atime) > 0) {
+ mdata->atime = imdata.atime;
+ }
+ }
ret = posix_store_mdata_xattr(this, NULL, -1, inode, mdata);
if (ret) {