From a6f0e7a4f1ca203762cae2ed5e426b52124c74dc Mon Sep 17 00:00:00 2001 From: Kotresh HR Date: Fri, 1 Jun 2018 01:48:31 -0400 Subject: posix/ctime: Fix fops racing in updating mtime/atime In distributed systems, there could be races with fops updating mtime/atime which could result in different mtime/atime for same file. So updating them only if time is greater than the existing makes sure, only the highest time is retained. If the mtime/atime update comes from the explicit utime syscall, it is allowed to set to previous time. Thanks Xavi for helping in rooting the issue. fixes: bz#1584981 Change-Id: If1230a75b96d7f9a828795189fcc699049e7826e Signed-off-by: Kotresh HR --- xlators/storage/posix/src/posix-metadata.c | 42 ++++++++++++++++++++++-------- 1 file changed, 31 insertions(+), 11 deletions(-) (limited to 'xlators/storage/posix/src/posix-metadata.c') diff --git a/xlators/storage/posix/src/posix-metadata.c b/xlators/storage/posix/src/posix-metadata.c index 5da46d6bd99..eb2f24dbd69 100644 --- a/xlators/storage/posix/src/posix-metadata.c +++ b/xlators/storage/posix/src/posix-metadata.c @@ -353,7 +353,8 @@ posix_compare_timespec (struct timespec *first, struct timespec *second) static int posix_set_mdata_xattr (xlator_t *this, const char *real_path, int fd, inode_t *inode, struct timespec *time, - struct iatt *stbuf, posix_mdata_flag_t *flag) + struct iatt *stbuf, posix_mdata_flag_t *flag, + gf_boolean_t update_utime) { posix_mdata_t *mdata = NULL; int ret = -1; @@ -428,14 +429,31 @@ posix_set_mdata_xattr (xlator_t *this, const char *real_path, int fd, * allowed to changed to older date. */ if (flag->ctime && - posix_compare_timespec (time, &mdata->ctime) > 0) { + posix_compare_timespec (time, &mdata->ctime) > 0) { mdata->ctime = *time; } - if (flag->mtime) { - mdata->mtime = *time; - } - if (flag->atime) { - mdata->atime = *time; + /* In distributed systems, there could races with fops updating + * mtime/atime which could result in different mtime/atime + * for same file. So this makes sure, only the highest time is + * retained. If the mtime/atime update comes from the explicit + * utime syscall, it is allowed to set to previous time + */ + if (update_utime) { + if (flag->mtime) { + mdata->mtime = *time; + } + if (flag->atime) { + mdata->atime = *time; + } + } else { + if (flag->mtime && + posix_compare_timespec (time, &mdata->mtime) > 0) { + mdata->mtime = *time; + } + if (flag->atime && + posix_compare_timespec (time, &mdata->atime) > 0) { + mdata->atime = *time; + } } if (inode->ia_type == IA_INVAL) { @@ -507,7 +525,7 @@ posix_update_utime_in_mdata (xlator_t *this, const char *real_path, int fd, flag.mtime = 0; flag.atime = 1; ret = posix_set_mdata_xattr (this, real_path, -1, inode, &tv, NULL, - &flag); + &flag, _gf_true); if (ret) { gf_msg (this->name, GF_LOG_WARNING, errno, P_MSG_SETMDATA_FAILED, @@ -526,7 +544,7 @@ posix_update_utime_in_mdata (xlator_t *this, const char *real_path, int fd, flag.atime = 0; ret = posix_set_mdata_xattr (this, real_path, -1, inode, &tv, NULL, - &flag); + &flag, _gf_true); if (ret) { gf_msg (this->name, GF_LOG_WARNING, errno, P_MSG_SETMDATA_FAILED, @@ -602,7 +620,8 @@ posix_set_ctime (call_frame_t *frame, xlator_t *this, const char* real_path, } ret = posix_set_mdata_xattr (this, real_path, fd, inode, - &frame->root->ctime, stbuf, &flag); + &frame->root->ctime, stbuf, &flag, + _gf_false); if (ret) { gf_msg (this->name, GF_LOG_WARNING, errno, P_MSG_SETMDATA_FAILED, @@ -629,7 +648,8 @@ posix_set_parent_ctime (call_frame_t *frame, xlator_t *this, if (inode && priv->ctime) { (void) posix_get_parent_mdata_flag (frame->root->flags, &flag); ret = posix_set_mdata_xattr (this, real_path, fd, inode, - &frame->root->ctime, stbuf, &flag); + &frame->root->ctime, stbuf, &flag, + _gf_false); if (ret) { gf_msg (this->name, GF_LOG_WARNING, errno, P_MSG_SETMDATA_FAILED, -- cgit