diff options
| -rw-r--r-- | xlators/storage/posix/src/posix.c | 70 |
1 files changed, 69 insertions, 1 deletions
diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c index 0cd6883c1b3..f6b99025557 100644 --- a/xlators/storage/posix/src/posix.c +++ b/xlators/storage/posix/src/posix.c @@ -404,6 +404,74 @@ out: } +static int +is_fresh_file (struct stat *stat) +{ + struct timeval tv; + + gettimeofday (&tv, NULL); + + if ((stat->st_ctime >= (tv.tv_sec - 1)) + && (stat->st_ctime <= tv.tv_sec)) + return 1; + + return 0; +} + + +int +posix_gfid_heal (xlator_t *this, const char *path, dict_t *xattr_req) +{ + /* The purpose of this function is to prevent a race + where an inode creation FOP (like mkdir/mknod/create etc) + races with lookup in the following way: + + {create thread} | {lookup thread} + | + t0 + mkdir ("name") | + t1 + | posix_gfid_set ("name", 2); + t2 + posix_gfid_set ("name", 1); | + t3 + lstat ("name"); | lstat ("name"); + + In the above case mkdir FOP would have resulted with GFID 2 while + it should have been GFID 1. It matters in the case where GFID would + have gotten set to 1 on other subvolumes of replciate/distribute + + The "solution" here is that, if we detect lookup is attempting to + set a GFID on a file which is created very recently, but does not + yet have a GFID (i.e, between t1 and t2), then "fake" it as though + posix_gfid_heal was called at t0 instead. + */ + + uuid_t uuid_curr; + int ret = 0; + struct stat stat = {0, }; + + if (!xattr_req) + goto out; + + if (sys_lstat (path, &stat) != 0) + goto out; + + ret = sys_lgetxattr (path, GFID_XATTR_KEY, uuid_curr, 16); + if (ret != 16) { + if (is_fresh_file (&stat)) { + ret = -1; + errno = ENOENT; + goto out; + } + } + + ret = posix_gfid_set (this, path, xattr_req); +out: + return ret; +} + + int32_t posix_lookup (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *xattr_req) @@ -425,7 +493,7 @@ posix_lookup (call_frame_t *frame, xlator_t *this, MAKE_REAL_PATH (real_path, this, loc->path); - posix_gfid_set (this, real_path, xattr_req); + posix_gfid_heal (this, real_path, xattr_req); op_ret = posix_lstat_with_gfid (this, real_path, &buf); op_errno = errno; |