2008-05-21 15:59:21

by Theodore Ts'o

Subject: [PATCH, E2FSPROGS] blkid: If the device mtime is newer that the cache time, force a revalidation

This fixes problems turned up by a test case written by Erez Zadok's
group which constantly reformats filesystems.

Signed-off-by: "Theodore Ts'o" <[email protected]>
---
lib/blkid/probe.c | 48 +++++++++++++++++++++++++++---------------------
1 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/lib/blkid/probe.c b/lib/blkid/probe.c
index 4964209..62ab392 100644
--- a/lib/blkid/probe.c
+++ b/lib/blkid/probe.c
@@ -1214,33 +1214,39 @@ blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
now = time(0);
diff = now - dev->bid_time;

- if ((now > dev->bid_time) && (diff > 0) &&
+ if (stat(dev->bid_name, &st) < 0) {
+ DBG(DEBUG_PROBE,
+ printf("blkid_verify: error %s (%d) while "
+ "trying to stat %s\n", strerror(errno), errno,
+ dev->bid_name));
+ open_err:
+ if ((errno == EPERM) || (errno == EACCES) || (errno == ENOENT)) {
+ /* We don't have read permission, just return cache data. */
+ DBG(DEBUG_PROBE, printf("returning unverified data for %s\n",
+ dev->bid_name));
+ return dev;
+ }
+ blkid_free_dev(dev);
+ return NULL;
+ }
+
+ if ((now >= dev->bid_time) &&
+ (st.st_mtime <= dev->bid_time) &&
((diff < BLKID_PROBE_MIN) ||
(dev->bid_flags & BLKID_BID_FL_VERIFIED &&
diff < BLKID_PROBE_INTERVAL)))
return dev;

DBG(DEBUG_PROBE,
- printf("need to revalidate %s (time since last check %llu)\n",
- dev->bid_name, (unsigned long long)diff));
-
- if (((probe.fd = open(dev->bid_name, O_RDONLY)) < 0) ||
- (fstat(probe.fd, &st) < 0)) {
- if (probe.fd >= 0) close(probe.fd);
- if ((errno != EPERM) && (errno != EACCES) &&
- (errno != ENOENT)) {
- DBG(DEBUG_PROBE,
- printf("blkid_verify: error %s (%d) while "
- "opening %s\n", strerror(errno), errno,
- dev->bid_name));
- blkid_free_dev(dev);
- return NULL;
- }
- /* We don't have read permission, just return cache data. */
- DBG(DEBUG_PROBE,
- printf("returning unverified data for %s\n",
- dev->bid_name));
- return dev;
+ printf("need to revalidate %s (cache time %d, stat time %d,\n\t"
+ "time since last check %lu)\n",
+ dev->bid_name, dev->bid_time, st.st_mtime, (unsigned long)diff));
+
+ if ((probe.fd = open(dev->bid_name, O_RDONLY)) < 0) {
+ DBG(DEBUG_PROBE, printf("blkid_verify: error %s (%d) while "
+ "opening %s\n", strerror(errno), errno,
+ dev->bid_name));
+ goto open_err;
}

probe.cache = cache;
--
1.5.4.1.144.gdfee-dirty