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author | scottl <scottl@FreeBSD.org> | 2014-05-06 20:40:16 +0000 |
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committer | scottl <scottl@FreeBSD.org> | 2014-05-06 20:40:16 +0000 |
commit | 66aaa46593a1aeeffe4990905cbc5140897985d8 (patch) | |
tree | 2161b2159ec3488f182ec5e1e7d13c5b23407578 | |
parent | 715111e7161516553983705259b859ac9b1de5be (diff) | |
download | FreeBSD-src-66aaa46593a1aeeffe4990905cbc5140897985d8.zip FreeBSD-src-66aaa46593a1aeeffe4990905cbc5140897985d8.tar.gz |
Due to reasons unknown at this time, the system can be forced to write
a journal block even when there are no journal entries to be written.
Until the root cause is found, handle this case by ensuring that a
valid journal segment is always written.
Second, the data buffer used for writing journal entries was never
being scrubbed of old data. Fix this.
Submitted by: Takehara Mikihito
Obtained from: Netflix, Inc.
MFC after: 3 days
-rw-r--r-- | sys/ufs/ffs/ffs_softdep.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c index c5fa748..0760f3e 100644 --- a/sys/ufs/ffs/ffs_softdep.c +++ b/sys/ufs/ffs/ffs_softdep.c @@ -1275,6 +1275,7 @@ static int stat_cleanup_blkrequests; /* Number of block cleanup requests */ static int stat_cleanup_inorequests; /* Number of inode cleanup requests */ static int stat_cleanup_retries; /* Number of cleanups that needed to flush */ static int stat_cleanup_failures; /* Number of cleanup requests that failed */ +static int stat_emptyjblocks; /* Number of potentially empty journal blocks */ SYSCTL_INT(_debug_softdep, OID_AUTO, max_softdeps, CTLFLAG_RW, &max_softdeps, 0, ""); @@ -1334,6 +1335,8 @@ SYSCTL_INT(_debug_softdep, OID_AUTO, cleanup_failures, CTLFLAG_RW, &stat_cleanup_failures, 0, ""); SYSCTL_INT(_debug_softdep, OID_AUTO, flushcache, CTLFLAG_RW, &softdep_flushcache, 0, ""); +SYSCTL_INT(_debug_softdep, OID_AUTO, emptyjblocks, CTLFLAG_RD, + &stat_emptyjblocks, 0, ""); SYSCTL_DECL(_vfs_ffs); @@ -3328,6 +3331,24 @@ softdep_process_journal(mp, needwk, flags) */ data = bp->b_data; off = 0; + + /* + * Always put a header on the first block. + * XXX As with below, there might not be a chance to get + * into the loop. Ensure that something valid is written. + */ + jseg_write(ump, jseg, data); + off += JREC_SIZE; + data = bp->b_data + off; + + /* + * XXX Something is wrong here. There's no work to do, + * but we need to perform and I/O and allow it to complete + * anyways. + */ + if (LIST_EMPTY(&ump->softdep_journal_pending)) + stat_emptyjblocks++; + while ((wk = LIST_FIRST(&ump->softdep_journal_pending)) != NULL) { if (cnt == 0) @@ -3377,6 +3398,11 @@ softdep_process_journal(mp, needwk, flags) data = bp->b_data + off; cnt--; } + + /* Clear any remaining space so we don't leak kernel data */ + if (size > off) + bzero(data, size - off); + /* * Write this one buffer and continue. */ |