diff options
Diffstat (limited to 'src/backend/storage/smgr/md.c')
| -rw-r--r-- | src/backend/storage/smgr/md.c | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c index 286dd3f7551..43edaf5d873 100644 --- a/src/backend/storage/smgr/md.c +++ b/src/backend/storage/smgr/md.c @@ -116,6 +116,8 @@ static MemoryContext MdCxt; /* context for all MdfdVec objects */ * mdnblocks(). */ #define EXTENSION_DONT_CHECK_SIZE (1 << 4) +/* don't try to open a segment, if not already open */ +#define EXTENSION_DONT_OPEN (1 << 5) /* local routines */ @@ -551,12 +553,6 @@ mdclose(SMgrRelation reln, ForkNumber forknum) } } -void -mdrelease(void) -{ - closeAllVfds(); -} - /* * mdprefetch() -- Initiate asynchronous read of the specified block of a relation */ @@ -605,11 +601,14 @@ mdwriteback(SMgrRelation reln, ForkNumber forknum, segnum_end; v = _mdfd_getseg(reln, forknum, blocknum, true /* not used */ , - EXTENSION_RETURN_NULL); + EXTENSION_DONT_OPEN); /* * We might be flushing buffers of already removed relations, that's - * ok, just ignore that case. + * ok, just ignore that case. If the segment file wasn't open already + * (ie from a recent mdwrite()), then we don't want to re-open it, to + * avoid a race with PROCSIGNAL_BARRIER_SMGRRELEASE that might leave + * us with a descriptor to a file that is about to be unlinked. */ if (!v) return; @@ -1202,7 +1201,8 @@ _mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno, /* some way to handle non-existent segments needs to be specified */ Assert(behavior & - (EXTENSION_FAIL | EXTENSION_CREATE | EXTENSION_RETURN_NULL)); + (EXTENSION_FAIL | EXTENSION_CREATE | EXTENSION_RETURN_NULL | + EXTENSION_DONT_OPEN)); targetseg = blkno / ((BlockNumber) RELSEG_SIZE); @@ -1213,6 +1213,10 @@ _mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno, return v; } + /* The caller only wants the segment if we already had it open. */ + if (behavior & EXTENSION_DONT_OPEN) + return NULL; + /* * The target segment is not yet open. Iterate over all the segments * between the last opened and the target segment. This way missing |