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libminixfs: fix buf leak

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. mfs: add asserts to catch similar problems in the future

Change-Id: I939230b8d63f100ac071696425b35496b2169bc4
This commit is contained in:
Ben Gras 2013-11-05 15:43:27 +01:00
parent 075dbe55f3
commit 7d6089f32d
2 changed files with 36 additions and 3 deletions
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30
lib/libminixfs/cache.c
View file

@ -619,6 +619,23 @@ void lmfs_rw_scattered(
static iovec_t iovec[NR_IOREQS];
u64_t pos;
int iov_per_block;
int start_in_use = bufs_in_use, start_bufqsize = bufqsize;
assert(bufqsize >= 0);
if(bufqsize == 0) return;
/* for READING, check all buffers on the list are obtained and held
* (count > 0)
*/
if (rw_flag == READING) {
for(i = 0; i < bufqsize; i++) {
assert(bufq[i] != NULL);
assert(bufq[i]->lmfs_count > 0);
}
/* therefore they are all 'in use' and must be at least this many */
assert(start_in_use >= start_bufqsize);
}
assert(dev != NO_DEV);
assert(!(fs_block_size % PAGE_SIZE));
@ -700,8 +717,10 @@ void lmfs_rw_scattered(
}
r -= fs_block_size;
}
bufq += nblocks;
bufqsize -= nblocks;
bufq += i;
bufqsize -= i;
if (rw_flag == READING) {
/* Don't bother reading more than the device is willing to
* give at this time. Don't forget to release those extras.
@ -720,6 +739,13 @@ void lmfs_rw_scattered(
break;
}
}
if(rw_flag == READING) {
assert(start_in_use >= start_bufqsize);
/* READING callers assume all bufs are released. */
assert(start_in_use - start_bufqsize == bufs_in_use);
}
}
/*===========================================================================*

9
servers/mfs/read.c
View file

@ -297,7 +297,7 @@ int *completed; /* number of bytes copied */
}
/* In all cases, bp now points to a valid buffer. */
assert(bp);
assert(bp != NULL);
if (rw_flag == WRITING && chunk != block_size && !block_spec &&
(off_t) ex64lo(position) >= rip->i_size && off == 0) {
@ -477,6 +477,7 @@ unsigned bytes_ahead; /* bytes beyond position for immediate use */
static unsigned int readqsize = 0;
static struct buf **read_q;
u64_t position_running;
int inuse_before = lmfs_bufs_in_use();
if(readqsize != nr_bufs) {
if(readqsize > 0) {
@ -512,6 +513,7 @@ unsigned bytes_ahead; /* bytes beyond position for immediate use */
bp = lmfs_get_block_ino(dev, block, PREFETCH, rip->i_num, position);
assert(bp != NULL);
assert(bp->lmfs_count > 0);
if (lmfs_dev(bp) != NO_DEV) return(bp);
/* The best guess for the number of blocks to prefetch: A lot.
@ -567,6 +569,7 @@ unsigned bytes_ahead; /* bytes beyond position for immediate use */
/* Acquire block buffers. */
for (;;) {
block_t thisblock;
assert(bp->lmfs_count > 0);
read_q[read_q_size++] = bp;
if (--blocks_ahead == 0) break;
@ -583,6 +586,8 @@ unsigned bytes_ahead; /* bytes beyond position for immediate use */
} else {
bp = get_block(dev, block, PREFETCH);
}
assert(bp);
assert(bp->lmfs_count > 0);
if (lmfs_dev(bp) != NO_DEV) {
/* Oops, block already in the cache, get out. */
put_block(bp, FULL_DATA_BLOCK);
@ -591,6 +596,8 @@ unsigned bytes_ahead; /* bytes beyond position for immediate use */
}
lmfs_rw_scattered(dev, read_q, read_q_size, READING);
assert(inuse_before == lmfs_bufs_in_use());
if(block_spec)
return get_block(dev, baseblock, NORMAL);
return(lmfs_get_block_ino(dev, baseblock, NORMAL, rip->i_num, position));