enum cl_page_type cp_type:CP_TYPE_BITS;
unsigned cp_defer_uptodate:1,
cp_ra_updated:1,
- cp_ra_used:1;
+ cp_ra_used:1,
+ /* fault page read grab extra referece */
+ cp_fault_ref:1,
+ /**
+ * if fault page got delete before returned to
+ * filemap_fault(), defer the vmpage detach/put
+ * until filemap_fault() has been handled.
+ */
+ cp_defer_detach:1;
/* which slab kmem index this memory allocated from */
short int cp_kmem_index;
return io->ci_type == CIT_FAULT && io->u.ci_fault.ft_mkwrite;
}
+static inline int cl_io_is_pagefault(const struct cl_io *io)
+{
+ return io->ci_type == CIT_FAULT && !io->u.ci_fault.ft_mkwrite;
+}
+
/**
* True, iff \a io is a truncate(2).
*/
unlock_page(vmpage);
result = 0;
}
- cl_page_put(env, page);
+ if (cl_io_is_pagefault(io) && result == 0) {
+ /**
+ * page fault, retain the cl_page reference until
+ * vvp_io_kernel_fault() release it.
+ */
+ page->cp_fault_ref = 1;
+ } else {
+ cl_page_put(env, page);
+ }
} else {
unlock_page(vmpage);
result = PTR_ERR(page);
trunc_sem_up_read(&lli->lli_trunc_sem);
}
-static int vvp_io_kernel_fault(struct vvp_fault_io *cfio)
+static void detach_and_deref_page(struct cl_page *clp, struct page *vmpage)
+{
+ if (!clp->cp_defer_detach)
+ return;
+
+ /**
+ * cl_page_delete0() took a vmpage reference, but not unlink the vmpage
+ * from its cl_page.
+ */
+ clp->cp_defer_detach = 0;
+ ClearPagePrivate(vmpage);
+ vmpage->private = 0;
+
+ put_page(vmpage);
+ atomic_dec(&clp->cp_ref);
+}
+
+static int vvp_io_kernel_fault(const struct lu_env *env,
+ struct vvp_fault_io *cfio)
{
struct vm_fault *vmf = cfio->ft_vmf;
+ struct file *vmff = cfio->ft_vma->vm_file;
+ struct address_space *mapping = vmff->f_mapping;
+ struct inode *inode = mapping->host;
+ struct page *vmpage = NULL;
+ struct cl_page *clp = NULL;
+ int rc = 0;
+ ENTRY;
+ ll_inode_size_lock(inode);
+retry:
cfio->ft_flags = ll_filemap_fault(cfio->ft_vma, vmf);
cfio->ft_flags_valid = 1;
if (vmf->page) {
+ /* success, vmpage is locked */
LL_CDEBUG_PAGE(D_PAGE, vmf->page, "got addr %p type NOPAGE\n",
get_vmf_address(vmf));
if (unlikely(!(cfio->ft_flags & VM_FAULT_LOCKED))) {
cfio->ft_vmpage = vmf->page;
- return 0;
+ /**
+ * ll_filemap_fault()->ll_readpage() could get an extra cl_page
+ * reference. So we have to get the cl_page's to check its
+ * cp_fault_ref and drop the reference later.
+ */
+ clp = cl_vmpage_page(vmf->page, NULL);
+
+ GOTO(unlock, rc = 0);
+ }
+
+ /* filemap_fault() fails, vmpage is not locked */
+ if (clp == NULL) {
+ vmpage = find_get_page(mapping, vmf->pgoff);
+ if (vmpage) {
+ lock_page(vmpage);
+ clp = cl_vmpage_page(vmpage, NULL);
+ unlock_page(vmpage);
+ }
}
if (cfio->ft_flags & VM_FAULT_SIGBUS) {
+ pgoff_t max_idx;
+
+ /**
+ * ll_filemap_fault()->ll_readpage() could fill vmpage
+ * correctly, and unlock the vmpage, while memory pressure or
+ * truncate could detach cl_page from vmpage, and kernel
+ * filemap_fault() will wait_on_page_locked(vmpage) and find
+ * out that the vmpage has been cleared its uptodate bit,
+ * so it returns VM_FAULT_SIGBUS.
+ *
+ * In this case, we'd retry the filemap_fault()->ll_readpage()
+ * to rebuild the cl_page and fill vmpage with uptodated data.
+ */
+ if (likely(vmpage)) {
+ bool need_retry = false;
+
+ if (clp) {
+ if (clp->cp_defer_detach) {
+ detach_and_deref_page(clp, vmpage);
+ /**
+ * check i_size to make sure it's not
+ * over EOF, we don't want to call
+ * filemap_fault() repeatedly since it
+ * returns VM_FAULT_SIGBUS without even
+ * trying if vmf->pgoff is over EOF.
+ */
+ max_idx = DIV_ROUND_UP(
+ i_size_read(inode), PAGE_SIZE);
+ if (vmf->pgoff < max_idx)
+ need_retry = true;
+ }
+ if (clp->cp_fault_ref) {
+ clp->cp_fault_ref = 0;
+ /* ref not released in ll_readpage() */
+ cl_page_put(env, clp);
+ }
+ if (need_retry)
+ goto retry;
+ }
+ }
+
CDEBUG(D_PAGE, "got addr %p - SIGBUS\n", get_vmf_address(vmf));
- return -EFAULT;
+ GOTO(unlock, rc = -EFAULT);
}
if (cfio->ft_flags & VM_FAULT_OOM) {
CDEBUG(D_PAGE, "got addr %p - OOM\n", get_vmf_address(vmf));
- return -ENOMEM;
+ GOTO(unlock, rc = -ENOMEM);
}
if (cfio->ft_flags & VM_FAULT_RETRY)
- return -EAGAIN;
+ GOTO(unlock, rc = -EAGAIN);
CERROR("unknown error in page fault %d\n", cfio->ft_flags);
-
- return -EINVAL;
+ rc = -EINVAL;
+unlock:
+ ll_inode_size_unlock(inode);
+ if (clp) {
+ if (clp->cp_defer_detach && vmpage)
+ detach_and_deref_page(clp, vmpage);
+
+ /* additional cl_page ref has been taken in ll_readpage() */
+ if (clp->cp_fault_ref) {
+ clp->cp_fault_ref = 0;
+ /* ref not released in ll_readpage() */
+ cl_page_put(env, clp);
+ }
+ /* ref taken in this function */
+ cl_page_put(env, clp);
+ }
+ if (vmpage)
+ put_page(vmpage);
+ return rc;
}
static void mkwrite_commit_callback(const struct lu_env *env, struct cl_io *io,
LASSERT(cfio->ft_vmpage != NULL);
lock_page(cfio->ft_vmpage);
} else {
- result = vvp_io_kernel_fault(cfio);
+ result = vvp_io_kernel_fault(env, cfio);
if (result != 0)
RETURN(result);
}
ll_ra_count_put(ll_i2sbi(inode), 1);
if (ioret == 0) {
+ /**
+ * cp_defer_uptodate is used for readahead page, and the
+ * vmpage Uptodate bit is deferred to set in ll_readpage/
+ * ll_io_read_page.
+ */
if (!cp->cp_defer_uptodate)
SetPageUptodate(vmpage);
} else if (cp->cp_defer_uptodate) {
LASSERT(PageLocked(vmpage));
LASSERT((struct cl_page *)vmpage->private == cp);
- /* Drop the reference count held in vvp_page_init */
- refc = atomic_dec_return(&cp->cp_ref);
- LASSERTF(refc >= 1, "page = %p, refc = %d\n", cp, refc);
-
- ClearPagePrivate(vmpage);
- vmpage->private = 0;
-
- /*
- * The reference from vmpage to cl_page is removed,
- * but the reference back is still here. It is removed
- * later in cl_page_free().
+ /**
+ * clear vmpage uptodate bit, since ll_read_ahead_pages()->
+ * ll_read_ahead_page() could pick up this stale vmpage and
+ * take it as uptodated.
+ */
+ ClearPageUptodate(vmpage);
+ /**
+ * vvp_io_kernel_fault()->ll_readpage() set cp_fault_ref
+ * and need it to check cl_page to retry the page fault read.
*/
+ if (cp->cp_fault_ref) {
+ cp->cp_defer_detach = 1;
+ /**
+ * get a vmpage reference, so that filemap_fault()
+ * won't free it from pagecache.
+ */
+ get_page(vmpage);
+ } else {
+ /* Drop the reference count held in vvp_page_init */
+ refc = atomic_dec_return(&cp->cp_ref);
+ LASSERTF(refc >= 1, "page = %p, refc = %d\n", cp, refc);
+ ClearPagePrivate(vmpage);
+ vmpage->private = 0;
+
+ /*
+ * The reference from vmpage to cl_page is removed,
+ * but the reference back is still here. It is removed
+ * later in cl_page_free().
+ */
+ }
}
EXIT;
#include <pthread.h>
/*
- * Usage: rw_seq_cst_vs_drop_caches /mnt/lustre/file0 /mnt/lustre2/file0
+ * Usage: rw_seq_cst_vs_drop_caches [-m] /mnt/lustre/file0 /mnt/lustre2/file0
* Race reads of the same file on two client mounts vs writes and drop
* caches to detect sequential consistency violations. Run
* which case the wait status ($?) will be 134.
*/
+int mmap_mode; /* -m flag */
+
+void usage(void)
+{
+ fprintf(stdout,
+ "%s: rw_seq_cst_vs_drop_caches [-m] /mnt/lustre/file0 /mnt/lustre2/file0\n"
+" -m : use mmap to read/write file\n", __func__);
+}
+
#define handle_error(msg) \
do { perror(msg); exit(EXIT_FAILURE); } while (0)
*/
static uint64_t u, u_max = UINT64_MAX / 2;
static uint64_t v[2];
+char *ptr;
static void *access_thread_start(void *unused)
{
+ char *ptr2 = NULL;
ssize_t rc;
int i;
+ if (mmap_mode) {
+ ptr2 = mmap(NULL, sizeof(v[1]), PROT_READ,
+ MAP_PRIVATE | MAP_POPULATE, fd[1], 0);
+ if (ptr2 == MAP_FAILED)
+ handle_error("mmap");
+ }
+
do {
for (i = 0; i < 2; i++) {
- rc = pread(fd[i], &v[i], sizeof(v[i]), 0);
- if (rc < 0 || rc != sizeof(v[i]))
- handle_error("pread");
+ if (mmap_mode) {
+ memcpy(&v[i], i == 0 ? ptr : ptr2,
+ sizeof(v[i]));
+ } else {
+ rc = pread(fd[i], &v[i], sizeof(v[i]), 0);
+ if (rc < 0 || rc != sizeof(v[i]))
+ handle_error("pread");
+ }
}
} while (v[0] <= v[1]);
fprintf(stderr, "error: u = %"PRIu64", v = %"PRIu64", %"PRIu64"\n",
u, v[0], v[1]);
+ if (mmap_mode)
+ munmap(ptr2, sizeof(v[i]));
abort();
}
pthread_t access_thread;
struct stat st[2];
ssize_t rc;
- int i;
+ int i, ch;
setvbuf(stderr, stderr_buf, _IOLBF, sizeof(stderr_buf));
- if (argc != 3) {
- fprintf(stderr, "Usage: %s /mnt/lustre/file0 /mnt/lustre2/file0\n", argv[0]);
+ while ((ch = getopt(argc, argv, "m")) >= 0) {
+ switch (ch) {
+ case 'm':
+ mmap_mode = 1;
+ break;
+ default:
+ usage();
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ if (argc != 2) {
+ usage();
exit(EXIT_FAILURE);
}
assert(!(drop_caches_fd < 0));
for (i = 0; i < 2; i++) {
- fd[i] = open(argv[i + 1], O_RDWR|O_CREAT|O_TRUNC, 0666);
+ fd[i] = open(argv[i], O_RDWR|O_CREAT|O_TRUNC, 0666);
if (fd[i] < 0)
handle_error("open");
exit(EXIT_FAILURE);
}
- rc = pwrite(fd[0], &u, sizeof(u), 0);
- if (rc < 0 || rc != sizeof(u))
- handle_error("pwrite");
+ if (mmap_mode) {
+ if (ftruncate(fd[0], sizeof(u)) < 0)
+ handle_error("ftruncate");
+
+ ptr = mmap(NULL, sizeof(u), PROT_READ|PROT_WRITE, MAP_SHARED,
+ fd[0], 0);
+ if (ptr == MAP_FAILED)
+ handle_error("mmap");
+ memcpy(ptr, &u, sizeof(u));
+ } else {
+ rc = pwrite(fd[0], &u, sizeof(u), 0);
+ if (rc < 0 || rc != sizeof(u))
+ handle_error("pwrite");
+ }
rc = pthread_create(&access_thread, NULL, &access_thread_start, NULL);
if (rc != 0)
handle_error("pthread_create");
for (u = 1; u <= u_max; u++) {
- rc = pwrite(fd[0], &u, sizeof(u), 0);
- if (rc < 0 || rc != sizeof(u))
- handle_error("pwrite");
+ if (mmap_mode) {
+ memcpy(ptr, &u, sizeof(u));
+ } else {
+ rc = pwrite(fd[0], &u, sizeof(u), 0);
+ if (rc < 0 || rc != sizeof(u))
+ handle_error("pwrite");
+ }
rc = write(drop_caches_fd, "3\n", 2);
if (rc < 0 || rc != 2)
if (rc != 0)
handle_error("pthread_join");
+ if (mmap_mode)
+ munmap(ptr, sizeof(u));
+
return 0;
}
init_logging
ALWAYS_EXCEPT="$SANITYN_EXCEPT "
-# bug number for skipped test: LU-7105 LU-14541
-ALWAYS_EXCEPT+=" 28 16f"
+# bug number for skipped test: LU-7105
+ALWAYS_EXCEPT+=" 28 "
# UPDATE THE COMMENT ABOVE WITH BUG NUMBERS WHEN CHANGING ALWAYS_EXCEPT!
if [ $mds1_FSTYPE = "zfs" ]; then
}
run_test 16f "rw sequential consistency vs drop_caches"
+test_16g() {
+ local file1=$DIR1/$tfile
+ local file2=$DIR2/$tfile
+ local duration=20
+ local status
+
+ timeout --preserve-status --signal=USR1 $duration \
+ rw_seq_cst_vs_drop_caches -m $file1 $file2
+ status=$?
+
+ case $((status & 0x7f)) in
+ 0)
+ echo OK # Computers must be fast now.
+ ;;
+ 6) # SIGABRT
+ error "sequential consistency violation detected"
+ ;;
+ 10) # SIGUSR1
+ echo TIMEOUT # This is fine.
+ ;;
+ *)
+ error "strange status '$status'"
+ ;;
+ esac
+
+ rm -f $file1
+}
+run_test 16g "mmap rw sequential consistency vs drop_caches"
+
test_16h() {
local tf=$DIR/$tdir/$tfile
local tf2=$DIR2/$tdir/$tfile
git://git.whamcloud.com / fs / lustre-release.git / commitdiff