Fix lseek(SEEK_DATA/SEEK_HOLE) mmap consistency
When using lseek(2) to report data/holes memory mapped regions of the file were ignored. This could result in incorrect results. To handle this zfs_holey_common() was updated to asynchronously writeback any dirty mmap(2) regions prior to reporting holes. Additionally, while not strictly required, the dn_struct_rwlock is now held over the dirty check to prevent the dnode structure from changing. This ensures that a clean dnode can't be dirtied before the data/hole is located. The range lock is now also taken to ensure the call cannot race with zfs_write(). Furthermore, the code was refactored to provide a dnode_is_dirty() helper function which checks the dnode for any dirty records to determine its dirtiness. Reviewed-by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Rich Ercolani <rincebrain@gmail.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #11900 Closes #12724
This commit is contained in:
parent
4b87c1981d
commit
de198f2d95
@ -221,6 +221,7 @@ AC_CONFIG_FILES([
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tests/zfs-tests/cmd/mktree/Makefile
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tests/zfs-tests/cmd/mmap_exec/Makefile
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tests/zfs-tests/cmd/mmap_libaio/Makefile
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tests/zfs-tests/cmd/mmap_seek/Makefile
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tests/zfs-tests/cmd/mmapwrite/Makefile
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tests/zfs-tests/cmd/nvlist_to_lua/Makefile
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tests/zfs-tests/cmd/randfree_file/Makefile
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@ -59,6 +59,8 @@ enum symfollow { NO_FOLLOW = NOFOLLOW };
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#include <sys/file.h>
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#include <sys/filedesc.h>
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#include <sys/syscallsubr.h>
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#include <sys/vm.h>
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#include <vm/vm_object.h>
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typedef struct vop_vector vnodeops_t;
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#define VOP_FID VOP_VPTOFH
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@ -83,6 +85,22 @@ vn_is_readonly(vnode_t *vp)
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#define vn_has_cached_data(vp) \
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((vp)->v_object != NULL && \
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(vp)->v_object->resident_page_count > 0)
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static __inline void
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vn_flush_cached_data(vnode_t *vp, boolean_t sync)
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{
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#if __FreeBSD_version > 1300054
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if (vm_object_mightbedirty(vp->v_object)) {
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#else
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if (vp->v_object->flags & OBJ_MIGHTBEDIRTY) {
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#endif
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int flags = sync ? OBJPC_SYNC : 0;
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zfs_vmobject_wlock(vp->v_object);
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vm_object_page_clean(vp->v_object, 0, 0, flags);
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zfs_vmobject_wunlock(vp->v_object);
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}
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}
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#define vn_exists(vp) do { } while (0)
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#define vn_invalid(vp) do { } while (0)
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#define vn_renamepath(tdvp, svp, tnm, lentnm) do { } while (0)
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@ -116,7 +116,8 @@ typedef struct zfs_soft_state {
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#define Z_ISLNK(type) ((type) == VLNK)
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#define Z_ISDIR(type) ((type) == VDIR)
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#define zn_has_cached_data(zp) vn_has_cached_data(ZTOV(zp))
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#define zn_has_cached_data(zp) vn_has_cached_data(ZTOV(zp))
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#define zn_flush_cached_data(zp, sync) vn_flush_cached_data(ZTOV(zp), sync)
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#define zn_rlimit_fsize(zp, uio) \
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vn_rlimit_fsize(ZTOV(zp), GET_UIO_STRUCT(uio), zfs_uio_td(uio))
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@ -71,6 +71,7 @@ extern "C" {
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#define Z_ISDIR(type) S_ISDIR(type)
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#define zn_has_cached_data(zp) ((zp)->z_is_mapped)
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#define zn_flush_cached_data(zp, sync) write_inode_now(ZTOI(zp), sync)
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#define zn_rlimit_fsize(zp, uio) (0)
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/*
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@ -425,6 +425,7 @@ boolean_t dnode_add_ref(dnode_t *dn, void *ref);
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void dnode_rele(dnode_t *dn, void *ref);
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void dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting);
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int dnode_try_claim(objset_t *os, uint64_t object, int slots);
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boolean_t dnode_is_dirty(dnode_t *dn);
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void dnode_setdirty(dnode_t *dn, dmu_tx_t *tx);
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void dnode_set_dirtyctx(dnode_t *dn, dmu_tx_t *tx, void *tag);
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void dnode_sync(dnode_t *dn, dmu_tx_t *tx);
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@ -1586,7 +1586,7 @@ Allow no-operation writes.
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The occurrence of nopwrites will further depend on other pool properties
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.Pq i.a. the checksumming and compression algorithms .
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.
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.It Sy zfs_dmu_offset_next_sync Ns = Ns Sy 0 Ns | ns 1 Pq int
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.It Sy zfs_dmu_offset_next_sync Ns = Ns Sy 0 Ns | Ns 1 Pq int
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Enable forcing TXG sync to find holes.
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When enabled forces ZFS to act like prior versions when
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.Sy SEEK_HOLE No or Sy SEEK_DATA
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@ -2093,42 +2093,41 @@ int
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dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole, uint64_t *off)
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{
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dnode_t *dn;
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int i, err;
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boolean_t clean = B_TRUE;
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int err;
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restart:
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err = dnode_hold(os, object, FTAG, &dn);
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if (err)
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return (err);
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/*
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* Check if dnode is dirty
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*/
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for (i = 0; i < TXG_SIZE; i++) {
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if (multilist_link_active(&dn->dn_dirty_link[i])) {
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clean = B_FALSE;
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break;
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rw_enter(&dn->dn_struct_rwlock, RW_READER);
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if (dnode_is_dirty(dn)) {
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/*
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* If the zfs_dmu_offset_next_sync module option is enabled
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* then strict hole reporting has been requested. Dirty
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* dnodes must be synced to disk to accurately report all
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* holes. When disabled (the default) dirty dnodes are
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* reported to not have any holes which is always safe.
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*
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* When called by zfs_holey_common() the zp->z_rangelock
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* is held to prevent zfs_write() and mmap writeback from
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* re-dirtying the dnode after txg_wait_synced().
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*/
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if (zfs_dmu_offset_next_sync) {
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rw_exit(&dn->dn_struct_rwlock);
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dnode_rele(dn, FTAG);
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txg_wait_synced(dmu_objset_pool(os), 0);
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goto restart;
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}
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}
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/*
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* If compatibility option is on, sync any current changes before
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* we go trundling through the block pointers.
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*/
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if (!clean && zfs_dmu_offset_next_sync) {
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clean = B_TRUE;
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dnode_rele(dn, FTAG);
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txg_wait_synced(dmu_objset_pool(os), 0);
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err = dnode_hold(os, object, FTAG, &dn);
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if (err)
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return (err);
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}
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if (clean)
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err = dnode_next_offset(dn,
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(hole ? DNODE_FIND_HOLE : 0), off, 1, 1, 0);
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else
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err = SET_ERROR(EBUSY);
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} else {
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err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK |
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(hole ? DNODE_FIND_HOLE : 0), off, 1, 1, 0);
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}
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rw_exit(&dn->dn_struct_rwlock);
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dnode_rele(dn, FTAG);
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return (err);
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@ -1648,6 +1648,26 @@ dnode_try_claim(objset_t *os, uint64_t object, int slots)
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slots, NULL, NULL));
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}
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/*
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* Checks if the dnode contains any uncommitted dirty records.
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*/
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boolean_t
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dnode_is_dirty(dnode_t *dn)
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{
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mutex_enter(&dn->dn_mtx);
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for (int i = 0; i < TXG_SIZE; i++) {
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if (list_head(&dn->dn_dirty_records[i]) != NULL) {
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mutex_exit(&dn->dn_mtx);
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return (B_TRUE);
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}
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}
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mutex_exit(&dn->dn_mtx);
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return (B_FALSE);
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}
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void
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dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
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{
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@ -85,6 +85,7 @@ zfs_fsync(znode_t *zp, int syncflag, cred_t *cr)
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static int
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zfs_holey_common(znode_t *zp, ulong_t cmd, loff_t *off)
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{
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zfs_locked_range_t *lr;
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uint64_t noff = (uint64_t)*off; /* new offset */
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uint64_t file_sz;
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int error;
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@ -100,12 +101,18 @@ zfs_holey_common(znode_t *zp, ulong_t cmd, loff_t *off)
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else
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hole = B_FALSE;
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/* Flush any mmap()'d data to disk */
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if (zn_has_cached_data(zp))
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zn_flush_cached_data(zp, B_FALSE);
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lr = zfs_rangelock_enter(&zp->z_rangelock, 0, file_sz, RL_READER);
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error = dmu_offset_next(ZTOZSB(zp)->z_os, zp->z_id, hole, &noff);
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zfs_rangelock_exit(lr);
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if (error == ESRCH)
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return (SET_ERROR(ENXIO));
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/* file was dirty, so fall back to using generic logic */
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/* File was dirty, so fall back to using generic logic */
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if (error == EBUSY) {
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if (hole)
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*off = file_sz;
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@ -675,7 +675,7 @@ tests = ['migration_001_pos', 'migration_002_pos', 'migration_003_pos',
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tags = ['functional', 'migration']
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[tests/functional/mmap]
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tests = ['mmap_write_001_pos', 'mmap_read_001_pos']
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tests = ['mmap_write_001_pos', 'mmap_read_001_pos', 'mmap_seek_001_pos']
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tags = ['functional', 'mmap']
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[tests/functional/mount]
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@ -19,6 +19,7 @@ SUBDIRS = \
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mktree \
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mmap_exec \
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mmap_libaio \
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mmap_seek \
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mmapwrite \
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nvlist_to_lua \
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randwritecomp \
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1
tests/zfs-tests/cmd/mmap_seek/.gitignore
vendored
Normal file
1
tests/zfs-tests/cmd/mmap_seek/.gitignore
vendored
Normal file
@ -0,0 +1 @@
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/mmap_seek
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tests/zfs-tests/cmd/mmap_seek/Makefile.am
Normal file
6
tests/zfs-tests/cmd/mmap_seek/Makefile.am
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@ -0,0 +1,6 @@
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include $(top_srcdir)/config/Rules.am
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pkgexecdir = $(datadir)/@PACKAGE@/zfs-tests/bin
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pkgexec_PROGRAMS = mmap_seek
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mmap_seek_SOURCES = mmap_seek.c
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tests/zfs-tests/cmd/mmap_seek/mmap_seek.c
Normal file
147
tests/zfs-tests/cmd/mmap_seek/mmap_seek.c
Normal file
@ -0,0 +1,147 @@
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/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2021 by Lawrence Livermore National Security, LLC.
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*/
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <errno.h>
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static void
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seek_data(int fd, off_t offset, off_t expected)
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{
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off_t data_offset = lseek(fd, offset, SEEK_DATA);
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if (data_offset != expected) {
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fprintf(stderr, "lseek(fd, %d, SEEK_DATA) = %d (expected %d)\n",
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(int)offset, (int)data_offset, (int)expected);
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exit(2);
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}
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}
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static void
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seek_hole(int fd, off_t offset, off_t expected)
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{
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off_t hole_offset = lseek(fd, offset, SEEK_HOLE);
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if (hole_offset != expected) {
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fprintf(stderr, "lseek(fd, %d, SEEK_HOLE) = %d (expected %d)\n",
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(int)offset, (int)hole_offset, (int)expected);
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exit(2);
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}
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}
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int
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main(int argc, char **argv)
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{
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char *execname = argv[0];
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char *file_path = argv[1];
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char *buf = NULL;
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int err;
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if (argc != 4) {
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(void) printf("usage: %s <file name> <file size> "
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"<block size>\n", argv[0]);
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exit(1);
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}
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int fd = open(file_path, O_RDWR | O_CREAT, 0666);
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if (fd == -1) {
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(void) fprintf(stderr, "%s: %s: ", execname, file_path);
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perror("open");
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exit(2);
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}
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off_t file_size = atoi(argv[2]);
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off_t block_size = atoi(argv[3]);
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if (block_size * 2 > file_size) {
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(void) fprintf(stderr, "file size must be at least "
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"double the block size\n");
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exit(2);
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}
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err = ftruncate(fd, file_size);
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if (err == -1) {
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perror("ftruncate");
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exit(2);
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}
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if ((buf = mmap(NULL, file_size, PROT_READ | PROT_WRITE,
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MAP_SHARED, fd, 0)) == MAP_FAILED) {
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perror("mmap");
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exit(2);
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}
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/* Verify the file is sparse and reports no data. */
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seek_data(fd, 0, -1);
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/* Verify the file is reported as a hole. */
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seek_hole(fd, 0, 0);
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/* Verify search beyond end of file is an error. */
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seek_data(fd, 2 * file_size, -1);
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seek_hole(fd, 2 * file_size, -1);
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/* Dirty the first byte. */
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memset(buf, 'a', 1);
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seek_data(fd, 0, 0);
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seek_data(fd, block_size, -1);
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seek_hole(fd, 0, block_size);
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seek_hole(fd, block_size, block_size);
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/* Dirty the first half of the file. */
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memset(buf, 'b', file_size / 2);
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seek_data(fd, 0, 0);
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seek_data(fd, block_size, block_size);
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seek_hole(fd, 0, P2ROUNDUP(file_size / 2, block_size));
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seek_hole(fd, block_size, P2ROUNDUP(file_size / 2, block_size));
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/* Dirty the whole file. */
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memset(buf, 'c', file_size);
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seek_data(fd, 0, 0);
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seek_data(fd, file_size * 3 / 4,
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P2ROUNDUP(file_size * 3 / 4, block_size));
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seek_hole(fd, 0, file_size);
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seek_hole(fd, file_size / 2, file_size);
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/* Punch a hole (required compression be enabled). */
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memset(buf + block_size, 0, block_size);
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seek_data(fd, 0, 0);
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seek_data(fd, block_size, 2 * block_size);
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seek_hole(fd, 0, block_size);
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seek_hole(fd, block_size, block_size);
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seek_hole(fd, 2 * block_size, file_size);
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err = munmap(buf, file_size);
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if (err == -1) {
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perror("munmap");
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exit(2);
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}
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close(fd);
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return (0);
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}
|
@ -209,6 +209,7 @@ export ZFSTEST_FILES='badsend
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mktree
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mmap_exec
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mmap_libaio
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mmap_seek
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mmapwrite
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nvlist_to_lua
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randfree_file
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@ -33,6 +33,7 @@ DEADMAN_FAILMODE deadman.failmode zfs_deadman_failmode
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DEADMAN_SYNCTIME_MS deadman.synctime_ms zfs_deadman_synctime_ms
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DEADMAN_ZIOTIME_MS deadman.ziotime_ms zfs_deadman_ziotime_ms
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DISABLE_IVSET_GUID_CHECK disable_ivset_guid_check zfs_disable_ivset_guid_check
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DMU_OFFSET_NEXT_SYNC dmu_offset_next_sync zfs_dmu_offset_next_sync
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INITIALIZE_CHUNK_SIZE initialize_chunk_size zfs_initialize_chunk_size
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INITIALIZE_VALUE initialize_value zfs_initialize_value
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KEEP_LOG_SPACEMAPS_AT_EXPORT keep_log_spacemaps_at_export zfs_keep_log_spacemaps_at_export
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|
@ -4,7 +4,8 @@ dist_pkgdata_SCRIPTS = \
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cleanup.ksh \
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mmap_read_001_pos.ksh \
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mmap_write_001_pos.ksh \
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mmap_libaio_001_pos.ksh
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mmap_libaio_001_pos.ksh \
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mmap_seek_001_pos.ksh
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dist_pkgdata_DATA = \
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mmap.cfg
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|
67
tests/zfs-tests/tests/functional/mmap/mmap_seek_001_pos.ksh
Executable file
67
tests/zfs-tests/tests/functional/mmap/mmap_seek_001_pos.ksh
Executable file
@ -0,0 +1,67 @@
|
||||
#!/bin/ksh -p
|
||||
#
|
||||
# CDDL HEADER START
|
||||
#
|
||||
# The contents of this file are subject to the terms of the
|
||||
# Common Development and Distribution License (the "License").
|
||||
# You may not use this file except in compliance with the License.
|
||||
#
|
||||
# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
|
||||
# or http://www.opensolaris.org/os/licensing.
|
||||
# See the License for the specific language governing permissions
|
||||
# and limitations under the License.
|
||||
#
|
||||
# When distributing Covered Code, include this CDDL HEADER in each
|
||||
# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
|
||||
# If applicable, add the following below this CDDL HEADER, with the
|
||||
# fields enclosed by brackets "[]" replaced with your own identifying
|
||||
# information: Portions Copyright [yyyy] [name of copyright owner]
|
||||
#
|
||||
# CDDL HEADER END
|
||||
#
|
||||
|
||||
#
|
||||
# Copyright (c) 2021 by Lawrence Livermore National Security, LLC.
|
||||
#
|
||||
|
||||
. $STF_SUITE/include/libtest.shlib
|
||||
. $STF_SUITE/tests/functional/mmap/mmap.cfg
|
||||
|
||||
#
|
||||
# DESCRIPTION:
|
||||
# lseek() data/holes for an mmap()'d file.
|
||||
#
|
||||
# STRATEGY:
|
||||
# 1. Enable compression and hole reporting for dirty files.
|
||||
# 2. Call mmap_seek binary test case for various record sizes.
|
||||
#
|
||||
|
||||
verify_runnable "global"
|
||||
|
||||
function cleanup
|
||||
{
|
||||
log_must zfs set compression=off $TESTPOOL/$TESTFS
|
||||
log_must zfs set recordsize=128k $TESTPOOL/$TESTFS
|
||||
log_must rm -f $TESTDIR/test-mmap-file
|
||||
log_must set_tunable64 DMU_OFFSET_NEXT_SYNC $dmu_offset_next_sync
|
||||
}
|
||||
|
||||
log_assert "lseek() data/holes for an mmap()'d file."
|
||||
|
||||
log_onexit cleanup
|
||||
|
||||
# Enable hole reporting for dirty files.
|
||||
typeset dmu_offset_next_sync=$(get_tunable DMU_OFFSET_NEXT_SYNC)
|
||||
log_must set_tunable64 DMU_OFFSET_NEXT_SYNC 1
|
||||
|
||||
# Compression must be enabled to convert zero'd blocks to holes.
|
||||
# This behavior is checked by the mmap_seek test.
|
||||
log_must zfs set compression=on $TESTPOOL/$TESTFS
|
||||
|
||||
for bs in 4096 8192 16384 32768 65536 131072; do
|
||||
log_must zfs set recordsize=$bs $TESTPOOL/$TESTFS
|
||||
log_must mmap_seek $TESTDIR/test-mmap-file $((1024*1024)) $bs
|
||||
log_must rm $TESTDIR/test-mmap-file
|
||||
done
|
||||
|
||||
log_pass "lseek() data/holes for an mmap()'d file succeeded."
|
Loading…
Reference in New Issue
Block a user