The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=85cff1455a8c3422c6ba8a9f895b5d65118f3499
commit 85cff1455a8c3422c6ba8a9f895b5d65118f3499 Author: Konstantin Belousov <[email protected]> AuthorDate: 2022-10-17 15:26:43 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2022-10-19 17:24:07 +0000 tmpfs: implement FIOSEEKDATA and FIOSEEKHOLE providing the support for lseek(2) SEEK_DATA and SEEK_HOLE. Reviewed by: markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D37024 --- sys/fs/tmpfs/tmpfs_vnops.c | 130 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) diff --git a/sys/fs/tmpfs/tmpfs_vnops.c b/sys/fs/tmpfs/tmpfs_vnops.c index 9bcf835aa627..aaeaa843eb43 100644 --- a/sys/fs/tmpfs/tmpfs_vnops.c +++ b/sys/fs/tmpfs/tmpfs_vnops.c @@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$"); #include <sys/dirent.h> #include <sys/fcntl.h> #include <sys/file.h> +#include <sys/filio.h> #include <sys/limits.h> #include <sys/lockf.h> #include <sys/lock.h> @@ -63,6 +64,9 @@ __FBSDID("$FreeBSD$"); #include <vm/vm.h> #include <vm/vm_param.h> #include <vm/vm_object.h> +#include <vm/vm_page.h> +#include <vm/vm_pager.h> +#include <vm/swap_pager.h> #include <fs/tmpfs/tmpfs_vnops.h> #include <fs/tmpfs/tmpfs.h> @@ -1820,6 +1824,131 @@ restart_locked: return (ENOENT); } +static off_t +tmpfs_seek_data_locked(vm_object_t obj, off_t noff) +{ + vm_page_t m; + vm_pindex_t p, p_m, p_swp; + + p = OFF_TO_IDX(noff); + m = vm_page_find_least(obj, p); + + /* + * Microoptimize the most common case for SEEK_DATA, where + * there is no hole and the page is resident. + */ + if (m != NULL && vm_page_any_valid(m) && m->pindex == p) + return (noff); + + p_swp = swap_pager_find_least(obj, p); + if (p_swp == p) + return (noff); + + p_m = m == NULL ? obj->size : m->pindex; + return (IDX_TO_OFF(MIN(p_m, p_swp))); +} + +static off_t +tmpfs_seek_next(off_t noff) +{ + return (noff + PAGE_SIZE - (noff & PAGE_MASK)); +} + +static int +tmpfs_seek_clamp(struct tmpfs_node *tn, off_t *noff, bool seekdata) +{ + if (*noff < tn->tn_size) + return (0); + if (seekdata) + return (ENXIO); + *noff = tn->tn_size; + return (0); +} + +static off_t +tmpfs_seek_hole_locked(vm_object_t obj, off_t noff) +{ + vm_page_t m; + vm_pindex_t p, p_swp; + + for (;; noff = tmpfs_seek_next(noff)) { + /* + * Walk over the largest sequential run of the valid pages. + */ + for (m = vm_page_lookup(obj, OFF_TO_IDX(noff)); + m != NULL && vm_page_any_valid(m); + m = vm_page_next(m), noff = tmpfs_seek_next(noff)) + ; + + /* + * Found a hole in the object's page queue. Check if + * there is a hole in the swap at the same place. + */ + p = OFF_TO_IDX(noff); + p_swp = swap_pager_find_least(obj, p); + if (p_swp != p) { + noff = IDX_TO_OFF(p); + break; + } + } + return (noff); +} + +static int +tmpfs_seek_datahole(struct vnode *vp, off_t *off, bool seekdata) +{ + struct tmpfs_node *tn; + vm_object_t obj; + off_t noff; + int error; + + if (vp->v_type != VREG) + return (ENOTTY); + tn = VP_TO_TMPFS_NODE(vp); + noff = *off; + if (noff < 0) + return (ENXIO); + error = tmpfs_seek_clamp(tn, &noff, seekdata); + if (error != 0) + return (error); + obj = tn->tn_reg.tn_aobj; + + VM_OBJECT_RLOCK(obj); + noff = seekdata ? tmpfs_seek_data_locked(obj, noff) : + tmpfs_seek_hole_locked(obj, noff); + VM_OBJECT_RUNLOCK(obj); + + error = tmpfs_seek_clamp(tn, &noff, seekdata); + if (error == 0) + *off = noff; + return (error); +} + +static int +tmpfs_ioctl(struct vop_ioctl_args *ap) +{ + struct vnode *vp = ap->a_vp; + int error = 0; + + switch (ap->a_command) { + case FIOSEEKDATA: + case FIOSEEKHOLE: + error = vn_lock(vp, LK_SHARED); + if (error != 0) { + error = EBADF; + break; + } + error = tmpfs_seek_datahole(vp, (off_t *)ap->a_data, + ap->a_command == FIOSEEKDATA); + VOP_UNLOCK(vp); + break; + default: + error = ENOTTY; + break; + } + return (error); +} + /* * Vnode operations vector used for files stored in a tmpfs file system. */ @@ -1863,6 +1992,7 @@ struct vop_vector tmpfs_vnodeop_entries = { .vop_unlock = vop_unlock, .vop_islocked = vop_islocked, .vop_add_writecount = vop_stdadd_writecount_nomsync, + .vop_ioctl = tmpfs_ioctl, }; VFS_VOP_VECTOR_REGISTER(tmpfs_vnodeop_entries);
