The vnode pager (used when you do file-backed mmaps) must use the
underlying physical sector size when aligning I/O transfer sizes. It cannot assume 512 bytes. We assume the underlying sector size is a power of 2. If it isn't, mmap() will break badly anyway (in the same way mmap broke with NFS when NFS tried to cache piecemeal write ranges in buffers, before we enforced read-buffer-before-write-piecemeal for NFS). Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
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commit
24579ca1d7
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=51340
@ -58,6 +58,7 @@
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#include <sys/mount.h>
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#include <sys/buf.h>
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#include <sys/vmmeter.h>
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#include <sys/conf.h>
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#include <vm/vm.h>
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#include <vm/vm_prot.h>
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@ -196,6 +197,10 @@ vnode_pager_haspage(object, pindex, before, after)
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int bsize;
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int pagesperblock, blocksperpage;
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/*
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* If no vp or vp is doomed or marked transparent to VM, we do not
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* have the page.
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*/
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if ((vp == NULL) || (vp->v_flag & VDOOMED))
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return FALSE;
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@ -708,10 +713,13 @@ vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
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size = object->un_pager.vnp.vnp_size - foff;
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/*
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* round up physical size for real devices
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* round up physical size for real devices.
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*/
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if (dp->v_type == VBLK || dp->v_type == VCHR)
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size = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1);
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if (dp->v_type == VBLK || dp->v_type == VCHR) {
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int secmask = dp->v_rdev->si_bsize_phys - 1;
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KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1));
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size = (size + secmask) & ~secmask;
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}
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bp = getpbuf(&vnode_pbuf_freecnt);
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kva = (vm_offset_t) bp->b_data;
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