fusefs: improve the short read fix from r349279
VOP_GETPAGES intentionally tries to read beyond EOF, so fuse_read_biobackend can't rely on bp->b_resid > 0 indicating a short read. And adjusting bp->b_count after a short read seems to cause some sort of resource leak. Instead, store the shortfall in the bp->b_fsprivate1 field. Sponsored by: The FreeBSD Foundation
This commit is contained in:
Alan Somers
parent
44f654fdc5
commit
17575bad85
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/projects/fuse2/; revision=349332
@ -348,8 +348,8 @@ fuse_read_biobackend(struct vnode *vp, struct uio *uio, int ioflag,
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*/
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n = 0;
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if (on < bcount - bp->b_resid)
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n = MIN((unsigned)(bcount - bp->b_resid - on),
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if (on < bcount - (intptr_t)bp->b_fsprivate1)
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n = MIN((unsigned)(bcount - (intptr_t)bp->b_fsprivate1 - on),
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uio->uio_resid);
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if (n > 0) {
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SDT_PROBE2(fusefs, , io, read_bio_backend_feed, n, bp);
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@ -358,9 +358,10 @@ fuse_read_biobackend(struct vnode *vp, struct uio *uio, int ioflag,
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vfs_bio_brelse(bp, ioflag);
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SDT_PROBE4(fusefs, , io, read_bio_backend_end, err,
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uio->uio_resid, n, bp);
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if (bp->b_resid > 0) {
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if ((intptr_t)bp->b_fsprivate1 > 0) {
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/* Short read indicates EOF */
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(void)fuse_vnode_setsize(vp, uio->uio_offset);
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bp->b_fsprivate1 = (void*)0;
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break;
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}
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}
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@ -891,16 +892,23 @@ fuse_io_strategy(struct vnode *vp, struct buf *bp)
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KASSERT(!(bp->b_flags & B_DONE),
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("fuse_io_strategy: bp %p already marked done", bp));
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if (bp->b_iocmd == BIO_READ) {
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ssize_t left;
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io.iov_len = uiop->uio_resid = bp->b_bcount;
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io.iov_base = bp->b_data;
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uiop->uio_rw = UIO_READ;
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uiop->uio_offset = ((off_t)bp->b_lblkno) * biosize;
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error = fuse_read_directbackend(vp, uiop, cred, fufh);
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left = uiop->uio_resid;
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/*
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* Store the amount we failed to read in the buffer's private
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* field, so callers can truncate the file if necessary'
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*/
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bp->b_fsprivate1 = (void*)(intptr_t)left;
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if (!error && uiop->uio_resid) {
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int nread = bp->b_bcount - uiop->uio_resid;
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int left = uiop->uio_resid;
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bzero((char *)bp->b_data + nread, left);
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if (fuse_data_cache_mode != FUSE_CACHE_WB ||
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@ -914,11 +922,12 @@ fuse_io_strategy(struct vnode *vp, struct buf *bp)
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* doesn't get exposed by a future truncate
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* that extends the file.
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*
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* XXX To prevent lock order problems, we must
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* To prevent lock order problems, we must
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* truncate the file upstack
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*/
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SDT_PROBE2(fusefs, , io, trace, 1,
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"Short read of a clean file");
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uiop->uio_resid = 0;
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} else {
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/*
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* If dirty writes _are_ cached beyond EOF,
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@ -29,6 +29,8 @@
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*/
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extern "C" {
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#include <sys/mman.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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@ -76,11 +78,13 @@ class Io: public FuseTest,
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public WithParamInterface<tuple<uint32_t, uint32_t, bool>> {
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public:
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int m_backing_fd, m_control_fd, m_test_fd;
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off_t m_filesize;
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Io(): m_backing_fd(-1), m_control_fd(-1) {};
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void SetUp()
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{
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m_filesize = 0;
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m_backing_fd = open("backing_file", O_RDWR | O_CREAT | O_TRUNC, 0644);
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if (m_backing_fd < 0)
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FAIL() << strerror(errno);
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@ -126,10 +130,11 @@ void SetUp()
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ssize_t isize = in.body.write.size;
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off_t iofs = in.body.write.offset;
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void *buf = out.body.bytes;
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ssize_t osize;
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ASSERT_LE(0, pread(m_backing_fd, buf, isize, iofs))
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<< strerror(errno);
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out.header.len = sizeof(struct fuse_out_header) + isize;
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osize = pread(m_backing_fd, buf, isize, iofs);
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ASSERT_LE(0, osize) << strerror(errno);
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out.header.len = sizeof(struct fuse_out_header) + osize;
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})));
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EXPECT_CALL(*m_mock, process(
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ResultOf([=](auto in) {
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@ -182,21 +187,52 @@ void do_ftruncate(off_t offs)
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{
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ASSERT_EQ(0, ftruncate(m_test_fd, offs)) << strerror(errno);
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ASSERT_EQ(0, ftruncate(m_control_fd, offs)) << strerror(errno);
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m_filesize = offs;
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}
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void do_mapread(ssize_t size, off_t offs)
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{
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void *control_buf, *p;
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off_t pg_offset, page_mask;
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size_t map_size;
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page_mask = getpagesize() - 1;
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pg_offset = offs & page_mask;
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map_size = pg_offset + size;
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p = mmap(NULL, map_size, PROT_READ, MAP_FILE | MAP_SHARED, m_test_fd,
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offs - pg_offset);
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ASSERT_NE(p, MAP_FAILED) << strerror(errno);
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control_buf = malloc(size);
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ASSERT_NE(NULL, control_buf) << strerror(errno);
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ASSERT_EQ(size, pread(m_control_fd, control_buf, size, offs))
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<< strerror(errno);
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compare((void*)((char*)p + pg_offset), control_buf, offs, size);
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ASSERT_EQ(0, munmap(p, map_size)) << strerror(errno);
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free(control_buf);
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}
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void do_read(ssize_t size, off_t offs)
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{
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void *test_buf, *control_buf;
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ssize_t r;
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test_buf = malloc(size);
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ASSERT_NE(NULL, test_buf) << strerror(errno);
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control_buf = malloc(size);
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ASSERT_NE(NULL, control_buf) << strerror(errno);
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ASSERT_EQ(size, pread(m_test_fd, test_buf, size, offs))
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<< strerror(errno);
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ASSERT_EQ(size, pread(m_control_fd, control_buf, size, offs))
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<< strerror(errno);
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errno = 0;
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r = pread(m_test_fd, test_buf, size, offs);
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ASSERT_NE(-1, r) << strerror(errno);
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ASSERT_EQ(size, r) << "unexpected short read";
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r = pread(m_control_fd, control_buf, size, offs);
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ASSERT_NE(-1, r) << strerror(errno);
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ASSERT_EQ(size, r) << "unexpected short read";
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compare(test_buf, control_buf, offs, size);
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@ -204,6 +240,43 @@ void do_read(ssize_t size, off_t offs)
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free(test_buf);
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}
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void do_mapwrite(ssize_t size, off_t offs)
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{
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char *buf;
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void *p;
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off_t pg_offset, page_mask;
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size_t map_size;
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long i;
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page_mask = getpagesize() - 1;
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pg_offset = offs & page_mask;
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map_size = pg_offset + size;
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buf = (char*)malloc(size);
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ASSERT_NE(NULL, buf) << strerror(errno);
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for (i=0; i < size; i++)
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buf[i] = random();
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if (offs + size > m_filesize) {
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/*
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* Must manually extend. vm_mmap_vnode will not implicitly
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* extend a vnode
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*/
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do_ftruncate(offs + size);
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}
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p = mmap(NULL, map_size, PROT_READ | PROT_WRITE,
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MAP_FILE | MAP_SHARED, m_test_fd, offs - pg_offset);
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ASSERT_NE(p, MAP_FAILED) << strerror(errno);
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bcopy(buf, (char*)p + pg_offset, size);
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ASSERT_EQ(size, pwrite(m_control_fd, buf, size, offs))
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<< strerror(errno);
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free(buf);
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ASSERT_EQ(0, munmap(p, map_size)) << strerror(errno);
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}
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void do_write(ssize_t size, off_t offs)
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{
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char *buf;
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@ -218,6 +291,9 @@ void do_write(ssize_t size, off_t offs)
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<< strerror(errno);
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ASSERT_EQ(size, pwrite(m_control_fd, buf, size, offs))
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<< strerror(errno);
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m_filesize = std::max(m_filesize, offs + size);
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free(buf);
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}
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};
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@ -240,6 +316,18 @@ TEST_P(Io, extend_from_dirty_page)
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do_read(rsize, rofs);
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}
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/*
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* mapwrite into a newly extended part of a file.
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*
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* fsx -c 100 -i 100 -l 524288 -o 131072 -N5 -P /tmp -S19 fsx.bin
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*/
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TEST_P(Io, extend_by_mapwrite)
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{
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do_mapwrite(0x849e, 0x29a3a); /* [0x29a3a, 0x31ed7] */
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do_mapwrite(0x3994, 0x3c7d8); /* [0x3c7d8, 0x4016b] */
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do_read(0xf556, 0x30c16); /* [0x30c16, 0x4016b] */
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}
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/*
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* When writing the last page of a file, it must be written synchronously.
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* Otherwise the cached page can become invalid by a subsequent extend
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@ -249,16 +337,20 @@ TEST_P(Io, extend_from_dirty_page)
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*/
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TEST_P(Io, last_page)
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{
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off_t wofs0 = 0x1134f;
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ssize_t wsize0 = 0xcc77;
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off_t wofs1 = 0x2096a;
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ssize_t wsize1 = 0xdfa7;
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off_t rofs = 0x1a3aa;
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ssize_t rsize = 0xb5b7;
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do_write(0xcc77, 0x1134f); /* [0x1134f, 0x1dfc5] */
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do_write(0xdfa7, 0x2096a); /* [0x2096a, 0x2e910] */
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do_read(0xb5b7, 0x1a3aa); /* [0x1a3aa, 0x25960] */
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}
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do_write(wsize0, wofs0);
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do_write(wsize1, wofs1);
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do_read(rsize, rofs);
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/*
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* Read a hole using mmap
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*
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* fsx -c 100 -i 100 -l 524288 -o 131072 -N11 -P /tmp -S14 fsx.bin
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*/
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TEST_P(Io, mapread_hole)
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{
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do_write(0x123b7, 0xf205); /* [0xf205, 0x215bb] */
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do_mapread(0xeeea, 0x2f4c); /* [0x2f4c, 0x11e35] */
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}
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/*
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