fusefs: during ftruncate, discard cached data past truncation point
During truncate, fusefs was discarding entire cached blocks, but it wasn't zeroing out the unused portion of a final partial block. This resulted in reads returning stale data. PR: 233783 Reported by: fsx Sponsored by: The FreeBSD Foundation
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parent
d3a8f2dd09
commit
e312493b37
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/projects/fuse2/; revision=345823
@ -79,6 +79,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/fcntl.h>
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#include <sys/fnv_hash.h>
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#include <sys/priv.h>
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#include <sys/buf.h>
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#include <security/mac/mac_framework.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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@ -413,17 +414,45 @@ fuse_vnode_setsize(struct vnode *vp, struct ucred *cred, off_t newsize)
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{
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struct fuse_vnode_data *fvdat = VTOFUD(vp);
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off_t oldsize;
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size_t iosize;
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struct buf *bp = NULL;
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int err = 0;
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ASSERT_VOP_ELOCKED(vp, "fuse_vnode_setsize");
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iosize = fuse_iosize(vp);
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oldsize = fvdat->filesize;
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fvdat->filesize = newsize;
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fvdat->flag |= FN_SIZECHANGE;
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if (newsize < oldsize) {
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daddr_t lbn;
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size_t zsize;
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err = vtruncbuf(vp, cred, newsize, fuse_iosize(vp));
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if (err)
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goto out;
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if (newsize % iosize == 0)
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goto out;
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/*
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* Zero the contents of the last partial block.
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* Sure seems like vtruncbuf should do this for us.
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*/
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lbn = newsize / iosize;
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bp = getblk(vp, lbn, iosize, PCATCH, 0, 0);
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if (!bp) {
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err = EINTR;
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goto out;
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}
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if (!(bp->b_flags & B_CACHE))
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goto out; /* Nothing to do */
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zsize = (lbn + 1) * iosize - newsize;
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bzero(bp->b_data + newsize - lbn * iosize, zsize);
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}
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out:
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if (bp)
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brelse(bp);
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vnode_pager_setsize(vp, newsize);
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return err;
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}
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@ -366,6 +366,116 @@ TEST_F(Setattr, truncate) {
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EXPECT_EQ(0, truncate(FULLPATH, newsize)) << strerror(errno);
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}
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/*
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* Truncating a file should discard cached data past the truncation point.
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* This is a regression test for bug 233783. The bug only applies when
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* vfs.fusefs.data_cache_mode=1 or 2, but the test should pass regardless.
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*/
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TEST_F(Setattr, truncate_discards_cached_data) {
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const char FULLPATH[] = "mountpoint/some_file.txt";
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const char RELPATH[] = "some_file.txt";
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void *w0buf, *rbuf, *expected;
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off_t w0_offset = 0x1b8df;
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size_t w0_size = 0x61e8;
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off_t r_offset = 0xe1e6;
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off_t r_size = 0xe229;
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size_t trunc0_size = 0x10016;
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size_t trunc1_size = 131072;
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size_t cur_size = 0;
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const uint64_t ino = 42;
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mode_t mode = S_IFREG | 0644;
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int fd;
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w0buf = malloc(w0_size);
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ASSERT_NE(NULL, w0buf) << strerror(errno);
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memset(w0buf, 'X', w0_size);
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rbuf = malloc(r_size);
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ASSERT_NE(NULL, rbuf) << strerror(errno);
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expected = malloc(r_size);
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ASSERT_NE(NULL, expected) << strerror(errno);
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memset(expected, 0, r_size);
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expect_lookup(RELPATH, ino, mode, 0, 1);
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expect_open(ino, O_RDWR, 1);
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EXPECT_CALL(*m_mock, process(
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ResultOf([=](auto in) {
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return (in->header.opcode == FUSE_GETATTR &&
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in->header.nodeid == ino);
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}, Eq(true)),
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_)
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).WillRepeatedly(Invoke(ReturnImmediate([&](auto i __unused, auto out) {
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SET_OUT_HEADER_LEN(out, attr);
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out->body.attr.attr.ino = ino;
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out->body.attr.attr.mode = mode;
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out->body.attr.attr.size = cur_size;
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})));
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/*
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* The exact pattern of FUSE_WRITE operations depends on the setting of
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* vfs.fusefs.data_cache_mode. But it's not important for this test.
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* Just set the mocks to accept anything
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*/
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EXPECT_CALL(*m_mock, process(
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ResultOf([=](auto in) {
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return (in->header.opcode == FUSE_WRITE);
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}, Eq(true)),
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_)
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).WillRepeatedly(Invoke(ReturnImmediate([&](auto in, auto out) {
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SET_OUT_HEADER_LEN(out, write);
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out->body.attr.attr.ino = ino;
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out->body.write.size = in->body.write.size;
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cur_size = std::max(cur_size,
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in->body.write.size + in->body.write.offset);
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})));
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EXPECT_CALL(*m_mock, process(
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ResultOf([=](auto in) {
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return (in->header.opcode == FUSE_SETATTR &&
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in->header.nodeid == ino &&
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(in->body.setattr.valid & FATTR_SIZE));
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}, Eq(true)),
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_)
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).WillRepeatedly(Invoke(ReturnImmediate([&](auto in, auto out) {
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auto trunc_size = in->body.setattr.size;
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SET_OUT_HEADER_LEN(out, attr);
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out->body.attr.attr.ino = ino;
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out->body.attr.attr.mode = mode;
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out->body.attr.attr.size = trunc_size;
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cur_size = trunc_size;
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})));
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/* exact pattern of FUSE_READ depends on vfs.fusefs.data_cache_mode */
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EXPECT_CALL(*m_mock, process(
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ResultOf([=](auto in) {
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return (in->header.opcode == FUSE_READ);
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}, Eq(true)),
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_)
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).WillRepeatedly(Invoke(ReturnImmediate([&](auto in, auto out) {
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auto osize = std::min(cur_size - in->body.read.offset,
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(size_t)in->body.read.size);
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out->header.len = sizeof(struct fuse_out_header) + osize;
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bzero(out->body.bytes, osize);
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})));
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fd = open(FULLPATH, O_RDWR, 0644);
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ASSERT_LE(0, fd) << strerror(errno);
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ASSERT_EQ((ssize_t)w0_size, pwrite(fd, w0buf, w0_size, w0_offset));
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/* 1st truncate should discard cached data */
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EXPECT_EQ(0, ftruncate(fd, trunc0_size)) << strerror(errno);
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/* 2nd truncate extends file into previously cached data */
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EXPECT_EQ(0, ftruncate(fd, trunc1_size)) << strerror(errno);
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/* Read should return all zeros */
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ASSERT_EQ((ssize_t)r_size, pread(fd, rbuf, r_size, r_offset));
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ASSERT_EQ(0, memcmp(expected, rbuf, r_size));
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free(expected);
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free(rbuf);
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free(w0buf);
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}
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/* Change a file's timestamps */
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TEST_F(Setattr, utimensat) {
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const char FULLPATH[] = "mountpoint/some_file.txt";
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