Date: Tue, 11 Jun 2019 23:46:32 +0000 (UTC) From: Alan Somers <asomers@FreeBSD.org> To: src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: svn commit: r348978 - in projects/fuse2: sys/fs/fuse tests/sys/fs/fusefs Message-ID: <201906112346.x5BNkWVI013382@repo.freebsd.org>
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Author: asomers Date: Tue Jun 11 23:46:31 2019 New Revision: 348978 URL: https://svnweb.freebsd.org/changeset/base/348978 Log: fusefs: fix a page fault with writeback cacheing When truncating a file downward through a dirty buffer, it's neccessary to update the buffer's b->dirtyend. Sponsored by: The FreeBSD Foundation Modified: projects/fuse2/sys/fs/fuse/fuse_node.c projects/fuse2/tests/sys/fs/fusefs/io.cc Modified: projects/fuse2/sys/fs/fuse/fuse_node.c ============================================================================== --- projects/fuse2/sys/fs/fuse/fuse_node.c Tue Jun 11 23:43:29 2019 (r348977) +++ projects/fuse2/sys/fs/fuse/fuse_node.c Tue Jun 11 23:46:31 2019 (r348978) @@ -415,6 +415,7 @@ fuse_vnode_setsize(struct vnode *vp, off_t newsize) goto out; /* Nothing to do */ MPASS(bp->b_flags & B_VMIO); vfs_bio_clrbuf(bp); + bp->b_dirtyend = MIN(bp->b_dirtyend, newsize - lbn * iosize); } out: if (bp) Modified: projects/fuse2/tests/sys/fs/fusefs/io.cc ============================================================================== --- projects/fuse2/tests/sys/fs/fusefs/io.cc Tue Jun 11 23:43:29 2019 (r348977) +++ projects/fuse2/tests/sys/fs/fusefs/io.cc Tue Jun 11 23:46:31 2019 (r348978) @@ -59,10 +59,10 @@ Io(): m_backing_fd(-1), m_control_fd(-1) {}; void SetUp() { - m_backing_fd = open("backing_file", O_RDWR | O_CREAT | O_TRUNC); + m_backing_fd = open("backing_file", O_RDWR | O_CREAT | O_TRUNC, 0644); if (m_backing_fd < 0) FAIL() << strerror(errno); - m_control_fd = open("control", O_RDWR | O_CREAT | O_TRUNC); + m_control_fd = open("control", O_RDWR | O_CREAT | O_TRUNC, 0644); if (m_control_fd < 0) FAIL() << strerror(errno); srandom(22'9'1982); // Seed with my birthday @@ -251,12 +251,12 @@ TEST_F(Io, read_hole_from_cached_block) } /* - * Reliable panic; I don't yet know why. - * Disabled because it panics. + * Truncating a file into a dirty buffer should not causing anything untoward + * to happen when that buffer is eventually flushed. * * fsx -WR -P /tmp -S839 -d -N6 fsx.bin */ -TEST_F(Io, DISABLED_fault_on_nofault_entry) +TEST_F(Io, truncate_into_dirty_buffer) { off_t wofs0 = 0x3bad7; ssize_t wsize0 = 0x4529; @@ -272,5 +272,39 @@ TEST_F(Io, DISABLED_fault_on_nofault_entry) do_ftruncate(truncsize0); do_read(rsize, rofs); do_ftruncate(truncsize1); + close(m_test_fd); +} + +/* + * Truncating a file into a dirty buffer should not causing anything untoward + * to happen when that buffer is eventually flushed, even when the buffer's + * dirty_off is > 0. + * + * Based on this command with a few steps removed: + * fsx -WR -P /tmp -S677 -d -N8 fsx.bin + */ +TEST_F(Io, truncate_into_dirty_buffer2) +{ + off_t truncsize0 = 0x344f3; + off_t wofs = 0x2790c; + ssize_t wsize = 0xd86a; + off_t truncsize1 = 0x2de38; + off_t rofs2 = 0x1fd7a; + ssize_t rsize2 = 0xc594; + off_t truncsize2 = 0x31e71; + + /* Sets the file size to something larger than the next write */ + do_ftruncate(truncsize0); + /* + * Creates a dirty buffer. The part in lbn 2 doesn't flush + * synchronously. + */ + do_write(wsize, wofs); + /* Truncates part of the dirty buffer created in step 2 */ + do_ftruncate(truncsize1); + /* XXX ?I don't know why this is necessary? */ + do_read(rsize2, rofs2); + /* Truncates the dirty buffer */ + do_ftruncate(truncsize2); close(m_test_fd); }
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