diff options
| -rw-r--r-- | NEWS | 10 | ||||
| -rw-r--r-- | src/shred.c | 21 | ||||
| -rwxr-xr-x | tests/misc/shred-exact.sh | 11 |
3 files changed, 27 insertions, 15 deletions
@@ -37,6 +37,11 @@ GNU coreutils NEWS -*- outline -*- rm -I now prompts for confirmation before removing a write protected file. [Bug introduced in coreutils-6.8] + shred once again uses direct I/O on systems requiring aligned buffers. + Also direct I/O failures for odd sized writes at end of file are now handled. + [The "last write" bug was introduced in coreutils-5.3.0 but masked + by the alignment bug introduced in coreutils-6.0] + tail --retry -f now waits for the files specified to appear. Before, tail would immediately exit when such a file is inaccessible during the initial open. @@ -92,9 +97,8 @@ GNU coreutils NEWS -*- outline -*- Reservoir sampling is used to limit memory usage based on the number of outputs, rather than the number of inputs. - shred once again uses direct I/O where available, and increases write block - size from 12KiB to 64KiB when possible. - [Direct I/O regression introduced in coreutils-6.0] + shred increases write block size from 12KiB to 64KiB when possible, + to align with other utilities and reduce the system call overhead. split --line-bytes=SIZE, now only allocates memory as needed rather than allocating SIZE bytes at program start. diff --git a/src/shred.c b/src/shred.c index 9ff723865..98dd8726c 100644 --- a/src/shred.c +++ b/src/shred.c @@ -394,7 +394,7 @@ dopass (int fd, char const *qname, off_t *sizep, int type, char pass_string[PASS_NAME_SIZE]; /* Name of current pass */ bool write_error = false; bool other_error = false; - bool first_write = true; + bool tried_without_directio = false; /* Printable previous offset into the file */ char previous_offset_buf[LONGEST_HUMAN_READABLE + 1]; @@ -443,7 +443,7 @@ dopass (int fd, char const *qname, off_t *sizep, int type, if (type < 0) randread (s, pbuf, lim); /* Loop to retry partial writes. */ - for (soff = 0; soff < lim; soff += ssize, first_write = false) + for (soff = 0; soff < lim; soff += ssize) { ssize = write (fd, pbuf + soff, lim - soff); if (ssize <= 0) @@ -459,17 +459,15 @@ dopass (int fd, char const *qname, off_t *sizep, int type, int errnum = errno; char buf[INT_BUFSIZE_BOUND (uintmax_t)]; - /* If the first write of the first pass for a given file - has just failed with EINVAL, turn off direct mode I/O - and try again. This works around a bug in Linux kernel - 2.4 whereby opening with O_DIRECT would succeed for some - file system types (e.g., ext3), but any attempt to - access a file through the resulting descriptor would - fail with EINVAL. */ - if (k == 1 && first_write && errno == EINVAL) + /* Retry without direct I/O since this may not be supported + at all on some (file) systems, or with the current size. + I.E. a specified --size that is not aligned, or when + dealing with slop at the end of a file with --exact. */ + if (k == 1 && !tried_without_directio && errno == EINVAL) { direct_mode (fd, false); ssize = 0; + tried_without_directio = true; continue; } error (0, errnum, _("%s: error writing at offset %s"), @@ -478,7 +476,8 @@ dopass (int fd, char const *qname, off_t *sizep, int type, /* 'shred' is often used on bad media, before throwing it out. Thus, it shouldn't give up on bad blocks. This code works because lim is always a multiple of - SECTOR_SIZE, except at the end. */ + SECTOR_SIZE, except at the end. This size constraint + also enables direct I/O on some (file) systems. */ verify (PERIODIC_OUTPUT_SIZE % SECTOR_SIZE == 0); verify (NONPERIODIC_OUTPUT_SIZE % SECTOR_SIZE == 0); if (errnum == EIO && 0 <= size && (soff | SECTOR_MASK) < lim) diff --git a/tests/misc/shred-exact.sh b/tests/misc/shred-exact.sh index 0cdc91fc0..eb30a7d69 100755 --- a/tests/misc/shred-exact.sh +++ b/tests/misc/shred-exact.sh @@ -1,5 +1,5 @@ #!/bin/sh -# make sure that neither --exact nor --zero gobbles a command line argument +# Test functionality of --exact # Copyright (C) 2000-2013 Free Software Foundation, Inc. @@ -20,6 +20,7 @@ print_ver_ shred +# make sure that neither --exact nor --zero gobbles a command line argument for opt in --exact --zero; do echo a > a || fail=1 echo bb > b || fail=1 @@ -33,4 +34,12 @@ for opt in --exact --zero; do test -f c && fail=1 done + +# make sure direct I/O is handled appropriately at end of file +# Create a 1MiB file as we'll probably not be using blocks larger than that +# (i.e. we want to test failed writes not at the start). +truncate -s1MiB file.slop || framework_failure_ +truncate -s+1 file.slop || framework_failure_ +shred --exact -n1 file.slop || fail=1 + Exit $fail |