diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/shred.c | 21 |
1 files changed, 10 insertions, 11 deletions
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) |