Patrick Williams | c124f4f | 2015-09-15 14:41:29 -0500 | [diff] [blame] | 1 | CentOS 5.8 kernels and headers support the sync_file_range() system call, |
| 2 | but glibc 2.5 doesn't provide the syscall stub. It appears that this |
| 3 | problem is known but will never be fixed: |
| 4 | |
| 5 | https://bugzilla.redhat.com/show_bug.cgi?id=518581 |
| 6 | |
| 7 | Bug 518581 - [RHEL5] glibc misses sync_file_range syscall interface |
| 8 | |
| 9 | Status: CLOSED CANTFIX |
| 10 | Last Closed: 2009-11-22 22:19:55 |
| 11 | |
| 12 | Kirby Zhou 2009-08-20 23:37:55 EDT |
| 13 | |
| 14 | Description of problem: |
| 15 | |
| 16 | glibc misses sync_file_range syscall interface. The header file and |
| 17 | man page both say 'sync_file_range' should exist. From man page, |
| 18 | sync_file_range should exist sinc kernel-2.6.17 |
| 19 | |
| 20 | Andreas Schwab 2009-08-21 03:24:24 EDT |
| 21 | |
| 22 | It has only been added to glibc 2.6, and cannot be backported due to |
| 23 | ABI breakage. You can always fall back to syscall(3). |
| 24 | |
| 25 | Ulrich Drepper 2009-11-22 22:19:55 EST |
| 26 | |
| 27 | As comment #1 says, no chance to backport this. |
| 28 | |
| 29 | See the syscall man page for instructions. |
| 30 | |
| 31 | Jon E 2010-03-19 10:32:37 EDT |
| 32 | |
| 33 | then why document it if it's broken and you're not going to fix it? |
| 34 | .. might want to FTFM over at sync_file_range(2) - in the meantime - |
| 35 | borrowing from glibc 2.6 .. any thoughts on this implementation for a |
| 36 | hacky workaround for those still on your "ancient releases" .. (eg: |
| 37 | RHEL5.3)?: |
| 38 | |
| 39 | #ifdef ULI_WONT_FIX_THIS_IN_GLIBC2.5 |
| 40 | #define NR_sync_file_range 277 |
| 41 | int sync_file_range (int fd, __off64_t from, __off64_t to, unsigned int flags) |
| 42 | { |
| 43 | return syscall (NR_sync_file_range, fd, |
| 44 | __LONG_LONG_PAIR ((long) (from >> 32), (long) from), |
| 45 | __LONG_LONG_PAIR ((long) (to >> 32), (long) to), |
| 46 | flags); |
| 47 | } |
| 48 | #endif |
| 49 | |
| 50 | assuming of course that you're on an x86_64 and include/asm- |
| 51 | x86_64/unistd.h has the correct entry |
| 52 | |
| 53 | (fwiw - fio is starting to use this now) |
| 54 | |
| 55 | Rather than attempting to provide an implementation using syscall(), |
| 56 | we take the more conservative route and ignore header support for |
| 57 | sync_file_range() flags when the glibc version is <= 2.5. |
| 58 | |
| 59 | Upstream-Status: Inappropriate [everyone else builds on newer hosts :-)] |
| 60 | |
| 61 | Signed-off-by: Donn Seeley <donn.seeley@windriver.com> |
| 62 | Signed-off-by: Lei Liu <lei.liu2@windriver.com> |
| 63 | --- |
| 64 | src/archives.c | 4 ++-- |
| 65 | 1 file changed, 2 insertions(+), 2 deletions(-) |
| 66 | |
| 67 | --- a/src/archives.c |
| 68 | +++ b/src/archives.c |
| 69 | @@ -75,7 +75,7 @@ |
| 70 | /* Ignore the return code as it should be considered equivalent to an |
| 71 | * asynchronous hint for the kernel, we are doing an fsync() later on |
| 72 | * anyway. */ |
| 73 | -#if defined(SYNC_FILE_RANGE_WRITE) |
| 74 | +#if defined(SYNC_FILE_RANGE_WRITE) && __GLIBC_PREREQ(2, 6) |
| 75 | sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WRITE); |
| 76 | #elif defined(HAVE_POSIX_FADVISE) |
| 77 | posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED); |
| 78 | @@ -1179,7 +1179,7 @@ |
| 79 | return 0; |
| 80 | } |
| 81 | |
| 82 | -#if defined(SYNC_FILE_RANGE_WAIT_BEFORE) |
| 83 | +#if defined(SYNC_FILE_RANGE_WAIT_BEFORE) && __GLIBC_PREREQ(2, 6) |
| 84 | static void |
| 85 | tar_writeback_barrier(struct fileinlist *files, struct pkginfo *pkg) |
| 86 | { |