1. 16 Feb, 2015 1 commit
    • Matthew Wilcox's avatar
      vfs: remove get_xip_mem · e748dcd0
      Matthew Wilcox authored
      All callers of get_xip_mem() are now gone.  Remove checks for it,
      initialisers of it, documentation of it and the only implementation of it.
       Also remove mm/filemap_xip.c as it is now empty.  Also remove
      documentation of the long-gone get_xip_page().
      Signed-off-by: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
      Cc: Andreas Dilger <andreas.dilger@intel.com>
      Cc: Boaz Harrosh <boaz@plexistor.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Jan Kara <jack@suse.cz>
      Cc: Jens Axboe <axboe@kernel.dk>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Randy Dunlap <rdunlap@infradead.org>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  2. 20 Jan, 2015 1 commit
  3. 13 Dec, 2014 1 commit
  4. 03 Mar, 2013 1 commit
  5. 23 Feb, 2013 1 commit
    • Mel Gorman's avatar
      mm/fadvise.c: drain all pagevecs if POSIX_FADV_DONTNEED fails to discard all pages · 67d46b29
      Mel Gorman authored
      Rob van der Heij reported the following (paraphrased) on private mail.
      	The scenario is that I want to avoid backups to fill up the page
      	cache and purge stuff that is more likely to be used again (this is
      	with s390x Linux on z/VM, so I don't give it as much memory that
      	we don't care anymore). So I have something with LD_PRELOAD that
      	intercepts the close() call (from tar, in this case) and issues
      	a posix_fadvise() just before closing the file.
      	This mostly works, except for small files (less than 14 pages)
      	that remains in page cache after the face.
      Unfortunately Rob has not had a chance to test this exact patch but the
      test program below should be reproducing the problem he described.
      The issue is the per-cpu pagevecs for LRU additions.  If the pages are
      added by one CPU but fadvise() is called on another then the pages
      remain resident as the invalidate_mapping_pages() only drains the local
      pagevecs via its call to pagevec_release().  The user-visible effect is
      that a program that uses fadvise() properly is not obeyed.
      A possible fix for this is to put the necessary smarts into
      invalidate_mapping_pages() to globally drain the LRU pagevecs if a
      pagevec page could not be discarded.  The downside with this is that an
      inode cache shrink would send a global IPI and memory pressure
      potentially causing global IPI storms is very undesirable.
      Instead, this patch adds a check during fadvise(POSIX_FADV_DONTNEED) to
      check if invalidate_mapping_pages() discarded all the requested pages.
      If a subset of pages are discarded it drains the LRU pagevecs and tries
      again.  If the second attempt fails, it assumes it is due to the pages
      being mapped, locked or dirty and does not care.  With this patch, an
      application using fadvise() correctly will be obeyed but there is a
      downside that a malicious application can force the kernel to send
      global IPIs and increase overhead.
      If accepted, I would like this to be considered as a -stable candidate.
      It's not an urgent issue but it's a system call that is not working as
      advertised which is weak.
      The following test program demonstrates the problem.  It should never
      report that pages are still resident but will without this patch.  It
      assumes that CPU 0 and 1 exist.
      int main() {
      	int fd;
      	int pagesize = getpagesize();
      	ssize_t written = 0, expected;
      	char *buf;
      	unsigned char *vec;
      	int resident, i;
      	cpu_set_t set;
      	/* Prepare a buffer for writing */
      	expected = FILESIZE_PAGES * pagesize;
      	buf = malloc(expected + 1);
      	if (buf == NULL) {
      	buf[expected] = 0;
      	memset(buf, 'a', expected);
      	/* Prepare the mincore vec */
      	vec = malloc(FILESIZE_PAGES);
      	if (vec == NULL) {
      	/* Bind ourselves to CPU 0 */
      	CPU_SET(0, &set);
      	if (sched_setaffinity(getpid(), sizeof(set), &set) == -1) {
      	/* open file, unlink and write buffer */
      	fd = open("fadvise-test-file", O_CREAT|O_EXCL|O_RDWR);
      	if (fd == -1) {
      	while (written < expected) {
      		ssize_t this_write;
      		this_write = write(fd, buf + written, expected - written);
      		if (this_write == -1) {
      		written += this_write;
      	 * Force ourselves to another CPU. If fadvise only flushes the local
      	 * CPUs pagevecs then the fadvise will fail to discard all file pages
      	CPU_SET(1, &set);
      	if (sched_setaffinity(getpid(), sizeof(set), &set) == -1) {
      	/* sync and fadvise to discard the page cache */
      	if (posix_fadvise(fd, 0, expected, POSIX_FADV_DONTNEED) == -1) {
      	/* map the file and use mincore to see which parts of it are resident */
      	buf = mmap(NULL, expected, PROT_READ, MAP_SHARED, fd, 0);
      	if (buf == NULL) {
      	if (mincore(buf, expected, vec) == -1) {
      	/* Check residency */
      	for (i = 0, resident = 0; i < FILESIZE_PAGES; i++) {
      		if (vec[i])
      	if (resident != 0) {
      		printf("Nr unexpected pages resident: %d\n", resident);
      	munmap(buf, expected);
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Reported-by: default avatarRob van der Heij <rvdheij@gmail.com>
      Tested-by: default avatarRob van der Heij <rvdheij@gmail.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  6. 22 Feb, 2013 1 commit
  7. 26 Sep, 2012 2 commits
  8. 31 Jul, 2012 1 commit
  9. 10 Jan, 2012 1 commit
  10. 06 Mar, 2010 1 commit
    • Wu Fengguang's avatar
      readahead: introduce FMODE_RANDOM for POSIX_FADV_RANDOM · 0141450f
      Wu Fengguang authored
      This fixes inefficient page-by-page reads on POSIX_FADV_RANDOM.
      POSIX_FADV_RANDOM used to set ra_pages=0, which leads to poor performance:
      a 16K read will be carried out in 4 _sync_ 1-page reads.
      In other places, ra_pages==0 means
      - it's ramfs/tmpfs/hugetlbfs/sysfs/configfs
      - some IO error happened
      where multi-page read IO won't help or should be avoided.
      POSIX_FADV_RANDOM actually want a different semantics: to disable the
      *heuristic* readahead algorithm, and to use a dumb one which faithfully
      submit read IO for whatever application requests.
      So introduce a flag FMODE_RANDOM for POSIX_FADV_RANDOM.
      Note that the random hint is not likely to help random reads performance
      noticeably.  And it may be too permissive on huge request size (its IO
      size is not limited by read_ahead_kb).
      In Quentin's report (http://lkml.org/lkml/2009/12/24/145), the overall
      (NFS read) performance of the application increased by 313%!
      Tested-by: default avatarQuentin Barnes <qbarnes+nfs@yahoo-inc.com>
      Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Steven Whitehouse <swhiteho@redhat.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
      Cc: Chuck Lever <chuck.lever@oracle.com>
      Cc: <stable@kernel.org>			[2.6.33.x]
      Cc: <qbarnes+nfs@yahoo-inc.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  11. 16 Jun, 2009 1 commit
  12. 14 Jan, 2009 1 commit
    • Heiko Carstens's avatar
      [CVE-2009-0029] System call wrapper special cases · 6673e0c3
      Heiko Carstens authored
      System calls with an unsigned long long argument can't be converted with
      the standard wrappers since that would include a cast to long, which in
      turn means that we would lose the upper 32 bit on 32 bit architectures.
      Also semctl can't use the standard wrapper since it has a 'union'
      So we handle them as special case and add some extra wrappers instead.
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
  13. 16 Oct, 2008 1 commit
  14. 28 Apr, 2008 1 commit
  15. 05 Feb, 2008 1 commit
    • Masatake YAMATO's avatar
      check ADVICE of fadvise64_64 even if get_xip_page is given · b5beb1ca
      Masatake YAMATO authored
      I've written some test programs in ltp project.  During writing I met an
      problem which I cannot solve in user land.  So I wrote a patch for linux
      kernel.  Please, include this patch if acceptable.
      The test program tests the 4th parameter of fadvise64_64:
          long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice);
      My test case calls fadvise64_64 with invalid advice value and checks errno is
      set to EINVAL.  About the advice parameter man page says:
          Permissible values for advice include:
      	   EINVAL An invalid value was specified for advice.
      However, I got a bug report that the system call invocations
      in my test case returned 0 unexpectedly.
      I've inspected the kernel code:
          asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
      	    struct file *file = fget(fd);
      	    struct address_space *mapping;
      	    struct backing_dev_info *bdi;
      	    loff_t endbyte;			/* inclusive */
      	    pgoff_t start_index;
      	    pgoff_t end_index;
      	    unsigned long nrpages;
      	    int ret = 0;
      	    if (!file)
      		    return -EBADF;
      	    if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
      		    ret = -ESPIPE;
      		    goto out;
      	    mapping = file->f_mapping;
      	    if (!mapping || len < 0) {
      		    ret = -EINVAL;
      		    goto out;
      	    if (mapping->a_ops->get_xip_page)
      		    /* no bad return value, but ignore advice */
      		    goto out;
      	    return ret;
      I found the advice parameter is just ignored in the case
      mapping->a_ops->get_xip_page is given. This behavior is different from
      what is written on the man page. Is this o.k.?
      get_xip_page is given if CONFIG_EXT2_FS_XIP is true.
      Anyway I cannot find the easy way to detect get_xip_page
      field is given or CONFIG_EXT2_FS_XIP is true from the
      user space.
      I propose the following patch which checks the advice parameter
      even if get_xip_page is given.
      Signed-off-by: default avatarMasatake YAMATO <yamato@redhat.com>
      Acked-by: default avatarCarsten Otte <cotte@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  16. 08 Dec, 2006 1 commit
  17. 06 Aug, 2006 1 commit
    • Andrew Morton's avatar
      [PATCH] fadvise() make POSIX_FADV_NOREUSE a no-op · 60c371bc
      Andrew Morton authored
      The POSIX_FADV_NOREUSE hint means "the application will use this range of the
      file a single time".  It seems to be intended that the implementation will use
      this hint to perform drop-behind of that part of the file when the application
      gets around to reading or writing it.
      However for reasons which aren't obvious (or sane?) I mapped
      POSIX_FADV_NOREUSE onto POSIX_FADV_WILLNEED.  ie: it does readahead.
      That's daft.  So for now, make POSIX_FADV_NOREUSE a no-op.
      This is a non-back-compatible change.  If someone was using POSIX_FADV_NOREUSE
      to perform readahead, they lose.  The likelihood is low.
      If/when we later implement POSIX_FADV_NOREUSE things will get interesting - to
      do it fully we'll need to maintain file offset/length ranges and peform all
      sorts of complex tricks, and managing the lifetime of those ranges' data
      structures will be interesting..
      A sensible implementation would probably ignore the file range and would
      simply mark the entire file as needing some form of drop-behind treatment.
      Cc: Michael Kerrisk <mtk-manpages@gmx.net>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
  18. 10 Jul, 2006 1 commit
  19. 31 Mar, 2006 1 commit
    • Andrew Morton's avatar
      [PATCH] sys_sync_file_range() · f79e2abb
      Andrew Morton authored
      Remove the recently-added LINUX_FADV_ASYNC_WRITE and LINUX_FADV_WRITE_WAIT
      fadvise() additions, do it in a new sys_sync_file_range() syscall instead.
      - It's more flexible.  Things which would require two or three syscalls with
        fadvise() can be done in a single syscall.
      - Using fadvise() in this manner is something not covered by POSIX.
      The patch wires up the syscall for x86.
      The sycall is implemented in the new fs/sync.c.  The intention is that we can
      move sys_fsync(), sys_fdatasync() and perhaps sys_sync() into there later.
      Documentation for the syscall is in fs/sync.c.
      A test app (sync_file_range.c) is in
      The available-to-GPL-modules do_sync_file_range() is for knfsd: "A COMMIT can
      say NFS_DATA_SYNC or NFS_FILE_SYNC.  I can skip the ->fsync call for
      NFS_DATA_SYNC which is hopefully the more common."
      Note: the `async' writeout mode SYNC_FILE_RANGE_WRITE will turn synchronous if
      the queue is congested.  This is trivial to fix: add a new flag bit, set
      wbc->nonblocking.  But I'm not sure that we want to expose implementation
      details down to that level.
      Note: it's notable that we can sync an fd which wasn't opened for writing.
      Same with fsync() and fdatasync()).
      Note: the code takes some care to handle attempts to sync file contents
      outside the 16TB offset on 32-bit machines.  It makes such attempts appear to
      succeed, for best 32-bit/64-bit compatibility.  Perhaps it should make such
      requests fail...
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Michael Kerrisk <mtk-manpages@gmx.net>
      Cc: Ulrich Drepper <drepper@redhat.com>
      Cc: Neil Brown <neilb@cse.unsw.edu.au>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
  20. 24 Mar, 2006 1 commit
    • Andrew Morton's avatar
      [PATCH] fadvise(): write commands · ebcf28e1
      Andrew Morton authored
      Add two new linux-specific fadvise extensions():
      LINUX_FADV_ASYNC_WRITE: start async writeout of any dirty pages between file
      offsets `offset' and `offset+len'.  Any pages which are currently under
      writeout are skipped, whether or not they are dirty.
      LINUX_FADV_WRITE_WAIT: wait upon writeout of any dirty pages between file
      offsets `offset' and `offset+len'.
      By combining these two operations the application may do several things:
      LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk.
      LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE: push all of the currently dirty
      pages at the disk.
      of the currently dirty pages at the disk, wait until they have been written.
      It should be noted that none of these operations write out the file's
      metadata.  So unless the application is strictly performing overwrites of
      already-instantiated disk blocks, there are no guarantees here that the data
      will be available after a crash.
      To complete this suite of operations I guess we should have a "sync file
      metadata only" operation.  This gives applications access to all the building
      blocks needed for all sorts of sync operations.  But sync-metadata doesn't fit
      well with the fadvise() interface.  Probably it should be a new syscall:
      The patch also diddles with the meaning of `endbyte' in sys_fadvise64_64().
      It is made to represent that last affected byte in the file (ie: it is
      inclusive).  Generally, all these byterange and pagerange functions are
      inclusive so we can easily represent EOF with -1.
      As Ulrich notes, these two functions are somewhat abusive of the fadvise()
      concept, which appears to be "set the future policy for this fd".
      But these commands are a perfect fit with the fadvise() impementation, and
      several of the existing fadvise() commands are synchronous and don't affect
      future policy either.   I think we can live with the slight incongruity.
      Cc: Michael Kerrisk <mtk-manpages@gmx.net>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
  21. 08 Jan, 2006 1 commit
  22. 24 Jun, 2005 1 commit
  23. 16 Apr, 2005 1 commit
    • Linus Torvalds's avatar
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds authored
      Initial git repository build. I'm not bothering with the full history,
      even though we have it. We can create a separate "historical" git
      archive of that later if we want to, and in the meantime it's about
      3.2GB when imported into git - space that would just make the early
      git days unnecessarily complicated, when we don't have a lot of good
      infrastructure for it.
      Let it rip!