1. 31 Mar, 2006 1 commit
  2. 28 Mar, 2006 1 commit
  3. 26 Mar, 2006 1 commit
  4. 25 Mar, 2006 1 commit
    • Chen, Kenneth W's avatar
      [PATCH] direct-io: bug fix in dio handling write error · 174e27c6
      Chen, Kenneth W authored
      There is a bug in direct-io on propagating write error up to the higher I/O
      layer.  When performing an async ODIRECT write to a block device, if a
      device error occurred (like media error or disk is pulled), the error code
      is only propagated from device driver to the DIO layer.  The error code
      stops at finished_one_bio().  The aysnc write, however, is supposedly have
      a corresponding AIO event with appropriate return code (in this case -EIO).
       Application which waits on the async write event, will hang forever since
      such AIO event is lost forever (if such app did not use the timeout option
      in io_getevents call.  Regardless, an AIO event is lost).
      
      The discovery of above bug leads to another discovery of potential race
      window with dio->result.  The fundamental problem is that dio->result is
      overloaded with dual use: an indicator of fall back path for partial dio
      write, and an error indicator used in the I/O completion path.  In the
      event of device error, the setting of -EIO to dio->result clashes with
      value used to track partial write that activates the fall back path.
      
      It was also pointed out that it is impossible to use dio->result to track
      partial write and at the same time to track error returned from device
      driver.  Because direct_io_work can only determines whether it is a partial
      write at the end of io submission and in mid stream of those io submission,
      a return code could be coming back from the driver.  Thus messing up all
      the subsequent logic.
      
      Proposed fix is to separating out error code returned by the IO completion
      path from partial IO submit tracking.  A new variable is added to dio
      structure specifically to track io error returned in the completion path.
      Signed-off-by: default avatarKen Chen <kenneth.w.chen@intel.com>
      Acked-by: default avatarZach Brown <zach.brown@oracle.com>
      Acked-by: default avatarSuparna Bhattacharya <suparna@in.ibm.com>
      Cc: Badari Pulavarty <pbadari@us.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      174e27c6
  5. 14 Mar, 2006 1 commit
  6. 03 Feb, 2006 1 commit
    • Jeff Moyer's avatar
      [PATCH] fix O_DIRECT read of last block in a sparse file · 35dc8161
      Jeff Moyer authored
      Currently, if you open a file O_DIRECT, truncate it to a size that is not a
      multiple of the disk block size, and then try to read the last block in the
      file, the read will return 0.  The problem is in do_direct_IO, here:
      
              /* Handle holes */
              if (!buffer_mapped(map_bh)) {
                      char *kaddr;
      
      		...
      
                      if (dio->block_in_file >=
                              i_size_read(dio->inode)>>blkbits) {
                              /* We hit eof */
                              page_cache_release(page);
                              goto out;
                      }
      
      We shift off any remaining bytes in the final block of the I/O, resulting
      in a 0-sized read.  I've attached a patch that fixes this.  I'm not happy
      about how ugly the math is getting, so suggestions are more than welcome.
      
      I've tested this with a simple program that performs the steps outlined for
      reproducing the problem above.  Without the patch, we get a 0-sized result
      from read.  With the patch, we get the correct return value from the short
      read.
      Signed-off-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Cc: Badari Pulavarty <pbadari@us.ibm.com>
      Cc: Suparna Bhattacharya <suparna@in.ibm.com>
      Cc: Mingming Cao <cmm@us.ibm.com>
      Cc: Joel Becker <Joel.Becker@oracle.com>
      Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      35dc8161
  7. 09 Jan, 2006 1 commit
  8. 29 Oct, 2005 1 commit
    • Nick Piggin's avatar
      [PATCH] core remove PageReserved · b5810039
      Nick Piggin authored
      Remove PageReserved() calls from core code by tightening VM_RESERVED
      handling in mm/ to cover PageReserved functionality.
      
      PageReserved special casing is removed from get_page and put_page.
      
      All setting and clearing of PageReserved is retained, and it is now flagged
      in the page_alloc checks to help ensure we don't introduce any refcount
      based freeing of Reserved pages.
      
      MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
      deprecated.  We never completely handled it correctly anyway, and is be
      reintroduced in future if required (Hugh has a proof of concept).
      
      Once PageReserved() calls are removed from kernel/power/swsusp.c, and all
      arch/ and driver code, the Set and Clear calls, and the PG_reserved bit can
      be trivially removed.
      
      Last real user of PageReserved is swsusp, which uses PageReserved to
      determine whether a struct page points to valid memory or not.  This still
      needs to be addressed (a generic page_is_ram() should work).
      
      A last caveat: the ZERO_PAGE is now refcounted and managed with rmap (and
      thus mapcounted and count towards shared rss).  These writes to the struct
      page could cause excessive cacheline bouncing on big systems.  There are a
      number of ways this could be addressed if it is an issue.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      
      Refcount bug fix for filemap_xip.c
      Signed-off-by: default avatarCarsten Otte <cotte@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      b5810039
  9. 24 Jun, 2005 1 commit
  10. 16 Apr, 2005 2 commits
    • Daniel McNeil's avatar
      [PATCH] Direct IO async short read fix · 29504ff3
      Daniel McNeil authored
      The direct I/O code is mapping the read request to the file system block.  If
      the file size was not on a block boundary, the result would show the the read
      reading past EOF.  This was only happening for the AIO case.  The non-AIO case
      truncates the result to match file size (in direct_io_worker).  This patch
      does the same thing for the AIO case, it truncates the result to match the
      file size if the read reads past EOF.
      
      When I/O completes the result can be truncated to match the file size
      without using i_size_read(), thus the aio result now matches the number of
      bytes read to the end of file.
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      29504ff3
    • 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!
      1da177e4