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  1. 14 Jan, 2009 5 commits
  3. 05 Jan, 2009 1 commit
    • Alain Knaff's avatar
      vfs: lseek(fd, 0, SEEK_CUR) race condition · 5b6f1eb9
      Alain Knaff authored 
      
This patch fixes a race condition in lseek. While it is expected that
unpredictable behaviour may result while repositioning the offset of a
file descriptor concurrently with reading/writing to the same file
descriptor, this should not happen when merely *reading* the file
descriptor's offset.

Unfortunately, the only portable way in Unix to read a file
descriptor's offset is lseek(fd, 0, SEEK_CUR); however executing this
concurrently with read/write may mess up the position.

[with fixes from akpm]
Signed-off-by: default avatarAlain Knaff <alain@knaff.lu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      5b6f1eb9
  5. 23 Oct, 2008 1 commit
  7. 02 Jul, 2008 1 commit
    • Andi Kleen's avatar
      Remove BKL from remote_llseek v2 · 9465efc9
      Andi Kleen authored 
      
- Replace remote_llseek with generic_file_llseek_unlocked (to force compilation
failures in all users)
- Change all users to either use generic_file_llseek_unlocked directly or
take the BKL around. I changed the file systems who don't use the BKL
for anything (CIFS, GFS) to call it directly. NCPFS and SMBFS and NFS
take the BKL, but explicitely in their own source now.

I moved them all over in a single patch to avoid unbisectable sections.

Open problem: 32bit kernels can corrupt fpos because its modification
is not atomic, but they can do that anyways because there's other paths who
modify it without BKL.

Do we need a special lock for the pos/f_version = 0 checks?

Trond says the NFS BKL is likely not needed, but keep it for now
until his full audit.

v2: Use generic_file_llseek_unlocked instead of remote_llseek_unlocked
    and factor duplicated code (suggested by hch)

Cc: Trond.Myklebust@netapp.com
Cc: swhiteho@redhat.com
Cc: sfrench@samba.org
Cc: vandrove@vc.cvut.cz
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      9465efc9
  9. 22 Apr, 2008 1 commit
  11. 08 Feb, 2008 1 commit
  13. 28 Jan, 2008 1 commit
  15. 24 Jan, 2008 1 commit
  17. 14 Nov, 2007 1 commit
    • Arjan van de Ven's avatar
      mark sys_open/sys_read exports unused · cb51f973
      Arjan van de Ven authored 
      sys_open / sys_read were used in the early 1.2 days to load firmware from
disk inside drivers.  Since 2.0 or so this was deprecated behavior, but
several drivers still were using this.  Since a few years we have a
request_firmware() API that implements this in a nice, consistent way.
Only some old ISA sound drivers (pre-ALSA) still straggled along for some
time....  however with commit c2b1239a

 the
last user is now gone.

This is a good thing, since using sys_open / sys_read etc for firmware is a
very buggy to dangerous thing to do; these operations put an fd in the
process file descriptor table....  which then can be tampered with from
other threads for example.  For those who don't want the firmware loader,
filp_open()/vfs_read are the better APIs to use, without this security
issue.

The patch below marks sys_open and sys_read unused now that they're
really not used anymore, and for deletion in the 2.6.25 timeframe.
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cb51f973
  19. 09 Oct, 2007 1 commit
    • Pavel Emelyanov's avatar
      Cleanup macros for distinguishing mandatory locks · a16877ca
      Pavel Emelyanov authored 
      
The combination of S_ISGID bit set and S_IXGRP bit unset is used to mark the
inode as "mandatory lockable" and there's a macro for this check called
MANDATORY_LOCK(inode).  However, fs/locks.c and some filesystems still perform
the explicit i_mode checking.  Besides, Andrew pointed out, that this macro is
buggy itself, as it dereferences the inode arg twice.

Convert this macro into static inline function and switch its users to it,
making the code shorter and more readable.

The __mandatory_lock() helper is to be used in places where the IS_MANDLOCK()
for superblock is already known to be true.
Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      a16877ca
  21. 10 Jul, 2007 3 commits
  23. 08 May, 2007 2 commits
  25. 12 Feb, 2007 1 commit
    • Eric Dumazet's avatar
      [PATCH] FS: speed up rw_verify_area() · 163da958
      Eric Dumazet authored 
      
oprofile hunting showed a stall in rw_verify_area(), because of triple
indirection and potential cache misses.
(file->f_path.dentry->d_inode->i_flock)

By moving initialization of 'struct inode' pointer before the pos/count
sanity tests, we allow the compiler and processor to perform two loads by
anticipation, reducing stall, without prefetch() hints.  Even x86 arch has
enough registers to not use temporary variables and not increase text size.

I validated this patch running a bench and studied oprofile changes, and
absolute perf of the test program.

Results of my epoll_pipe_bench (source available on request) on a Pentium-M
1.6 GHz machine

Before :
# ./epoll_pipe_bench -l 30 -t 20
Avg: 436089 evts/sec read_count=8843037 write_count=8843040 21.218390 samples
per call
(best value out of 10 runs)

After :
# ./epoll_pipe_bench -l 30 -t 20
Avg: 470980 evts/sec read_count=9549871 write_count=9549894 21.216694 samples
per call
(best value out of 10 runs)

oprofile CPU_CLK_UNHALTED events gave a reduction from 5.3401 % to 2.5851 %
for the rw_verify_area() function.
Signed-off-by: default avatarEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      163da958
  27. 11 Feb, 2007 1 commit
  29. 13 Dec, 2006 1 commit
  31. 08 Dec, 2006 1 commit
  33. 01 Oct, 2006 4 commits
  35. 10 Jul, 2006 1 commit
  37. 11 Apr, 2006 1 commit
  39. 28 Mar, 2006 1 commit
  41. 25 Mar, 2006 1 commit
  43. 09 Jan, 2006 1 commit
  45. 04 Jan, 2006 1 commit
    • Linus Torvalds's avatar
      Relax the rw_verify_area() error checking. · e28cc715
      Linus Torvalds authored 
      
In particular, allow over-large read- or write-requests to be downgraded
to a more reasonable range, rather than considering them outright errors.

We want to protect lower layers from (the sadly all too common) overflow
conditions, but prefer to do so by chopping the requests up, rather than
just refusing them outright.

Cc: Peter Anvin <hpa@zytor.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      e28cc715
  47. 29 Sep, 2005 1 commit
  49. 07 Sep, 2005 1 commit
  51. 12 Jul, 2005 1 commit
    • Robert Love's avatar
      [PATCH] inotify · 0eeca283
      Robert Love authored 
      
inotify is intended to correct the deficiencies of dnotify, particularly
its inability to scale and its terrible user interface:

        * dnotify requires the opening of one fd per each directory
          that you intend to watch. This quickly results in too many
          open files and pins removable media, preventing unmount.
        * dnotify is directory-based. You only learn about changes to
          directories. Sure, a change to a file in a directory affects
          the directory, but you are then forced to keep a cache of
          stat structures.
        * dnotify's interface to user-space is awful.  Signals?

inotify provides a more usable, simple, powerful solution to file change
notification:

        * inotify's interface is a system call that returns a fd, not SIGIO.
	  You get a single fd, which is select()-able.
        * inotify has an event that says "the filesystem that the item
          you were watching is on was unmounted."
        * inotify can watch directories or files.

Inotify is currently used by Beagle (a desktop search infrastructure),
Gamin (a FAM replacement), and other projects.

See Documentation/filesystems/inotify.txt.
Signed-off-by: default avatarRobert Love <rml@novell.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      0eeca283
  53. 23 Jun, 2005 1 commit
  55. 16 Apr, 2005 2 commits