04 Jan, 2012

1 commit


29 Oct, 2010

1 commit


22 May, 2010

2 commits


28 Sep, 2009

1 commit


03 Oct, 2008

1 commit

  • The previous patch db203d53d474aa068984e409d807628f5841da1b ("mm:
    tiny-shmem fix lock ordering: mmap_sem vs i_mutex") to fix the lock
    ordering in tiny-shmem breaks shared anonymous and IPC memory on NOMMU
    architectures because it was using the expanding truncate to signal ramfs
    to allocate a physically contiguous RAM backing the inode (otherwise it is
    unusable for "memory mapping" it to userspace).

    However do_truncate is what caused the lock ordering error, due to it
    taking i_mutex. In this case, we can actually just call ramfs directly to
    allocate memory for the mapping, rather than go via truncate.

    Acked-by: David Howells
    Acked-by: Hugh Dickins
    Signed-off-by: Nick Piggin
    Cc: Matt Mackall
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Nick Piggin
     

01 Oct, 2006

1 commit


23 Jun, 2006

1 commit

  • Extend the get_sb() filesystem operation to take an extra argument that
    permits the VFS to pass in the target vfsmount that defines the mountpoint.

    The filesystem is then required to manually set the superblock and root dentry
    pointers. For most filesystems, this should be done with simple_set_mnt()
    which will set the superblock pointer and then set the root dentry to the
    superblock's s_root (as per the old default behaviour).

    The get_sb() op now returns an integer as there's now no need to return the
    superblock pointer.

    This patch permits a superblock to be implicitly shared amongst several mount
    points, such as can be done with NFS to avoid potential inode aliasing. In
    such a case, simple_set_mnt() would not be called, and instead the mnt_root
    and mnt_sb would be set directly.

    The patch also makes the following changes:

    (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
    pointer argument and return an integer, so most filesystems have to change
    very little.

    (*) If one of the convenience function is not used, then get_sb() should
    normally call simple_set_mnt() to instantiate the vfsmount. This will
    always return 0, and so can be tail-called from get_sb().

    (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
    dcache upon superblock destruction rather than shrink_dcache_anon().

    This is required because the superblock may now have multiple trees that
    aren't actually bound to s_root, but that still need to be cleaned up. The
    currently called functions assume that the whole tree is rooted at s_root,
    and that anonymous dentries are not the roots of trees which results in
    dentries being left unculled.

    However, with the way NFS superblock sharing are currently set to be
    implemented, these assumptions are violated: the root of the filesystem is
    simply a dummy dentry and inode (the real inode for '/' may well be
    inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
    with child trees.

    [*] Anonymous until discovered from another tree.

    (*) The documentation has been adjusted, including the additional bit of
    changing ext2_* into foo_* in the documentation.

    [akpm@osdl.org: convert ipath_fs, do other stuff]
    Signed-off-by: David Howells
    Acked-by: Al Viro
    Cc: Nathan Scott
    Cc: Roland Dreier
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

29 Mar, 2006

1 commit

  • This is a conversion to make the various file_operations structs in fs/
    const. Basically a regexp job, with a few manual fixups

    The goal is both to increase correctness (harder to accidentally write to
    shared datastructures) and reducing the false sharing of cachelines with
    things that get dirty in .data (while .rodata is nicely read only and thus
    cache clean)

    Signed-off-by: Arjan van de Ven
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Arjan van de Ven
     

07 Jan, 2006

1 commit

  • The attached patch makes ramfs support shared-writable mmaps by:

    (1) Attempting to perform a contiguous block allocation to the requested size
    when truncate attempts to increase the file from zero size, such as
    happens when:

    fd = shm_open("/file/on/ramfs", ...):
    ftruncate(fd, size_requested);
    addr = mmap(NULL, subsize, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_SHARED,
    fd, offset);

    (2) Permitting any shared-writable mapping over any contiguous set of extant
    pages. get_unmapped_area() will return the address into the actual ramfs
    pages. The mapping may start anywhere and be of any size, but may not go
    over the end of file. Multiple mappings may overlap in any way.

    (3) Not permitting a file to be shrunk if it would truncate any shared
    mappings (private mappings are copied).

    Thus this patch provides support for POSIX shared memory on NOMMU kernels,
    with certain limitations such as there being a large enough block of pages
    available to support the allocation and it only working on directly mappable
    filesystems.

    Signed-off-by: David Howells
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Howells
     

17 Apr, 2005

1 commit

  • 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!

    Linus Torvalds