06 Sep, 2011

4 commits


23 Jul, 2011

5 commits

  • unlinkat - Remove a directory entry

    size[4] Tunlinkat tag[2] dirfid[4] name[s] flag[4]
    size[4] Runlinkat tag[2]

    older Tremove have the below request format

    size[4] Tremove tag[2] fid[4]

    The remove message is used to remove a directory entry either file or directory
    The remove opreation is actually a directory opertation and should ideally have
    dirfid, if not we cannot represent the fid on server with anything other than
    name. We will have to derive the directory name from fid in the Tremove request.

    NOTE: The operation doesn't clunk the unlink fid.

    Signed-off-by: Aneesh Kumar K.V
    Signed-off-by: Eric Van Hensbergen

    Aneesh Kumar K.V
     
  • renameat - change name of file or directory

    size[4] Trenameat tag[2] olddirfid[4] oldname[s] newdirfid[4] newname[s]
    size[4] Rrenameat tag[2]

    older Trename have the below request format

    size[4] Trename tag[2] fid[4] newdirfid[4] name[s]

    The rename message is used to change the name of a file, possibly moving it
    to a new directory. The rename opreation is actually a directory opertation
    and should ideally have olddirfid, if not we cannot represent the fid on server
    with anything other than name. We will have to derive the old directory name
    from fid in the Trename request.

    Signed-off-by: Aneesh Kumar K.V
    Signed-off-by: Eric Van Hensbergen

    Aneesh Kumar K.V
     
  • This make sure we don't end up reusing the unlinked inode object.
    The ideal way is to use inode i_generation. But i_generation is
    not available in userspace always.

    Signed-off-by: Aneesh Kumar K.V
    Signed-off-by: Eric Van Hensbergen

    Aneesh Kumar K.V
     
  • This make sure we don't use wrong inode from the inode hash. The inode number
    of the file deleted is reused by the next file system object created
    and if we only use inode number for inode hash lookup we could end up
    with wrong struct inode.

    Also compare inode generation number. Not all Linux file system provide
    st_gen in userspace. So it could be 0;

    Signed-off-by: Aneesh Kumar K.V
    Signed-off-by: Eric Van Hensbergen

    Aneesh Kumar K.V
     
  • Now that VFS does the right thing remove the work around.

    Signed-off-by: Aneesh Kumar K.V
    Signed-off-by: Eric Van Hensbergen

    Aneesh Kumar K.V
     

20 Jul, 2011

2 commits


28 May, 2011

1 commit


26 May, 2011

2 commits


23 Mar, 2011

4 commits


15 Mar, 2011

15 commits


13 Jan, 2011

1 commit

  • here we actually *want* ->d_op for root; setting it allows to get rid
    of kludge in v9fs_kill_super() since now we have proper ->d_release()
    for root and don't need to call it manually.

    Signed-off-by: Al Viro

    Al Viro
     

11 Jan, 2011

2 commits


07 Jan, 2011

4 commits

  • dcache_inode_lock can be replaced with per-inode locking. Use existing
    inode->i_lock for this. This is slightly non-trivial because we sometimes
    need to find the inode from the dentry, which requires d_inode to be
    stabilised (either with refcount or d_lock).

    Signed-off-by: Nick Piggin

    Nick Piggin
     
  • Reduce some branches and memory accesses in dcache lookup by adding dentry
    flags to indicate common d_ops are set, rather than having to check them.
    This saves a pointer memory access (dentry->d_op) in common path lookup
    situations, and saves another pointer load and branch in cases where we
    have d_op but not the particular operation.

    Patched with:

    git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i

    Signed-off-by: Nick Piggin

    Nick Piggin
     
  • RCU free the struct inode. This will allow:

    - Subsequent store-free path walking patch. The inode must be consulted for
    permissions when walking, so an RCU inode reference is a must.
    - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
    to take i_lock no longer need to take sb_inode_list_lock to walk the list in
    the first place. This will simplify and optimize locking.
    - Could remove some nested trylock loops in dcache code
    - Could potentially simplify things a bit in VM land. Do not need to take the
    page lock to follow page->mapping.

    The downsides of this is the performance cost of using RCU. In a simple
    creat/unlink microbenchmark, performance drops by about 10% due to inability to
    reuse cache-hot slab objects. As iterations increase and RCU freeing starts
    kicking over, this increases to about 20%.

    In cases where inode lifetimes are longer (ie. many inodes may be allocated
    during the average life span of a single inode), a lot of this cache reuse is
    not applicable, so the regression caused by this patch is smaller.

    The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
    however this adds some complexity to list walking and store-free path walking,
    so I prefer to implement this at a later date, if it is shown to be a win in
    real situations. I haven't found a regression in any non-micro benchmark so I
    doubt it will be a problem.

    Signed-off-by: Nick Piggin

    Nick Piggin
     
  • dcache_lock no longer protects anything. remove it.

    Signed-off-by: Nick Piggin

    Nick Piggin