Eric Lee / smarc-fsl-linux-kernel

18 Jul, 2007

2 commits

  • 6dd4ee7ca   ext4: Expand extra_inodes space per the s_{want,min}_extra_isize fields ... Browse Code »

    We need to make sure that existing ext3 filesystems can also avail the
    new fields that have been added to the ext4 inode. We use
    s_want_extra_isize and s_min_extra_isize to decide by how much we should
    expand the inode. If EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE feature is set
    then we expand the inode by max(s_want_extra_isize, s_min_extra_isize ,
    sizeof(ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE) bytes. Actually it is
    still an open question about whether users should be able to set
    s_*_extra_isize smaller than the known fields or not.

    This patch also adds the functionality to expand inodes to include the
    newly added fields. We start by trying to expand by s_want_extra_isize
    bytes and if its fails we try to expand by s_min_extra_isize bytes. This
    is done by changing the i_extra_isize if enough space is available in
    the inode and no EAs are present. If EAs are present and there is enough
    space in the inode then the EAs in the inode are shifted to make space.
    If enough space is not available in the inode due to the EAs then 1 or
    more EAs are shifted to the external EA block. In the worst case when
    even the external EA block does not have enough space we inform the user
    that some EA would need to be deleted or s_min_extra_isize would have to
    be reduced.

    Signed-off-by: Andreas Dilger
    Signed-off-by: Kalpak Shah
    Signed-off-by: Mingming Cao
    Signed-off-by: "Theodore Ts'o"

    Kalpak Shah
     
  • ef7f38359   ext4: Add nanosecond timestamps ... Browse Code »

    This patch adds nanosecond timestamps for ext4. This involves adding
    *time_extra fields to the ext4_inode to extend the timestamps to
    64-bits. Creation time is also added by this patch.

    These extended fields will fit into an inode if the filesystem was
    formatted with large inodes (-I 256 or larger) and there are currently
    no EAs consuming all of the available space. For new inodes we always
    reserve enough space for the kernel's known extended fields, but for
    inodes created with an old kernel this might not have been the case. So
    this patch also adds the EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE feature
    flag(ro-compat so that older kernels can't create inodes with a smaller
    extra_isize). which indicates if the fields fitting inside
    s_min_extra_isize are available or not. If the expansion of inodes if
    unsuccessful then this feature will be disabled. This feature is only
    enabled if requested by the sysadmin.

    None of the extended inode fields is critical for correct filesystem
    operation.

    Signed-off-by: Andreas Dilger
    Signed-off-by: Kalpak Shah
    Signed-off-by: Eric Sandeen
    Signed-off-by: Dave Kleikamp
    Signed-off-by: Mingming Cao
    Signed-off-by: "Theodore Ts'o"

    Kalpak Shah
     

02 Mar, 2007

1 commit

  • 8a2bfdcbf   [PATCH] ext[34]: EA block reference count racing fix ... Browse Code »
    45

    There are race issues around ext[34] xattr block release code.

    ext[34]_xattr_release_block() checks the reference count of xattr block
    (h_refcount) and frees that xattr block if it is the last one reference it.
    Unlike ext2, the check of this counter is unprotected by any lock.
    ext[34]_xattr_release_block() will free the mb_cache entry before freeing
    that xattr block. There is a small window between the check for the re
    h_refcount ==1 and the call to mb_cache_entry_free(). During this small
    window another inode might find this xattr block from the mbcache and reuse
    it, racing a refcount updates. The xattr block will later be freed by the
    first inode without notice other inode is still use it. Later if that
    block is reallocated as a datablock for other file, then more serious
    problem might happen.

    We need put a lock around places checking the refount as well to avoid
    racing issue. Another place need this kind of protection is in
    ext3_xattr_block_set(), where it will modify the xattr block content in-
    the-fly if the refcount is 1 (means it's the only inode reference it).

    This will also fix another issue: the xattr block may not get freed at all
    if no lock is to protect the refcount check at the release time. It is
    possible that the last two inodes could release the shared xattr block at
    the same time. But both of them think they are not the last one so only
    decreased the h_refcount without freeing xattr block at all.

    We need to call lock_buffer() after ext3_journal_get_write_access() to
    avoid deadlock (because the later will call lock_buffer()/unlock_buffer
    () as well).

    Signed-off-by: Mingming Cao
    Cc: Andreas Gruenbacher
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mingming Cao
     

08 Dec, 2006

1 commit

12 Oct, 2006

4 commits