On Mon, May 07, 2012 at 04:21:28PM -0700, Srinivas Eeda wrote:
> Current local alloc handles single contiguous free chunk of clusters. This
> patch enhances local alloc to handle discontigous free chunks. It adds a new
> ocfs2_local_alloc_rec structure which tracks single contiguous free chunk. An
> array of these sit in the bitmap itself and track discontiguous chunks. In
> best case there is only one record and increases as the filesystem gets
> fragmented. Number of records at a time are limited depending on the size
> of the bitmap and the max limit is defined by OCFS2_MAX_LOCAL_ALLOC_RECS.
>
> Signed-off-by: Srinivas Eeda <srinivas.e...@oracle.com>
> ---
> fs/ocfs2/localalloc.c | 10 ++++++++++
> fs/ocfs2/ocfs2.h | 8 ++++++++
> fs/ocfs2/ocfs2_fs.h | 48 ++++++++++++++++++++++++++++++++++++++++++------
> 3 files changed, 60 insertions(+), 6 deletions(-)
>
> diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
> index 210c352..4190e53 100644
> --- a/fs/ocfs2/localalloc.c
> +++ b/fs/ocfs2/localalloc.c
> @@ -48,6 +48,16 @@
>
> #define OCFS2_LOCAL_ALLOC(dinode) (&((dinode)->id2.i_lab))
>
> +#define OCFS2_LOCAL_ALLOC_REC_SZ(la) (le16_to_cpu(la->la_rec_count) *\
> + sizeof(struct ocfs2_local_alloc_rec))
> +#define OCFS2_LOCAL_ALLOC_BITMAP(la) ((char *)(&(la->la_recs)) +\
> + OCFS2_LOCAL_ALLOC_REC_SZ(la))
> +#define OCFS2_LOCAL_ALLOC_BITS_PER_REC (sizeof(struct
> ocfs2_local_alloc_rec)*8)
> +
> +/* Maximum number of local alloc records */
> +#define OCFS2_MAX_LOCAL_ALLOC_REC_LIMIT 128
> +
> +
> static u32 ocfs2_local_alloc_count_bits(struct ocfs2_dinode *alloc);
>
> static int ocfs2_local_alloc_find_clear_bits(struct ocfs2_super *osb,
> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
> index d355e6e..d4c36d2 100644
> --- a/fs/ocfs2/ocfs2.h
> +++ b/fs/ocfs2/ocfs2.h
> @@ -367,6 +367,7 @@ struct ocfs2_super
> * by osb_lock */
>
> struct buffer_head *local_alloc_bh;
> + struct inode *local_alloc_inode;
>
> u64 la_last_gd;
>
> @@ -522,6 +523,13 @@ static inline int ocfs2_supports_discontig_bg(struct
> ocfs2_super *osb)
> return 0;
> }
>
> +static inline int ocfs2_supports_discontig_la(struct ocfs2_super *osb)
> +{
> + if (osb->s_feature_incompat & OCFS2_FEATURE_INCOMPAT_DISCONTIG_LA)
> + return 1;
> + return 0;
> +}
> +
> static inline unsigned int ocfs2_link_max(struct ocfs2_super *osb)
> {
> if (ocfs2_supports_indexed_dirs(osb))
> diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
> index 938387a..6a0fe02 100644
> --- a/fs/ocfs2/ocfs2_fs.h
> +++ b/fs/ocfs2/ocfs2_fs.h
> @@ -102,7 +102,8 @@
> | OCFS2_FEATURE_INCOMPAT_INDEXED_DIRS \
> | OCFS2_FEATURE_INCOMPAT_REFCOUNT_TREE
> \
> | OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG
> \
> - | OCFS2_FEATURE_INCOMPAT_CLUSTERINFO)
> + | OCFS2_FEATURE_INCOMPAT_CLUSTERINFO \
> + | OCFS2_FEATURE_INCOMPAT_DISCONTIG_LA)
> #define OCFS2_FEATURE_RO_COMPAT_SUPP (OCFS2_FEATURE_RO_COMPAT_UNWRITTEN \
> | OCFS2_FEATURE_RO_COMPAT_USRQUOTA \
> | OCFS2_FEATURE_RO_COMPAT_GRPQUOTA)
> @@ -177,6 +178,9 @@
> */
> #define OCFS2_FEATURE_INCOMPAT_CLUSTERINFO 0x4000
>
> +/* Discontiguous local alloc */
> +#define OCFS2_FEATURE_INCOMPAT_DISCONTIG_LA 0x8000
I really wish this could be an RO_COMPAT flag, but I think that
recovery on RO mounts will break with this. Mark, please confirm, but I
think it has to be INCOMPAT.
> @@ -664,14 +668,19 @@ struct ocfs2_super_block {
> * Local allocation bitmap for OCFS2 slots
> * Note that it exists inside an ocfs2_dinode, so all offsets are
> * relative to the start of ocfs2_dinode.id2.
> + * Each ocfs2_local_alloc_rec tracks one contigous chunk of clusters.
> */
> +struct ocfs2_local_alloc_rec {
> + __le32 la_start; /* 1st cluster in this extent */
> + __le32 la_clusters; /* Number of contiguous clusters */
> +};
> +
> struct ocfs2_local_alloc
> {
> /*00*/ __le32 la_bm_off; /* Starting bit offset in main bitmap */
> __le16 la_size; /* Size of included bitmap, in bytes */
> - __le16 la_reserved1;
> - __le64 la_reserved2;
> -/*10*/ __u8 la_bitmap[0];
> + __le16 la_rec_count; /* Number of discontiguous records */
> + struct ocfs2_local_alloc_rec la_recs[0]; /* Localalloc records */
> };
You can't delete la_bitmap. Any filesystem without DISCONTIG_LA
will be expecting the inline bitmap to start there.
> @@ -1380,11 +1389,24 @@ static inline u16 ocfs2_local_alloc_size(struct
> super_block *sb)
> u16 size;
>
> size = sb->s_blocksize -
> - offsetof(struct ocfs2_dinode, id2.i_lab.la_bitmap);
> + offsetof(struct ocfs2_dinode, id2.i_lab.la_recs);
> + size -= sizeof(struct ocfs2_local_alloc_rec);
You can't do this without checking for DISCONTIG_LA. Again,
filesystems without DISCONTIG_LA will be starting at la_bitmap.
Joel
--
"If at first you don't succeed, cover all traces that you tried."
-Unknown
http://www.jlbec.org/
jl...@evilplan.org
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