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Date: Sun, 12 Aug 2012 13:02:08 +0900
From: Namjae Jeon <linkinjeon@...il.com>
To: jack@...e.cz
Cc: linux-kernel@...r.kernel.org, Namjae Jeon <linkinjeon@...il.com>,
Namjae Jeon <namjae.jeon@...sung.com>,
Ashish Sangwan <a.sangwan@...sung.com>
Subject: Re: [PATCH] udf: extent cache implementation for manipulating block map
Hi Jan.
Would you check this patch if you return from vacation ?
Thanks.
2012/7/29, Namjae Jeon <linkinjeon@...il.com>:
> From: Namjae Jeon <namjae.jeon@...sung.com>
>
> While mapping logical blocks of a file to physical blocks on the partition,
> everytime UDF read file metadata from the begining which decrease
> preformance.
> The drawback of this scheme is more prominent while reading large files.
> For example, while reading a large file of ~5GB, read speed will
> gradually become less as we near the end of file because of the time
> taken in calculating the corresponding physical block.
>
> This patch implements caching and remembers the location of the last read
> extent. Instead of reading file metadata from begining, start from the
> cached location.
>
> Signed-off-by: Namjae Jeon <namjae.jeon@...sung.com>
> Signed-off-by: Ashish Sangwan <a.sangwan@...sung.com>
> Signed-off-by: Bonggil Bak <bgbak@...sung.com>
> ---
> fs/udf/ialloc.c | 2 ++
> fs/udf/inode.c | 83
> ++++++++++++++++++++++++++++++++++++++++++++++++++----
> fs/udf/udf_i.h | 13 +++++++++
> fs/udf/udfdecl.h | 13 +++++++++
> 4 files changed, 105 insertions(+), 6 deletions(-)
>
> diff --git a/fs/udf/ialloc.c b/fs/udf/ialloc.c
> index 7e5aae4..7dd86a4 100644
> --- a/fs/udf/ialloc.c
> +++ b/fs/udf/ialloc.c
> @@ -117,6 +117,8 @@ struct inode *udf_new_inode(struct inode *dir, umode_t
> mode, int *err)
> iinfo->i_lenAlloc = 0;
> iinfo->i_use = 0;
> iinfo->i_checkpoint = 1;
> + memset(&iinfo->cached_extent, 0, sizeof(struct udf_ext_cache));
> + mutex_init(&(iinfo->i_extent_cache_lock));
> if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_AD_IN_ICB))
> iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB;
> else if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD))
> diff --git a/fs/udf/inode.c b/fs/udf/inode.c
> index fafaad7..cf34dec 100644
> --- a/fs/udf/inode.c
> +++ b/fs/udf/inode.c
> @@ -345,7 +345,7 @@ static int udf_get_block(struct inode *inode, sector_t
> block,
> iinfo->i_next_alloc_goal++;
> }
>
> -
> + udf_clear_extent_cache(iinfo);
> phys = inode_getblk(inode, block, &err, &new);
> if (!phys)
> goto abort;
> @@ -1117,6 +1117,7 @@ int udf_setsize(struct inode *inode, loff_t newsize)
> iinfo = UDF_I(inode);
> if (newsize > inode->i_size) {
> down_write(&iinfo->i_data_sem);
> + udf_clear_extent_cache(iinfo);
> if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
> if (bsize <
> (udf_file_entry_alloc_offset(inode) + newsize)) {
> @@ -1137,6 +1138,7 @@ int udf_setsize(struct inode *inode, loff_t newsize)
> } else {
> if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
> down_write(&iinfo->i_data_sem);
> + udf_clear_extent_cache(iinfo);
> memset(iinfo->i_ext.i_data + iinfo->i_lenEAttr + newsize,
> 0x00, bsize - newsize -
> udf_file_entry_alloc_offset(inode));
> @@ -1150,6 +1152,7 @@ int udf_setsize(struct inode *inode, loff_t newsize)
> if (err)
> return err;
> down_write(&iinfo->i_data_sem);
> + udf_clear_extent_cache(iinfo);
> truncate_setsize(inode, newsize);
> udf_truncate_extents(inode);
> up_write(&iinfo->i_data_sem);
> @@ -1267,6 +1270,8 @@ static void udf_fill_inode(struct inode *inode, struct
> buffer_head *bh)
> iinfo->i_lenAlloc = 0;
> iinfo->i_next_alloc_block = 0;
> iinfo->i_next_alloc_goal = 0;
> + memset(&iinfo->cached_extent, 0, sizeof(struct udf_ext_cache));
> + mutex_init(&(iinfo->i_extent_cache_lock));
> if (fe->descTag.tagIdent == cpu_to_le16(TAG_IDENT_EFE)) {
> iinfo->i_efe = 1;
> iinfo->i_use = 0;
> @@ -2118,14 +2123,21 @@ int8_t inode_bmap(struct inode *inode, sector_t
> block,
> unsigned char blocksize_bits = inode->i_sb->s_blocksize_bits;
> loff_t lbcount = 0, bcount =
> (loff_t) block << blocksize_bits;
> - int8_t etype;
> + int8_t etype = -1;
> struct udf_inode_info *iinfo;
>
> iinfo = UDF_I(inode);
> - pos->offset = 0;
> - pos->block = iinfo->i_location;
> - pos->bh = NULL;
> - *elen = 0;
> +
> + if (udf_read_extent_cache(inode, &bcount, &lbcount, elen,
> + pos, eloc, &etype)) {
> + if (etype != -1)
> + goto cache_hit;
> + } else {
> + pos->offset = 0;
> + pos->block = iinfo->i_location;
> + pos->bh = NULL;
> + *elen = 0;
> + }
>
> do {
> etype = udf_next_aext(inode, pos, eloc, elen, 1);
> @@ -2137,11 +2149,70 @@ int8_t inode_bmap(struct inode *inode, sector_t
> block,
> lbcount += *elen;
> } while (lbcount <= bcount);
>
> + /* update extent cache */
> + udf_update_extent_cache(inode, elen, pos, &lbcount, eloc, &etype);
> +
> +cache_hit:
> *offset = (bcount + *elen - lbcount) >> blocksize_bits;
>
> return etype;
> }
>
> +int udf_read_extent_cache(struct inode *inode, loff_t *bcount,
> + loff_t *lbcount, uint32_t *elen,
> + struct extent_position *pos,
> + struct kernel_lb_addr *eloc, int8_t *etype)
> +{
> + int ret = 0;
> + struct udf_inode_info *iinfo;
> +
> + iinfo = UDF_I(inode);
> + mutex_lock(&iinfo->i_extent_cache_lock);
> + if (((iinfo->cached_extent.last_block - iinfo->cached_extent.elen)
> + <= *bcount) && (iinfo->cached_extent.last_block != 0)) {
> + *elen = iinfo->cached_extent.elen;
> + *lbcount = iinfo->cached_extent.last_block;
> + memcpy(&pos->block, &iinfo->cached_extent.epos,
> + sizeof(struct kernel_lb_addr));
> + pos->offset = iinfo->cached_extent.offset;
> + if (iinfo->cached_extent.p_block_nr != 0)
> + pos->bh = udf_tread(inode->i_sb,
> + iinfo->cached_extent.p_block_nr);
> + if (in_range(iinfo->cached_extent.last_block,
> + iinfo->cached_extent.elen, *bcount)) {
> + *etype = iinfo->cached_extent.etype;
> + memcpy(eloc, &(iinfo->cached_extent.eloc),
> + sizeof(struct kernel_lb_addr));
> + }
> + ret = 1;
> + }
> + mutex_unlock(&iinfo->i_extent_cache_lock);
> + return ret;
> +}
> +
> +void udf_update_extent_cache(struct inode *inode, uint32_t *elen,
> + struct extent_position *pos, loff_t *lbcount,
> + struct kernel_lb_addr *eloc, int8_t *etype)
> +{
> + struct udf_inode_info *iinfo;
> + iinfo = UDF_I(inode);
> + mutex_lock(&iinfo->i_extent_cache_lock);
> + if (pos->bh != NULL)
> + iinfo->cached_extent.p_block_nr =
> + udf_get_lb_pblock(inode->i_sb, &pos->block, 0);
> + else
> + iinfo->cached_extent.p_block_nr = 0;
> + iinfo->cached_extent.elen = *elen;
> + iinfo->cached_extent.last_block = *lbcount;
> + iinfo->cached_extent.etype = *etype;
> + memcpy(&(iinfo->cached_extent.eloc), eloc,
> + sizeof(struct kernel_lb_addr));
> + memcpy(&iinfo->cached_extent.epos, &pos->block,
> + sizeof(struct kernel_lb_addr));
> + iinfo->cached_extent.offset = pos->offset;
> + mutex_unlock(&iinfo->i_extent_cache_lock);
> +}
> +
> long udf_block_map(struct inode *inode, sector_t block)
> {
> struct kernel_lb_addr eloc;
> diff --git a/fs/udf/udf_i.h b/fs/udf/udf_i.h
> index bb8309d..ec168a9 100644
> --- a/fs/udf/udf_i.h
> +++ b/fs/udf/udf_i.h
> @@ -1,6 +1,16 @@
> #ifndef _UDF_I_H
> #define _UDF_I_H
>
> +struct udf_ext_cache {
> + struct kernel_lb_addr epos;
> + uint32_t offset;
> + uint32_t p_block_nr;
> + struct kernel_lb_addr eloc;
> + uint32_t elen;
> + int8_t etype;
> + loff_t last_block;
> +};
> +
> /*
> * The i_data_sem and i_mutex serve for protection of allocation
> information
> * of a regular files and symlinks. This includes all extents belonging to
> @@ -35,6 +45,9 @@ struct udf_inode_info {
> __u8 *i_data;
> } i_ext;
> struct rw_semaphore i_data_sem;
> + struct udf_ext_cache cached_extent;
> + /* Mutex for protecting extent cache */
> + struct mutex i_extent_cache_lock;
> struct inode vfs_inode;
> };
>
> diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
> index de038da..b3d9f50 100644
> --- a/fs/udf/udfdecl.h
> +++ b/fs/udf/udfdecl.h
> @@ -44,6 +44,7 @@ extern __printf(3, 4) void _udf_warn(struct super_block
> *sb,
>
> #define udf_fixed_to_variable(x) ( ( ( (x) >> 5 ) * 39 ) + ( (x) &
> 0x0000001F ) )
> #define udf_variable_to_fixed(x) ( ( ( (x) / 39 ) << 5 ) + ( (x) % 39 ) )
> +#define in_range(last, len, b) ((b) >= (last - len) && (b) < last)
>
> #define UDF_EXTENT_LENGTH_MASK 0x3FFFFFFF
> #define UDF_EXTENT_FLAG_MASK 0xC0000000
> @@ -52,6 +53,11 @@ extern __printf(3, 4) void _udf_warn(struct super_block
> *sb,
> #define UDF_NAME_LEN 256
> #define UDF_PATH_LEN 1023
>
> +static inline void udf_clear_extent_cache(struct udf_inode_info *iinfo)
> +{
> + iinfo->cached_extent.last_block = 0;
> +}
> +
> static inline size_t udf_file_entry_alloc_offset(struct inode *inode)
> {
> struct udf_inode_info *iinfo = UDF_I(inode);
> @@ -165,6 +171,13 @@ extern int8_t udf_next_aext(struct inode *, struct
> extent_position *,
> extern int8_t udf_current_aext(struct inode *, struct extent_position *,
> struct kernel_lb_addr *, uint32_t *, int);
>
> +int udf_read_extent_cache(struct inode *inode, loff_t *bcount, loff_t
> *lbcount,
> + uint32_t *elen, struct extent_position *pos,
> + struct kernel_lb_addr *eloc, int8_t *etype);
> +void udf_update_extent_cache(struct inode *inode, uint32_t *elen,
> + struct extent_position *pos, loff_t *lbcount,
> + struct kernel_lb_addr *eloc, int8_t *etype);
> +
> /* misc.c */
> extern struct buffer_head *udf_tgetblk(struct super_block *, int);
> extern struct buffer_head *udf_tread(struct super_block *, int);
> --
> 1.7.9.5
>
>
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