4 files changed, 98 insertions, 11 deletions

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index cbae1ed0b7c1..7a12e48ad819 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -67,6 +67,74 @@ static void udf_update_extents(struct inode *,
                                struct extent_position *);
 static int udf_get_block(struct inode *, sector_t, struct buffer_head *, int);
 
+static void __udf_clear_extent_cache(struct inode *inode)
+{
+        struct udf_inode_info *iinfo = UDF_I(inode);
+
+        if (iinfo->cached_extent.lstart != -1) {
+                brelse(iinfo->cached_extent.epos.bh);
+                iinfo->cached_extent.lstart = -1;
+        }
+}
+
+/* Invalidate extent cache */
+static void udf_clear_extent_cache(struct inode *inode)
+{
+        struct udf_inode_info *iinfo = UDF_I(inode);
+
+        spin_lock(&iinfo->i_extent_cache_lock);
+        __udf_clear_extent_cache(inode);
+        spin_unlock(&iinfo->i_extent_cache_lock);
+}
+
+/* Return contents of extent cache */
+static int udf_read_extent_cache(struct inode *inode, loff_t bcount,
+                                 loff_t *lbcount, struct extent_position *pos)
+{
+        struct udf_inode_info *iinfo = UDF_I(inode);
+        int ret = 0;
+
+        spin_lock(&iinfo->i_extent_cache_lock);
+        if ((iinfo->cached_extent.lstart <= bcount) &&
+            (iinfo->cached_extent.lstart != -1)) {
+                /* Cache hit */
+                *lbcount = iinfo->cached_extent.lstart;
+                memcpy(pos, &iinfo->cached_extent.epos,
+                       sizeof(struct extent_position));
+                if (pos->bh)
+                        get_bh(pos->bh);
+                ret = 1;
+        }
+        spin_unlock(&iinfo->i_extent_cache_lock);
+        return ret;
+}
+
+/* Add extent to extent cache */
+static void udf_update_extent_cache(struct inode *inode, loff_t estart,
+                                    struct extent_position *pos, int next_epos)
+{
+        struct udf_inode_info *iinfo = UDF_I(inode);
+
+        spin_lock(&iinfo->i_extent_cache_lock);
+        /* Invalidate previously cached extent */
+        __udf_clear_extent_cache(inode);
+        if (pos->bh)
+                get_bh(pos->bh);
+        memcpy(&iinfo->cached_extent.epos, pos,
+               sizeof(struct extent_position));
+        iinfo->cached_extent.lstart = estart;
+        if (next_epos)
+                switch (iinfo->i_alloc_type) {
+                case ICBTAG_FLAG_AD_SHORT:
+                        iinfo->cached_extent.epos.offset -=
+                        sizeof(struct short_ad);
+                        break;
+                case ICBTAG_FLAG_AD_LONG:
+                        iinfo->cached_extent.epos.offset -=
+                        sizeof(struct long_ad);
+                }
+        spin_unlock(&iinfo->i_extent_cache_lock);
+}
 
 void udf_evict_inode(struct inode *inode)
 {
@@ -90,6 +158,7 @@ void udf_evict_inode(struct inode *inode)
         }
         kfree(iinfo->i_ext.i_data);
         iinfo->i_ext.i_data = NULL;
+        udf_clear_extent_cache(inode);
         if (want_delete) {
                 udf_free_inode(inode);
         }
@@ -105,6 +174,7 @@ static void udf_write_failed(struct address_space *mapping, loff_t to)
                 truncate_pagecache(inode, to, isize);
                 if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
                         down_write(&iinfo->i_data_sem);
+                        udf_clear_extent_cache(inode);
                         udf_truncate_extents(inode);
                         up_write(&iinfo->i_data_sem);
                 }
@@ -372,7 +442,7 @@ static int udf_get_block(struct inode *inode, sector_t block,
                 iinfo->i_next_alloc_goal++;
         }
 
-
+        udf_clear_extent_cache(inode);
         phys = inode_getblk(inode, block, &err, &new);
         if (!phys)
                 goto abort;
@@ -1171,6 +1241,7 @@ set_size:
         } else {
                 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
                         down_write(&iinfo->i_data_sem);
+                        udf_clear_extent_cache(inode);
                         memset(iinfo->i_ext.i_data + iinfo->i_lenEAttr + newsize,
                                0x00, bsize - newsize -
                                udf_file_entry_alloc_offset(inode));
@@ -1184,6 +1255,7 @@ set_size:
                 if (err)
                         return err;
                 down_write(&iinfo->i_data_sem);
+                udf_clear_extent_cache(inode);
                 truncate_setsize(inode, newsize);
                 udf_truncate_extents(inode);
                 up_write(&iinfo->i_data_sem);
@@ -2156,11 +2228,12 @@ int8_t inode_bmap(struct inode *inode, sector_t block,
         struct udf_inode_info *iinfo;
 
         iinfo = UDF_I(inode);
-        pos->offset = 0;
-        pos->block = iinfo->i_location;
-        pos->bh = NULL;
+        if (!udf_read_extent_cache(inode, bcount, &lbcount, pos)) {
+                pos->offset = 0;
+                pos->block = iinfo->i_location;
+                pos->bh = NULL;
+        }
         *elen = 0;
-
         do {
                 etype = udf_next_aext(inode, pos, eloc, elen, 1);
                 if (etype == -1) {
@@ -2170,7 +2243,8 @@ int8_t inode_bmap(struct inode *inode, sector_t block,
                 }
                 lbcount += *elen;
         } while (lbcount <= bcount);
-
+        /* update extent cache */
+        udf_update_extent_cache(inode, lbcount - *elen, pos, 1);
         *offset = (bcount + *elen - lbcount) >> blocksize_bits;
 
         return etype;
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 186adbf94b20..da8ce9f14387 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -134,6 +134,8 @@ static struct inode *udf_alloc_inode(struct super_block *sb)
         ei->i_next_alloc_goal = 0;
         ei->i_strat4096 = 0;
         init_rwsem(&ei->i_data_sem);
+        ei->cached_extent.lstart = -1;
+        spin_lock_init(&ei->i_extent_cache_lock);
 
         return &ei->vfs_inode;
 }
diff --git a/fs/udf/udf_i.h b/fs/udf/udf_i.h
index bb8309dcd5c1..b5cd8ed2aa12 100644
--- a/fs/udf/udf_i.h
+++ b/fs/udf/udf_i.h
@@ -1,6 +1,19 @@
 #ifndef _UDF_I_H
 #define _UDF_I_H
 
+struct extent_position {
+        struct buffer_head *bh;
+        uint32_t offset;
+        struct kernel_lb_addr block;
+};
+
+struct udf_ext_cache {
+        /* Extent position */
+        struct extent_position epos;
+        /* Start logical offset in bytes */
+        loff_t lstart;
+};
+
 /*
  * 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 +48,9 @@ struct udf_inode_info {
                 __u8            *i_data;
         } i_ext;
         struct rw_semaphore     i_data_sem;
+        struct udf_ext_cache cached_extent;
+        /* Spinlock for protecting extent cache */
+        spinlock_t i_extent_cache_lock;
         struct inode vfs_inode;
 };
 
diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
index de038da6f6bd..be7dabbbcb49 100644
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -113,11 +113,6 @@ struct ustr {
         uint8_t u_len;
 };
 
-struct extent_position {
-        struct buffer_head *bh;
-        uint32_t offset;
-        struct kernel_lb_addr block;
-};
 
 /* super.c */