Add read/only support for extents to ext2fs_bmap()

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/ext2fs/bmap.c b/lib/ext2fs/bmap.c
index 76cac3f..24f05fd 100644 (file)
--- a/lib/ext2fs/bmap.c
+++ b/lib/ext2fs/bmap.c
@@ -14,6 +14,7 @@
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
+#include <errno.h>
 
 #include "ext2_fs.h"
 #include "ext2fs.h"
@@ -128,13 +129,14 @@ static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags,
        return retval;
 }
 
-errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
-                     char *block_buf, int bmap_flags, blk_t block,
-                     blk_t *phys_blk)
+errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
+                      char *block_buf, int bmap_flags, blk64_t block,
+                      int *ret_flags, blk64_t *phys_blk)
 {
        struct ext2_inode inode_buf;
+       ext2_extent_handle_t handle = 0;
        blk_t addr_per_block;
-       blk_t   b;
+       blk_t   b, blk32;
        char    *buf = 0;
        errcode_t       retval = 0;
        int             blocks_alloc = 0, inode_dirty = 0;
@@ -142,6 +144,9 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
        if (!(bmap_flags & BMAP_SET))
                *phys_blk = 0;
 
+       if (ret_flags)
+               *ret_flags = 0;
+
        /* Read inode structure if necessary */
        if (!inode) {
                retval = ext2fs_read_inode(fs, ino, &inode_buf);
@@ -151,6 +156,37 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
        }
        addr_per_block = (blk_t) fs->blocksize >> 2;
 
+       if (inode->i_flags & EXT4_EXTENTS_FL) {
+               struct ext2fs_extent    extent;
+               int                     offset;
+
+               if (bmap_flags & BMAP_SET) {
+                       retval = EXT2_ET_EXTENT_NOT_SUPPORTED;
+                       goto done;
+               }
+               retval = ext2fs_extent_open(fs, ino, &handle);
+               if (retval)
+                       goto done;
+               retval = ext2fs_extent_goto(handle, block);
+               if (retval) {
+                       /* If the extent is not found, return phys_blk = 0 */
+                       if (retval == EXT2_ET_EXTENT_NOT_FOUND)
+                               retval = 0;
+                       goto done;
+               }
+               retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
+               if (retval)
+                       goto done;
+               offset = block - extent.e_lblk;
+               if (block >= extent.e_lblk && (offset <= extent.e_len)) {
+                       *phys_blk = extent.e_pblk + offset;
+                       if (ret_flags && extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
+                               *ret_flags |= BMAP_RET_UNINIT;
+               }
+               retval = 0;
+               goto done;
+       }
+
        if (!block_buf) {
                retval = ext2fs_get_array(2, fs->blocksize, &buf);
                if (retval)
@@ -185,6 +221,7 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
        
        /* Indirect block */
        block -= EXT2_NDIR_BLOCKS;
+       blk32 = *phys_blk;
        if (block < addr_per_block) {
                b = inode_bmap(inode, EXT2_IND_BLOCK);
                if (!b) {
@@ -202,7 +239,9 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
                        blocks_alloc++;
                }
                retval = block_ind_bmap(fs, bmap_flags, b, block_buf, 
-                                       &blocks_alloc, block, phys_blk);
+                                       &blocks_alloc, block, &blk32);
+               if (retval == 0)
+                       *phys_blk = blk32;
                goto done;
        }
        
@@ -225,7 +264,9 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
                        blocks_alloc++;
                }
                retval = block_dind_bmap(fs, bmap_flags, b, block_buf, 
-                                        &blocks_alloc, block, phys_blk);
+                                        &blocks_alloc, block, &blk32);
+               if (retval == 0)
+                       *phys_blk = blk32;
                goto done;
        }
 
@@ -247,10 +288,14 @@ errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
                blocks_alloc++;
        }
        retval = block_tind_bmap(fs, bmap_flags, b, block_buf, 
-                                &blocks_alloc, block, phys_blk);
+                                &blocks_alloc, block, &blk32);
+       if (retval == 0)
+               *phys_blk = blk32;
 done:
        if (buf)
                ext2fs_free_mem(&buf);
+       if (handle)
+               ext2fs_extent_free(handle);
        if ((retval == 0) && (blocks_alloc || inode_dirty)) {
                inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
                retval = ext2fs_write_inode(fs, ino, inode);
@@ -258,5 +303,19 @@ done:
        return retval;
 }
 
-
-
+errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
+                     char *block_buf, int bmap_flags, blk_t block,
+                     blk_t *phys_blk)
+{
+       errcode_t ret;
+       blk64_t ret_blk;
+
+       ret = ext2fs_bmap2(fs, ino, inode, block_buf, bmap_flags, block,
+                           0, &ret_blk);
+       if (ret)
+               return ret;
+       if (ret_blk >= ((long long) 1 << 32))
+               return EOVERFLOW;
+       *phys_blk = ret_blk;
+       return 0;
+}

diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 563ec30..02d2b42 100644 (file)
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -454,6 +454,11 @@ typedef struct ext2_icount *ext2_icount_t;
 #define BMAP_SET       0x0002
 
 /*
+ * Returned flags from ext2fs_bmap
+ */
+#define BMAP_RET_UNINIT        0x0001
+
+/*
  * Flags for imager.c functions
  */
 #define IMAGER_FLAG_INODEMAP   1
@@ -668,7 +673,10 @@ extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino,
                             struct ext2_inode *inode, 
                             char *block_buf, int bmap_flags,
                             blk_t block, blk_t *phys_blk);
-
+extern errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, 
+                             struct ext2_inode *inode,
+                             char *block_buf, int bmap_flags, blk64_t block,
+                             int *ret_flags, blk64_t *phys_blk);
 
 #if 0
 /* bmove.c */