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libext2fs: add new function ext2fs_extent_set_bmap() 

Allows unmapping or remapping single mapped logical blocks,
and mapping currently unmapped blocks.

Also implements ext2fs_extent_fix_parents() to fix parent
index logical starts, if the first index of a node changes
its logical start block.

Currently this can result in unnecessary new single-block extents; I
think perhaps ext2fs_extent_insert should grow a flag to request
merging with a nearby extent?

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
bitmap-optimize
Eric Sandeen 2008-05-20 10:17:46 -05:00 committed by Theodore Ts'o
parent 01229db57e
commit f4e9963c09
3 changed files with 367 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
lib/ext2fs/ext2fs.h
View File

@ -335,6 +335,11 @@ typedef struct ext2_extent_path *ext2_extent_path_t;
#define EXT2_EXTENT_INSERT_AFTER 0x0001 /* insert after handle loc'n */
#define EXT2_EXTENT_INSERT_NOSPLIT 0x0002 /* insert may not cause split */
/*
* Flags used by ext2fs_extent_set_bmap()
*/
#define EXT2_EXTENT_SET_BMAP_UNINIT 0x0001
/*
* Data structure returned by ext2fs_extent_get_info()
*/
@ -814,6 +819,9 @@ extern errcode_t ext2fs_extent_replace(ext2_extent_handle_t handle, int flags,
struct ext2fs_extent *extent);
extern errcode_t ext2fs_extent_insert(ext2_extent_handle_t handle, int flags,
struct ext2fs_extent *extent);
extern errcode_t ext2fs_extent_set_bmap(ext2_extent_handle_t handle,
blk64_t logical, blk64_t physical,
int flags);
extern errcode_t ext2fs_extent_delete(ext2_extent_handle_t handle, int flags);
extern errcode_t ext2fs_extent_get_info(ext2_extent_handle_t handle,
struct ext2_extent_info *info);

409
lib/ext2fs/extent.c
View File

@ -651,6 +651,64 @@ errcode_t ext2fs_extent_goto(ext2_extent_handle_t handle,
return extent_goto(handle, 0, blk);
}
/*
* Traverse back up to root fixing parents of current node as needed.
*
* If we changed start of first entry in a node, fix parent index start
* and so on.
*
* Safe to call for any position in node; if not at the first entry,
* will simply return.
*/
static errcode_t ext2fs_extent_fix_parents(ext2_extent_handle_t handle)
{
int retval = 0;
blk64_t start;
struct extent_path *path;
struct ext2fs_extent extent;
EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
if (!(handle->fs->flags & EXT2_FLAG_RW))
return EXT2_ET_RO_FILSYS;
if (!handle->path)
return EXT2_ET_NO_CURRENT_NODE;
path = handle->path + handle->level;
if (!path->curr)
return EXT2_ET_NO_CURRENT_NODE;
retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
if (retval)
goto done;
/* modified node's start block */
start = extent.e_lblk;
/* traverse up until index not first, or startblk matches, or top */
while (handle->level > 0 &&
(path->left == path->entries - 1)) {
retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP, &extent);
if (retval)
goto done;
if (extent.e_lblk == start)
break;
path = handle->path + handle->level;
extent.e_len += (extent.e_lblk - start);
extent.e_lblk = start;
retval = ext2fs_extent_replace(handle, 0, &extent);
if (retval)
goto done;
update_path(handle);
}
/* put handle back to where we started */
retval = ext2fs_extent_goto(handle, start);
done:
return retval;
}
errcode_t ext2fs_extent_replace(ext2_extent_handle_t handle,
int flags EXT2FS_ATTR((unused)),
struct ext2fs_extent *extent)
@ -990,6 +1048,219 @@ errout:
return retval;
}
/*
* Sets the physical block for a logical file block in the extent tree.
*
* May: map unmapped, unmap mapped, or remap mapped blocks.
*
* Mapping an unmapped block adds a single-block extent.
*
* Unmapping first or last block modifies extent in-place
* - But may need to fix parent's starts too in first-block case
*
* Mapping any unmapped block requires adding a (single-block) extent
* and inserting into proper point in tree.
*
* Modifying (unmapping or remapping) a block in the middle
* of an extent requires splitting the extent.
* - Remapping case requires new single-block extent.
*
* Remapping first or last block adds an extent.
*
* We really need extent adding to be smart about merging.
*/
errcode_t ext2fs_extent_set_bmap(ext2_extent_handle_t handle,
blk64_t logical, blk64_t physical, int flags)
{
errcode_t ec, retval = 0;
int mapped = 1; /* logical is mapped? */
int orig_height;
int extent_uninit = 0;
int new_uninit = 0;
int max_len = EXT_INIT_MAX_LEN;
blk64_t orig_lblk;
struct extent_path *path;
struct ext2fs_extent extent;
struct ext2fs_extent newextent;
struct ext2_extent_info info;
EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
if (!(handle->fs->flags & EXT2_FLAG_RW))
return EXT2_ET_RO_FILSYS;
if (!handle->path)
return EXT2_ET_NO_CURRENT_NODE;
path = handle->path + handle->level;
if (flags & EXT2_EXTENT_SET_BMAP_UNINIT) {
new_uninit = 1;
max_len = EXT_UNINIT_MAX_LEN;
}
/* if (re)mapping, set up new extent to insert */
if (physical) {
newextent.e_len = 1;
newextent.e_pblk = physical;
newextent.e_lblk = logical;
newextent.e_flags = EXT2_EXTENT_FLAGS_LEAF;
if (new_uninit)
newextent.e_flags |= EXT2_EXTENT_FLAGS_UNINIT;
}
/* special case if the extent tree is completely empty */
if ((handle->max_depth == 0) && (path->entries == 0)) {
retval = ext2fs_extent_insert(handle, 0, &newextent);
goto done;
}
/* save our original location in the extent tree */
if ((retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT,
&extent))) {
if (retval != EXT2_ET_NO_CURRENT_NODE)
return retval;
memset(&extent, 0, sizeof(extent));
}
if ((retval = ext2fs_extent_get_info(handle, &info)))
return retval;
orig_height = info.max_depth - info.curr_level;
orig_lblk = extent.e_lblk;
/* go to the logical spot we want to (re/un)map */
retval = ext2fs_extent_goto(handle, logical);
if (retval) {
if (retval == EXT2_ET_EXTENT_NOT_FOUND) {
retval = 0;
mapped = 0;
if (!physical) {
dbg_printf("block already unmapped\n");
goto done;
}
} else
goto done;
}
/*
* This may be the extent *before* the requested logical,
* if it's currently unmapped.
*/
retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
if (retval)
goto done;
if (extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
extent_uninit = 1;
/* check if already pointing to the requested physical */
if (mapped && (new_uninit == extent_uninit) &&
(extent.e_pblk + (logical - extent.e_lblk) == physical)) {
dbg_printf("physical block unchanged\n");
goto done;
}
if (!mapped) {
dbg_printf("mapping unmapped logical block\n");
if ((logical == extent.e_lblk + extent.e_len) &&
(physical == extent.e_pblk + extent.e_len) &&
(new_uninit == extent_uninit) &&
(extent.e_len < max_len-1)) {
extent.e_len++;
retval = ext2fs_extent_replace(handle, 0, &extent);
} else
retval = ext2fs_extent_insert(handle,
EXT2_EXTENT_INSERT_AFTER, &newextent);
if (retval)
goto done;
retval = ext2fs_extent_fix_parents(handle);
if (retval)
goto done;
} else if ((logical == extent.e_lblk) && (extent.e_len == 1)) {
dbg_printf("(re/un)mapping only block in extent\n");
if (physical) {
extent.e_pblk = physical;
retval = ext2fs_extent_replace(handle, 0, &extent);
} else {
retval = ext2fs_extent_delete(handle, 0);
if (retval)
goto done;
ec = ext2fs_extent_fix_parents(handle);
if (ec != EXT2_ET_NO_CURRENT_NODE)
retval = ec;
}
if (retval)
goto done;
} else if (logical == extent.e_lblk + extent.e_len - 1) {
dbg_printf("(re/un)mapping last block in extent\n");
extent.e_len--;
retval = ext2fs_extent_replace(handle, 0, &extent);
if (retval)
goto done;
if (physical) {
retval = ext2fs_extent_insert(handle,
EXT2_EXTENT_INSERT_AFTER, &newextent);
if (retval)
goto done;
}
} else if (logical == extent.e_lblk) {
dbg_printf("(re/un)mapping first block in extent\n");
extent.e_pblk++;
extent.e_lblk++;
extent.e_len--;
retval = ext2fs_extent_replace(handle, 0, &extent);
if (retval)
goto done;
if (physical) {
/* insert new extent ahead of current */
retval = ext2fs_extent_insert(handle,
0, &newextent);
if (retval)
goto done;
} else {
retval = ext2fs_extent_fix_parents(handle);
if (retval)
goto done;
}
} else {
__u32 orig_length;
dbg_printf("(re/un)mapping in middle of extent\n");
/* need to split this extent; later */
orig_length = extent.e_len;
/* shorten pre-split extent */
extent.e_len = (logical - extent.e_lblk);
retval = ext2fs_extent_replace(handle, 0, &extent);
if (retval)
goto done;
/* insert our new extent, if any */
if (physical) {
/* insert new extent after current */
retval = ext2fs_extent_insert(handle,
EXT2_EXTENT_INSERT_AFTER, &newextent);
if (retval)
goto done;
}
/* add post-split extent */
extent.e_pblk += extent.e_len + 1;
extent.e_lblk += extent.e_len + 1;
extent.e_len = orig_length - extent.e_len - 1;
retval = ext2fs_extent_insert(handle,
EXT2_EXTENT_INSERT_AFTER, &extent);
if (retval)
goto done;
}
done:
/* get handle back to its position */
if (orig_height > handle->max_depth)
orig_height = handle->max_depth; /* In case we shortened the tree */
extent_goto(handle, orig_height, orig_lblk);
return retval;
}
errcode_t ext2fs_extent_delete(ext2_extent_handle_t handle,
int flags EXT2FS_ATTR((unused)))
{
@ -1079,6 +1350,21 @@ ss_request_table *extra_cmds = &extent_cmds;
ext2_ino_t current_ino = 0;
ext2_extent_handle_t current_handle;
int common_extent_args_process(int argc, char *argv[], int min_argc,
int max_argc, const char *cmd,
const char *usage, int flags)
{
if (common_args_process(argc, argv, min_argc, max_argc, cmd,
usage, flags))
return 1;
if (!current_handle) {
com_err(cmd, 0, "Extent handle not open");
return 1;
}
return 0;
}
void do_inode(int argc, char *argv[])
{
ext2_ino_t inode;
@ -1207,7 +1493,8 @@ void do_delete_node(int argc, char *argv[])
errcode_t retval;
int err;
if (check_fs_read_write(argv[0]))
if (common_extent_args_process(argc, argv, 1, 1, "delete_node",
"", CHECK_FS_RW | CHECK_FS_BITMAPS))
return;
retval = ext2fs_extent_delete(current_handle, 0);
@ -1221,11 +1508,13 @@ void do_delete_node(int argc, char *argv[])
void do_replace_node(int argc, char *argv[])
{
const char *usage = "[--uninit] <lblk> <len> <pblk>";
errcode_t retval;
struct ext2fs_extent extent;
int err;
if (check_fs_read_write(argv[0]))
if (common_extent_args_process(argc, argv, 3, 5, "replace_node",
usage, CHECK_FS_RW | CHECK_FS_BITMAPS))
return;
extent.e_flags = 0;
@ -1237,22 +1526,19 @@ void do_replace_node(int argc, char *argv[])
}
if (argc != 4) {
fprintf(stderr, "usage: %s <lblk> <len> <pblk>\n", argv[0]);
fprintf(stderr, "Usage: %s %s\n", argv[0], usage);
return;
}
extent.e_lblk = parse_ulong(argv[1], argv[0],
"logical block", &err);
extent.e_lblk = parse_ulong(argv[1], argv[0], "logical block", &err);
if (err)
return;
extent.e_len = parse_ulong(argv[2], argv[0],
"logical block", &err);
extent.e_len = parse_ulong(argv[2], argv[0], "logical block", &err);
if (err)
return;
extent.e_pblk = parse_ulong(argv[3], argv[0],
"logical block", &err);
extent.e_pblk = parse_ulong(argv[3], argv[0], "logical block", &err);
if (err)
return;
@ -1271,17 +1557,10 @@ void do_split_node(int argc, char *argv[])
int err;
int flags = 0;
if (check_fs_open(argv[0]))
if (common_extent_args_process(argc, argv, 1, 1, "split_node",
"", CHECK_FS_RW | CHECK_FS_BITMAPS))
return;
if (check_fs_read_write(argv[0]))
return;
if (!current_handle) {
com_err(argv[0], 0, "Extent handle not open");
return;
}
retval = extent_node_split(current_handle, flags);
if (retval) {
com_err(argv[0], retval, 0);
@ -1292,13 +1571,15 @@ void do_split_node(int argc, char *argv[])
void do_insert_node(int argc, char *argv[])
{
const char *usage = "[--after] [--uninit] <lblk> <len> <pblk>";
errcode_t retval;
struct ext2fs_extent extent;
char *cmd;
int err;
int flags = 0;
if (check_fs_read_write(argv[0]))
if (common_extent_args_process(argc, argv, 3, 6, "insert_node",
usage, CHECK_FS_RW | CHECK_FS_BITMAPS))
return;
cmd = argv[0];
@ -1322,7 +1603,7 @@ void do_insert_node(int argc, char *argv[])
}
if (argc != 4) {
fprintf(stderr, "usage: %s [--after] <lblk> <len> <pblk>\n", cmd);
fprintf(stderr, "usage: %s %s\n", cmd, usage);
return;
}
@ -1349,8 +1630,54 @@ void do_insert_node(int argc, char *argv[])
do_current_node(argc, argv);
}
void do_set_bmap(int argc, char **argv)
{
const char *usage = "[--uninit] <lblk> <pblk>";
errcode_t retval;
blk_t logical;
blk_t physical;
char *cmd = argv[0];
int flags = 0;
int err;
if (common_extent_args_process(argc, argv, 3, 5, "set_bmap",
usage, CHECK_FS_RW | CHECK_FS_BITMAPS))
return;
if (argc > 2 && !strcmp(argv[1], "--uninit")) {
argc--;
argv++;
flags |= EXT2_EXTENT_SET_BMAP_UNINIT;
}
if (argc != 3) {
fprintf(stderr, "Usage: %s %s\n", cmd, usage);
return;
}
logical = parse_ulong(argv[1], cmd,
"logical block", &err);
if (err)
return;
physical = parse_ulong(argv[2], cmd,
"physical block", &err);
if (err)
return;
retval = ext2fs_extent_set_bmap(current_handle, logical,
(blk64_t) physical, flags);
if (retval) {
com_err(cmd, retval, 0);
return;
}
if (current_handle->path && current_handle->path[0].curr)
do_current_node(argc, argv);
}
void do_print_all(int argc, char **argv)
{
const char *usage = "[--leaf-only|--reverse|--reverse-leaf]";
struct ext2fs_extent extent;
errcode_t retval;
errcode_t end_err = EXT2_ET_EXTENT_NO_NEXT;
@ -1358,22 +1685,10 @@ void do_print_all(int argc, char **argv)
int first_op = EXT2_EXTENT_ROOT;
if (check_fs_open(argv[0]))
if (common_extent_args_process(argc, argv, 1, 2, "print_all",
usage, 0))
return;
if (!current_handle) {
com_err(argv[0], 0, "Extent handle not open");
return;
}
if (argc > 2) {
print_usage:
fprintf(stderr,
"Usage: %s [--leaf-only|--reverse|--reverse-leaf]\n",
argv[0]);
return;
}
if (argc == 2) {
if (!strcmp(argv[1], "--leaf-only"))
op = EXT2_EXTENT_NEXT_LEAF;
@ -1385,8 +1700,10 @@ void do_print_all(int argc, char **argv)
op = EXT2_EXTENT_PREV_LEAF;
first_op = EXT2_EXTENT_LAST_LEAF;
end_err = EXT2_ET_EXTENT_NO_PREV;
} else
goto print_usage;
} else {
fprintf(stderr, "Usage: %s %s\n", argv[0], usage);
return;
}
}
retval = ext2fs_extent_get(current_handle, first_op, &extent);
@ -1415,14 +1732,9 @@ void do_info(int argc, char **argv)
struct ext2_extent_info info;
errcode_t retval;
if (check_fs_open(argv[0]))
if (common_extent_args_process(argc, argv, 1, 1, "info", "", 0))
return;
if (!current_handle) {
com_err(argv[0], 0, "Extent handle not open");
return;
}
retval = ext2fs_extent_get_info(current_handle, &info);
if (retval) {
com_err(argv[0], retval, 0);
@ -1455,19 +1767,10 @@ void do_goto_block(int argc, char **argv)
blk_t blk;
int level = 0;
if (check_fs_open(argv[0]))
if (common_extent_args_process(argc, argv, 2, 3, "goto_block",
"block [level]", 0))
return;
if (!current_handle) {
com_err(argv[0], 0, "Extent handle not open");
return;
}
if (argc < 2 || argc > 3) {
fprintf(stderr, "%s block [level]\n", argv[0]);
return;
}
if (strtoblk(argv[0], argv[1], &blk))
return;

3
lib/ext2fs/extent_dbg.ct
View File

@ -55,6 +55,9 @@ request do_insert_node, "Insert node",
request do_split_node, "Split node",
split_node, split;
request do_set_bmap, "Set block mapping",
set_bmap;
request do_replace_node, "Insert node",
replace_node, replace;