This function deallocates a range of blocks from a passed-in file.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
---
lib/ext2fs/Makefile.in | 32 ++++-
lib/ext2fs/ext2fs.h | 6 +
lib/ext2fs/punch.c | 324 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 356 insertions(+), 6 deletions(-)
create mode 100644 lib/ext2fs/punch.c
diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
index f25c0b7..763694d 100644
--- a/lib/ext2fs/Makefile.in
+++ b/lib/ext2fs/Makefile.in
@@ -69,6 +69,7 @@ OBJS= $(DEBUGFS_LIB_OBJS) $(RESIZE_LIB_OBJS) $(E2IMAGE_LIB_OBJS) \
newdir.o \
openfs.o \
progress.o \
+ punch.o \
read_bb.o \
read_bb_file.o \
res_gdt.o \
@@ -135,6 +136,8 @@ SRCS= ext2_err.c \
$(srcdir)/native.c \
$(srcdir)/newdir.c \
$(srcdir)/openfs.c \
+ $(srcdir)/progress.c \
+ $(srcdir)/punch.c \
$(srcdir)/read_bb.c \
$(srcdir)/read_bb_file.c \
$(srcdir)/res_gdt.c \
@@ -412,7 +415,7 @@ alloc_tables.o: $(srcdir)/alloc_tables.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
$(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
$(srcdir)/ext2_io.h $(top_builddir)/lib/ext2fs/ext2_err.h \
- $(srcdir)/ext2_ext_attr.h $(srcdir)/bitops.h
+ $(srcdir)/ext2_ext_attr.h $(srcdir)/bitops.h $(srcdir)/ext2fsP.h
badblocks.o: $(srcdir)/badblocks.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fsP.h \
$(srcdir)/ext2fs.h $(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h \
@@ -434,7 +437,7 @@ bitmaps.o: $(srcdir)/bitmaps.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
$(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
$(srcdir)/ext2_io.h $(top_builddir)/lib/ext2fs/ext2_err.h \
- $(srcdir)/ext2_ext_attr.h $(srcdir)/bitops.h
+ $(srcdir)/ext2_ext_attr.h $(srcdir)/bitops.h $(srcdir)/ext2fsP.h
bitops.o: $(srcdir)/bitops.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
$(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
@@ -541,10 +544,17 @@ freefs.o: $(srcdir)/freefs.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/ext2_ext_attr.h \
$(srcdir)/bitops.h
gen_bitmap.o: $(srcdir)/gen_bitmap.c $(srcdir)/ext2_fs.h \
- $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
- $(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
- $(srcdir)/ext2_io.h $(top_builddir)/lib/ext2fs/ext2_err.h \
- $(srcdir)/ext2_ext_attr.h $(srcdir)/bitops.h
+ $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fsP.h \
+ $(srcdir)/ext2fs.h $(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h \
+ $(top_srcdir)/lib/et/com_err.h $(srcdir)/ext2_io.h \
+ $(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/ext2_ext_attr.h \
+ $(srcdir)/bitops.h
+gen_bitmap64.o: $(srcdir)/gen_bitmap64.c $(srcdir)/ext2_fs.h \
+ $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fsP.h \
+ $(srcdir)/ext2fs.h $(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h \
+ $(top_srcdir)/lib/et/com_err.h $(srcdir)/ext2_io.h \
+ $(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/ext2_ext_attr.h \
+ $(srcdir)/bitops.h $(srcdir)/bmap64.h
get_pathname.o: $(srcdir)/get_pathname.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
$(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
@@ -655,6 +665,16 @@ openfs.o: $(srcdir)/openfs.c $(srcdir)/ext2_fs.h \
$(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
$(srcdir)/ext2_io.h $(top_builddir)/lib/ext2fs/ext2_err.h \
$(srcdir)/ext2_ext_attr.h $(srcdir)/bitops.h $(srcdir)/e2image.h
+progress.o: $(srcdir)/progress.c $(srcdir)/ext2fs.h \
+ $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2_fs.h \
+ $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h $(srcdir)/ext2_io.h \
+ $(top_builddir)/lib/ext2fs/ext2_err.h $(srcdir)/ext2_ext_attr.h \
+ $(srcdir)/bitops.h $(srcdir)/ext2fsP.h
+punch.o: $(srcdir)/punch.c $(srcdir)/ext2_fs.h \
+ $(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
+ $(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
+ $(srcdir)/ext2_io.h $(top_builddir)/lib/ext2fs/ext2_err.h \
+ $(srcdir)/ext2_ext_attr.h $(srcdir)/bitops.h
read_bb.o: $(srcdir)/read_bb.c $(srcdir)/ext2_fs.h \
$(top_builddir)/lib/ext2fs/ext2_types.h $(srcdir)/ext2fs.h \
$(srcdir)/ext2_fs.h $(srcdir)/ext3_extents.h $(top_srcdir)/lib/et/com_err.h \
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index e2c3b09..f3531c0 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -1209,6 +1209,12 @@ extern errcode_t ext2fs_check_if_mounted(const char *file, int *mount_flags);
extern errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
char *mtpt, int mtlen);
+/* punch.c */
+extern errcode_t ext2fs_punch(ext2_filsys fs, ext2_ino_t ino,
+ struct ext2_inode *inode,
+ char *block_buf, blk64_t start,
+ blk64_t end);
+
/* namei.c */
extern errcode_t ext2fs_lookup(ext2_filsys fs, ext2_ino_t dir, const char *name,
int namelen, char *buf, ext2_ino_t *inode);
diff --git a/lib/ext2fs/punch.c b/lib/ext2fs/punch.c
new file mode 100644
index 0000000..8c6ec54
--- /dev/null
+++ b/lib/ext2fs/punch.c
@@ -0,0 +1,324 @@
+/*
+ * punch.c --- deallocate blocks allocated to an inode
+ *
+ * Copyright (C) 2010 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <errno.h>
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+#undef PUNCH_DEBUG
+
+/*
+ * This function returns 1 if the specified block is all zeros
+ */
+static int check_zero_block(char *buf, int blocksize)
+{
+ char *cp = buf;
+ int left = blocksize;
+
+ while (left > 0) {
+ if (*cp++)
+ return 0;
+ left--;
+ }
+ return 1;
+}
+
+/*
+ * This clever recursive function handles i_blocks[] as well as
+ * indirect, double indirect, and triple indirect blocks. It iterates
+ * over the entries in the i_blocks array or indirect blocks, and for
+ * each one, will recursively handle any indirect blocks and then
+ * frees and deallocates the blocks.
+ */
+static errcode_t ind_punch(ext2_filsys fs, struct ext2_inode *inode,
+ char *block_buf, blk_t *p, int level,
+ blk_t start, blk_t count, int max)
+{
+ errcode_t retval;
+ blk_t b, offset;
+ int i, incr;
+ int freed = 0;
+
+#ifdef PUNCH_DEBUG
+ printf("Entering ind_punch, level %d, start %u, count %u, "
+ "max %d\n", level, start, count, max);
+#endif
+ incr = 1 << ((EXT2_BLOCK_SIZE_BITS(fs->super)-2)*level);
+ for (i=0, offset=0; i < max; i++, p++, offset += incr) {
+ if (offset > count)
+ break;
+ if (*p == 0 || (offset+incr) <= start)
+ continue;
+ b = *p;
+ if (level > 0) {
+ blk_t start2;
+#ifdef PUNCH_DEBUG
+ printf("Reading indirect block %u\n", b);
+#endif
+ retval = ext2fs_read_ind_block(fs, b, block_buf);
+ if (retval)
+ return retval;
+ start2 = (start > offset) ? start - offset : 0;
+ retval = ind_punch(fs, inode, block_buf + fs->blocksize,
+ (blk_t *) block_buf, level - 1,
+ start2, count - offset,
+ fs->blocksize >> 2);
+ if (retval)
+ return retval;
+ retval = ext2fs_write_ind_block(fs, b, block_buf);
+ if (retval)
+ return retval;
+ if (!check_zero_block(block_buf, fs->blocksize))
+ continue;
+ }
+#ifdef PUNCH_DEBUG
+ printf("Freeing block %u (offset %d)\n", b, offset);
+#endif
+ ext2fs_block_alloc_stats(fs, b, -1);
+ *p = 0;
+ freed++;
+ }
+#ifdef PUNCH_DEBUG
+ printf("Freed %d blocks\n", freed);
+#endif
+ return ext2fs_iblk_sub_blocks(fs, inode, freed);
+}
+
+static errcode_t ext2fs_punch_ind(ext2_filsys fs, struct ext2_inode *inode,
+ char *block_buf, blk_t start, blk_t count)
+{
+ errcode_t retval;
+ char *buf = 0;
+ int level;
+ int num = EXT2_NDIR_BLOCKS;
+ blk_t *bp = inode->i_block;
+ blk_t addr_per_block;
+ blk_t max = EXT2_NDIR_BLOCKS;
+
+ if (!block_buf) {
+ retval = ext2fs_get_array(3, fs->blocksize, &buf);
+ if (retval)
+ return retval;
+ block_buf = buf;
+ }
+
+ addr_per_block = (blk_t) fs->blocksize >> 2;
+
+ for (level=0; level < 4; level++, max *= addr_per_block) {
+#ifdef PUNCH_DEBUG
+ printf("Main loop level %d, start %u count %u "
+ "max %d num %d\n", level, start, count, max, num);
+#endif
+ if (start < max) {
+ retval = ind_punch(fs, inode, block_buf, bp, level,
+ start, count, num);
+ if (retval)
+ goto errout;
+ if (count > max)
+ count -= max - start;
+ else
+ break;
+ start = 0;
+ } else
+ start -= max;
+ bp += num;
+ if (level == 0) {
+ num = 1;
+ max = 1;
+ }
+ }
+ retval = 0;
+errout:
+ if (buf)
+ ext2fs_free_mem(&buf);
+ return retval;
+}
+
+#ifdef PUNCH_DEBUG
+
+#define dbg_printf(f, a...) printf(f, ## a)
+
+static void dbg_print_extent(char *desc, struct ext2fs_extent *extent)
+{
+ if (desc)
+ printf("%s: ", desc);
+ printf("extent: lblk %llu--%llu, len %u, pblk %llu, flags: ",
+ extent->e_lblk, extent->e_lblk + extent->e_len - 1,
+ extent->e_len, extent->e_pblk);
+ if (extent->e_flags & EXT2_EXTENT_FLAGS_LEAF)
+ fputs("LEAF ", stdout);
+ if (extent->e_flags & EXT2_EXTENT_FLAGS_UNINIT)
+ fputs("UNINIT ", stdout);
+ if (extent->e_flags & EXT2_EXTENT_FLAGS_SECOND_VISIT)
+ fputs("2ND_VISIT ", stdout);
+ if (!extent->e_flags)
+ fputs("(none)", stdout);
+ fputc('\n', stdout);
+
+}
+#else
+#define dbg_print_extent(desc, ex) do { } while (0)
+#define dbg_printf(f, a...) do { } while (0)
+#endif
+
+static errcode_t ext2fs_punch_extent(ext2_filsys fs, ext2_ino_t ino,
+ struct ext2_inode *inode,
+ blk64_t start, blk64_t end)
+{
+ ext2_extent_handle_t handle = 0;
+ struct ext2fs_extent extent;
+ errcode_t retval;
+ blk64_t free_start, next;
+ __u32 free_count, newlen;
+ int freed = 0;
+
+ retval = ext2fs_extent_open2(fs, ino, inode, &handle);
+ if (retval)
+ return retval;
+ ext2fs_extent_goto(handle, start);
+ retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
+ if (retval)
+ goto errout;
+ while (1) {
+ dbg_print_extent("main loop", &extent);
+ next = extent.e_lblk + extent.e_len;
+ dbg_printf("start %llu, end %llu, next %llu\n",
+ (unsigned long long) start,
+ (unsigned long long) end,
+ (unsigned long long) next);
+ if (start <= extent.e_lblk) {
+ if (end < extent.e_lblk)
+ goto next_extent;
+ dbg_printf("Case #1\n");
+ /* Start of deleted region before extent;
+ adjust beginning of extent */
+ free_start = extent.e_pblk;
+ if (next > end)
+ free_count = end - extent.e_lblk + 1;
+ else
+ free_count = extent.e_len;
+ extent.e_len -= free_count;
+ extent.e_lblk += free_count;
+ extent.e_pblk += free_count;
+ } else if (end >= next-1) {
+ if (start >= next)
+ break;
+ /* End of deleted region after extent;
+ adjust end of extent */
+ dbg_printf("Case #2\n");
+ newlen = start - extent.e_lblk;
+ free_start = extent.e_pblk + newlen;
+ free_count = extent.e_len - newlen;
+ extent.e_len = newlen;
+ } else {
+ struct ext2fs_extent newex;
+
+ dbg_printf("Case #3\n");
+ /* The hard case; we need to split the extent */
+ newex.e_pblk = extent.e_pblk +
+ (end + 1 - extent.e_lblk);
+ newex.e_lblk = end + 1;
+ newex.e_len = next - end - 1;
+ newex.e_flags = extent.e_flags;
+
+ extent.e_len = start - extent.e_lblk;
+ free_start = extent.e_pblk + extent.e_len;
+ free_count = end - start + 1;
+
+ dbg_print_extent("inserting", &newex);
+ retval = ext2fs_extent_insert(handle,
+ EXT2_EXTENT_INSERT_AFTER, &newex);
+ if (retval)
+ goto errout;
+ /* Now pointing at inserted extent; so go back */
+ retval = ext2fs_extent_get(handle,
+ EXT2_EXTENT_PREV_LEAF,
+ &newex);
+ if (retval)
+ goto errout;
+ }
+ if (extent.e_len) {
+ dbg_print_extent("replacing", &extent);
+ retval = ext2fs_extent_replace(handle, 0, &extent);
+ } else {
+ dbg_printf("deleting current extent\n");
+ retval = ext2fs_extent_delete(handle, 0);
+ }
+ if (retval)
+ goto errout;
+ dbg_printf("Free start %llu, free count = %u\n",
+ free_start, free_count);
+ while (free_count-- > 0) {
+ ext2fs_block_alloc_stats(fs, free_start++, -1);
+ freed++;
+ }
+ next_extent:
+ retval = ext2fs_extent_get(handle, EXT2_EXTENT_NEXT_LEAF,
+ &extent);
+ if (retval == EXT2_ET_EXTENT_NO_NEXT)
+ break;
+ if (retval)
+ goto errout;
+ }
+ dbg_printf("Freed %d blocks\n", freed);
+ retval = ext2fs_iblk_sub_blocks(fs, inode, freed);
+errout:
+ ext2fs_extent_free(handle);
+ return retval;
+}
+
+/*
+ * Deallocate all logical blocks starting at start to end, inclusive.
+ * If end is ~0, then this is effectively truncate.
+ */
+extern errcode_t ext2fs_punch(ext2_filsys fs, ext2_ino_t ino,
+ struct ext2_inode *inode,
+ char *block_buf, blk64_t start,
+ blk64_t end)
+{
+ errcode_t retval;
+ struct ext2_inode inode_buf;
+
+ if (start > end)
+ return EINVAL;
+
+ if (start == end)
+ return 0;
+
+ /* Read inode structure if necessary */
+ if (!inode) {
+ retval = ext2fs_read_inode(fs, ino, &inode_buf);
+ if (retval)
+ return retval;
+ inode = &inode_buf;
+ }
+ if (inode->i_flags & EXT4_EXTENTS_FL)
+ retval = ext2fs_punch_extent(fs, ino, inode, start, end);
+ else {
+ blk_t count;
+
+ if (start > ~0U)
+ return 0;
+ count = ((end - start) < ~0U) ? (end - start) : ~0U;
+ retval = ext2fs_punch_ind(fs, inode, block_buf,
+ (blk_t) start, count);
+ }
+ if (retval)
+ return retval;
+
+ return ext2fs_write_inode(fs, ino, inode);
+}
--
1.7.0.4
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