by Robert Yang

[permalink] [raw]

Subject: [PATCH V3 09/11] misc/create_inode.c: handle hardlinks

Create the inode and save the native inode number when we meet the hard
link (st_nlink > 1) at the first time, use ext2fs_link() to link the
name to the target inode number when we meet the same native inode
number again.

This algorithm is referred this from the genext2fs.

Signed-off-by: Robert Yang <[email protected]>
Reviewed-by: Darren Hart <[email protected]>
---
misc/create_inode.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++
misc/create_inode.h | 18 +++++++++++
misc/mke2fs.c | 12 +++++++
3 files changed, 118 insertions(+)

diff --git a/misc/create_inode.c b/misc/create_inode.c
index f1af6a9..6ff041d 100644
--- a/misc/create_inode.c
+++ b/misc/create_inode.c
@@ -10,6 +10,44 @@
#define S_BLKSIZE 512
#endif

+/* For saving the hard links */
+int hdlink_cnt = HDLINK_CNT;
+
+/* Link an inode number to a directory */
+static errcode_t add_link(ext2_ino_t parent_ino, ext2_ino_t ino, const char *name)
+{
+ struct ext2_inode inode;
+ errcode_t retval;
+
+ retval = ext2fs_read_inode(current_fs, ino, &inode);
+ if (retval) {
+ com_err(__FUNCTION__, retval, "while reading inode %u", ino);
+ return retval;
+ }
+
+ retval = ext2fs_link(current_fs, parent_ino, name, ino, inode.i_flags);
+ if (retval == EXT2_ET_DIR_NO_SPACE) {
+ retval = ext2fs_expand_dir(current_fs, parent_ino);
+ if (retval) {
+ com_err(__FUNCTION__, retval, "while expanding directory");
+ return retval;
+ }
+ retval = ext2fs_link(current_fs, parent_ino, name, ino, inode.i_flags);
+ }
+ if (retval) {
+ com_err(__FUNCTION__, retval, "while linking %s", name);
+ return retval;
+ }
+
+ inode.i_links_count++;
+
+ retval = ext2fs_write_inode(current_fs, ino, &inode);
+ if (retval)
+ com_err(__FUNCTION__, retval, "while writing inode %u", ino);
+
+ return retval;
+}
+
/* Fill the uid, gid, mode and time for the inode */
static void fill_inode(struct ext2_inode *inode, struct stat *st)
{
@@ -270,6 +308,17 @@ fail:
return retval;
}

+int is_hardlink(ext2_ino_t ino)
+{
+ int i;
+
+ for(i = 0; i < hdlinks.count; i++) {
+ if(hdlinks.hdl[i].src_ino == ino)
+ return i;
+ }
+ return -1;
+}
+
/* Copy the native file to the fs */
errcode_t do_write_internal(ext2_ino_t cwd, const char *src, const char *dest)
{
@@ -380,9 +429,11 @@ errcode_t populate_fs(ext2_ino_t parent_ino, const char *source_dir)
struct dirent *dent;
struct stat st;
char ln_target[PATH_MAX];
+ unsigned int save_inode;
ext2_ino_t ino;
errcode_t retval;
int read_cnt;
+ int hdlink;

root = EXT2_ROOT_INO;

@@ -404,6 +455,22 @@ errcode_t populate_fs(ext2_ino_t parent_ino, const char *source_dir)
lstat(dent->d_name, &st);
name = dent->d_name;

+ /* Check for hardlinks */
+ save_inode = 0;
+ if (!S_ISDIR(st.st_mode) && !S_ISLNK(st.st_mode) && st.st_nlink > 1) {
+ hdlink = is_hardlink(st.st_ino);
+ if (hdlink >= 0) {
+ retval = add_link(parent_ino,
+ hdlinks.hdl[hdlink].dst_ino, name);
+ if (retval) {
+ com_err(__FUNCTION__, retval, "while linking %s", name);
+ return retval;
+ }
+ continue;
+ } else
+ save_inode = 1;
+ }
+
switch(st.st_mode & S_IFMT) {
case S_IFCHR:
case S_IFBLK:
@@ -472,6 +539,27 @@ errcode_t populate_fs(ext2_ino_t parent_ino, const char *source_dir)
_("while setting inode for \"%s\""), name);
return retval;
}
+
+ /* Save the hardlink ino */
+ if (save_inode) {
+ /*
+ * Check whether need more memory, and we don't need
+ * free() since the lifespan will be over after the fs
+ * populated.
+ */
+ if (hdlinks.count == hdlink_cnt) {
+ if ((hdlinks.hdl = realloc (hdlinks.hdl,
+ (hdlink_cnt + HDLINK_CNT) *
+ sizeof (struct hdlink_s))) == NULL) {
+ com_err(name, errno, "Not enough memory");
+ return errno;
+ }
+ hdlink_cnt += HDLINK_CNT;
+ }
+ hdlinks.hdl[hdlinks.count].src_ino = st.st_ino;
+ hdlinks.hdl[hdlinks.count].dst_ino = ino;
+ hdlinks.count++;
+ }
}
closedir(dh);
return retval;
diff --git a/misc/create_inode.h b/misc/create_inode.h
index 9fc97fa..2b6d429 100644
--- a/misc/create_inode.h
+++ b/misc/create_inode.h
@@ -6,9 +6,27 @@
#include "ext2fs/ext2fs.h"
#include "nls-enable.h"

+struct hdlink_s
+{
+ ext2_ino_t src_ino;
+ ext2_ino_t dst_ino;
+};
+
+struct hdlinks_s
+{
+ int count;
+ struct hdlink_s *hdl;
+};
+
+struct hdlinks_s hdlinks;
+
ext2_filsys current_fs;
ext2_ino_t root;

+/* For saving the hard links */
+#define HDLINK_CNT 4
+extern int hdlink_cnt;
+
/* For populating the filesystem */
extern errcode_t populate_fs(ext2_ino_t parent_ino, const char *source_dir);
extern errcode_t do_mknod_internal(ext2_ino_t cwd, const char *name, struct stat *st);
diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index eab5463..10cdfd2 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -2802,6 +2802,18 @@ no_journal:
if (!quiet)
printf("%s", _("Copying files into the device: "));

+ /*
+ * Allocate memory for the hardlinks, we don't need free()
+ * since the lifespan will be over after the fs populated.
+ */
+ if ((hdlinks.hdl = (struct hdlink_s *)
+ malloc(hdlink_cnt * sizeof(struct hdlink_s))) == NULL) {
+ fprintf(stderr, "%s", _("\nNot enough memory\n"));
+ retval = ext2fs_close(fs);
+ return retval;
+ }
+
+ hdlinks.count = 0;
current_fs = fs;
root = EXT2_ROOT_INO;
retval = populate_fs(root, root_dir);
--
1.7.10.4