debugfs, libext2fs: minor fixups to xattr support

Add magic number checking to the extended attribute editing handle;
move inline data to the head of the attribute list when writing so
that inline data ends up in the inode area; and always zero the
attribute space before writing to ensure that we can delete the last
xattr.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
index 9b38c08..d50bb42 100644 (file)
--- a/debugfs/debugfs.c
+++ b/debugfs/debugfs.c
@@ -549,6 +549,7 @@ static int dump_attr(char *name, char *value, size_t value_len, void *data)
 static void dump_inode_attributes(FILE *out, ext2_ino_t ino)
 {
        struct ext2_xattr_handle *h;
+       size_t sz;
        errcode_t err;
 
        err = ext2fs_xattrs_open(current_fs, ino, &h);
@@ -559,7 +560,8 @@ static void dump_inode_attributes(FILE *out, ext2_ino_t ino)
        if (err)
                goto out;
 
-       if (ext2fs_xattrs_count(h) == 0)
+       err = ext2fs_xattrs_count(h, &sz);
+       if (err || sz == 0)
                goto out;
 
        fprintf(out, "Extended attributes:\n");

diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index 007103d..51c88d0 100644 (file)
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -512,4 +512,7 @@ ec  EXT2_ET_INLINE_DATA_NO_BLOCK,
 ec     EXT2_ET_INLINE_DATA_NO_SPACE,
        "No free space in inline data"
 
+ec     EXT2_ET_MAGIC_EA_HANDLE,
+       "Wrong magic number for extended attribute structure"
+
        end

diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index a7b6116..3756e8b 100644 (file)
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -1183,7 +1183,7 @@ errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
 errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle);
 errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
                               struct ext2_inode_large *inode);
-size_t ext2fs_xattrs_count(struct ext2_xattr_handle *handle);
+errcode_t ext2fs_xattrs_count(struct ext2_xattr_handle *handle, size_t *count);
 errcode_t ext2fs_xattr_inode_max_size(ext2_filsys fs, ext2_ino_t ino,
                                      size_t *size);
 

diff --git a/lib/ext2fs/ext_attr.c b/lib/ext2fs/ext_attr.c
index e8dee53..308d21d 100644 (file)
--- a/lib/ext2fs/ext_attr.c
+++ b/lib/ext2fs/ext_attr.c
@@ -195,6 +195,7 @@ struct ext2_xattr {
 };
 
 struct ext2_xattr_handle {
+       errcode_t magic;
        ext2_filsys fs;
        struct ext2_xattr *attrs;
        size_t length, count;
@@ -238,6 +239,24 @@ static struct ea_name_index ea_names[] = {
        {0, NULL},
 };
 
+static void move_inline_data_to_front(struct ext2_xattr_handle *h)
+{
+       struct ext2_xattr *x;
+       struct ext2_xattr tmp;
+
+       for (x = h->attrs + 1; x < h->attrs + h->length; x++) {
+               if (!x->name)
+                       continue;
+
+               if (strcmp(x->name, "system.data") == 0) {
+                       memcpy(&tmp, x, sizeof(tmp));
+                       memcpy(x, h->attrs, sizeof(tmp));
+                       memcpy(h->attrs, &tmp, sizeof(tmp));
+                       return;
+               }
+       }
+}
+
 static const char *find_ea_prefix(int index)
 {
        struct ea_name_index *e;
@@ -412,6 +431,7 @@ static errcode_t write_xattrs_to_buffer(struct ext2_xattr_handle *handle,
        unsigned int entry_size, value_size;
        int idx, ret;
 
+       memset(entries_start, 0, storage_size);
        /* For all remaining x...  */
        for (; x < handle->attrs + handle->length; x++) {
                if (!x->name)
@@ -471,6 +491,7 @@ errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle)
        unsigned int i;
        errcode_t err;
 
+       EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
        i = EXT2_INODE_SIZE(handle->fs->super);
        if (i < sizeof(*inode))
                i = sizeof(*inode);
@@ -484,6 +505,8 @@ errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle)
        if (err)
                goto out;
 
+       move_inline_data_to_front(handle);
+
        x = handle->attrs;
        /* Does the inode have size for EA? */
        if (EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
@@ -511,7 +534,7 @@ errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle)
 
 write_ea_block:
        /* Write the EA block */
-       err = ext2fs_get_memzero(handle->fs->blocksize, &block_buf);
+       err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
        if (err)
                goto out;
 
@@ -590,6 +613,7 @@ static errcode_t read_xattrs_from_buffer(struct ext2_xattr_handle *handle,
                x++;
 
        entry = entries;
+       remain = storage_size;
        while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
                __u32 hash;
 
@@ -682,6 +706,7 @@ errcode_t ext2fs_xattrs_read(struct ext2_xattr_handle *handle)
        int i;
        errcode_t err;
 
+       EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
        i = EXT2_INODE_SIZE(handle->fs->super);
        if (i < sizeof(*inode))
                i = sizeof(*inode);
@@ -781,6 +806,7 @@ errcode_t ext2fs_xattrs_iterate(struct ext2_xattr_handle *h,
        errcode_t err;
        int ret;
 
+       EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
        for (x = h->attrs; x < h->attrs + h->length; x++) {
                if (!x->name)
                        continue;
@@ -802,6 +828,7 @@ errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
        void *val;
        errcode_t err;
 
+       EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
        for (x = h->attrs; x < h->attrs + h->length; x++) {
                if (!x->name)
                        continue;
@@ -893,6 +920,7 @@ errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
        char *new_value;
        errcode_t err;
 
+       EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
        last_empty = NULL;
        for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
                if (!x->name) {
@@ -958,6 +986,7 @@ errcode_t ext2fs_xattr_remove(struct ext2_xattr_handle *handle,
        struct ext2_xattr *x;
        errcode_t err;
 
+       EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
        for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
                if (!x->name)
                        continue;
@@ -991,6 +1020,7 @@ errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
        if (err)
                return err;
 
+       h->magic = EXT2_ET_MAGIC_EA_HANDLE;
        h->length = 4;
        err = ext2fs_get_arrayzero(h->length, sizeof(struct ext2_xattr),
                                   &h->attrs);
@@ -1010,6 +1040,7 @@ errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle)
        struct ext2_xattr_handle *h = *handle;
        errcode_t err;
 
+       EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
        if (h->dirty) {
                err = ext2fs_xattrs_write(h);
                if (err)
@@ -1022,7 +1053,9 @@ errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle)
        return 0;
 }
 
-size_t ext2fs_xattrs_count(struct ext2_xattr_handle *handle)
+errcode_t ext2fs_xattrs_count(struct ext2_xattr_handle *handle, size_t *count)
 {
-       return handle->count;
+       EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
+       *count = handle->count;
+       return 0;
 }