bitmaps and inode table, the userspace tool thus
just passes the new number of blocks.
+EXT4_IOC_SWAP_BOOT Swap i_blocks and associated attributes
+ (like i_blocks, i_size, i_flags, ...) from
+ the specified inode with inode
+ EXT4_BOOT_LOADER_INO (#5). This is typically
+ used to store a boot loader in a secure part of
+ the filesystem, where it can't be changed by a
+ normal user by accident.
+ The data blocks of the previous boot loader
+ will be associated with the given inode.
+
..............................................................................
References
#define EXT4_IOC_ALLOC_DA_BLKS _IO('f', 12)
#define EXT4_IOC_MOVE_EXT _IOWR('f', 15, struct move_extent)
#define EXT4_IOC_RESIZE_FS _IOW('f', 16, __u64)
+#define EXT4_IOC_SWAP_BOOT _IO('f', 17)
#if defined(__KERNEL__) && defined(CONFIG_COMPAT)
/*
return ino == EXT4_ROOT_INO ||
ino == EXT4_USR_QUOTA_INO ||
ino == EXT4_GRP_QUOTA_INO ||
+ ino == EXT4_BOOT_LOADER_INO ||
ino == EXT4_JOURNAL_INO ||
ino == EXT4_RESIZE_INO ||
(ino >= EXT4_FIRST_INO(sb) &&
/* move_extent.c */
+extern void ext4_double_down_write_data_sem(struct inode *first,
+ struct inode *second);
+extern void ext4_double_up_write_data_sem(struct inode *orig_inode,
+ struct inode *donor_inode);
+void ext4_inode_double_lock(struct inode *inode1, struct inode *inode2);
+void ext4_inode_double_unlock(struct inode *inode1, struct inode *inode2);
extern int ext4_move_extents(struct file *o_filp, struct file *d_filp,
__u64 start_orig, __u64 start_donor,
__u64 len, __u64 *moved_len);
* NeilBrown 1999oct15
*/
if (inode->i_nlink == 0) {
- if (inode->i_mode == 0 ||
- !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
+ if ((inode->i_mode == 0 ||
+ !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
+ ino != EXT4_BOOT_LOADER_INO) {
/* this inode is deleted */
ret = -ESTALE;
goto bad_inode;
/* The only unlinked inodes we let through here have
* valid i_mode and are being read by the orphan
* recovery code: that's fine, we're about to complete
- * the process of deleting those. */
+ * the process of deleting those.
+ * OR it is the EXT4_BOOT_LOADER_INO which is
+ * not initialized on a new filesystem. */
}
ei->i_flags = le32_to_cpu(raw_inode->i_flags);
inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
else
init_special_inode(inode, inode->i_mode,
new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
+ } else if (ino == EXT4_BOOT_LOADER_INO) {
+ make_bad_inode(inode);
} else {
ret = -EIO;
EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
#include <asm/uaccess.h>
#include "ext4_jbd2.h"
#include "ext4.h"
+#include "ext4_extents.h"
#define MAX_32_NUM ((((unsigned long long) 1) << 32) - 1)
+/**
+ * Swap memory between @a and @b for @len bytes.
+ *
+ * @a: pointer to first memory area
+ * @b: pointer to second memory area
+ * @len: number of bytes to swap
+ *
+ */
+static void memswap(void *a, void *b, size_t len)
+{
+ unsigned char *ap, *bp;
+ unsigned char tmp;
+
+ ap = (unsigned char *)a;
+ bp = (unsigned char *)b;
+ while (len-- > 0) {
+ tmp = *ap;
+ *ap = *bp;
+ *bp = tmp;
+ ap++;
+ bp++;
+ }
+}
+
+/**
+ * Swap i_data and associated attributes between @inode1 and @inode2.
+ * This function is used for the primary swap between inode1 and inode2
+ * and also to revert this primary swap in case of errors.
+ *
+ * Therefore you have to make sure, that calling this method twice
+ * will revert all changes.
+ *
+ * @inode1: pointer to first inode
+ * @inode2: pointer to second inode
+ */
+static void swap_inode_data(struct inode *inode1, struct inode *inode2)
+{
+ loff_t isize;
+ struct ext4_inode_info *ei1;
+ struct ext4_inode_info *ei2;
+
+ ei1 = EXT4_I(inode1);
+ ei2 = EXT4_I(inode2);
+
+ memswap(&inode1->i_flags, &inode2->i_flags, sizeof(inode1->i_flags));
+ memswap(&inode1->i_version, &inode2->i_version,
+ sizeof(inode1->i_version));
+ memswap(&inode1->i_blocks, &inode2->i_blocks,
+ sizeof(inode1->i_blocks));
+ memswap(&inode1->i_bytes, &inode2->i_bytes, sizeof(inode1->i_bytes));
+ memswap(&inode1->i_atime, &inode2->i_atime, sizeof(inode1->i_atime));
+ memswap(&inode1->i_mtime, &inode2->i_mtime, sizeof(inode1->i_mtime));
+
+ memswap(ei1->i_data, ei2->i_data, sizeof(ei1->i_data));
+ memswap(&ei1->i_flags, &ei2->i_flags, sizeof(ei1->i_flags));
+ memswap(&ei1->i_disksize, &ei2->i_disksize, sizeof(ei1->i_disksize));
+ memswap(&ei1->i_es_tree, &ei2->i_es_tree, sizeof(ei1->i_es_tree));
+ memswap(&ei1->i_es_lru_nr, &ei2->i_es_lru_nr, sizeof(ei1->i_es_lru_nr));
+
+ isize = i_size_read(inode1);
+ i_size_write(inode1, i_size_read(inode2));
+ i_size_write(inode2, isize);
+}
+
+/**
+ * Swap the information from the given @inode and the inode
+ * EXT4_BOOT_LOADER_INO. It will basically swap i_data and all other
+ * important fields of the inodes.
+ *
+ * @sb: the super block of the filesystem
+ * @inode: the inode to swap with EXT4_BOOT_LOADER_INO
+ *
+ */
+static long swap_inode_boot_loader(struct super_block *sb,
+ struct inode *inode)
+{
+ handle_t *handle;
+ int err;
+ struct inode *inode_bl;
+ struct ext4_inode_info *ei;
+ struct ext4_inode_info *ei_bl;
+ struct ext4_sb_info *sbi;
+
+ if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode)) {
+ err = -EINVAL;
+ goto swap_boot_out;
+ }
+
+ if (!inode_owner_or_capable(inode) || !capable(CAP_SYS_ADMIN)) {
+ err = -EPERM;
+ goto swap_boot_out;
+ }
+
+ sbi = EXT4_SB(sb);
+ ei = EXT4_I(inode);
+
+ inode_bl = ext4_iget(sb, EXT4_BOOT_LOADER_INO);
+ if (IS_ERR(inode_bl)) {
+ err = PTR_ERR(inode_bl);
+ goto swap_boot_out;
+ }
+ ei_bl = EXT4_I(inode_bl);
+
+ filemap_flush(inode->i_mapping);
+ filemap_flush(inode_bl->i_mapping);
+
+ /* Protect orig inodes against a truncate and make sure,
+ * that only 1 swap_inode_boot_loader is running. */
+ ext4_inode_double_lock(inode, inode_bl);
+
+ truncate_inode_pages(&inode->i_data, 0);
+ truncate_inode_pages(&inode_bl->i_data, 0);
+
+ /* Wait for all existing dio workers */
+ ext4_inode_block_unlocked_dio(inode);
+ ext4_inode_block_unlocked_dio(inode_bl);
+ inode_dio_wait(inode);
+ inode_dio_wait(inode_bl);
+
+ handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2);
+ if (IS_ERR(handle)) {
+ err = -EINVAL;
+ goto swap_boot_out;
+ }
+
+ /* Protect extent tree against block allocations via delalloc */
+ ext4_double_down_write_data_sem(inode, inode_bl);
+
+ if (inode_bl->i_nlink == 0) {
+ /* this inode has never been used as a BOOT_LOADER */
+ set_nlink(inode_bl, 1);
+ i_uid_write(inode_bl, 0);
+ i_gid_write(inode_bl, 0);
+ inode_bl->i_flags = 0;
+ ei_bl->i_flags = 0;
+ inode_bl->i_version = 1;
+ i_size_write(inode_bl, 0);
+ inode_bl->i_mode = S_IFREG;
+ if (EXT4_HAS_INCOMPAT_FEATURE(sb,
+ EXT4_FEATURE_INCOMPAT_EXTENTS)) {
+ ext4_set_inode_flag(inode_bl, EXT4_INODE_EXTENTS);
+ ext4_ext_tree_init(handle, inode_bl);
+ } else
+ memset(ei_bl->i_data, 0, sizeof(ei_bl->i_data));
+ }
+
+ swap_inode_data(inode, inode_bl);
+
+ inode->i_ctime = inode_bl->i_ctime = ext4_current_time(inode);
+
+ spin_lock(&sbi->s_next_gen_lock);
+ inode->i_generation = sbi->s_next_generation++;
+ inode_bl->i_generation = sbi->s_next_generation++;
+ spin_unlock(&sbi->s_next_gen_lock);
+
+ ext4_discard_preallocations(inode);
+
+ err = ext4_mark_inode_dirty(handle, inode);
+ if (err < 0) {
+ ext4_warning(inode->i_sb,
+ "couldn't mark inode #%lu dirty (err %d)",
+ inode->i_ino, err);
+ /* Revert all changes: */
+ swap_inode_data(inode, inode_bl);
+ } else {
+ err = ext4_mark_inode_dirty(handle, inode_bl);
+ if (err < 0) {
+ ext4_warning(inode_bl->i_sb,
+ "couldn't mark inode #%lu dirty (err %d)",
+ inode_bl->i_ino, err);
+ /* Revert all changes: */
+ swap_inode_data(inode, inode_bl);
+ ext4_mark_inode_dirty(handle, inode);
+ }
+ }
+
+ ext4_journal_stop(handle);
+
+ ext4_double_up_write_data_sem(inode, inode_bl);
+
+ ext4_inode_resume_unlocked_dio(inode);
+ ext4_inode_resume_unlocked_dio(inode_bl);
+
+ ext4_inode_double_unlock(inode, inode_bl);
+
+ iput(inode_bl);
+
+swap_boot_out:
+ return err;
+}
+
long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
return err;
}
+ case EXT4_IOC_SWAP_BOOT:
+ if (!(filp->f_mode & FMODE_WRITE))
+ return -EBADF;
+ return swap_inode_boot_loader(sb, inode);
+
case EXT4_IOC_RESIZE_FS: {
ext4_fsblk_t n_blocks_count;
struct super_block *sb = inode->i_sb;
}
/**
- * double_down_write_data_sem - Acquire two inodes' write lock of i_data_sem
+ * ext4_double_down_write_data_sem - Acquire two inodes' write lock
+ * of i_data_sem
*
* Acquire write lock of i_data_sem of the two inodes
*/
-static void
-double_down_write_data_sem(struct inode *first, struct inode *second)
+void
+ext4_double_down_write_data_sem(struct inode *first, struct inode *second)
{
if (first < second) {
down_write(&EXT4_I(first)->i_data_sem);
}
/**
- * double_up_write_data_sem - Release two inodes' write lock of i_data_sem
+ * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem
*
* @orig_inode: original inode structure to be released its lock first
* @donor_inode: donor inode structure to be released its lock second
* Release write lock of i_data_sem of two inodes (orig and donor).
*/
-static void
-double_up_write_data_sem(struct inode *orig_inode, struct inode *donor_inode)
+void
+ext4_double_up_write_data_sem(struct inode *orig_inode,
+ struct inode *donor_inode)
{
up_write(&EXT4_I(orig_inode)->i_data_sem);
up_write(&EXT4_I(donor_inode)->i_data_sem);
* necessary, just swap data blocks between orig and donor.
*/
if (uninit) {
- double_down_write_data_sem(orig_inode, donor_inode);
+ ext4_double_down_write_data_sem(orig_inode, donor_inode);
/* If any of extents in range became initialized we have to
* fallback to data copying */
uninit = mext_check_coverage(orig_inode, orig_blk_offset,
goto drop_data_sem;
if (!uninit) {
- double_up_write_data_sem(orig_inode, donor_inode);
+ ext4_double_up_write_data_sem(orig_inode, donor_inode);
goto data_copy;
}
if ((page_has_private(pagep[0]) &&
donor_inode, orig_blk_offset,
block_len_in_page, err);
drop_data_sem:
- double_up_write_data_sem(orig_inode, donor_inode);
+ ext4_double_up_write_data_sem(orig_inode, donor_inode);
goto unlock_pages;
}
data_copy:
* Extents are swapped already, but we are not able to copy data.
* Try to swap extents to it's original places
*/
- double_down_write_data_sem(orig_inode, donor_inode);
+ ext4_double_down_write_data_sem(orig_inode, donor_inode);
replaced_count = mext_replace_branches(handle, donor_inode, orig_inode,
orig_blk_offset,
block_len_in_page, &err2);
- double_up_write_data_sem(orig_inode, donor_inode);
+ ext4_double_up_write_data_sem(orig_inode, donor_inode);
if (replaced_count != block_len_in_page) {
EXT4_ERROR_INODE_BLOCK(orig_inode, (sector_t)(orig_blk_offset),
"Unable to copy data block,"
}
/**
- * mext_inode_double_lock - Lock i_mutex on both @inode1 and @inode2
+ * ext4_inode_double_lock - Lock i_mutex on both @inode1 and @inode2
*
* @inode1: the inode structure
* @inode2: the inode structure
*
* Lock two inodes' i_mutex
*/
-static void
-mext_inode_double_lock(struct inode *inode1, struct inode *inode2)
+void
+ext4_inode_double_lock(struct inode *inode1, struct inode *inode2)
{
BUG_ON(inode1 == inode2);
if (inode1 < inode2) {
}
/**
- * mext_inode_double_unlock - Release i_mutex on both @inode1 and @inode2
+ * ext4_inode_double_unlock - Release i_mutex on both @inode1 and @inode2
*
* @inode1: the inode that is released first
* @inode2: the inode that is released second
*
*/
-static void
-mext_inode_double_unlock(struct inode *inode1, struct inode *inode2)
+void
+ext4_inode_double_unlock(struct inode *inode1, struct inode *inode2)
{
mutex_unlock(&inode1->i_mutex);
mutex_unlock(&inode2->i_mutex);
return -EINVAL;
}
/* Protect orig and donor inodes against a truncate */
- mext_inode_double_lock(orig_inode, donor_inode);
+ ext4_inode_double_lock(orig_inode, donor_inode);
/* Wait for all existing dio workers */
ext4_inode_block_unlocked_dio(orig_inode);
inode_dio_wait(donor_inode);
/* Protect extent tree against block allocations via delalloc */
- double_down_write_data_sem(orig_inode, donor_inode);
+ ext4_double_down_write_data_sem(orig_inode, donor_inode);
/* Check the filesystem environment whether move_extent can be done */
ret = mext_check_arguments(orig_inode, donor_inode, orig_start,
donor_start, &len);
* b. racing with ->readpage, ->write_begin, and ext4_get_block
* in move_extent_per_page
*/
- double_up_write_data_sem(orig_inode, donor_inode);
+ ext4_double_up_write_data_sem(orig_inode, donor_inode);
while (orig_page_offset <= seq_end_page) {
block_len_in_page = rest_blocks;
}
- double_down_write_data_sem(orig_inode, donor_inode);
+ ext4_double_down_write_data_sem(orig_inode, donor_inode);
if (ret < 0)
break;
ext4_ext_drop_refs(holecheck_path);
kfree(holecheck_path);
}
- double_up_write_data_sem(orig_inode, donor_inode);
+ ext4_double_up_write_data_sem(orig_inode, donor_inode);
ext4_inode_resume_unlocked_dio(orig_inode);
ext4_inode_resume_unlocked_dio(donor_inode);
- mext_inode_double_unlock(orig_inode, donor_inode);
+ ext4_inode_double_unlock(orig_inode, donor_inode);
return ret;
}
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