linux/fs/ext4/orphan.c

/*
 * Ext4 orphan inode handling
 */
#include <linux/fs.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>

#include "ext4.h"
#include "ext4_jbd2.h"

static int ext4_orphan_file_add(handle_t *handle, struct inode *inode)
{ … }

/*
 * ext4_orphan_add() links an unlinked or truncated inode into a list of
 * such inodes, starting at the superblock, in case we crash before the
 * file is closed/deleted, or in case the inode truncate spans multiple
 * transactions and the last transaction is not recovered after a crash.
 *
 * At filesystem recovery time, we walk this list deleting unlinked
 * inodes and truncating linked inodes in ext4_orphan_cleanup().
 *
 * Orphan list manipulation functions must be called under i_rwsem unless
 * we are just creating the inode or deleting it.
 */
int ext4_orphan_add(handle_t *handle, struct inode *inode)
{ … }

static int ext4_orphan_file_del(handle_t *handle, struct inode *inode)
{ … }

/*
 * ext4_orphan_del() removes an unlinked or truncated inode from the list
 * of such inodes stored on disk, because it is finally being cleaned up.
 */
int ext4_orphan_del(handle_t *handle, struct inode *inode)
{ … }

#ifdef CONFIG_QUOTA
static int ext4_quota_on_mount(struct super_block *sb, int type)
{ … }
#endif

static void ext4_process_orphan(struct inode *inode,
				int *nr_truncates, int *nr_orphans)
{ … }

/* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
 * the superblock) which were deleted from all directories, but held open by
 * a process at the time of a crash.  We walk the list and try to delete these
 * inodes at recovery time (only with a read-write filesystem).
 *
 * In order to keep the orphan inode chain consistent during traversal (in
 * case of crash during recovery), we link each inode into the superblock
 * orphan list_head and handle it the same way as an inode deletion during
 * normal operation (which journals the operations for us).
 *
 * We only do an iget() and an iput() on each inode, which is very safe if we
 * accidentally point at an in-use or already deleted inode.  The worst that
 * can happen in this case is that we get a "bit already cleared" message from
 * ext4_free_inode().  The only reason we would point at a wrong inode is if
 * e2fsck was run on this filesystem, and it must have already done the orphan
 * inode cleanup for us, so we can safely abort without any further action.
 */
void ext4_orphan_cleanup(struct super_block *sb, struct ext4_super_block *es)
{ … }

void ext4_release_orphan_info(struct super_block *sb)
{ … }

static struct ext4_orphan_block_tail *ext4_orphan_block_tail(
						struct super_block *sb,
						struct buffer_head *bh)
{ … }

static int ext4_orphan_file_block_csum_verify(struct super_block *sb,
					      struct buffer_head *bh)
{ … }

/* This gets called only when checksumming is enabled */
void ext4_orphan_file_block_trigger(struct jbd2_buffer_trigger_type *triggers,
				    struct buffer_head *bh,
				    void *data, size_t size)
{ … }

int ext4_init_orphan_info(struct super_block *sb)
{ … }

int ext4_orphan_file_empty(struct super_block *sb)
{ … }