/**
* switch_gc_head - switch the garbage collection journal head.
* @c: UBIFS file-system description object
* @buf: buffer to write
* @len: length of the buffer to write
* @lnum: LEB number written is returned here
* @offs: offset written is returned here
*
* This function switch the GC head to the next LEB which is reserved in
* @c->gc_lnum. Returns %0 in case of success, %-EAGAIN if commit is required,
* and other negative error code in case of failures.
*/
static int switch_gc_head(struct ubifs_info *c)
{
int err, gc_lnum = c->gc_lnum;
struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
ubifs_assert(gc_lnum != -1);
dbg_gc("switch GC head from LEB %d:%d to LEB %d (waste %d bytes)",
wbuf->lnum, wbuf->offs + wbuf->used, gc_lnum,
c->leb_size - wbuf->offs - wbuf->used);
err = ubifs_wbuf_sync_nolock(wbuf);
if (err)
return err;
/*
* The GC write-buffer was synchronized, we may safely unmap
* 'c->gc_lnum'.
*/
err = ubifs_leb_unmap(c, gc_lnum);
if (err)
return err;
err = ubifs_wbuf_sync_nolock(wbuf);
if (err)
return err;
err = ubifs_add_bud_to_log(c, GCHD, gc_lnum, 0);
if (err)
return err;
c->gc_lnum = -1;
err = ubifs_wbuf_seek_nolock(wbuf, gc_lnum, 0, UBI_LONGTERM);
return err;
}
/**
* ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode.
* @c: UBIFS file-system description object
* @inode: inode to synchronize
*
* This function synchronizes write-buffers which contain nodes belonging to
* @inode. Returns zero in case of success and a negative error code in case of
* failure.
*/
int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)
{
int i, err = 0;
for (i = 0; i < c->jhead_cnt; i++) {
struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
if (i == GCHD)
/*
* GC head is special, do not look at it. Even if the
* head contains something related to this inode, it is
* a _copy_ of corresponding on-flash node which sits
* somewhere else.
*/
continue;
if (!wbuf_has_ino(wbuf, inode->i_ino))
continue;
mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
if (wbuf_has_ino(wbuf, inode->i_ino))
err = ubifs_wbuf_sync_nolock(wbuf);
mutex_unlock(&wbuf->io_mutex);
if (err) {
ubifs_ro_mode(c, err);
return err;
}
}
return 0;
}
/**
* ubifs_wbuf_seek_nolock - seek write-buffer.
* @wbuf: write-buffer
* @lnum: logical eraseblock number to seek to
* @offs: logical eraseblock offset to seek to
* @dtype: data type
*
* This function targets the write buffer to logical eraseblock @lnum:@offs.
* The write-buffer is synchronized if it is not empty. Returns zero in case of
* success and a negative error code in case of failure.
*/
int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs,
int dtype)
{
const struct ubifs_info *c = wbuf->c;
dbg_io("LEB %d:%d", lnum, offs);
ubifs_assert(lnum >= 0 && lnum < c->leb_cnt);
ubifs_assert(offs >= 0 && offs <= c->leb_size);
ubifs_assert(offs % c->min_io_size == 0 && !(offs & 7));
ubifs_assert(lnum != wbuf->lnum);
if (wbuf->used > 0) {
int err = ubifs_wbuf_sync_nolock(wbuf);
if (err)
return err;
}
spin_lock(&wbuf->lock);
wbuf->lnum = lnum;
wbuf->offs = offs;
wbuf->avail = c->min_io_size;
wbuf->used = 0;
spin_unlock(&wbuf->lock);
wbuf->dtype = dtype;
return 0;
}
/**
* ubifs_bg_wbufs_sync - synchronize write-buffers.
* @c: UBIFS file-system description object
*
* This function is called by background thread to synchronize write-buffers.
* Returns zero in case of success and a negative error code in case of
* failure.
*/
int ubifs_bg_wbufs_sync(struct ubifs_info *c)
{
int err, i;
ubifs_assert(!c->ro_media && !c->ro_mount);
if (!c->need_wbuf_sync)
return 0;
c->need_wbuf_sync = 0;
if (c->ro_error) {
err = -EROFS;
goto out_timers;
}
dbg_io("synchronize");
for (i = 0; i < c->jhead_cnt; i++) {
struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
cond_resched();
/*
* If the mutex is locked then wbuf is being changed, so
* synchronization is not necessary.
*/
if (mutex_is_locked(&wbuf->io_mutex))
continue;
mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
if (!wbuf->need_sync) {
mutex_unlock(&wbuf->io_mutex);
continue;
}
err = ubifs_wbuf_sync_nolock(wbuf);
mutex_unlock(&wbuf->io_mutex);
if (err) {
ubifs_err("cannot sync write-buffer, error %d", err);
ubifs_ro_mode(c, err);
goto out_timers;
}
}
return 0;
out_timers:
/* Cancel all timers to prevent repeated errors */
for (i = 0; i < c->jhead_cnt; i++) {
struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
cancel_wbuf_timer_nolock(wbuf);
mutex_unlock(&wbuf->io_mutex);
}
return err;
}
/**
* write_head - write data to a journal head.
* @c: UBIFS file-system description object
* @jhead: journal head
* @buf: buffer to write
* @len: length to write
* @lnum: LEB number written is returned here
* @offs: offset written is returned here
* @sync: non-zero if the write-buffer has to by synchronized
*
* This function is the same as 'write_node()' but it does not assume the
* buffer it is writing is a node, so it does not prepare it (which means
* initializing common header and calculating CRC).
*/
static int write_head(struct ubifs_info *c, int jhead, void *buf, int len,
int *lnum, int *offs, int sync)
{
int err;
struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf;
ubifs_assert(jhead != GCHD);
*lnum = c->jheads[jhead].wbuf.lnum;
*offs = c->jheads[jhead].wbuf.offs + c->jheads[jhead].wbuf.used;
dbg_jrn("jhead %d, LEB %d:%d, len %d", jhead, *lnum, *offs, len);
err = ubifs_wbuf_write_nolock(wbuf, buf, len);
if (err)
return err;
if (sync)
err = ubifs_wbuf_sync_nolock(wbuf);
return err;
}
/**
* ubifs_sync_wbufs_by_inodes - synchronize write-buffers which have data.
* belonging to specified inodes.
* @c: UBIFS file-system description object
* @inodes: array of inodes
* @count: number of elements in @inodes
*
* This function synchronizes write-buffers which contain nodes belonging to
* any inode specified in @inodes array. Returns zero in case of success and a
* negative error code in case of failure.
*/
int ubifs_sync_wbufs_by_inodes(struct ubifs_info *c,
struct inode * const *inodes, int count)
{
int i, j, err = 0;
ubifs_assert(count);
for (i = 0; i < c->jhead_cnt; i++) {
struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
if (i == GCHD)
/*
* GC head is special, do not look at it. Even if the
* head contains something related to this inode, it is
* a _copy_ of corresponding on-flash node which sits
* somewhere else.
*/
continue;
for (j = 0; j < count && !err; j++)
if (wbuf_has_ino(wbuf, inodes[j]->i_ino)) {
mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
if (wbuf_has_ino(wbuf, inodes[j]->i_ino))
err = ubifs_wbuf_sync_nolock(wbuf);
mutex_unlock(&wbuf->io_mutex);
break;
}
if (err) {
ubifs_ro_mode(c, err);
break;
}
}
return err;
}