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journal.c
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/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors: Artem Bityutskiy (Битюцкий Артём)
* Adrian Hunter
*/
/*
* This file implements UBIFS journal.
*
* The journal consists of 2 parts - the log and bud LEBs. The log has fixed
* length and position, while a bud logical eraseblock is any LEB in the main
* area. Buds contain file system data - data nodes, inode nodes, etc. The log
* contains only references to buds and some other stuff like commit
* start node. The idea is that when we commit the journal, we do
* not copy the data, the buds just become indexed. Since after the commit the
* nodes in bud eraseblocks become leaf nodes of the file system index tree, we
* use term "bud". Analogy is obvious, bud eraseblocks contain nodes which will
* become leafs in the future.
*
* The journal is multi-headed because we want to write data to the journal as
* optimally as possible. It is nice to have nodes belonging to the same inode
* in one LEB, so we may write data owned by different inodes to different
* journal heads, although at present only one data head is used.
*
* For recovery reasons, the base head contains all inode nodes, all directory
* entry nodes and all truncate nodes. This means that the other heads contain
* only data nodes.
*
* Bud LEBs may be half-indexed. For example, if the bud was not full at the
* time of commit, the bud is retained to continue to be used in the journal,
* even though the "front" of the LEB is now indexed. In that case, the log
* reference contains the offset where the bud starts for the purposes of the
* journal.
*
* The journal size has to be limited, because the larger is the journal, the
* longer it takes to mount UBIFS (scanning the journal) and the more memory it
* takes (indexing in the TNC).
*
* All the journal write operations like 'ubifs_jnl_update()' here, which write
* multiple UBIFS nodes to the journal at one go, are atomic with respect to
* unclean reboots. Should the unclean reboot happen, the recovery code drops
* all the nodes.
*/
#include "ubifs.h"
/**
* zero_ino_node_unused - zero out unused fields of an on-flash inode node.
* @ino: the inode to zero out
*/
static inline void zero_ino_node_unused(struct ubifs_ino_node *ino)
{
memset(ino->padding1, 0, 4);
memset(ino->padding2, 0, 26);
}
/**
* zero_dent_node_unused - zero out unused fields of an on-flash directory
* entry node.
* @dent: the directory entry to zero out
*/
static inline void zero_dent_node_unused(struct ubifs_dent_node *dent)
{
dent->padding1 = 0;
}
/**
* zero_trun_node_unused - zero out unused fields of an on-flash truncation
* node.
* @trun: the truncation node to zero out
*/
static inline void zero_trun_node_unused(struct ubifs_trun_node *trun)
{
memset(trun->padding, 0, 12);
}
static void ubifs_add_auth_dirt(struct ubifs_info *c, int lnum)
{
if (ubifs_authenticated(c))
ubifs_add_dirt(c, lnum, ubifs_auth_node_sz(c));
}
/**
* reserve_space - reserve space in the journal.
* @c: UBIFS file-system description object
* @jhead: journal head number
* @len: node length
*
* This function reserves space in journal head @head. If the reservation
* succeeded, the journal head stays locked and later has to be unlocked using
* 'release_head()'. Returns zero in case of success, %-EAGAIN if commit has to
* be done, and other negative error codes in case of other failures.
*/
static int reserve_space(struct ubifs_info *c, int jhead, int len)
{
int err = 0, err1, retries = 0, avail, lnum, offs, squeeze;
struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf;
/*
* Typically, the base head has smaller nodes written to it, so it is
* better to try to allocate space at the ends of eraseblocks. This is
* what the squeeze parameter does.
*/
ubifs_assert(c, !c->ro_media && !c->ro_mount);
squeeze = (jhead == BASEHD);
again:
mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
if (c->ro_error) {
err = -EROFS;
goto out_unlock;
}
avail = c->leb_size - wbuf->offs - wbuf->used;
if (wbuf->lnum != -1 && avail >= len)
return 0;
/*
* Write buffer wasn't seek'ed or there is no enough space - look for an
* LEB with some empty space.
*/
lnum = ubifs_find_free_space(c, len, &offs, squeeze);
if (lnum >= 0)
goto out;
err = lnum;
if (err != -ENOSPC)
goto out_unlock;
/*
* No free space, we have to run garbage collector to make
* some. But the write-buffer mutex has to be unlocked because
* GC also takes it.
*/
dbg_jnl("no free space in jhead %s, run GC", dbg_jhead(jhead));
mutex_unlock(&wbuf->io_mutex);
lnum = ubifs_garbage_collect(c, 0);
if (lnum < 0) {
err = lnum;
if (err != -ENOSPC)
return err;
/*
* GC could not make a free LEB. But someone else may
* have allocated new bud for this journal head,
* because we dropped @wbuf->io_mutex, so try once
* again.
*/
dbg_jnl("GC couldn't make a free LEB for jhead %s",
dbg_jhead(jhead));
if (retries++ < 2) {
dbg_jnl("retry (%d)", retries);
goto again;
}
dbg_jnl("return -ENOSPC");
return err;
}
mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
dbg_jnl("got LEB %d for jhead %s", lnum, dbg_jhead(jhead));
avail = c->leb_size - wbuf->offs - wbuf->used;
if (wbuf->lnum != -1 && avail >= len) {
/*
* Someone else has switched the journal head and we have
* enough space now. This happens when more than one process is
* trying to write to the same journal head at the same time.
*/
dbg_jnl("return LEB %d back, already have LEB %d:%d",
lnum, wbuf->lnum, wbuf->offs + wbuf->used);
err = ubifs_return_leb(c, lnum);
if (err)
goto out_unlock;
return 0;
}
offs = 0;
out:
/*
* Make sure we synchronize the write-buffer before we add the new bud
* to the log. Otherwise we may have a power cut after the log
* reference node for the last bud (@lnum) is written but before the
* write-buffer data are written to the next-to-last bud
* (@wbuf->lnum). And the effect would be that the recovery would see
* that there is corruption in the next-to-last bud.
*/
err = ubifs_wbuf_sync_nolock(wbuf);
if (err)
goto out_return;
err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
if (err)
goto out_return;
err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs);
if (err)
goto out_unlock;
return 0;
out_unlock:
mutex_unlock(&wbuf->io_mutex);
return err;
out_return:
/* An error occurred and the LEB has to be returned to lprops */
ubifs_assert(c, err < 0);
err1 = ubifs_return_leb(c, lnum);
if (err1 && err == -EAGAIN)
/*
* Return original error code only if it is not %-EAGAIN,
* which is not really an error. Otherwise, return the error
* code of 'ubifs_return_leb()'.
*/
err = err1;
mutex_unlock(&wbuf->io_mutex);
return err;
}
static int ubifs_hash_nodes(struct ubifs_info *c, void *node,
int len, struct shash_desc *hash)
{
int auth_node_size = ubifs_auth_node_sz(c);
int err;
while (1) {
const struct ubifs_ch *ch = node;
int nodelen = le32_to_cpu(ch->len);
ubifs_assert(c, len >= auth_node_size);
if (len == auth_node_size)
break;
ubifs_assert(c, len > nodelen);
ubifs_assert(c, ch->magic == cpu_to_le32(UBIFS_NODE_MAGIC));
err = ubifs_shash_update(c, hash, (void *)node, nodelen);
if (err)
return err;
node += ALIGN(nodelen, 8);
len -= ALIGN(nodelen, 8);
}
return ubifs_prepare_auth_node(c, node, hash);
}
/**
* 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 writes data to the reserved space of journal head @jhead.
* Returns zero in case of success and a negative error code in case of
* failure.
*/
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(c, jhead != GCHD);
*lnum = c->jheads[jhead].wbuf.lnum;
*offs = c->jheads[jhead].wbuf.offs + c->jheads[jhead].wbuf.used;
dbg_jnl("jhead %s, LEB %d:%d, len %d",
dbg_jhead(jhead), *lnum, *offs, len);
if (ubifs_authenticated(c)) {
err = ubifs_hash_nodes(c, buf, len, c->jheads[jhead].log_hash);
if (err)
return err;
}
err = ubifs_wbuf_write_nolock(wbuf, buf, len);
if (err)
return err;
if (sync)
err = ubifs_wbuf_sync_nolock(wbuf);
return err;
}
/**
* make_reservation - reserve journal space.
* @c: UBIFS file-system description object
* @jhead: journal head
* @len: how many bytes to reserve
*
* This function makes space reservation in journal head @jhead. The function
* takes the commit lock and locks the journal head, and the caller has to
* unlock the head and finish the reservation with 'finish_reservation()'.
* Returns zero in case of success and a negative error code in case of
* failure.
*
* Note, the journal head may be unlocked as soon as the data is written, while
* the commit lock has to be released after the data has been added to the
* TNC.
*/
static int make_reservation(struct ubifs_info *c, int jhead, int len)
{
int err, cmt_retries = 0, nospc_retries = 0;
again:
down_read(&c->commit_sem);
err = reserve_space(c, jhead, len);
if (!err)
/* c->commit_sem will get released via finish_reservation(). */
return 0;
up_read(&c->commit_sem);
if (err == -ENOSPC) {
/*
* GC could not make any progress. We should try to commit
* once because it could make some dirty space and GC would
* make progress, so make the error -EAGAIN so that the below
* will commit and re-try.
*/
if (nospc_retries++ < 2) {
dbg_jnl("no space, retry");
err = -EAGAIN;
}
/*
* This means that the budgeting is incorrect. We always have
* to be able to write to the media, because all operations are
* budgeted. Deletions are not budgeted, though, but we reserve
* an extra LEB for them.
*/
}
if (err != -EAGAIN)
goto out;
/*
* -EAGAIN means that the journal is full or too large, or the above
* code wants to do one commit. Do this and re-try.
*/
if (cmt_retries > 128) {
/*
* This should not happen unless the journal size limitations
* are too tough.
*/
ubifs_err(c, "stuck in space allocation");
err = -ENOSPC;
goto out;
} else if (cmt_retries > 32)
ubifs_warn(c, "too many space allocation re-tries (%d)",
cmt_retries);
dbg_jnl("-EAGAIN, commit and retry (retried %d times)",
cmt_retries);
cmt_retries += 1;
err = ubifs_run_commit(c);
if (err)
return err;
goto again;
out:
ubifs_err(c, "cannot reserve %d bytes in jhead %d, error %d",
len, jhead, err);
if (err == -ENOSPC) {
/* This are some budgeting problems, print useful information */
down_write(&c->commit_sem);
dump_stack();
ubifs_dump_budg(c, &c->bi);
ubifs_dump_lprops(c);
cmt_retries = dbg_check_lprops(c);
up_write(&c->commit_sem);
}
return err;
}
/**
* release_head - release a journal head.
* @c: UBIFS file-system description object
* @jhead: journal head
*
* This function releases journal head @jhead which was locked by
* the 'make_reservation()' function. It has to be called after each successful
* 'make_reservation()' invocation.
*/
static inline void release_head(struct ubifs_info *c, int jhead)
{
mutex_unlock(&c->jheads[jhead].wbuf.io_mutex);
}
/**
* finish_reservation - finish a reservation.
* @c: UBIFS file-system description object
*
* This function finishes journal space reservation. It must be called after
* 'make_reservation()'.
*/
static void finish_reservation(struct ubifs_info *c)
{
up_read(&c->commit_sem);
}
/**
* get_dent_type - translate VFS inode mode to UBIFS directory entry type.
* @mode: inode mode
*/
static int get_dent_type(int mode)
{
switch (mode & S_IFMT) {
case S_IFREG:
return UBIFS_ITYPE_REG;
case S_IFDIR:
return UBIFS_ITYPE_DIR;
case S_IFLNK:
return UBIFS_ITYPE_LNK;
case S_IFBLK:
return UBIFS_ITYPE_BLK;
case S_IFCHR:
return UBIFS_ITYPE_CHR;
case S_IFIFO:
return UBIFS_ITYPE_FIFO;
case S_IFSOCK:
return UBIFS_ITYPE_SOCK;
default:
BUG();
}
return 0;
}
/**
* pack_inode - pack an inode node.
* @c: UBIFS file-system description object
* @ino: buffer in which to pack inode node
* @inode: inode to pack
* @last: indicates the last node of the group
*/
static void pack_inode(struct ubifs_info *c, struct ubifs_ino_node *ino,
const struct inode *inode, int last)
{
int data_len = 0, last_reference = !inode->i_nlink;
struct ubifs_inode *ui = ubifs_inode(inode);
ino->ch.node_type = UBIFS_INO_NODE;
ino_key_init_flash(c, &ino->key, inode->i_ino);
ino->creat_sqnum = cpu_to_le64(ui->creat_sqnum);
ino->atime_sec = cpu_to_le64(inode->i_atime.tv_sec);
ino->atime_nsec = cpu_to_le32(inode->i_atime.tv_nsec);
ino->ctime_sec = cpu_to_le64(inode->i_ctime.tv_sec);
ino->ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);
ino->mtime_sec = cpu_to_le64(inode->i_mtime.tv_sec);
ino->mtime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
ino->uid = cpu_to_le32(i_uid_read(inode));
ino->gid = cpu_to_le32(i_gid_read(inode));
ino->mode = cpu_to_le32(inode->i_mode);
ino->flags = cpu_to_le32(ui->flags);
ino->size = cpu_to_le64(ui->ui_size);
ino->nlink = cpu_to_le32(inode->i_nlink);
ino->compr_type = cpu_to_le16(ui->compr_type);
ino->data_len = cpu_to_le32(ui->data_len);
ino->xattr_cnt = cpu_to_le32(ui->xattr_cnt);
ino->xattr_size = cpu_to_le32(ui->xattr_size);
ino->xattr_names = cpu_to_le32(ui->xattr_names);
zero_ino_node_unused(ino);
/*
* Drop the attached data if this is a deletion inode, the data is not
* needed anymore.
*/
if (!last_reference) {
memcpy(ino->data, ui->data, ui->data_len);
data_len = ui->data_len;
}
ubifs_prep_grp_node(c, ino, UBIFS_INO_NODE_SZ + data_len, last);
}
/**
* mark_inode_clean - mark UBIFS inode as clean.
* @c: UBIFS file-system description object
* @ui: UBIFS inode to mark as clean
*
* This helper function marks UBIFS inode @ui as clean by cleaning the
* @ui->dirty flag and releasing its budget. Note, VFS may still treat the
* inode as dirty and try to write it back, but 'ubifs_write_inode()' would
* just do nothing.
*/
static void mark_inode_clean(struct ubifs_info *c, struct ubifs_inode *ui)
{
if (ui->dirty)
ubifs_release_dirty_inode_budget(c, ui);
ui->dirty = 0;
}
static void set_dent_cookie(struct ubifs_info *c, struct ubifs_dent_node *dent)
{
if (c->double_hash)
dent->cookie = prandom_u32();
else
dent->cookie = 0;
}
/**
* ubifs_jnl_update - update inode.
* @c: UBIFS file-system description object
* @dir: parent inode or host inode in case of extended attributes
* @nm: directory entry name
* @inode: inode to update
* @deletion: indicates a directory entry deletion i.e unlink or rmdir
* @xent: non-zero if the directory entry is an extended attribute entry
*
* This function updates an inode by writing a directory entry (or extended
* attribute entry), the inode itself, and the parent directory inode (or the
* host inode) to the journal.
*
* The function writes the host inode @dir last, which is important in case of
* extended attributes. Indeed, then we guarantee that if the host inode gets
* synchronized (with 'fsync()'), and the write-buffer it sits in gets flushed,
* the extended attribute inode gets flushed too. And this is exactly what the
* user expects - synchronizing the host inode synchronizes its extended
* attributes. Similarly, this guarantees that if @dir is synchronized, its
* directory entry corresponding to @nm gets synchronized too.
*
* If the inode (@inode) or the parent directory (@dir) are synchronous, this
* function synchronizes the write-buffer.
*
* This function marks the @dir and @inode inodes as clean and returns zero on
* success. In case of failure, a negative error code is returned.
*/
int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
const struct fscrypt_name *nm, const struct inode *inode,
int deletion, int xent)
{
int err, dlen, ilen, len, lnum, ino_offs, dent_offs;
int aligned_dlen, aligned_ilen, sync = IS_DIRSYNC(dir);
int last_reference = !!(deletion && inode->i_nlink == 0);
struct ubifs_inode *ui = ubifs_inode(inode);
struct ubifs_inode *host_ui = ubifs_inode(dir);
struct ubifs_dent_node *dent;
struct ubifs_ino_node *ino;
union ubifs_key dent_key, ino_key;
u8 hash_dent[UBIFS_HASH_ARR_SZ];
u8 hash_ino[UBIFS_HASH_ARR_SZ];
u8 hash_ino_host[UBIFS_HASH_ARR_SZ];
ubifs_assert(c, mutex_is_locked(&host_ui->ui_mutex));
dlen = UBIFS_DENT_NODE_SZ + fname_len(nm) + 1;
ilen = UBIFS_INO_NODE_SZ;
/*
* If the last reference to the inode is being deleted, then there is
* no need to attach and write inode data, it is being deleted anyway.
* And if the inode is being deleted, no need to synchronize
* write-buffer even if the inode is synchronous.
*/
if (!last_reference) {
ilen += ui->data_len;
sync |= IS_SYNC(inode);
}
aligned_dlen = ALIGN(dlen, 8);
aligned_ilen = ALIGN(ilen, 8);
len = aligned_dlen + aligned_ilen + UBIFS_INO_NODE_SZ;
/* Make sure to also account for extended attributes */
if (ubifs_authenticated(c))
len += ALIGN(host_ui->data_len, 8) + ubifs_auth_node_sz(c);
else
len += host_ui->data_len;
dent = kzalloc(len, GFP_NOFS);
if (!dent)
return -ENOMEM;
/* Make reservation before allocating sequence numbers */
err = make_reservation(c, BASEHD, len);
if (err)
goto out_free;
if (!xent) {
dent->ch.node_type = UBIFS_DENT_NODE;
if (nm->hash)
dent_key_init_hash(c, &dent_key, dir->i_ino, nm->hash);
else
dent_key_init(c, &dent_key, dir->i_ino, nm);
} else {
dent->ch.node_type = UBIFS_XENT_NODE;
xent_key_init(c, &dent_key, dir->i_ino, nm);
}
key_write(c, &dent_key, dent->key);
dent->inum = deletion ? 0 : cpu_to_le64(inode->i_ino);
dent->type = get_dent_type(inode->i_mode);
dent->nlen = cpu_to_le16(fname_len(nm));
memcpy(dent->name, fname_name(nm), fname_len(nm));
dent->name[fname_len(nm)] = '\0';
set_dent_cookie(c, dent);
zero_dent_node_unused(dent);
ubifs_prep_grp_node(c, dent, dlen, 0);
err = ubifs_node_calc_hash(c, dent, hash_dent);
if (err)
goto out_release;
ino = (void *)dent + aligned_dlen;
pack_inode(c, ino, inode, 0);
err = ubifs_node_calc_hash(c, ino, hash_ino);
if (err)
goto out_release;
ino = (void *)ino + aligned_ilen;
pack_inode(c, ino, dir, 1);
err = ubifs_node_calc_hash(c, ino, hash_ino_host);
if (err)
goto out_release;
if (last_reference) {
err = ubifs_add_orphan(c, inode->i_ino);
if (err) {
release_head(c, BASEHD);
goto out_finish;
}
ui->del_cmtno = c->cmt_no;
}
err = write_head(c, BASEHD, dent, len, &lnum, &dent_offs, sync);
if (err)
goto out_release;
if (!sync) {
struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
ubifs_wbuf_add_ino_nolock(wbuf, inode->i_ino);
ubifs_wbuf_add_ino_nolock(wbuf, dir->i_ino);
}
release_head(c, BASEHD);
kfree(dent);
ubifs_add_auth_dirt(c, lnum);
if (deletion) {
if (nm->hash)
err = ubifs_tnc_remove_dh(c, &dent_key, nm->minor_hash);
else
err = ubifs_tnc_remove_nm(c, &dent_key, nm);
if (err)
goto out_ro;
err = ubifs_add_dirt(c, lnum, dlen);
} else
err = ubifs_tnc_add_nm(c, &dent_key, lnum, dent_offs, dlen,
hash_dent, nm);
if (err)
goto out_ro;
/*
* Note, we do not remove the inode from TNC even if the last reference
* to it has just been deleted, because the inode may still be opened.
* Instead, the inode has been added to orphan lists and the orphan
* subsystem will take further care about it.
*/
ino_key_init(c, &ino_key, inode->i_ino);
ino_offs = dent_offs + aligned_dlen;
err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, ilen, hash_ino);
if (err)
goto out_ro;
ino_key_init(c, &ino_key, dir->i_ino);
ino_offs += aligned_ilen;
err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs,
UBIFS_INO_NODE_SZ + host_ui->data_len, hash_ino_host);
if (err)
goto out_ro;
finish_reservation(c);
spin_lock(&ui->ui_lock);
ui->synced_i_size = ui->ui_size;
spin_unlock(&ui->ui_lock);
if (xent) {
spin_lock(&host_ui->ui_lock);
host_ui->synced_i_size = host_ui->ui_size;
spin_unlock(&host_ui->ui_lock);
}
mark_inode_clean(c, ui);
mark_inode_clean(c, host_ui);
return 0;
out_finish:
finish_reservation(c);
out_free:
kfree(dent);
return err;
out_release:
release_head(c, BASEHD);
kfree(dent);
out_ro:
ubifs_ro_mode(c, err);
if (last_reference)
ubifs_delete_orphan(c, inode->i_ino);
finish_reservation(c);
return err;
}
/**
* ubifs_jnl_write_data - write a data node to the journal.
* @c: UBIFS file-system description object
* @inode: inode the data node belongs to
* @key: node key
* @buf: buffer to write
* @len: data length (must not exceed %UBIFS_BLOCK_SIZE)
*
* This function writes a data node to the journal. Returns %0 if the data node
* was successfully written, and a negative error code in case of failure.
*/
int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
const union ubifs_key *key, const void *buf, int len)
{
struct ubifs_data_node *data;
int err, lnum, offs, compr_type, out_len, compr_len, auth_len;
int dlen = COMPRESSED_DATA_NODE_BUF_SZ, allocated = 1;
int write_len;
struct ubifs_inode *ui = ubifs_inode(inode);
bool encrypted = ubifs_crypt_is_encrypted(inode);
u8 hash[UBIFS_HASH_ARR_SZ];
dbg_jnlk(key, "ino %lu, blk %u, len %d, key ",
(unsigned long)key_inum(c, key), key_block(c, key), len);
ubifs_assert(c, len <= UBIFS_BLOCK_SIZE);
if (encrypted)
dlen += UBIFS_CIPHER_BLOCK_SIZE;
auth_len = ubifs_auth_node_sz(c);
data = kmalloc(dlen + auth_len, GFP_NOFS | __GFP_NOWARN);
if (!data) {
/*
* Fall-back to the write reserve buffer. Note, we might be
* currently on the memory reclaim path, when the kernel is
* trying to free some memory by writing out dirty pages. The
* write reserve buffer helps us to guarantee that we are
* always able to write the data.
*/
allocated = 0;
mutex_lock(&c->write_reserve_mutex);
data = c->write_reserve_buf;
}
data->ch.node_type = UBIFS_DATA_NODE;
key_write(c, key, &data->key);
data->size = cpu_to_le32(len);
if (!(ui->flags & UBIFS_COMPR_FL))
/* Compression is disabled for this inode */
compr_type = UBIFS_COMPR_NONE;
else
compr_type = ui->compr_type;
out_len = compr_len = dlen - UBIFS_DATA_NODE_SZ;
ubifs_compress(c, buf, len, &data->data, &compr_len, &compr_type);
ubifs_assert(c, compr_len <= UBIFS_BLOCK_SIZE);
if (encrypted) {
err = ubifs_encrypt(inode, data, compr_len, &out_len, key_block(c, key));
if (err)
goto out_free;
} else {
data->compr_size = 0;
out_len = compr_len;
}
dlen = UBIFS_DATA_NODE_SZ + out_len;
if (ubifs_authenticated(c))
write_len = ALIGN(dlen, 8) + auth_len;
else
write_len = dlen;
data->compr_type = cpu_to_le16(compr_type);
/* Make reservation before allocating sequence numbers */
err = make_reservation(c, DATAHD, write_len);
if (err)
goto out_free;
ubifs_prepare_node(c, data, dlen, 0);
err = write_head(c, DATAHD, data, write_len, &lnum, &offs, 0);
if (err)
goto out_release;
err = ubifs_node_calc_hash(c, data, hash);
if (err)
goto out_release;
ubifs_wbuf_add_ino_nolock(&c->jheads[DATAHD].wbuf, key_inum(c, key));
release_head(c, DATAHD);
ubifs_add_auth_dirt(c, lnum);
err = ubifs_tnc_add(c, key, lnum, offs, dlen, hash);
if (err)
goto out_ro;
finish_reservation(c);
if (!allocated)
mutex_unlock(&c->write_reserve_mutex);
else
kfree(data);
return 0;
out_release:
release_head(c, DATAHD);
out_ro:
ubifs_ro_mode(c, err);
finish_reservation(c);
out_free:
if (!allocated)
mutex_unlock(&c->write_reserve_mutex);
else
kfree(data);
return err;
}
/**
* ubifs_jnl_write_inode - flush inode to the journal.
* @c: UBIFS file-system description object
* @inode: inode to flush
*
* This function writes inode @inode to the journal. If the inode is
* synchronous, it also synchronizes the write-buffer. Returns zero in case of
* success and a negative error code in case of failure.
*/
int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode)
{
int err, lnum, offs;
struct ubifs_ino_node *ino;
struct ubifs_inode *ui = ubifs_inode(inode);
int sync = 0, write_len, ilen = UBIFS_INO_NODE_SZ;
int last_reference = !inode->i_nlink;
u8 hash[UBIFS_HASH_ARR_SZ];
dbg_jnl("ino %lu, nlink %u", inode->i_ino, inode->i_nlink);
/*
* If the inode is being deleted, do not write the attached data. No
* need to synchronize the write-buffer either.
*/
if (!last_reference) {
ilen += ui->data_len;
sync = IS_SYNC(inode);
}
if (ubifs_authenticated(c))
write_len = ALIGN(ilen, 8) + ubifs_auth_node_sz(c);
else
write_len = ilen;
ino = kmalloc(write_len, GFP_NOFS);
if (!ino)
return -ENOMEM;
/* Make reservation before allocating sequence numbers */
err = make_reservation(c, BASEHD, write_len);
if (err)
goto out_free;
pack_inode(c, ino, inode, 1);
err = ubifs_node_calc_hash(c, ino, hash);
if (err)
goto out_release;
err = write_head(c, BASEHD, ino, write_len, &lnum, &offs, sync);
if (err)
goto out_release;
if (!sync)
ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf,
inode->i_ino);
release_head(c, BASEHD);
ubifs_add_auth_dirt(c, lnum);
if (last_reference) {
err = ubifs_tnc_remove_ino(c, inode->i_ino);
if (err)
goto out_ro;
ubifs_delete_orphan(c, inode->i_ino);
err = ubifs_add_dirt(c, lnum, ilen);
} else {
union ubifs_key key;
ino_key_init(c, &key, inode->i_ino);
err = ubifs_tnc_add(c, &key, lnum, offs, ilen, hash);
}
if (err)
goto out_ro;
finish_reservation(c);
spin_lock(&ui->ui_lock);
ui->synced_i_size = ui->ui_size;
spin_unlock(&ui->ui_lock);
kfree(ino);
return 0;
out_release:
release_head(c, BASEHD);
out_ro:
ubifs_ro_mode(c, err);
finish_reservation(c);
out_free:
kfree(ino);
return err;
}
/**
* ubifs_jnl_delete_inode - delete an inode.
* @c: UBIFS file-system description object
* @inode: inode to delete
*
* This function deletes inode @inode which includes removing it from orphans,
* deleting it from TNC and, in some cases, writing a deletion inode to the
* journal.
*
* When regular file inodes are unlinked or a directory inode is removed, the
* 'ubifs_jnl_update()' function writes a corresponding deletion inode and
* direntry to the media, and adds the inode to orphans. After this, when the
* last reference to this inode has been dropped, this function is called. In
* general, it has to write one more deletion inode to the media, because if
* a commit happened between 'ubifs_jnl_update()' and
* 'ubifs_jnl_delete_inode()', the deletion inode is not in the journal
* anymore, and in fact it might not be on the flash anymore, because it might
* have been garbage-collected already. And for optimization reasons UBIFS does
* not read the orphan area if it has been unmounted cleanly, so it would have
* no indication in the journal that there is a deleted inode which has to be
* removed from TNC.
*
* However, if there was no commit between 'ubifs_jnl_update()' and
* 'ubifs_jnl_delete_inode()', then there is no need to write the deletion
* inode to the media for the second time. And this is quite a typical case.
*
* This function returns zero in case of success and a negative error code in
* case of failure.
*/
int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode)
{
int err;
struct ubifs_inode *ui = ubifs_inode(inode);
ubifs_assert(c, inode->i_nlink == 0);
if (ui->del_cmtno != c->cmt_no)
/* A commit happened for sure */
return ubifs_jnl_write_inode(c, inode);
down_read(&c->commit_sem);
/*
* Check commit number again, because the first test has been done
* without @c->commit_sem, so a commit might have happened.
*/
if (ui->del_cmtno != c->cmt_no) {
up_read(&c->commit_sem);
return ubifs_jnl_write_inode(c, inode);
}
err = ubifs_tnc_remove_ino(c, inode->i_ino);
if (err)
ubifs_ro_mode(c, err);
else
ubifs_delete_orphan(c, inode->i_ino);
up_read(&c->commit_sem);
return err;
}
/**
* ubifs_jnl_xrename - cross rename two directory entries.
* @c: UBIFS file-system description object
* @fst_dir: parent inode of 1st directory entry to exchange
* @fst_inode: 1st inode to exchange
* @fst_nm: name of 1st inode to exchange
* @snd_dir: parent inode of 2nd directory entry to exchange
* @snd_inode: 2nd inode to exchange
* @snd_nm: name of 2nd inode to exchange