/* * This file is part of UBIFS. * * Copyright (C) 2006-2008 Nokia Corporation. * Copyright (C) 2006, 2007 University of Szeged, Hungary * * 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 * Zoltan Sogor */ /* * This file implements UBIFS I/O subsystem which provides various I/O-related * helper functions (reading/writing/checking/validating nodes) and implements * write-buffering support. Write buffers help to save space which otherwise * would have been wasted for padding to the nearest minimal I/O unit boundary. * Instead, data first goes to the write-buffer and is flushed when the * buffer is full or when it is not used for some time (by timer). This is * similar to the mechanism is used by JFFS2. * * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by * mutexes defined inside these objects. Since sometimes upper-level code * has to lock the write-buffer (e.g. journal space reservation code), many * functions related to write-buffers have "nolock" suffix which means that the * caller has to lock the write-buffer before calling this function. * * UBIFS stores nodes at 64 bit-aligned addresses. If the node length is not * aligned, UBIFS starts the next node from the aligned address, and the padded * bytes may contain any rubbish. In other words, UBIFS does not put padding * bytes in those small gaps. Common headers of nodes store real node lengths, * not aligned lengths. Indexing nodes also store real lengths in branches. * * UBIFS uses padding when it pads to the next min. I/O unit. In this case it * uses padding nodes or padding bytes, if the padding node does not fit. * * All UBIFS nodes are protected by CRC checksums and UBIFS checks all nodes * every time they are read from the flash media. */ #include #include #include "ubifs.h" /** * ubifs_ro_mode - switch UBIFS to read read-only mode. * @c: UBIFS file-system description object * @err: error code which is the reason of switching to R/O mode */ void ubifs_ro_mode(struct ubifs_info *c, int err) { if (!c->ro_error) { c->ro_error = 1; c->no_chk_data_crc = 0; c->vfs_sb->s_flags |= MS_RDONLY; ubifs_warn("switched to read-only mode, error %d", err); dbg_dump_stack(); } } /** * ubifs_check_node - check node. * @c: UBIFS file-system description object * @buf: node to check * @lnum: logical eraseblock number * @offs: offset within the logical eraseblock * @quiet: print no messages * @must_chk_crc: indicates whether to always check the CRC * * This function checks node magic number and CRC checksum. This function also * validates node length to prevent UBIFS from becoming crazy when an attacker * feeds it a file-system image with incorrect nodes. For example, too large * node length in the common header could cause UBIFS to read memory outside of * allocated buffer when checking the CRC checksum. * * This function may skip data nodes CRC checking if @c->no_chk_data_crc is * true, which is controlled by corresponding UBIFS mount option. However, if * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is * checked. Similarly, if @c->always_chk_crc is true, @c->no_chk_data_crc is * ignored and CRC is checked. * * This function returns zero in case of success and %-EUCLEAN in case of bad * CRC or magic. */ int ubifs_check_node(const struct ubifs_info *c, const void *buf, int lnum, int offs, int quiet, int must_chk_crc) { int err = -EINVAL, type, node_len; uint32_t crc, node_crc, magic; const struct ubifs_ch *ch = buf; ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0); ubifs_assert(!(offs & 7) && offs < c->leb_size); magic = le32_to_cpu(ch->magic); if (magic != UBIFS_NODE_MAGIC) { if (!quiet) ubifs_err("bad magic %#08x, expected %#08x", magic, UBIFS_NODE_MAGIC); err = -EUCLEAN; goto out; } type = ch->node_type; if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) { if (!quiet) ubifs_err("bad node type %d", type); goto out; } node_len = le32_to_cpu(ch->len); if (node_len + offs > c->leb_size) goto out_len; if (c->ranges[type].max_len == 0) { if (node_len != c->ranges[type].len) goto out_len; } else if (node_len < c->ranges[type].min_len || node_len > c->ranges[type].max_len) goto out_len; if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->always_chk_crc && c->no_chk_data_crc) return 0; crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8); node_crc = le32_to_cpu(ch->crc); if (crc != node_crc) { if (!quiet) ubifs_err("bad CRC: calculated %#08x, read %#08x", crc, node_crc); err = -EUCLEAN; goto out; } return 0; out_len: if (!quiet) ubifs_err("bad node length %d", node_len); out: if (!quiet) { ubifs_err("bad node at LEB %d:%d", lnum, offs); dbg_dump_node(c, buf); dbg_dump_stack(); } return err; } /** * ubifs_pad - pad flash space. * @c: UBIFS file-system description object * @buf: buffer to put padding to * @pad: how many bytes to pad * * The flash media obliges us to write only in chunks of %c->min_io_size and * when we have to write less data we add padding node to the write-buffer and * pad it to the next minimal I/O unit's boundary. Padding nodes help when the * media is being scanned. If the amount of wasted space is not enough to fit a * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes * pattern (%UBIFS_PADDING_BYTE). * * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is * used. */ void ubifs_pad(const struct ubifs_info *c, void *buf, int pad) { uint32_t crc; ubifs_assert(pad >= 0 && !(pad & 7)); if (pad >= UBIFS_PAD_NODE_SZ) { struct ubifs_ch *ch = buf; struct ubifs_pad_node *pad_node = buf; ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC); ch->node_type = UBIFS_PAD_NODE; ch->group_type = UBIFS_NO_NODE_GROUP; ch->padding[0] = ch->padding[1] = 0; ch->sqnum = 0; ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ); pad -= UBIFS_PAD_NODE_SZ; pad_node->pad_len = cpu_to_le32(pad); crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8); ch->crc = cpu_to_le32(crc); memset(buf + UBIFS_PAD_NODE_SZ, 0, pad); } else if (pad > 0) /* Too little space, padding node won't fit */ memset(buf, UBIFS_PADDING_BYTE, pad); } /** * next_sqnum - get next sequence number. * @c: UBIFS file-system description object */ static unsigned long long next_sqnum(struct ubifs_info *c) { unsigned long long sqnum; spin_lock(&c->cnt_lock); sqnum = ++c->max_sqnum; spin_unlock(&c->cnt_lock); if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) { if (sqnum >= SQNUM_WATERMARK) { ubifs_err("sequence number overflow %llu, end of life", sqnum); ubifs_ro_mode(c, -EINVAL); } ubifs_warn("running out of sequence numbers, end of life soon"); } return sqnum; } /** * ubifs_prepare_node - prepare node to be written to flash. * @c: UBIFS file-system description object * @node: the node to pad * @len: node length * @pad: if the buffer has to be padded * * This function prepares node at @node to be written to the media - it * calculates node CRC, fills the common header, and adds proper padding up to * the next minimum I/O unit if @pad is not zero. */ void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad) { uint32_t crc; struct ubifs_ch *ch = node; unsigned long long sqnum = next_sqnum(c); ubifs_assert(len >= UBIFS_CH_SZ); ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC); ch->len = cpu_to_le32(len); ch->group_type = UBIFS_NO_NODE_GROUP; ch->sqnum = cpu_to_le64(sqnum); ch->padding[0] = ch->padding[1] = 0; crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8); ch->crc = cpu_to_le32(crc); if (pad) { len = ALIGN(len, 8); pad = ALIGN(len, c->min_io_size) - len; ubifs_pad(c, node + len, pad); } } /** * ubifs_prep_grp_node - prepare node of a group to be written to flash. * @c: UBIFS file-system description object * @node: the node to pad * @len: node length * @last: indicates the last node of the group * * This function prepares node at @node to be written to the media - it * calculates node CRC and fills the common header. */ void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last) { uint32_t crc; struct ubifs_ch *ch = node; unsigned long long sqnum = next_sqnum(c); ubifs_assert(len >= UBIFS_CH_SZ); ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC); ch->len = cpu_to_le32(len); if (last) ch->group_type = UBIFS_LAST_OF_NODE_GROUP; else ch->group_type = UBIFS_IN_NODE_GROUP; ch->sqnum = cpu_to_le64(sqnum); ch->padding[0] = ch->padding[1] = 0; crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8); ch->crc = cpu_to_le32(crc); } /** * wbuf_timer_callback - write-buffer timer callback function. * @data: timer data (write-buffer descriptor) * * This function is called when the write-buffer timer expires. */ static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer) { struct ubifs_wbuf *wbuf = container_of(timer, struct ubifs_wbuf, timer); dbg_io("jhead %s", dbg_jhead(wbuf->jhead)); wbuf->need_sync = 1; wbuf->c->need_wbuf_sync = 1; ubifs_wake_up_bgt(wbuf->c); return HRTIMER_NORESTART; } /** * new_wbuf_timer - start new write-buffer timer. * @wbuf: write-buffer descriptor */ static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf) { ubifs_assert(!hrtimer_active(&wbuf->timer)); if (wbuf->no_timer) return; dbg_io("set timer for jhead %s, %llu-%llu millisecs", dbg_jhead(wbuf->jhead), div_u64(ktime_to_ns(wbuf->softlimit), USEC_PER_SEC), div_u64(ktime_to_ns(wbuf->softlimit) + wbuf->delta, USEC_PER_SEC)); hrtimer_start_range_ns(&wbuf->timer, wbuf->softlimit, wbuf->delta, HRTIMER_MODE_REL); } /** * cancel_wbuf_timer - cancel write-buffer timer. * @wbuf: write-buffer descriptor */ static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf) { if (wbuf->no_timer) return; wbuf->need_sync = 0; hrtimer_cancel(&wbuf->timer); } /** * ubifs_wbuf_sync_nolock - synchronize write-buffer. * @wbuf: write-buffer to synchronize * * This function synchronizes write-buffer @buf and returns zero in case of * success or a negative error code in case of failure. */ int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf) { struct ubifs_info *c = wbuf->c; int err, dirt; cancel_wbuf_timer_nolock(wbuf); if (!wbuf->used || wbuf->lnum == -1) /* Write-buffer is empty or not seeked */ return 0; dbg_io("LEB %d:%d, %d bytes, jhead %s", wbuf->lnum, wbuf->offs, wbuf->used, dbg_jhead(wbuf->jhead)); ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY)); ubifs_assert(!(wbuf->avail & 7)); ubifs_assert(wbuf->offs + c->min_io_size <= c->leb_size); ubifs_assert(!c->ro_media); if (c->ro_error) return -EROFS; ubifs_pad(c, wbuf->buf + wbuf->used, wbuf->avail); err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs, c->min_io_size, wbuf->dtype); if (err) { ubifs_err("cannot write %d bytes to LEB %d:%d", c->min_io_size, wbuf->lnum, wbuf->offs); dbg_dump_stack(); return err; } dirt = wbuf->avail; spin_lock(&wbuf->lock); wbuf->offs += c->min_io_size; wbuf->avail = c->min_io_size; wbuf->used = 0; wbuf->next_ino = 0; spin_unlock(&wbuf->lock); if (wbuf->sync_callback) err = wbuf->sync_callback(c, wbuf->lnum, c->leb_size - wbuf->offs, dirt); return err; } /** * 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, jhead %s", lnum, offs, dbg_jhead(wbuf->jhead)); 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); 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; } /** * ubifs_wbuf_write_nolock - write data to flash via write-buffer. * @wbuf: write-buffer * @buf: node to write * @len: node length * * This function writes data to flash via write-buffer @wbuf. This means that * the last piece of the node won't reach the flash media immediately if it * does not take whole minimal I/O unit. Instead, the node will sit in RAM * until the write-buffer is synchronized (e.g., by timer). * * This function returns zero in case of success and a negative error code in * case of failure. If the node cannot be written because there is no more * space in this logical eraseblock, %-ENOSPC is returned. */ int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len) { struct ubifs_info *c = wbuf->c; int err, written, n, aligned_len = ALIGN(len, 8), offs; dbg_io("%d bytes (%s) to jhead %s wbuf at LEB %d:%d", len, dbg_ntype(((struct ubifs_ch *)buf)->node_type), dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs + wbuf->used); ubifs_assert(len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt); ubifs_assert(wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0); ubifs_assert(!(wbuf->offs & 7) && wbuf->offs <= c->leb_size); ubifs_assert(wbuf->avail > 0 && wbuf->avail <= c->min_io_size); ubifs_assert(mutex_is_locked(&wbuf->io_mutex)); ubifs_assert(!c->ro_media); if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) { err = -ENOSPC; goto out; } cancel_wbuf_timer_nolock(wbuf); if (c->ro_error) return -EROFS; if (aligned_len <= wbuf->avail) { /* * The node is not very large and fits entirely within * write-buffer. */ memcpy(wbuf->buf + wbuf->used, buf, len); if (aligned_len == wbuf->avail) { dbg_io("flush jhead %s wbuf to LEB %d:%d", dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs); err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs, c->min_io_size, wbuf->dtype); if (err) goto out; spin_lock(&wbuf->lock); wbuf->offs += c->min_io_size; wbuf->avail = c->min_io_size; wbuf->used = 0; wbuf->next_ino = 0; spin_unlock(&wbuf->lock); } else { spin_lock(&wbuf->lock); wbuf->avail -= aligned_len; wbuf->used += aligned_len; spin_unlock(&wbuf->lock); } goto exit; } /* * The node is large enough and does not fit entirely within current * minimal I/O unit. We have to fill and flush write-buffer and switch * to the next min. I/O unit. */ dbg_io("flush jhead %s wbuf to LEB %d:%d", dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs); memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail); err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs, c->min_io_size, wbuf->dtype); if (err) goto out; offs = wbuf->offs + c->min_io_size; len -= wbuf->avail; aligned_len -= wbuf->avail; written = wbuf->avail; /* * The remaining data may take more whole min. I/O units, so write the * remains multiple to min. I/O unit size directly to the flash media. * We align node length to 8-byte boundary because we anyway flash wbuf * if the remaining space is less than 8 bytes. */ n = aligned_len >> c->min_io_shift; if (n) { n <<= c->min_io_shift; dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, offs); err = ubi_leb_write(c->ubi, wbuf->lnum, buf + written, offs, n, wbuf->dtype); if (err) goto out; offs += n; aligned_len -= n; len -= n; written += n; } spin_lock(&wbuf->lock); if (aligned_len) /* * And now we have what's left and what does not take whole * min. I/O unit, so write it to the write-buffer and we are * done. */ memcpy(wbuf->buf, buf + written, len); wbuf->offs = offs; wbuf->used = aligned_len; wbuf->avail = c->min_io_size - aligned_len; wbuf->next_ino = 0; spin_unlock(&wbuf->lock); exit: if (wbuf->sync_callback) { int free = c->leb_size - wbuf->offs - wbuf->used; err = wbuf->sync_callback(c, wbuf->lnum, free, 0); if (err) goto out; } if (wbuf->used) new_wbuf_timer_nolock(wbuf); return 0; out: ubifs_err("cannot write %d bytes to LEB %d:%d, error %d", len, wbuf->lnum, wbuf->offs, err); dbg_dump_node(c, buf); dbg_dump_stack(); dbg_dump_leb(c, wbuf->lnum); return err; } /** * ubifs_write_node - write node to the media. * @c: UBIFS file-system description object * @buf: the node to write * @len: node length * @lnum: logical eraseblock number * @offs: offset within the logical eraseblock * @dtype: node life-time hint (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN) * * This function automatically fills node magic number, assigns sequence * number, and calculates node CRC checksum. The length of the @buf buffer has * to be aligned to the minimal I/O unit size. This function automatically * appends padding node and padding bytes if needed. Returns zero in case of * success and a negative error code in case of failure. */ int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum, int offs, int dtype) { int err, buf_len = ALIGN(len, c->min_io_size); dbg_io("LEB %d:%d, %s, length %d (aligned %d)", lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len, buf_len); ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0); ubifs_assert(offs % c->min_io_size == 0 && offs < c->leb_size); ubifs_assert(!c->ro_media); if (c->ro_error) return -EROFS; ubifs_prepare_node(c, buf, len, 1); err = ubi_leb_write(c->ubi, lnum, buf, offs, buf_len, dtype); if (err) { ubifs_err("cannot write %d bytes to LEB %d:%d, error %d", buf_len, lnum, offs, err); dbg_dump_node(c, buf); dbg_dump_stack(); } return err; } /** * ubifs_read_node_wbuf - read node from the media or write-buffer. * @wbuf: wbuf to check for un-written data * @buf: buffer to read to * @type: node type * @len: node length * @lnum: logical eraseblock number * @offs: offset within the logical eraseblock * * This function reads a node of known type and length, checks it and stores * in @buf. If the node partially or fully sits in the write-buffer, this * function takes data from the buffer, otherwise it reads the flash media. * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative * error code in case of failure. */ int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len, int lnum, int offs) { const struct ubifs_info *c = wbuf->c; int err, rlen, overlap; struct ubifs_ch *ch = buf; dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs, dbg_ntype(type), len, dbg_jhead(wbuf->jhead)); ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0); ubifs_assert(!(offs & 7) && offs < c->leb_size); ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT); spin_lock(&wbuf->lock); overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs); if (!overlap) { /* We may safely unlock the write-buffer and read the data */ spin_unlock(&wbuf->lock); return ubifs_read_node(c, buf, type, len, lnum, offs); } /* Don't read under wbuf */ rlen = wbuf->offs - offs; if (rlen < 0) rlen = 0; /* Copy the rest from the write-buffer */ memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen); spin_unlock(&wbuf->lock); if (rlen > 0) { /* Read everything that goes before write-buffer */ err = ubi_read(c->ubi, lnum, buf, offs, rlen); if (err && err != -EBADMSG) { ubifs_err("failed to read node %d from LEB %d:%d, " "error %d", type, lnum, offs, err); dbg_dump_stack(); return err; } } if (type != ch->node_type) { ubifs_err("bad node type (%d but expected %d)", ch->node_type, type); goto out; } err = ubifs_check_node(c, buf, lnum, offs, 0, 0); if (err) { ubifs_err("expected node type %d", type); return err; } rlen = le32_to_cpu(ch->len); if (rlen != len) { ubifs_err("bad node length %d, expected %d", rlen, len); goto out; } return 0; out: ubifs_err("bad node at LEB %d:%d", lnum, offs); dbg_dump_node(c, buf); dbg_dump_stack(); return -EINVAL; } /** * ubifs_read_node - read node. * @c: UBIFS file-system description object * @buf: buffer to read to * @type: node type * @len: node length (not aligned) * @lnum: logical eraseblock number * @offs: offset within the logical eraseblock * * This function reads a node of known type and and length, checks it and * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched * and a negative error code in case of failure. */ int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len, int lnum, int offs) { int err, l; struct ubifs_ch *ch = buf; dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len); ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0); ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size); ubifs_assert(!(offs & 7) && offs < c->leb_size); ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT); err = ubi_read(c->ubi, lnum, buf, offs, len); if (err && err != -EBADMSG) { ubifs_err("cannot read node %d from LEB %d:%d, error %d", type, lnum, offs, err); return err; } if (type != ch->node_type) { ubifs_err("bad node type (%d but expected %d)", ch->node_type, type); goto out; } err = ubifs_check_node(c, buf, lnum, offs, 0, 0); if (err) { ubifs_err("expected node type %d", type); return err; } l = le32_to_cpu(ch->len); if (l != len) { ubifs_err("bad node length %d, expected %d", l, len); goto out; } return 0; out: ubifs_err("bad node at LEB %d:%d, LEB mapping status %d", lnum, offs, ubi_is_mapped(c->ubi, lnum)); dbg_dump_node(c, buf); dbg_dump_stack(); return -EINVAL; } /** * ubifs_wbuf_init - initialize write-buffer. * @c: UBIFS file-system description object * @wbuf: write-buffer to initialize * * This function initializes write-buffer. Returns zero in case of success * %-ENOMEM in case of failure. */ int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf) { size_t size; wbuf->buf = kmalloc(c->min_io_size, GFP_KERNEL); if (!wbuf->buf) return -ENOMEM; size = (c->min_io_size / UBIFS_CH_SZ + 1) * sizeof(ino_t); wbuf->inodes = kmalloc(size, GFP_KERNEL); if (!wbuf->inodes) { kfree(wbuf->buf); wbuf->buf = NULL; return -ENOMEM; } wbuf->used = 0; wbuf->lnum = wbuf->offs = -1; wbuf->avail = c->min_io_size; wbuf->dtype = UBI_UNKNOWN; wbuf->sync_callback = NULL; mutex_init(&wbuf->io_mutex); spin_lock_init(&wbuf->lock); wbuf->c = c; wbuf->next_ino = 0; hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); wbuf->timer.function = wbuf_timer_callback_nolock; wbuf->softlimit = ktime_set(WBUF_TIMEOUT_SOFTLIMIT, 0); wbuf->delta = WBUF_TIMEOUT_HARDLIMIT - WBUF_TIMEOUT_SOFTLIMIT; wbuf->delta *= 1000000000ULL; ubifs_assert(wbuf->delta <= ULONG_MAX); return 0; } /** * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array. * @wbuf: the write-buffer where to add * @inum: the inode number * * This function adds an inode number to the inode array of the write-buffer. */ void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum) { if (!wbuf->buf) /* NOR flash or something similar */ return; spin_lock(&wbuf->lock); if (wbuf->used) wbuf->inodes[wbuf->next_ino++] = inum; spin_unlock(&wbuf->lock); } /** * wbuf_has_ino - returns if the wbuf contains data from the inode. * @wbuf: the write-buffer * @inum: the inode number * * This function returns with %1 if the write-buffer contains some data from the * given inode otherwise it returns with %0. */ static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum) { int i, ret = 0; spin_lock(&wbuf->lock); for (i = 0; i < wbuf->next_ino; i++) if (inum == wbuf->inodes[i]) { ret = 1; break; } spin_unlock(&wbuf->lock); return ret; } /** * 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; }