| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * This file is part of UBIFS. |
| * |
| * Copyright (C) 2006-2008 Nokia Corporation. |
| * Copyright (C) 2006, 2007 University of Szeged, Hungary |
| * |
| * 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. |
| * |
| * UBIFS distinguishes between minimum write size (@c->min_io_size) and maximum |
| * write size (@c->max_write_size). The latter is the maximum amount of bytes |
| * the underlying flash is able to program at a time, and writing in |
| * @c->max_write_size units should presumably be faster. Obviously, |
| * @c->min_io_size <= @c->max_write_size. Write-buffers are of |
| * @c->max_write_size bytes in size for maximum performance. However, when a |
| * write-buffer is flushed, only the portion of it (aligned to @c->min_io_size |
| * boundary) which contains data is written, not the whole write-buffer, |
| * because this is more space-efficient. |
| * |
| * This optimization adds few complications to the code. Indeed, on the one |
| * hand, we want to write in optimal @c->max_write_size bytes chunks, which |
| * also means aligning writes at the @c->max_write_size bytes offsets. On the |
| * other hand, we do not want to waste space when synchronizing the write |
| * buffer, so during synchronization we writes in smaller chunks. And this makes |
| * the next write offset to be not aligned to @c->max_write_size bytes. So the |
| * have to make sure that the write-buffer offset (@wbuf->offs) becomes aligned |
| * to @c->max_write_size bytes again. We do this by temporarily shrinking |
| * write-buffer size (@wbuf->size). |
| * |
| * 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 CRC when |
| * they are read from the flash media. |
| */ |
| |
| #include <linux/crc32.h> |
| #include <linux/slab.h> |
| #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 |= SB_RDONLY; |
| ubifs_warn(c, "switched to read-only mode, error %d", err); |
| dump_stack(); |
| } |
| } |
| |
| /* |
| * Below are simple wrappers over UBI I/O functions which include some |
| * additional checks and UBIFS debugging stuff. See corresponding UBI function |
| * for more information. |
| */ |
| |
| int ubifs_leb_read(const struct ubifs_info *c, int lnum, void *buf, int offs, |
| int len, int even_ebadmsg) |
| { |
| int err; |
| |
| err = ubi_read(c->ubi, lnum, buf, offs, len); |
| /* |
| * In case of %-EBADMSG print the error message only if the |
| * @even_ebadmsg is true. |
| */ |
| if (err && (err != -EBADMSG || even_ebadmsg)) { |
| ubifs_err(c, "reading %d bytes from LEB %d:%d failed, error %d", |
| len, lnum, offs, err); |
| dump_stack(); |
| } |
| return err; |
| } |
| |
| int ubifs_leb_write(struct ubifs_info *c, int lnum, const void *buf, int offs, |
| int len) |
| { |
| int err; |
| |
| ubifs_assert(c, !c->ro_media && !c->ro_mount); |
| if (c->ro_error) |
| return -EROFS; |
| if (!dbg_is_tst_rcvry(c)) |
| err = ubi_leb_write(c->ubi, lnum, buf, offs, len); |
| else |
| err = dbg_leb_write(c, lnum, buf, offs, len); |
| if (err) { |
| ubifs_err(c, "writing %d bytes to LEB %d:%d failed, error %d", |
| len, lnum, offs, err); |
| ubifs_ro_mode(c, err); |
| dump_stack(); |
| } |
| return err; |
| } |
| |
| int ubifs_leb_change(struct ubifs_info *c, int lnum, const void *buf, int len) |
| { |
| int err; |
| |
| ubifs_assert(c, !c->ro_media && !c->ro_mount); |
| if (c->ro_error) |
| return -EROFS; |
| if (!dbg_is_tst_rcvry(c)) |
| err = ubi_leb_change(c->ubi, lnum, buf, len); |
| else |
| err = dbg_leb_change(c, lnum, buf, len); |
| if (err) { |
| ubifs_err(c, "changing %d bytes in LEB %d failed, error %d", |
| len, lnum, err); |
| ubifs_ro_mode(c, err); |
| dump_stack(); |
| } |
| return err; |
| } |
| |
| int ubifs_leb_unmap(struct ubifs_info *c, int lnum) |
| { |
| int err; |
| |
| ubifs_assert(c, !c->ro_media && !c->ro_mount); |
| if (c->ro_error) |
| return -EROFS; |
| if (!dbg_is_tst_rcvry(c)) |
| err = ubi_leb_unmap(c->ubi, lnum); |
| else |
| err = dbg_leb_unmap(c, lnum); |
| if (err) { |
| ubifs_err(c, "unmap LEB %d failed, error %d", lnum, err); |
| ubifs_ro_mode(c, err); |
| dump_stack(); |
| } |
| return err; |
| } |
| |
| int ubifs_leb_map(struct ubifs_info *c, int lnum) |
| { |
| int err; |
| |
| ubifs_assert(c, !c->ro_media && !c->ro_mount); |
| if (c->ro_error) |
| return -EROFS; |
| if (!dbg_is_tst_rcvry(c)) |
| err = ubi_leb_map(c->ubi, lnum); |
| else |
| err = dbg_leb_map(c, lnum); |
| if (err) { |
| ubifs_err(c, "mapping LEB %d failed, error %d", lnum, err); |
| ubifs_ro_mode(c, err); |
| dump_stack(); |
| } |
| return err; |
| } |
| |
| int ubifs_is_mapped(const struct ubifs_info *c, int lnum) |
| { |
| int err; |
| |
| err = ubi_is_mapped(c->ubi, lnum); |
| if (err < 0) { |
| ubifs_err(c, "ubi_is_mapped failed for LEB %d, error %d", |
| lnum, err); |
| dump_stack(); |
| } |
| return err; |
| } |
| |
| /** |
| * 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->mounting or @c->remounting_rw is true (we are |
| * mounting or re-mounting to R/W mode), @c->no_chk_data_crc is ignored and CRC |
| * is checked. This is because during mounting or re-mounting from R/O mode to |
| * R/W mode we may read journal nodes (when replying the journal or doing the |
| * recovery) and the journal nodes may potentially be corrupted, so checking is |
| * required. |
| * |
| * 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, dump_node = 1; |
| uint32_t crc, node_crc, magic; |
| const struct ubifs_ch *ch = buf; |
| |
| ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0); |
| ubifs_assert(c, !(offs & 7) && offs < c->leb_size); |
| |
| magic = le32_to_cpu(ch->magic); |
| if (magic != UBIFS_NODE_MAGIC) { |
| if (!quiet) |
| ubifs_err(c, "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(c, "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->mounting && |
| !c->remounting_rw && 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(c, "bad CRC: calculated %#08x, read %#08x", |
| crc, node_crc); |
| err = -EUCLEAN; |
| goto out; |
| } |
| |
| return 0; |
| |
| out_len: |
| if (!quiet) |
| ubifs_err(c, "bad node length %d", node_len); |
| if (type == UBIFS_DATA_NODE && node_len > UBIFS_DATA_NODE_SZ) |
| dump_node = 0; |
| out: |
| if (!quiet) { |
| ubifs_err(c, "bad node at LEB %d:%d", lnum, offs); |
| if (dump_node) { |
| ubifs_dump_node(c, buf); |
| } else { |
| int safe_len = min3(node_len, c->leb_size - offs, |
| (int)UBIFS_MAX_DATA_NODE_SZ); |
| pr_err("\tprevent out-of-bounds memory access\n"); |
| pr_err("\ttruncated data node length %d\n", safe_len); |
| pr_err("\tcorrupted data node:\n"); |
| print_hex_dump(KERN_ERR, "\t", DUMP_PREFIX_OFFSET, 32, 1, |
| buf, safe_len, 0); |
| } |
| 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(c, pad >= 0); |
| |
| 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(c, "sequence number overflow %llu, end of life", |
| sqnum); |
| ubifs_ro_mode(c, -EINVAL); |
| } |
| ubifs_warn(c, "running out of sequence numbers, end of life soon"); |
| } |
| |
| return sqnum; |
| } |
| |
| void ubifs_init_node(struct ubifs_info *c, void *node, int len, int pad) |
| { |
| struct ubifs_ch *ch = node; |
| unsigned long long sqnum = next_sqnum(c); |
| |
| ubifs_assert(c, 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; |
| |
| if (pad) { |
| len = ALIGN(len, 8); |
| pad = ALIGN(len, c->min_io_size) - len; |
| ubifs_pad(c, node + len, pad); |
| } |
| } |
| |
| void ubifs_crc_node(struct ubifs_info *c, void *node, int len) |
| { |
| struct ubifs_ch *ch = node; |
| uint32_t crc; |
| |
| crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8); |
| ch->crc = cpu_to_le32(crc); |
| } |
| |
| /** |
| * ubifs_prepare_node_hmac - prepare node to be written to flash. |
| * @c: UBIFS file-system description object |
| * @node: the node to pad |
| * @len: node length |
| * @hmac_offs: offset of the HMAC in the node |
| * @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. if @hmac_offs is positive then |
| * a HMAC is inserted into the node at the given offset. |
| * |
| * This function returns 0 for success or a negative error code otherwise. |
| */ |
| int ubifs_prepare_node_hmac(struct ubifs_info *c, void *node, int len, |
| int hmac_offs, int pad) |
| { |
| int err; |
| |
| ubifs_init_node(c, node, len, pad); |
| |
| if (hmac_offs > 0) { |
| err = ubifs_node_insert_hmac(c, node, len, hmac_offs); |
| if (err) |
| return err; |
| } |
| |
| ubifs_crc_node(c, node, len); |
| |
| return 0; |
| } |
| |
| /** |
| * 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) |
| { |
| /* |
| * Deliberately ignore return value since this function can only fail |
| * when a hmac offset is given. |
| */ |
| ubifs_prepare_node_hmac(c, node, len, 0, 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(c, 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. |
| * @timer: 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. |
| * @c: UBIFS file-system description object |
| * @wbuf: write-buffer descriptor |
| */ |
| static void new_wbuf_timer_nolock(struct ubifs_info *c, struct ubifs_wbuf *wbuf) |
| { |
| ktime_t softlimit = ms_to_ktime(dirty_writeback_interval * 10); |
| unsigned long long delta = dirty_writeback_interval; |
| |
| /* centi to milli, milli to nano, then 10% */ |
| delta *= 10ULL * NSEC_PER_MSEC / 10ULL; |
| |
| ubifs_assert(c, !hrtimer_active(&wbuf->timer)); |
| ubifs_assert(c, delta <= ULONG_MAX); |
| |
| if (wbuf->no_timer) |
| return; |
| dbg_io("set timer for jhead %s, %llu-%llu millisecs", |
| dbg_jhead(wbuf->jhead), |
| div_u64(ktime_to_ns(softlimit), USEC_PER_SEC), |
| div_u64(ktime_to_ns(softlimit) + delta, USEC_PER_SEC)); |
| hrtimer_start_range_ns(&wbuf->timer, softlimit, 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. |
| * |
| * Note, although write-buffers are of @c->max_write_size, this function does |
| * not necessarily writes all @c->max_write_size bytes to the flash. Instead, |
| * if the write-buffer is only partially filled with data, only the used part |
| * of the write-buffer (aligned on @c->min_io_size boundary) is synchronized. |
| * This way we waste less space. |
| */ |
| int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf) |
| { |
| struct ubifs_info *c = wbuf->c; |
| int err, dirt, sync_len; |
| |
| 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, !(wbuf->avail & 7)); |
| ubifs_assert(c, wbuf->offs + wbuf->size <= c->leb_size); |
| ubifs_assert(c, wbuf->size >= c->min_io_size); |
| ubifs_assert(c, wbuf->size <= c->max_write_size); |
| ubifs_assert(c, wbuf->size % c->min_io_size == 0); |
| ubifs_assert(c, !c->ro_media && !c->ro_mount); |
| if (c->leb_size - wbuf->offs >= c->max_write_size) |
| ubifs_assert(c, !((wbuf->offs + wbuf->size) % c->max_write_size)); |
| |
| if (c->ro_error) |
| return -EROFS; |
| |
| /* |
| * Do not write whole write buffer but write only the minimum necessary |
| * amount of min. I/O units. |
| */ |
| sync_len = ALIGN(wbuf->used, c->min_io_size); |
| dirt = sync_len - wbuf->used; |
| if (dirt) |
| ubifs_pad(c, wbuf->buf + wbuf->used, dirt); |
| err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, sync_len); |
| if (err) |
| return err; |
| |
| spin_lock(&wbuf->lock); |
| wbuf->offs += sync_len; |
| /* |
| * Now @wbuf->offs is not necessarily aligned to @c->max_write_size. |
| * But our goal is to optimize writes and make sure we write in |
| * @c->max_write_size chunks and to @c->max_write_size-aligned offset. |
| * Thus, if @wbuf->offs is not aligned to @c->max_write_size now, make |
| * sure that @wbuf->offs + @wbuf->size is aligned to |
| * @c->max_write_size. This way we make sure that after next |
| * write-buffer flush we are again at the optimal offset (aligned to |
| * @c->max_write_size). |
| */ |
| if (c->leb_size - wbuf->offs < c->max_write_size) |
| wbuf->size = c->leb_size - wbuf->offs; |
| else if (wbuf->offs & (c->max_write_size - 1)) |
| wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs; |
| else |
| wbuf->size = c->max_write_size; |
| wbuf->avail = wbuf->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 |
| * |
| * This function targets the write-buffer to logical eraseblock @lnum:@offs. |
| * The write-buffer has to be 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) |
| { |
| const struct ubifs_info *c = wbuf->c; |
| |
| dbg_io("LEB %d:%d, jhead %s", lnum, offs, dbg_jhead(wbuf->jhead)); |
| ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt); |
| ubifs_assert(c, offs >= 0 && offs <= c->leb_size); |
| ubifs_assert(c, offs % c->min_io_size == 0 && !(offs & 7)); |
| ubifs_assert(c, lnum != wbuf->lnum); |
| ubifs_assert(c, wbuf->used == 0); |
| |
| spin_lock(&wbuf->lock); |
| wbuf->lnum = lnum; |
| wbuf->offs = offs; |
| if (c->leb_size - wbuf->offs < c->max_write_size) |
| wbuf->size = c->leb_size - wbuf->offs; |
| else if (wbuf->offs & (c->max_write_size - 1)) |
| wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs; |
| else |
| wbuf->size = c->max_write_size; |
| wbuf->avail = wbuf->size; |
| wbuf->used = 0; |
| spin_unlock(&wbuf->lock); |
| |
| 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, !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(c, "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 max. write unit (@c->max_write_size). Instead, the node |
| * will sit in RAM until the write-buffer is synchronized (e.g., by timer, or |
| * because more data are appended to the write-buffer). |
| * |
| * 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); |
| |
| 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(c, len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt); |
| ubifs_assert(c, wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0); |
| ubifs_assert(c, !(wbuf->offs & 7) && wbuf->offs <= c->leb_size); |
| ubifs_assert(c, wbuf->avail > 0 && wbuf->avail <= wbuf->size); |
| ubifs_assert(c, wbuf->size >= c->min_io_size); |
| ubifs_assert(c, wbuf->size <= c->max_write_size); |
| ubifs_assert(c, wbuf->size % c->min_io_size == 0); |
| ubifs_assert(c, mutex_is_locked(&wbuf->io_mutex)); |
| ubifs_assert(c, !c->ro_media && !c->ro_mount); |
| ubifs_assert(c, !c->space_fixup); |
| if (c->leb_size - wbuf->offs >= c->max_write_size) |
| ubifs_assert(c, !((wbuf->offs + wbuf->size) % c->max_write_size)); |
| |
| 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 > len) { |
| ubifs_assert(c, aligned_len - len < 8); |
| ubifs_pad(c, wbuf->buf + wbuf->used + len, aligned_len - 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 = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, |
| wbuf->offs, wbuf->size); |
| if (err) |
| goto out; |
| |
| spin_lock(&wbuf->lock); |
| wbuf->offs += wbuf->size; |
| if (c->leb_size - wbuf->offs >= c->max_write_size) |
| wbuf->size = c->max_write_size; |
| else |
| wbuf->size = c->leb_size - wbuf->offs; |
| wbuf->avail = wbuf->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; |
| } |
| |
| written = 0; |
| |
| if (wbuf->used) { |
| /* |
| * The node is large enough and does not fit entirely within |
| * current available space. We have to fill and flush |
| * write-buffer and switch to the next max. write 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 = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, |
| wbuf->size); |
| if (err) |
| goto out; |
| |
| wbuf->offs += wbuf->size; |
| len -= wbuf->avail; |
| aligned_len -= wbuf->avail; |
| written += wbuf->avail; |
| } else if (wbuf->offs & (c->max_write_size - 1)) { |
| /* |
| * The write-buffer offset is not aligned to |
| * @c->max_write_size and @wbuf->size is less than |
| * @c->max_write_size. Write @wbuf->size bytes to make sure the |
| * following writes are done in optimal @c->max_write_size |
| * chunks. |
| */ |
| dbg_io("write %d bytes to LEB %d:%d", |
| wbuf->size, wbuf->lnum, wbuf->offs); |
| err = ubifs_leb_write(c, wbuf->lnum, buf, wbuf->offs, |
| wbuf->size); |
| if (err) |
| goto out; |
| |
| wbuf->offs += wbuf->size; |
| len -= wbuf->size; |
| aligned_len -= wbuf->size; |
| written += wbuf->size; |
| } |
| |
| /* |
| * The remaining data may take more whole max. write units, so write the |
| * remains multiple to max. write 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->max_write_shift; |
| if (n) { |
| n <<= c->max_write_shift; |
| dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, |
| wbuf->offs); |
| err = ubifs_leb_write(c, wbuf->lnum, buf + written, |
| wbuf->offs, n); |
| if (err) |
| goto out; |
| wbuf->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 |
| * max. write unit, so write it to the write-buffer and we are |
| * done. |
| */ |
| memcpy(wbuf->buf, buf + written, len); |
| if (aligned_len > len) { |
| ubifs_assert(c, aligned_len - len < 8); |
| ubifs_pad(c, wbuf->buf + len, aligned_len - len); |
| } |
| } |
| |
| if (c->leb_size - wbuf->offs >= c->max_write_size) |
| wbuf->size = c->max_write_size; |
| else |
| wbuf->size = c->leb_size - wbuf->offs; |
| wbuf->avail = wbuf->size - aligned_len; |
| wbuf->used = 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(c, wbuf); |
| |
| return 0; |
| |
| out: |
| ubifs_err(c, "cannot write %d bytes to LEB %d:%d, error %d", |
| len, wbuf->lnum, wbuf->offs, err); |
| ubifs_dump_node(c, buf); |
| dump_stack(); |
| ubifs_dump_leb(c, wbuf->lnum); |
| return err; |
| } |
| |
| /** |
| * ubifs_write_node_hmac - 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 |
| * @hmac_offs: offset of the HMAC within the node |
| * |
| * 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_hmac(struct ubifs_info *c, void *buf, int len, int lnum, |
| int offs, int hmac_offs) |
| { |
| 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(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0); |
| ubifs_assert(c, offs % c->min_io_size == 0 && offs < c->leb_size); |
| ubifs_assert(c, !c->ro_media && !c->ro_mount); |
| ubifs_assert(c, !c->space_fixup); |
| |
| if (c->ro_error) |
| return -EROFS; |
| |
| err = ubifs_prepare_node_hmac(c, buf, len, hmac_offs, 1); |
| if (err) |
| return err; |
| |
| err = ubifs_leb_write(c, lnum, buf, offs, buf_len); |
| if (err) |
| ubifs_dump_node(c, buf); |
| |
| 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 |
| * |
| * 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) |
| { |
| return ubifs_write_node_hmac(c, buf, len, lnum, offs, -1); |
| } |
| |
| /** |
| * 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(c, wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0); |
| ubifs_assert(c, !(offs & 7) && offs < c->leb_size); |
| ubifs_assert(c, 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 = ubifs_leb_read(c, lnum, buf, offs, rlen, 0); |
| if (err && err != -EBADMSG) |
| return err; |
| } |
| |
| if (type != ch->node_type) { |
| ubifs_err(c, "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(c, "expected node type %d", type); |
| return err; |
| } |
| |
| rlen = le32_to_cpu(ch->len); |
| if (rlen != len) { |
| ubifs_err(c, "bad node length %d, expected %d", rlen, len); |
| goto out; |
| } |
| |
| return 0; |
| |
| out: |
| ubifs_err(c, "bad node at LEB %d:%d", lnum, offs); |
| ubifs_dump_node(c, buf); |
| 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(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0); |
| ubifs_assert(c, len >= UBIFS_CH_SZ && offs + len <= c->leb_size); |
| ubifs_assert(c, !(offs & 7) && offs < c->leb_size); |
| ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT); |
| |
| err = ubifs_leb_read(c, lnum, buf, offs, len, 0); |
| if (err && err != -EBADMSG) |
| return err; |
| |
| if (type != ch->node_type) { |
| ubifs_errc(c, "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_errc(c, "expected node type %d", type); |
| return err; |
| } |
| |
| l = le32_to_cpu(ch->len); |
| if (l != len) { |
| ubifs_errc(c, "bad node length %d, expected %d", l, len); |
| goto out; |
| } |
| |
| return 0; |
| |
| out: |
| ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum, |
| offs, ubi_is_mapped(c->ubi, lnum)); |
| if (!c->probing) { |
| ubifs_dump_node(c, buf); |
| 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->max_write_size, GFP_KERNEL); |
| if (!wbuf->buf) |
| return -ENOMEM; |
| |
| size = (c->max_write_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; |
| /* |
| * If the LEB starts at the max. write size aligned address, then |
| * write-buffer size has to be set to @c->max_write_size. Otherwise, |
| * set it to something smaller so that it ends at the closest max. |
| * write size boundary. |
| */ |
| size = c->max_write_size - (c->leb_start % c->max_write_size); |
| wbuf->avail = wbuf->size = size; |
| 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; |
| 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; |
| } |