// 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 "kmem.h" #include "crc32.h" #include "ubifs.h" #include "defs.h" #include "debug.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; 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 = 0; off_t pos = (off_t)lnum * c->leb_size + offs; if (!len) return 0; /* * The %-EBADMSG may be ignored in some case, the buf may not be filled * with data in some buggy mtd drivers. So we'd better to reset the buf * content before reading. */ memset(buf, 0, len); if (lseek(c->dev_fd, pos, SEEK_SET) != pos) { err = -errno; goto out; } if (read(c->dev_fd, buf, len) != len) err = -errno; out: /* * 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 = 0; off_t pos = (off_t)lnum * c->leb_size + offs; ubifs_assert(c, !c->ro_media && !c->ro_mount); if (c->ro_error) return -EROFS; if (!c->libubi) { err = -ENODEV; goto out; } if (!len) return 0; if (lseek(c->dev_fd, pos, SEEK_SET) != pos) { err = -errno; goto out; } if (write(c->dev_fd, buf, len) != len) err = -errno; out: 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 = 0; off_t pos = (off_t)lnum * c->leb_size; ubifs_assert(c, !c->ro_media && !c->ro_mount); if (c->ro_error) return -EROFS; if (c->libubi) { err = ubi_leb_change_start(c->libubi, c->dev_fd, lnum, len); if (err) { ubifs_err(c, "ubi_leb_change_start failed"); err = -errno; goto out; } } if (!len) return 0; if (lseek(c->dev_fd, pos, SEEK_SET) != pos) { err = -errno; goto out; } if (write(c->dev_fd, buf, len) != len) err = -errno; out: 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 = 0; ubifs_assert(c, !c->ro_media && !c->ro_mount); if (c->ro_error) return -EROFS; if (!c->libubi) return -ENODEV; if (ubi_leb_unmap(c->dev_fd, lnum)) err = -errno; 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 = 0; ubifs_assert(c, !c->ro_media && !c->ro_mount); if (c->ro_error) return -EROFS; if (!c->libubi) return -ENODEV; if (ubi_leb_map(c->dev_fd, lnum)) err = -errno; 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 = 0; if (!c->libubi) return -ENODEV; if (ubi_is_mapped(c->dev_fd, lnum)) err = -errno; 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 * @len: node length * @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 len, 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(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); out: if (!quiet) { ubifs_err(c, "bad node at LEB %d:%d", lnum, offs); ubifs_dump_node(c, buf, len); 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(__unused 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); } /** * 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; 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_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, n, written = 0, 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; } 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; } 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) { int m = n - 1; dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, wbuf->offs); if (m) { /* '(n-1)<max_write_shift < len' is always true. */ m <<= c->max_write_shift; err = ubifs_leb_write(c, wbuf->lnum, buf + written, wbuf->offs, m); if (err) goto out; wbuf->offs += m; aligned_len -= m; len -= m; written += m; } /* * The non-written len of buf may be less than 'n' because * parameter 'len' is not 8 bytes aligned, so here we read * min(len, n) bytes from buf. */ n = 1 << c->max_write_shift; memcpy(wbuf->buf, buf + written, min(len, n)); if (n > len) { ubifs_assert(c, n - len < 8); ubifs_pad(c, wbuf->buf + len, n - len); } err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, n); if (err) goto out; wbuf->offs += n; aligned_len -= n; len -= min(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; } 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, written + len); 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, len); 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, len, 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, len); 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 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_err(c, "bad node type (%d but expected %d)", ch->node_type, type); goto out; } err = ubifs_check_node(c, buf, len, lnum, offs, 0, 0); if (err) { ubifs_err(c, "expected node type %d", type); return err; } l = le32_to_cpu(ch->len); if (l != len) { ubifs_err(c, "bad node length %d, expected %d", l, len); goto out; } return 0; out: ubifs_err(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum, offs, ubi_is_mapped(c->dev_fd, lnum)); ubifs_dump_node(c, buf, len); 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; /* * Different from linux kernel, there is no way to get leb_start in * userspace, set write-buffer size as @c->max_write_size directly. * Since wbuf->lnum is initialized as -1, wbuf->size will always be * reset in ubifs_wbuf_seek_nolock, it won't be any problems. */ size = 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; return 0; }