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Diffstat (limited to 'fs/ubifs/io.c')
| -rw-r--r-- | fs/ubifs/io.c | 914 |
1 files changed, 914 insertions, 0 deletions
diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c new file mode 100644 index 00000000000..3374f91b670 --- /dev/null +++ b/fs/ubifs/io.c @@ -0,0 +1,914 @@ +/* + * 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 + * similarto 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 <linux/crc32.h> +#include "ubifs.h" + +/** + * 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 + * + * 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 returns zero in case of success %-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 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; + + 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 void wbuf_timer_callback_nolock(unsigned long data) +{ + struct ubifs_wbuf *wbuf = (struct ubifs_wbuf *)data; + + wbuf->need_sync = 1; + wbuf->c->need_wbuf_sync = 1; + ubifs_wake_up_bgt(wbuf->c); +} + +/** + * new_wbuf_timer - start new write-buffer timer. + * @wbuf: write-buffer descriptor + */ +static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf) +{ + ubifs_assert(!timer_pending(&wbuf->timer)); + + if (!wbuf->timeout) + return; + + wbuf->timer.expires = jiffies + wbuf->timeout; + add_timer(&wbuf->timer); +} + +/** + * cancel_wbuf_timer - cancel write-buffer timer. + * @wbuf: write-buffer descriptor + */ +static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf) +{ + /* + * If the syncer is waiting for the lock (from the background thread's + * context) and another task is changing write-buffer then the syncing + * should be canceled. + */ + wbuf->need_sync = 0; + del_timer(&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", + wbuf->lnum, wbuf->offs, wbuf->used); + 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); + + if (c->ro_media) + 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", lnum, offs); + ubifs_assert(lnum >= 0 && lnum < c->leb_cnt); + ubifs_assert(offs >= 0 && offs <= c->leb_size); + ubifs_assert(offs % c->min_io_size == 0 && !(offs & 7)); + ubifs_assert(lnum != wbuf->lnum); + + if (wbuf->used > 0) { + int err = ubifs_wbuf_sync_nolock(wbuf); + + if (err) + return err; + } + + spin_lock(&wbuf->lock); + wbuf->lnum = lnum; + wbuf->offs = offs; + wbuf->avail = c->min_io_size; + wbuf->used = 0; + spin_unlock(&wbuf->lock); + wbuf->dtype = dtype; + + return 0; +} + +/** + * ubifs_bg_wbufs_sync - synchronize write-buffers. + * @c: UBIFS file-system description object + * + * This function is called by background thread to synchronize write-buffers. + * Returns zero in case of success and a negative error code in case of + * failure. + */ +int ubifs_bg_wbufs_sync(struct ubifs_info *c) +{ + int err, i; + + if (!c->need_wbuf_sync) + return 0; + c->need_wbuf_sync = 0; + + if (c->ro_media) { + 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 wbuf at LEB %d:%d", len, + dbg_ntype(((struct ubifs_ch *)buf)->node_type), 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)); + + if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) { + err = -ENOSPC; + goto out; + } + + cancel_wbuf_timer_nolock(wbuf); + + if (c->ro_media) + 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 wbuf to LEB %d:%d", 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 wbuf to LEB %d:%d", 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); + + if (c->ro_media) + 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", lnum, offs, dbg_ntype(type), len); + 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); + 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); + 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", lnum, offs); + 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; + init_timer(&wbuf->timer); + wbuf->timer.function = wbuf_timer_callback_nolock; + wbuf->timer.data = (unsigned long)wbuf; + wbuf->timeout = DEFAULT_WBUF_TIMEOUT; + wbuf->next_ino = 0; + + return 0; +} + +/** + * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array. + * @wbuf: the write-buffer whereto 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; +} |