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Diffstat (limited to 'fs/ubifs/io.c')
| -rw-r--r-- | fs/ubifs/io.c | 1200 |
1 files changed, 1200 insertions, 0 deletions
diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c new file mode 100644 index 000000000..0ad819c90 --- /dev/null +++ b/fs/ubifs/io.c @@ -0,0 +1,1200 @@ +/* + * This file is part of UBIFS. + * + * Copyright (C) 2006-2008 Nokia Corporation. + * Copyright (C) 2006, 2007 University of Szeged, Hungary + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 51 + * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Authors: Artem Bityutskiy (Битюцкий Артём) + * Adrian Hunter + * Zoltan Sogor + */ + +/* + * This file implements UBIFS I/O subsystem which provides various I/O-related + * helper functions (reading/writing/checking/validating nodes) and implements + * write-buffering support. Write buffers help to save space which otherwise + * would have been wasted for padding to the nearest minimal I/O unit boundary. + * Instead, data first goes to the write-buffer and is flushed when the + * buffer is full or when it is not used for some time (by timer). This is + * similar to the mechanism is used by JFFS2. + * + * 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; +} + +/** + * 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(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; + 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(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) { + int m = n - 1; + + dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, + wbuf->offs); + + if (m) { + /* '(n-1)<<c->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; + } + + 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 - 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) +{ + 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; + + ubifs_prepare_node(c, buf, len, 1); + err = ubifs_leb_write(c, lnum, buf, offs, buf_len); + if (err) + ubifs_dump_node(c, buf); + + return err; +} + +/** + * ubifs_read_node_wbuf - read node from the media or write-buffer. + * @wbuf: wbuf to check for un-written data + * @buf: buffer to read to + * @type: node type + * @len: node length + * @lnum: logical eraseblock number + * @offs: offset within the logical eraseblock + * + * This function reads a node of known type and length, checks it and stores + * in @buf. If the node partially or fully sits in the write-buffer, this + * function takes data from the buffer, otherwise it reads the flash media. + * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative + * error code in case of failure. + */ +int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len, + int lnum, int offs) +{ + const struct ubifs_info *c = wbuf->c; + int err, rlen, overlap; + struct ubifs_ch *ch = buf; + + dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs, + dbg_ntype(type), len, dbg_jhead(wbuf->jhead)); + ubifs_assert(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; +} |