| /* |
| * This file is part of UBIFS. |
| * |
| * Copyright (C) 2006-2008 Nokia Corporation. |
| * |
| * 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 |
| */ |
| |
| /* |
| * This file implements VFS file and inode operations for regular files, device |
| * nodes and symlinks as well as address space operations. |
| * |
| * UBIFS uses 2 page flags: @PG_private and @PG_checked. @PG_private is set if |
| * the page is dirty and is used for optimization purposes - dirty pages are |
| * not budgeted so the flag shows that 'ubifs_write_end()' should not release |
| * the budget for this page. The @PG_checked flag is set if full budgeting is |
| * required for the page e.g., when it corresponds to a file hole or it is |
| * beyond the file size. The budgeting is done in 'ubifs_write_begin()', because |
| * it is OK to fail in this function, and the budget is released in |
| * 'ubifs_write_end()'. So the @PG_private and @PG_checked flags carry |
| * information about how the page was budgeted, to make it possible to release |
| * the budget properly. |
| * |
| * A thing to keep in mind: inode @i_mutex is locked in most VFS operations we |
| * implement. However, this is not true for 'ubifs_writepage()', which may be |
| * called with @i_mutex unlocked. For example, when pdflush is doing background |
| * write-back, it calls 'ubifs_writepage()' with unlocked @i_mutex. At "normal" |
| * work-paths the @i_mutex is locked in 'ubifs_writepage()', e.g. in the |
| * "sys_write -> alloc_pages -> direct reclaim path". So, in 'ubifs_writepage()' |
| * we are only guaranteed that the page is locked. |
| * |
| * Similarly, @i_mutex is not always locked in 'ubifs_readpage()', e.g., the |
| * read-ahead path does not lock it ("sys_read -> generic_file_aio_read -> |
| * ondemand_readahead -> readpage"). In case of readahead, @I_SYNC flag is not |
| * set as well. However, UBIFS disables readahead. |
| */ |
| |
| #include "ubifs.h" |
| #include <linux/mount.h> |
| #include <linux/namei.h> |
| #include <linux/slab.h> |
| |
| static int read_block(struct inode *inode, void *addr, unsigned int block, |
| struct ubifs_data_node *dn) |
| { |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| int err, len, out_len; |
| union ubifs_key key; |
| unsigned int dlen; |
| |
| data_key_init(c, &key, inode->i_ino, block); |
| err = ubifs_tnc_lookup(c, &key, dn); |
| if (err) { |
| if (err == -ENOENT) |
| /* Not found, so it must be a hole */ |
| memset(addr, 0, UBIFS_BLOCK_SIZE); |
| return err; |
| } |
| |
| ubifs_assert(le64_to_cpu(dn->ch.sqnum) > |
| ubifs_inode(inode)->creat_sqnum); |
| len = le32_to_cpu(dn->size); |
| if (len <= 0 || len > UBIFS_BLOCK_SIZE) |
| goto dump; |
| |
| dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ; |
| out_len = UBIFS_BLOCK_SIZE; |
| err = ubifs_decompress(&dn->data, dlen, addr, &out_len, |
| le16_to_cpu(dn->compr_type)); |
| if (err || len != out_len) |
| goto dump; |
| |
| /* |
| * Data length can be less than a full block, even for blocks that are |
| * not the last in the file (e.g., as a result of making a hole and |
| * appending data). Ensure that the remainder is zeroed out. |
| */ |
| if (len < UBIFS_BLOCK_SIZE) |
| memset(addr + len, 0, UBIFS_BLOCK_SIZE - len); |
| |
| return 0; |
| |
| dump: |
| ubifs_err("bad data node (block %u, inode %lu)", |
| block, inode->i_ino); |
| dbg_dump_node(c, dn); |
| return -EINVAL; |
| } |
| |
| static int do_readpage(struct page *page) |
| { |
| void *addr; |
| int err = 0, i; |
| unsigned int block, beyond; |
| struct ubifs_data_node *dn; |
| struct inode *inode = page->mapping->host; |
| loff_t i_size = i_size_read(inode); |
| |
| dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx", |
| inode->i_ino, page->index, i_size, page->flags); |
| ubifs_assert(!PageChecked(page)); |
| ubifs_assert(!PagePrivate(page)); |
| |
| addr = kmap(page); |
| |
| block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT; |
| beyond = (i_size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT; |
| if (block >= beyond) { |
| /* Reading beyond inode */ |
| SetPageChecked(page); |
| memset(addr, 0, PAGE_CACHE_SIZE); |
| goto out; |
| } |
| |
| dn = kmalloc(UBIFS_MAX_DATA_NODE_SZ, GFP_NOFS); |
| if (!dn) { |
| err = -ENOMEM; |
| goto error; |
| } |
| |
| i = 0; |
| while (1) { |
| int ret; |
| |
| if (block >= beyond) { |
| /* Reading beyond inode */ |
| err = -ENOENT; |
| memset(addr, 0, UBIFS_BLOCK_SIZE); |
| } else { |
| ret = read_block(inode, addr, block, dn); |
| if (ret) { |
| err = ret; |
| if (err != -ENOENT) |
| break; |
| } else if (block + 1 == beyond) { |
| int dlen = le32_to_cpu(dn->size); |
| int ilen = i_size & (UBIFS_BLOCK_SIZE - 1); |
| |
| if (ilen && ilen < dlen) |
| memset(addr + ilen, 0, dlen - ilen); |
| } |
| } |
| if (++i >= UBIFS_BLOCKS_PER_PAGE) |
| break; |
| block += 1; |
| addr += UBIFS_BLOCK_SIZE; |
| } |
| if (err) { |
| if (err == -ENOENT) { |
| /* Not found, so it must be a hole */ |
| SetPageChecked(page); |
| dbg_gen("hole"); |
| goto out_free; |
| } |
| ubifs_err("cannot read page %lu of inode %lu, error %d", |
| page->index, inode->i_ino, err); |
| goto error; |
| } |
| |
| out_free: |
| kfree(dn); |
| out: |
| SetPageUptodate(page); |
| ClearPageError(page); |
| flush_dcache_page(page); |
| kunmap(page); |
| return 0; |
| |
| error: |
| kfree(dn); |
| ClearPageUptodate(page); |
| SetPageError(page); |
| flush_dcache_page(page); |
| kunmap(page); |
| return err; |
| } |
| |
| /** |
| * release_new_page_budget - release budget of a new page. |
| * @c: UBIFS file-system description object |
| * |
| * This is a helper function which releases budget corresponding to the budget |
| * of one new page of data. |
| */ |
| static void release_new_page_budget(struct ubifs_info *c) |
| { |
| struct ubifs_budget_req req = { .recalculate = 1, .new_page = 1 }; |
| |
| ubifs_release_budget(c, &req); |
| } |
| |
| /** |
| * release_existing_page_budget - release budget of an existing page. |
| * @c: UBIFS file-system description object |
| * |
| * This is a helper function which releases budget corresponding to the budget |
| * of changing one one page of data which already exists on the flash media. |
| */ |
| static void release_existing_page_budget(struct ubifs_info *c) |
| { |
| struct ubifs_budget_req req = { .dd_growth = c->bi.page_budget}; |
| |
| ubifs_release_budget(c, &req); |
| } |
| |
| static int write_begin_slow(struct address_space *mapping, |
| loff_t pos, unsigned len, struct page **pagep, |
| unsigned flags) |
| { |
| struct inode *inode = mapping->host; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
| struct ubifs_budget_req req = { .new_page = 1 }; |
| int uninitialized_var(err), appending = !!(pos + len > inode->i_size); |
| struct page *page; |
| |
| dbg_gen("ino %lu, pos %llu, len %u, i_size %lld", |
| inode->i_ino, pos, len, inode->i_size); |
| |
| /* |
| * At the slow path we have to budget before locking the page, because |
| * budgeting may force write-back, which would wait on locked pages and |
| * deadlock if we had the page locked. At this point we do not know |
| * anything about the page, so assume that this is a new page which is |
| * written to a hole. This corresponds to largest budget. Later the |
| * budget will be amended if this is not true. |
| */ |
| if (appending) |
| /* We are appending data, budget for inode change */ |
| req.dirtied_ino = 1; |
| |
| err = ubifs_budget_space(c, &req); |
| if (unlikely(err)) |
| return err; |
| |
| page = grab_cache_page_write_begin(mapping, index, flags); |
| if (unlikely(!page)) { |
| ubifs_release_budget(c, &req); |
| return -ENOMEM; |
| } |
| |
| if (!PageUptodate(page)) { |
| if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE) |
| SetPageChecked(page); |
| else { |
| err = do_readpage(page); |
| if (err) { |
| unlock_page(page); |
| page_cache_release(page); |
| return err; |
| } |
| } |
| |
| SetPageUptodate(page); |
| ClearPageError(page); |
| } |
| |
| if (PagePrivate(page)) |
| /* |
| * The page is dirty, which means it was budgeted twice: |
| * o first time the budget was allocated by the task which |
| * made the page dirty and set the PG_private flag; |
| * o and then we budgeted for it for the second time at the |
| * very beginning of this function. |
| * |
| * So what we have to do is to release the page budget we |
| * allocated. |
| */ |
| release_new_page_budget(c); |
| else if (!PageChecked(page)) |
| /* |
| * We are changing a page which already exists on the media. |
| * This means that changing the page does not make the amount |
| * of indexing information larger, and this part of the budget |
| * which we have already acquired may be released. |
| */ |
| ubifs_convert_page_budget(c); |
| |
| if (appending) { |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| |
| /* |
| * 'ubifs_write_end()' is optimized from the fast-path part of |
| * 'ubifs_write_begin()' and expects the @ui_mutex to be locked |
| * if data is appended. |
| */ |
| mutex_lock(&ui->ui_mutex); |
| if (ui->dirty) |
| /* |
| * The inode is dirty already, so we may free the |
| * budget we allocated. |
| */ |
| ubifs_release_dirty_inode_budget(c, ui); |
| } |
| |
| *pagep = page; |
| return 0; |
| } |
| |
| /** |
| * allocate_budget - allocate budget for 'ubifs_write_begin()'. |
| * @c: UBIFS file-system description object |
| * @page: page to allocate budget for |
| * @ui: UBIFS inode object the page belongs to |
| * @appending: non-zero if the page is appended |
| * |
| * This is a helper function for 'ubifs_write_begin()' which allocates budget |
| * for the operation. The budget is allocated differently depending on whether |
| * this is appending, whether the page is dirty or not, and so on. This |
| * function leaves the @ui->ui_mutex locked in case of appending. Returns zero |
| * in case of success and %-ENOSPC in case of failure. |
| */ |
| static int allocate_budget(struct ubifs_info *c, struct page *page, |
| struct ubifs_inode *ui, int appending) |
| { |
| struct ubifs_budget_req req = { .fast = 1 }; |
| |
| if (PagePrivate(page)) { |
| if (!appending) |
| /* |
| * The page is dirty and we are not appending, which |
| * means no budget is needed at all. |
| */ |
| return 0; |
| |
| mutex_lock(&ui->ui_mutex); |
| if (ui->dirty) |
| /* |
| * The page is dirty and we are appending, so the inode |
| * has to be marked as dirty. However, it is already |
| * dirty, so we do not need any budget. We may return, |
| * but @ui->ui_mutex hast to be left locked because we |
| * should prevent write-back from flushing the inode |
| * and freeing the budget. The lock will be released in |
| * 'ubifs_write_end()'. |
| */ |
| return 0; |
| |
| /* |
| * The page is dirty, we are appending, the inode is clean, so |
| * we need to budget the inode change. |
| */ |
| req.dirtied_ino = 1; |
| } else { |
| if (PageChecked(page)) |
| /* |
| * The page corresponds to a hole and does not |
| * exist on the media. So changing it makes |
| * make the amount of indexing information |
| * larger, and we have to budget for a new |
| * page. |
| */ |
| req.new_page = 1; |
| else |
| /* |
| * Not a hole, the change will not add any new |
| * indexing information, budget for page |
| * change. |
| */ |
| req.dirtied_page = 1; |
| |
| if (appending) { |
| mutex_lock(&ui->ui_mutex); |
| if (!ui->dirty) |
| /* |
| * The inode is clean but we will have to mark |
| * it as dirty because we are appending. This |
| * needs a budget. |
| */ |
| req.dirtied_ino = 1; |
| } |
| } |
| |
| return ubifs_budget_space(c, &req); |
| } |
| |
| /* |
| * This function is called when a page of data is going to be written. Since |
| * the page of data will not necessarily go to the flash straight away, UBIFS |
| * has to reserve space on the media for it, which is done by means of |
| * budgeting. |
| * |
| * This is the hot-path of the file-system and we are trying to optimize it as |
| * much as possible. For this reasons it is split on 2 parts - slow and fast. |
| * |
| * There many budgeting cases: |
| * o a new page is appended - we have to budget for a new page and for |
| * changing the inode; however, if the inode is already dirty, there is |
| * no need to budget for it; |
| * o an existing clean page is changed - we have budget for it; if the page |
| * does not exist on the media (a hole), we have to budget for a new |
| * page; otherwise, we may budget for changing an existing page; the |
| * difference between these cases is that changing an existing page does |
| * not introduce anything new to the FS indexing information, so it does |
| * not grow, and smaller budget is acquired in this case; |
| * o an existing dirty page is changed - no need to budget at all, because |
| * the page budget has been acquired by earlier, when the page has been |
| * marked dirty. |
| * |
| * UBIFS budgeting sub-system may force write-back if it thinks there is no |
| * space to reserve. This imposes some locking restrictions and makes it |
| * impossible to take into account the above cases, and makes it impossible to |
| * optimize budgeting. |
| * |
| * The solution for this is that the fast path of 'ubifs_write_begin()' assumes |
| * there is a plenty of flash space and the budget will be acquired quickly, |
| * without forcing write-back. The slow path does not make this assumption. |
| */ |
| static int ubifs_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| struct inode *inode = mapping->host; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
| int uninitialized_var(err), appending = !!(pos + len > inode->i_size); |
| int skipped_read = 0; |
| struct page *page; |
| |
| ubifs_assert(ubifs_inode(inode)->ui_size == inode->i_size); |
| ubifs_assert(!c->ro_media && !c->ro_mount); |
| |
| if (unlikely(c->ro_error)) |
| return -EROFS; |
| |
| /* Try out the fast-path part first */ |
| page = grab_cache_page_write_begin(mapping, index, flags); |
| if (unlikely(!page)) |
| return -ENOMEM; |
| |
| if (!PageUptodate(page)) { |
| /* The page is not loaded from the flash */ |
| if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE) { |
| /* |
| * We change whole page so no need to load it. But we |
| * do not know whether this page exists on the media or |
| * not, so we assume the latter because it requires |
| * larger budget. The assumption is that it is better |
| * to budget a bit more than to read the page from the |
| * media. Thus, we are setting the @PG_checked flag |
| * here. |
| */ |
| SetPageChecked(page); |
| skipped_read = 1; |
| } else { |
| err = do_readpage(page); |
| if (err) { |
| unlock_page(page); |
| page_cache_release(page); |
| return err; |
| } |
| } |
| |
| SetPageUptodate(page); |
| ClearPageError(page); |
| } |
| |
| err = allocate_budget(c, page, ui, appending); |
| if (unlikely(err)) { |
| ubifs_assert(err == -ENOSPC); |
| /* |
| * If we skipped reading the page because we were going to |
| * write all of it, then it is not up to date. |
| */ |
| if (skipped_read) { |
| ClearPageChecked(page); |
| ClearPageUptodate(page); |
| } |
| /* |
| * Budgeting failed which means it would have to force |
| * write-back but didn't, because we set the @fast flag in the |
| * request. Write-back cannot be done now, while we have the |
| * page locked, because it would deadlock. Unlock and free |
| * everything and fall-back to slow-path. |
| */ |
| if (appending) { |
| ubifs_assert(mutex_is_locked(&ui->ui_mutex)); |
| mutex_unlock(&ui->ui_mutex); |
| } |
| unlock_page(page); |
| page_cache_release(page); |
| |
| return write_begin_slow(mapping, pos, len, pagep, flags); |
| } |
| |
| /* |
| * Whee, we acquired budgeting quickly - without involving |
| * garbage-collection, committing or forcing write-back. We return |
| * with @ui->ui_mutex locked if we are appending pages, and unlocked |
| * otherwise. This is an optimization (slightly hacky though). |
| */ |
| *pagep = page; |
| return 0; |
| |
| } |
| |
| /** |
| * cancel_budget - cancel budget. |
| * @c: UBIFS file-system description object |
| * @page: page to cancel budget for |
| * @ui: UBIFS inode object the page belongs to |
| * @appending: non-zero if the page is appended |
| * |
| * This is a helper function for a page write operation. It unlocks the |
| * @ui->ui_mutex in case of appending. |
| */ |
| static void cancel_budget(struct ubifs_info *c, struct page *page, |
| struct ubifs_inode *ui, int appending) |
| { |
| if (appending) { |
| if (!ui->dirty) |
| ubifs_release_dirty_inode_budget(c, ui); |
| mutex_unlock(&ui->ui_mutex); |
| } |
| if (!PagePrivate(page)) { |
| if (PageChecked(page)) |
| release_new_page_budget(c); |
| else |
| release_existing_page_budget(c); |
| } |
| } |
| |
| static int ubifs_write_end(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, |
| struct page *page, void *fsdata) |
| { |
| struct inode *inode = mapping->host; |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| loff_t end_pos = pos + len; |
| int appending = !!(end_pos > inode->i_size); |
| |
| dbg_gen("ino %lu, pos %llu, pg %lu, len %u, copied %d, i_size %lld", |
| inode->i_ino, pos, page->index, len, copied, inode->i_size); |
| |
| if (unlikely(copied < len && len == PAGE_CACHE_SIZE)) { |
| /* |
| * VFS copied less data to the page that it intended and |
| * declared in its '->write_begin()' call via the @len |
| * argument. If the page was not up-to-date, and @len was |
| * @PAGE_CACHE_SIZE, the 'ubifs_write_begin()' function did |
| * not load it from the media (for optimization reasons). This |
| * means that part of the page contains garbage. So read the |
| * page now. |
| */ |
| dbg_gen("copied %d instead of %d, read page and repeat", |
| copied, len); |
| cancel_budget(c, page, ui, appending); |
| ClearPageChecked(page); |
| |
| /* |
| * Return 0 to force VFS to repeat the whole operation, or the |
| * error code if 'do_readpage()' fails. |
| */ |
| copied = do_readpage(page); |
| goto out; |
| } |
| |
| if (!PagePrivate(page)) { |
| SetPagePrivate(page); |
| atomic_long_inc(&c->dirty_pg_cnt); |
| __set_page_dirty_nobuffers(page); |
| } |
| |
| if (appending) { |
| i_size_write(inode, end_pos); |
| ui->ui_size = end_pos; |
| /* |
| * Note, we do not set @I_DIRTY_PAGES (which means that the |
| * inode has dirty pages), this has been done in |
| * '__set_page_dirty_nobuffers()'. |
| */ |
| __mark_inode_dirty(inode, I_DIRTY_DATASYNC); |
| ubifs_assert(mutex_is_locked(&ui->ui_mutex)); |
| mutex_unlock(&ui->ui_mutex); |
| } |
| |
| out: |
| unlock_page(page); |
| page_cache_release(page); |
| return copied; |
| } |
| |
| /** |
| * populate_page - copy data nodes into a page for bulk-read. |
| * @c: UBIFS file-system description object |
| * @page: page |
| * @bu: bulk-read information |
| * @n: next zbranch slot |
| * |
| * This function returns %0 on success and a negative error code on failure. |
| */ |
| static int populate_page(struct ubifs_info *c, struct page *page, |
| struct bu_info *bu, int *n) |
| { |
| int i = 0, nn = *n, offs = bu->zbranch[0].offs, hole = 0, read = 0; |
| struct inode *inode = page->mapping->host; |
| loff_t i_size = i_size_read(inode); |
| unsigned int page_block; |
| void *addr, *zaddr; |
| pgoff_t end_index; |
| |
| dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx", |
| inode->i_ino, page->index, i_size, page->flags); |
| |
| addr = zaddr = kmap(page); |
| |
| end_index = (i_size - 1) >> PAGE_CACHE_SHIFT; |
| if (!i_size || page->index > end_index) { |
| hole = 1; |
| memset(addr, 0, PAGE_CACHE_SIZE); |
| goto out_hole; |
| } |
| |
| page_block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT; |
| while (1) { |
| int err, len, out_len, dlen; |
| |
| if (nn >= bu->cnt) { |
| hole = 1; |
| memset(addr, 0, UBIFS_BLOCK_SIZE); |
| } else if (key_block(c, &bu->zbranch[nn].key) == page_block) { |
| struct ubifs_data_node *dn; |
| |
| dn = bu->buf + (bu->zbranch[nn].offs - offs); |
| |
| ubifs_assert(le64_to_cpu(dn->ch.sqnum) > |
| ubifs_inode(inode)->creat_sqnum); |
| |
| len = le32_to_cpu(dn->size); |
| if (len <= 0 || len > UBIFS_BLOCK_SIZE) |
| goto out_err; |
| |
| dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ; |
| out_len = UBIFS_BLOCK_SIZE; |
| err = ubifs_decompress(&dn->data, dlen, addr, &out_len, |
| le16_to_cpu(dn->compr_type)); |
| if (err || len != out_len) |
| goto out_err; |
| |
| if (len < UBIFS_BLOCK_SIZE) |
| memset(addr + len, 0, UBIFS_BLOCK_SIZE - len); |
| |
| nn += 1; |
| read = (i << UBIFS_BLOCK_SHIFT) + len; |
| } else if (key_block(c, &bu->zbranch[nn].key) < page_block) { |
| nn += 1; |
| continue; |
| } else { |
| hole = 1; |
| memset(addr, 0, UBIFS_BLOCK_SIZE); |
| } |
| if (++i >= UBIFS_BLOCKS_PER_PAGE) |
| break; |
| addr += UBIFS_BLOCK_SIZE; |
| page_block += 1; |
| } |
| |
| if (end_index == page->index) { |
| int len = i_size & (PAGE_CACHE_SIZE - 1); |
| |
| if (len && len < read) |
| memset(zaddr + len, 0, read - len); |
| } |
| |
| out_hole: |
| if (hole) { |
| SetPageChecked(page); |
| dbg_gen("hole"); |
| } |
| |
| SetPageUptodate(page); |
| ClearPageError(page); |
| flush_dcache_page(page); |
| kunmap(page); |
| *n = nn; |
| return 0; |
| |
| out_err: |
| ClearPageUptodate(page); |
| SetPageError(page); |
| flush_dcache_page(page); |
| kunmap(page); |
| ubifs_err("bad data node (block %u, inode %lu)", |
| page_block, inode->i_ino); |
| return -EINVAL; |
| } |
| |
| /** |
| * ubifs_do_bulk_read - do bulk-read. |
| * @c: UBIFS file-system description object |
| * @bu: bulk-read information |
| * @page1: first page to read |
| * |
| * This function returns %1 if the bulk-read is done, otherwise %0 is returned. |
| */ |
| static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu, |
| struct page *page1) |
| { |
| pgoff_t offset = page1->index, end_index; |
| struct address_space *mapping = page1->mapping; |
| struct inode *inode = mapping->host; |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| int err, page_idx, page_cnt, ret = 0, n = 0; |
| int allocate = bu->buf ? 0 : 1; |
| loff_t isize; |
| |
| err = ubifs_tnc_get_bu_keys(c, bu); |
| if (err) |
| goto out_warn; |
| |
| if (bu->eof) { |
| /* Turn off bulk-read at the end of the file */ |
| ui->read_in_a_row = 1; |
| ui->bulk_read = 0; |
| } |
| |
| page_cnt = bu->blk_cnt >> UBIFS_BLOCKS_PER_PAGE_SHIFT; |
| if (!page_cnt) { |
| /* |
| * This happens when there are multiple blocks per page and the |
| * blocks for the first page we are looking for, are not |
| * together. If all the pages were like this, bulk-read would |
| * reduce performance, so we turn it off for a while. |
| */ |
| goto out_bu_off; |
| } |
| |
| if (bu->cnt) { |
| if (allocate) { |
| /* |
| * Allocate bulk-read buffer depending on how many data |
| * nodes we are going to read. |
| */ |
| bu->buf_len = bu->zbranch[bu->cnt - 1].offs + |
| bu->zbranch[bu->cnt - 1].len - |
| bu->zbranch[0].offs; |
| ubifs_assert(bu->buf_len > 0); |
| ubifs_assert(bu->buf_len <= c->leb_size); |
| bu->buf = kmalloc(bu->buf_len, GFP_NOFS | __GFP_NOWARN); |
| if (!bu->buf) |
| goto out_bu_off; |
| } |
| |
| err = ubifs_tnc_bulk_read(c, bu); |
| if (err) |
| goto out_warn; |
| } |
| |
| err = populate_page(c, page1, bu, &n); |
| if (err) |
| goto out_warn; |
| |
| unlock_page(page1); |
| ret = 1; |
| |
| isize = i_size_read(inode); |
| if (isize == 0) |
| goto out_free; |
| end_index = ((isize - 1) >> PAGE_CACHE_SHIFT); |
| |
| for (page_idx = 1; page_idx < page_cnt; page_idx++) { |
| pgoff_t page_offset = offset + page_idx; |
| struct page *page; |
| |
| if (page_offset > end_index) |
| break; |
| page = find_or_create_page(mapping, page_offset, |
| GFP_NOFS | __GFP_COLD); |
| if (!page) |
| break; |
| if (!PageUptodate(page)) |
| err = populate_page(c, page, bu, &n); |
| unlock_page(page); |
| page_cache_release(page); |
| if (err) |
| break; |
| } |
| |
| ui->last_page_read = offset + page_idx - 1; |
| |
| out_free: |
| if (allocate) |
| kfree(bu->buf); |
| return ret; |
| |
| out_warn: |
| ubifs_warn("ignoring error %d and skipping bulk-read", err); |
| goto out_free; |
| |
| out_bu_off: |
| ui->read_in_a_row = ui->bulk_read = 0; |
| goto out_free; |
| } |
| |
| /** |
| * ubifs_bulk_read - determine whether to bulk-read and, if so, do it. |
| * @page: page from which to start bulk-read. |
| * |
| * Some flash media are capable of reading sequentially at faster rates. UBIFS |
| * bulk-read facility is designed to take advantage of that, by reading in one |
| * go consecutive data nodes that are also located consecutively in the same |
| * LEB. This function returns %1 if a bulk-read is done and %0 otherwise. |
| */ |
| static int ubifs_bulk_read(struct page *page) |
| { |
| struct inode *inode = page->mapping->host; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| pgoff_t index = page->index, last_page_read = ui->last_page_read; |
| struct bu_info *bu; |
| int err = 0, allocated = 0; |
| |
| ui->last_page_read = index; |
| if (!c->bulk_read) |
| return 0; |
| |
| /* |
| * Bulk-read is protected by @ui->ui_mutex, but it is an optimization, |
| * so don't bother if we cannot lock the mutex. |
| */ |
| if (!mutex_trylock(&ui->ui_mutex)) |
| return 0; |
| |
| if (index != last_page_read + 1) { |
| /* Turn off bulk-read if we stop reading sequentially */ |
| ui->read_in_a_row = 1; |
| if (ui->bulk_read) |
| ui->bulk_read = 0; |
| goto out_unlock; |
| } |
| |
| if (!ui->bulk_read) { |
| ui->read_in_a_row += 1; |
| if (ui->read_in_a_row < 3) |
| goto out_unlock; |
| /* Three reads in a row, so switch on bulk-read */ |
| ui->bulk_read = 1; |
| } |
| |
| /* |
| * If possible, try to use pre-allocated bulk-read information, which |
| * is protected by @c->bu_mutex. |
| */ |
| if (mutex_trylock(&c->bu_mutex)) |
| bu = &c->bu; |
| else { |
| bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN); |
| if (!bu) |
| goto out_unlock; |
| |
| bu->buf = NULL; |
| allocated = 1; |
| } |
| |
| bu->buf_len = c->max_bu_buf_len; |
| data_key_init(c, &bu->key, inode->i_ino, |
| page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT); |
| err = ubifs_do_bulk_read(c, bu, page); |
| |
| if (!allocated) |
| mutex_unlock(&c->bu_mutex); |
| else |
| kfree(bu); |
| |
| out_unlock: |
| mutex_unlock(&ui->ui_mutex); |
| return err; |
| } |
| |
| static int ubifs_readpage(struct file *file, struct page *page) |
| { |
| if (ubifs_bulk_read(page)) |
| return 0; |
| do_readpage(page); |
| unlock_page(page); |
| return 0; |
| } |
| |
| static int do_writepage(struct page *page, int len) |
| { |
| int err = 0, i, blen; |
| unsigned int block; |
| void *addr; |
| union ubifs_key key; |
| struct inode *inode = page->mapping->host; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| |
| #ifdef UBIFS_DEBUG |
| spin_lock(&ui->ui_lock); |
| ubifs_assert(page->index <= ui->synced_i_size << PAGE_CACHE_SIZE); |
| spin_unlock(&ui->ui_lock); |
| #endif |
| |
| /* Update radix tree tags */ |
| set_page_writeback(page); |
| |
| addr = kmap(page); |
| block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT; |
| i = 0; |
| while (len) { |
| blen = min_t(int, len, UBIFS_BLOCK_SIZE); |
| data_key_init(c, &key, inode->i_ino, block); |
| err = ubifs_jnl_write_data(c, inode, &key, addr, blen); |
| if (err) |
| break; |
| if (++i >= UBIFS_BLOCKS_PER_PAGE) |
| break; |
| block += 1; |
| addr += blen; |
| len -= blen; |
| } |
| if (err) { |
| SetPageError(page); |
| ubifs_err("cannot write page %lu of inode %lu, error %d", |
| page->index, inode->i_ino, err); |
| ubifs_ro_mode(c, err); |
| } |
| |
| ubifs_assert(PagePrivate(page)); |
| if (PageChecked(page)) |
| release_new_page_budget(c); |
| else |
| release_existing_page_budget(c); |
| |
| atomic_long_dec(&c->dirty_pg_cnt); |
| ClearPagePrivate(page); |
| ClearPageChecked(page); |
| |
| kunmap(page); |
| unlock_page(page); |
| end_page_writeback(page); |
| return err; |
| } |
| |
| /* |
| * When writing-back dirty inodes, VFS first writes-back pages belonging to the |
| * inode, then the inode itself. For UBIFS this may cause a problem. Consider a |
| * situation when a we have an inode with size 0, then a megabyte of data is |
| * appended to the inode, then write-back starts and flushes some amount of the |
| * dirty pages, the journal becomes full, commit happens and finishes, and then |
| * an unclean reboot happens. When the file system is mounted next time, the |
| * inode size would still be 0, but there would be many pages which are beyond |
| * the inode size, they would be indexed and consume flash space. Because the |
| * journal has been committed, the replay would not be able to detect this |
| * situation and correct the inode size. This means UBIFS would have to scan |
| * whole index and correct all inode sizes, which is long an unacceptable. |
| * |
| * To prevent situations like this, UBIFS writes pages back only if they are |
| * within the last synchronized inode size, i.e. the size which has been |
| * written to the flash media last time. Otherwise, UBIFS forces inode |
| * write-back, thus making sure the on-flash inode contains current inode size, |
| * and then keeps writing pages back. |
| * |
| * Some locking issues explanation. 'ubifs_writepage()' first is called with |
| * the page locked, and it locks @ui_mutex. However, write-back does take inode |
| * @i_mutex, which means other VFS operations may be run on this inode at the |
| * same time. And the problematic one is truncation to smaller size, from where |
| * we have to call 'truncate_setsize()', which first changes @inode->i_size, |
| * then drops the truncated pages. And while dropping the pages, it takes the |
| * page lock. This means that 'do_truncation()' cannot call 'truncate_setsize()' |
| * with @ui_mutex locked, because it would deadlock with 'ubifs_writepage()'. |
| * This means that @inode->i_size is changed while @ui_mutex is unlocked. |
| * |
| * XXX(truncate): with the new truncate sequence this is not true anymore, |
| * and the calls to truncate_setsize can be move around freely. They should |
| * be moved to the very end of the truncate sequence. |
| * |
| * But in 'ubifs_writepage()' we have to guarantee that we do not write beyond |
| * inode size. How do we do this if @inode->i_size may became smaller while we |
| * are in the middle of 'ubifs_writepage()'? The UBIFS solution is the |
| * @ui->ui_isize "shadow" field which UBIFS uses instead of @inode->i_size |
| * internally and updates it under @ui_mutex. |
| * |
| * Q: why we do not worry that if we race with truncation, we may end up with a |
| * situation when the inode is truncated while we are in the middle of |
| * 'do_writepage()', so we do write beyond inode size? |
| * A: If we are in the middle of 'do_writepage()', truncation would be locked |
| * on the page lock and it would not write the truncated inode node to the |
| * journal before we have finished. |
| */ |
| static int ubifs_writepage(struct page *page, struct writeback_control *wbc) |
| { |
| struct inode *inode = page->mapping->host; |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| loff_t i_size = i_size_read(inode), synced_i_size; |
| pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; |
| int err, len = i_size & (PAGE_CACHE_SIZE - 1); |
| void *kaddr; |
| |
| dbg_gen("ino %lu, pg %lu, pg flags %#lx", |
| inode->i_ino, page->index, page->flags); |
| ubifs_assert(PagePrivate(page)); |
| |
| /* Is the page fully outside @i_size? (truncate in progress) */ |
| if (page->index > end_index || (page->index == end_index && !len)) { |
| err = 0; |
| goto out_unlock; |
| } |
| |
| spin_lock(&ui->ui_lock); |
| synced_i_size = ui->synced_i_size; |
| spin_unlock(&ui->ui_lock); |
| |
| /* Is the page fully inside @i_size? */ |
| if (page->index < end_index) { |
| if (page->index >= synced_i_size >> PAGE_CACHE_SHIFT) { |
| err = inode->i_sb->s_op->write_inode(inode, NULL); |
| if (err) |
| goto out_unlock; |
| /* |
| * The inode has been written, but the write-buffer has |
| * not been synchronized, so in case of an unclean |
| * reboot we may end up with some pages beyond inode |
| * size, but they would be in the journal (because |
| * commit flushes write buffers) and recovery would deal |
| * with this. |
| */ |
| } |
| return do_writepage(page, PAGE_CACHE_SIZE); |
| } |
| |
| /* |
| * The page straddles @i_size. It must be zeroed out on each and every |
| * writepage invocation because it may be mmapped. "A file is mapped |
| * in multiples of the page size. For a file that is not a multiple of |
| * the page size, the remaining memory is zeroed when mapped, and |
| * writes to that region are not written out to the file." |
| */ |
| kaddr = kmap_atomic(page, KM_USER0); |
| memset(kaddr + len, 0, PAGE_CACHE_SIZE - len); |
| flush_dcache_page(page); |
| kunmap_atomic(kaddr, KM_USER0); |
| |
| if (i_size > synced_i_size) { |
| err = inode->i_sb->s_op->write_inode(inode, NULL); |
| if (err) |
| goto out_unlock; |
| } |
| |
| return do_writepage(page, len); |
| |
| out_unlock: |
| unlock_page(page); |
| return err; |
| } |
| |
| /** |
| * do_attr_changes - change inode attributes. |
| * @inode: inode to change attributes for |
| * @attr: describes attributes to change |
| */ |
| static void do_attr_changes(struct inode *inode, const struct iattr *attr) |
| { |
| if (attr->ia_valid & ATTR_UID) |
| inode->i_uid = attr->ia_uid; |
| if (attr->ia_valid & ATTR_GID) |
| inode->i_gid = attr->ia_gid; |
| if (attr->ia_valid & ATTR_ATIME) |
| inode->i_atime = timespec_trunc(attr->ia_atime, |
| inode->i_sb->s_time_gran); |
| if (attr->ia_valid & ATTR_MTIME) |
| inode->i_mtime = timespec_trunc(attr->ia_mtime, |
| inode->i_sb->s_time_gran); |
| if (attr->ia_valid & ATTR_CTIME) |
| inode->i_ctime = timespec_trunc(attr->ia_ctime, |
| inode->i_sb->s_time_gran); |
| if (attr->ia_valid & ATTR_MODE) { |
| umode_t mode = attr->ia_mode; |
| |
| if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) |
| mode &= ~S_ISGID; |
| inode->i_mode = mode; |
| } |
| } |
| |
| /** |
| * do_truncation - truncate an inode. |
| * @c: UBIFS file-system description object |
| * @inode: inode to truncate |
| * @attr: inode attribute changes description |
| * |
| * This function implements VFS '->setattr()' call when the inode is truncated |
| * to a smaller size. Returns zero in case of success and a negative error code |
| * in case of failure. |
| */ |
| static int do_truncation(struct ubifs_info *c, struct inode *inode, |
| const struct iattr *attr) |
| { |
| int err; |
| struct ubifs_budget_req req; |
| loff_t old_size = inode->i_size, new_size = attr->ia_size; |
| int offset = new_size & (UBIFS_BLOCK_SIZE - 1), budgeted = 1; |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| |
| dbg_gen("ino %lu, size %lld -> %lld", inode->i_ino, old_size, new_size); |
| memset(&req, 0, sizeof(struct ubifs_budget_req)); |
| |
| /* |
| * If this is truncation to a smaller size, and we do not truncate on a |
| * block boundary, budget for changing one data block, because the last |
| * block will be re-written. |
| */ |
| if (new_size & (UBIFS_BLOCK_SIZE - 1)) |
| req.dirtied_page = 1; |
| |
| req.dirtied_ino = 1; |
| /* A funny way to budget for truncation node */ |
| req.dirtied_ino_d = UBIFS_TRUN_NODE_SZ; |
| err = ubifs_budget_space(c, &req); |
| if (err) { |
| /* |
| * Treat truncations to zero as deletion and always allow them, |
| * just like we do for '->unlink()'. |
| */ |
| if (new_size || err != -ENOSPC) |
| return err; |
| budgeted = 0; |
| } |
| |
| truncate_setsize(inode, new_size); |
| |
| if (offset) { |
| pgoff_t index = new_size >> PAGE_CACHE_SHIFT; |
| struct page *page; |
| |
| page = find_lock_page(inode->i_mapping, index); |
| if (page) { |
| if (PageDirty(page)) { |
| /* |
| * 'ubifs_jnl_truncate()' will try to truncate |
| * the last data node, but it contains |
| * out-of-date data because the page is dirty. |
| * Write the page now, so that |
| * 'ubifs_jnl_truncate()' will see an already |
| * truncated (and up to date) data node. |
| */ |
| ubifs_assert(PagePrivate(page)); |
| |
| clear_page_dirty_for_io(page); |
| if (UBIFS_BLOCKS_PER_PAGE_SHIFT) |
| offset = new_size & |
| (PAGE_CACHE_SIZE - 1); |
| err = do_writepage(page, offset); |
| page_cache_release(page); |
| if (err) |
| goto out_budg; |
| /* |
| * We could now tell 'ubifs_jnl_truncate()' not |
| * to read the last block. |
| */ |
| } else { |
| /* |
| * We could 'kmap()' the page and pass the data |
| * to 'ubifs_jnl_truncate()' to save it from |
| * having to read it. |
| */ |
| unlock_page(page); |
| page_cache_release(page); |
| } |
| } |
| } |
| |
| mutex_lock(&ui->ui_mutex); |
| ui->ui_size = inode->i_size; |
| /* Truncation changes inode [mc]time */ |
| inode->i_mtime = inode->i_ctime = ubifs_current_time(inode); |
| /* Other attributes may be changed at the same time as well */ |
| do_attr_changes(inode, attr); |
| err = ubifs_jnl_truncate(c, inode, old_size, new_size); |
| mutex_unlock(&ui->ui_mutex); |
| |
| out_budg: |
| if (budgeted) |
| ubifs_release_budget(c, &req); |
| else { |
| c->bi.nospace = c->bi.nospace_rp = 0; |
| smp_wmb(); |
| } |
| return err; |
| } |
| |
| /** |
| * do_setattr - change inode attributes. |
| * @c: UBIFS file-system description object |
| * @inode: inode to change attributes for |
| * @attr: inode attribute changes description |
| * |
| * This function implements VFS '->setattr()' call for all cases except |
| * truncations to smaller size. Returns zero in case of success and a negative |
| * error code in case of failure. |
| */ |
| static int do_setattr(struct ubifs_info *c, struct inode *inode, |
| const struct iattr *attr) |
| { |
| int err, release; |
| loff_t new_size = attr->ia_size; |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| struct ubifs_budget_req req = { .dirtied_ino = 1, |
| .dirtied_ino_d = ALIGN(ui->data_len, 8) }; |
| |
| err = ubifs_budget_space(c, &req); |
| if (err) |
| return err; |
| |
| if (attr->ia_valid & ATTR_SIZE) { |
| dbg_gen("size %lld -> %lld", inode->i_size, new_size); |
| truncate_setsize(inode, new_size); |
| } |
| |
| mutex_lock(&ui->ui_mutex); |
| if (attr->ia_valid & ATTR_SIZE) { |
| /* Truncation changes inode [mc]time */ |
| inode->i_mtime = inode->i_ctime = ubifs_current_time(inode); |
| /* 'truncate_setsize()' changed @i_size, update @ui_size */ |
| ui->ui_size = inode->i_size; |
| } |
| |
| do_attr_changes(inode, attr); |
| |
| release = ui->dirty; |
| if (attr->ia_valid & ATTR_SIZE) |
| /* |
| * Inode length changed, so we have to make sure |
| * @I_DIRTY_DATASYNC is set. |
| */ |
| __mark_inode_dirty(inode, I_DIRTY_SYNC | I_DIRTY_DATASYNC); |
| else |
| mark_inode_dirty_sync(inode); |
| mutex_unlock(&ui->ui_mutex); |
| |
| if (release) |
| ubifs_release_budget(c, &req); |
| if (IS_SYNC(inode)) |
| err = inode->i_sb->s_op->write_inode(inode, NULL); |
| return err; |
| } |
| |
| int ubifs_setattr(struct dentry *dentry, struct iattr *attr) |
| { |
| int err; |
| struct inode *inode = dentry->d_inode; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| |
| dbg_gen("ino %lu, mode %#x, ia_valid %#x", |
| inode->i_ino, inode->i_mode, attr->ia_valid); |
| err = inode_change_ok(inode, attr); |
| if (err) |
| return err; |
| |
| err = dbg_check_synced_i_size(c, inode); |
| if (err) |
| return err; |
| |
| if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size < inode->i_size) |
| /* Truncation to a smaller size */ |
| err = do_truncation(c, inode, attr); |
| else |
| err = do_setattr(c, inode, attr); |
| |
| return err; |
| } |
| |
| static void ubifs_invalidatepage(struct page *page, unsigned long offset) |
| { |
| struct inode *inode = page->mapping->host; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| |
| ubifs_assert(PagePrivate(page)); |
| if (offset) |
| /* Partial page remains dirty */ |
| return; |
| |
| if (PageChecked(page)) |
| release_new_page_budget(c); |
| else |
| release_existing_page_budget(c); |
| |
| atomic_long_dec(&c->dirty_pg_cnt); |
| ClearPagePrivate(page); |
| ClearPageChecked(page); |
| } |
| |
| static void *ubifs_follow_link(struct dentry *dentry, struct nameidata *nd) |
| { |
| struct ubifs_inode *ui = ubifs_inode(dentry->d_inode); |
| |
| nd_set_link(nd, ui->data); |
| return NULL; |
| } |
| |
| int ubifs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
| { |
| struct inode *inode = file->f_mapping->host; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| int err; |
| |
| dbg_gen("syncing inode %lu", inode->i_ino); |
| |
| if (c->ro_mount) |
| /* |
| * For some really strange reasons VFS does not filter out |
| * 'fsync()' for R/O mounted file-systems as per 2.6.39. |
| */ |
| return 0; |
| |
| err = filemap_write_and_wait_range(inode->i_mapping, start, end); |
| if (err) |
| return err; |
| mutex_lock(&inode->i_mutex); |
| |
| /* Synchronize the inode unless this is a 'datasync()' call. */ |
| if (!datasync || (inode->i_state & I_DIRTY_DATASYNC)) { |
| err = inode->i_sb->s_op->write_inode(inode, NULL); |
| if (err) |
| goto out; |
| } |
| |
| /* |
| * Nodes related to this inode may still sit in a write-buffer. Flush |
| * them. |
| */ |
| err = ubifs_sync_wbufs_by_inode(c, inode); |
| out: |
| mutex_unlock(&inode->i_mutex); |
| return err; |
| } |
| |
| /** |
| * mctime_update_needed - check if mtime or ctime update is needed. |
| * @inode: the inode to do the check for |
| * @now: current time |
| * |
| * This helper function checks if the inode mtime/ctime should be updated or |
| * not. If current values of the time-stamps are within the UBIFS inode time |
| * granularity, they are not updated. This is an optimization. |
| */ |
| static inline int mctime_update_needed(const struct inode *inode, |
| const struct timespec *now) |
| { |
| if (!timespec_equal(&inode->i_mtime, now) || |
| !timespec_equal(&inode->i_ctime, now)) |
| return 1; |
| return 0; |
| } |
| |
| /** |
| * update_ctime - update mtime and ctime of an inode. |
| * @c: UBIFS file-system description object |
| * @inode: inode to update |
| * |
| * This function updates mtime and ctime of the inode if it is not equivalent to |
| * current time. Returns zero in case of success and a negative error code in |
| * case of failure. |
| */ |
| static int update_mctime(struct ubifs_info *c, struct inode *inode) |
| { |
| struct timespec now = ubifs_current_time(inode); |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| |
| if (mctime_update_needed(inode, &now)) { |
| int err, release; |
| struct ubifs_budget_req req = { .dirtied_ino = 1, |
| .dirtied_ino_d = ALIGN(ui->data_len, 8) }; |
| |
| err = ubifs_budget_space(c, &req); |
| if (err) |
| return err; |
| |
| mutex_lock(&ui->ui_mutex); |
| inode->i_mtime = inode->i_ctime = ubifs_current_time(inode); |
| release = ui->dirty; |
| mark_inode_dirty_sync(inode); |
| mutex_unlock(&ui->ui_mutex); |
| if (release) |
| ubifs_release_budget(c, &req); |
| } |
| |
| return 0; |
| } |
| |
| static ssize_t ubifs_aio_write(struct kiocb *iocb, const struct iovec *iov, |
| unsigned long nr_segs, loff_t pos) |
| { |
| int err; |
| struct inode *inode = iocb->ki_filp->f_mapping->host; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| |
| err = update_mctime(c, inode); |
| if (err) |
| return err; |
| |
| return generic_file_aio_write(iocb, iov, nr_segs, pos); |
| } |
| |
| static int ubifs_set_page_dirty(struct page *page) |
| { |
| int ret; |
| |
| ret = __set_page_dirty_nobuffers(page); |
| /* |
| * An attempt to dirty a page without budgeting for it - should not |
| * happen. |
| */ |
| ubifs_assert(ret == 0); |
| return ret; |
| } |
| |
| static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags) |
| { |
| /* |
| * An attempt to release a dirty page without budgeting for it - should |
| * not happen. |
| */ |
| if (PageWriteback(page)) |
| return 0; |
| ubifs_assert(PagePrivate(page)); |
| ubifs_assert(0); |
| ClearPagePrivate(page); |
| ClearPageChecked(page); |
| return 1; |
| } |
| |
| /* |
| * mmap()d file has taken write protection fault and is being made writable. |
| * UBIFS must ensure page is budgeted for. |
| */ |
| static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma, |
| struct vm_fault *vmf) |
| { |
| struct page *page = vmf->page; |
| struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
| struct ubifs_info *c = inode->i_sb->s_fs_info; |
| struct timespec now = ubifs_current_time(inode); |
| struct ubifs_budget_req req = { .new_page = 1 }; |
| int err, update_time; |
| |
| dbg_gen("ino %lu, pg %lu, i_size %lld", inode->i_ino, page->index, |
| i_size_read(inode)); |
| ubifs_assert(!c->ro_media && !c->ro_mount); |
| |
| if (unlikely(c->ro_error)) |
| return VM_FAULT_SIGBUS; /* -EROFS */ |
| |
| /* |
| * We have not locked @page so far so we may budget for changing the |
| * page. Note, we cannot do this after we locked the page, because |
| * budgeting may cause write-back which would cause deadlock. |
| * |
| * At the moment we do not know whether the page is dirty or not, so we |
| * assume that it is not and budget for a new page. We could look at |
| * the @PG_private flag and figure this out, but we may race with write |
| * back and the page state may change by the time we lock it, so this |
| * would need additional care. We do not bother with this at the |
| * moment, although it might be good idea to do. Instead, we allocate |
| * budget for a new page and amend it later on if the page was in fact |
| * dirty. |
| * |
| * The budgeting-related logic of this function is similar to what we |
| * do in 'ubifs_write_begin()' and 'ubifs_write_end()'. Glance there |
| * for more comments. |
| */ |
| update_time = mctime_update_needed(inode, &now); |
| if (update_time) |
| /* |
| * We have to change inode time stamp which requires extra |
| * budgeting. |
| */ |
| req.dirtied_ino = 1; |
| |
| err = ubifs_budget_space(c, &req); |
| if (unlikely(err)) { |
| if (err == -ENOSPC) |
| ubifs_warn("out of space for mmapped file " |
| "(inode number %lu)", inode->i_ino); |
| return VM_FAULT_SIGBUS; |
| } |
| |
| lock_page(page); |
| if (unlikely(page->mapping != inode->i_mapping || |
| page_offset(page) > i_size_read(inode))) { |
| /* Page got truncated out from underneath us */ |
| err = -EINVAL; |
| goto out_unlock; |
| } |
| |
| if (PagePrivate(page)) |
| release_new_page_budget(c); |
| else { |
| if (!PageChecked(page)) |
| ubifs_convert_page_budget(c); |
| SetPagePrivate(page); |
| atomic_long_inc(&c->dirty_pg_cnt); |
| __set_page_dirty_nobuffers(page); |
| } |
| |
| if (update_time) { |
| int release; |
| struct ubifs_inode *ui = ubifs_inode(inode); |
| |
| mutex_lock(&ui->ui_mutex); |
| inode->i_mtime = inode->i_ctime = ubifs_current_time(inode); |
| release = ui->dirty; |
| mark_inode_dirty_sync(inode); |
| mutex_unlock(&ui->ui_mutex); |
| if (release) |
| ubifs_release_dirty_inode_budget(c, ui); |
| } |
| |
| unlock_page(page); |
| return 0; |
| |
| out_unlock: |
| unlock_page(page); |
| ubifs_release_budget(c, &req); |
| if (err) |
| err = VM_FAULT_SIGBUS; |
| return err; |
| } |
| |
| static const struct vm_operations_struct ubifs_file_vm_ops = { |
| .fault = filemap_fault, |
| .page_mkwrite = ubifs_vm_page_mkwrite, |
| }; |
| |
| static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| int err; |
| |
| err = generic_file_mmap(file, vma); |
| if (err) |
| return err; |
| vma->vm_ops = &ubifs_file_vm_ops; |
| return 0; |
| } |
| |
| const struct address_space_operations ubifs_file_address_operations = { |
| .readpage = ubifs_readpage, |
| .writepage = ubifs_writepage, |
| .write_begin = ubifs_write_begin, |
| .write_end = ubifs_write_end, |
| .invalidatepage = ubifs_invalidatepage, |
| .set_page_dirty = ubifs_set_page_dirty, |
| .releasepage = ubifs_releasepage, |
| }; |
| |
| const struct inode_operations ubifs_file_inode_operations = { |
| .setattr = ubifs_setattr, |
| .getattr = ubifs_getattr, |
| #ifdef CONFIG_UBIFS_FS_XATTR |
| .setxattr = ubifs_setxattr, |
| .getxattr = ubifs_getxattr, |
| .listxattr = ubifs_listxattr, |
| .removexattr = ubifs_removexattr, |
| #endif |
| }; |
| |
| const struct inode_operations ubifs_symlink_inode_operations = { |
| .readlink = generic_readlink, |
| .follow_link = ubifs_follow_link, |
| .setattr = ubifs_setattr, |
| .getattr = ubifs_getattr, |
| #ifdef CONFIG_UBIFS_FS_XATTR |
| .setxattr = ubifs_setxattr, |
| .getxattr = ubifs_getxattr, |
| .listxattr = ubifs_listxattr, |
| .removexattr = ubifs_removexattr, |
| #endif |
| }; |
| |
| const struct file_operations ubifs_file_operations = { |
| .llseek = generic_file_llseek, |
| .read = do_sync_read, |
| .write = do_sync_write, |
| .aio_read = generic_file_aio_read, |
| .aio_write = ubifs_aio_write, |
| .mmap = ubifs_file_mmap, |
| .fsync = ubifs_fsync, |
| .unlocked_ioctl = ubifs_ioctl, |
| .splice_read = generic_file_splice_read, |
| .splice_write = generic_file_splice_write, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = ubifs_compat_ioctl, |
| #endif |
| }; |