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1663 lines
46 KiB
1663 lines
46 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* This file is part of UBIFS. |
|
* |
|
* Copyright (C) 2006-2008 Nokia Corporation. |
|
* |
|
* 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 |
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* 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 |
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* 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 |
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* '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 |
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* called with @i_mutex unlocked. For example, when flusher thread is doing |
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* background write-back, it calls 'ubifs_writepage()' with unlocked @i_mutex. |
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* At "normal" work-paths the @i_mutex is locked in 'ubifs_writepage()', e.g. |
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* in the "sys_write -> alloc_pages -> direct reclaim path". So, in |
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* 'ubifs_writepage()' we are only guaranteed that the page is locked. |
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* |
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* Similarly, @i_mutex is not always locked in 'ubifs_read_folio()', e.g., the |
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* read-ahead path does not lock it ("sys_read -> generic_file_aio_read -> |
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* ondemand_readahead -> read_folio"). In case of readahead, @I_SYNC flag is not |
|
* set as well. However, UBIFS disables readahead. |
|
*/ |
|
|
|
#include "ubifs.h" |
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#include <linux/mount.h> |
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#include <linux/slab.h> |
|
#include <linux/migrate.h> |
|
|
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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(c, 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; |
|
|
|
if (IS_ENCRYPTED(inode)) { |
|
err = ubifs_decrypt(inode, dn, &dlen, block); |
|
if (err) |
|
goto dump; |
|
} |
|
|
|
out_len = UBIFS_BLOCK_SIZE; |
|
err = ubifs_decompress(c, &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(c, "bad data node (block %u, inode %lu)", |
|
block, inode->i_ino); |
|
ubifs_dump_node(c, dn, UBIFS_MAX_DATA_NODE_SZ); |
|
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; |
|
struct ubifs_info *c = inode->i_sb->s_fs_info; |
|
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(c, !PageChecked(page)); |
|
ubifs_assert(c, !PagePrivate(page)); |
|
|
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addr = kmap(page); |
|
|
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block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT; |
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beyond = (i_size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT; |
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if (block >= beyond) { |
|
/* Reading beyond inode */ |
|
SetPageChecked(page); |
|
memset(addr, 0, PAGE_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 { |
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ret = read_block(inode, addr, block, dn); |
|
if (ret) { |
|
err = ret; |
|
if (err != -ENOENT) |
|
break; |
|
} else if (block + 1 == beyond) { |
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int dlen = le32_to_cpu(dn->size); |
|
int ilen = i_size & (UBIFS_BLOCK_SIZE - 1); |
|
|
|
if (ilen && ilen < dlen) |
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memset(addr + ilen, 0, dlen - ilen); |
|
} |
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} |
|
if (++i >= UBIFS_BLOCKS_PER_PAGE) |
|
break; |
|
block += 1; |
|
addr += UBIFS_BLOCK_SIZE; |
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} |
|
if (err) { |
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struct ubifs_info *c = inode->i_sb->s_fs_info; |
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if (err == -ENOENT) { |
|
/* Not found, so it must be a hole */ |
|
SetPageChecked(page); |
|
dbg_gen("hole"); |
|
goto out_free; |
|
} |
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ubifs_err(c, "cannot read page %lu of inode %lu, error %d", |
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page->index, inode->i_ino, err); |
|
goto error; |
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} |
|
|
|
out_free: |
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kfree(dn); |
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out: |
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SetPageUptodate(page); |
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ClearPageError(page); |
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flush_dcache_page(page); |
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kunmap(page); |
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return 0; |
|
|
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error: |
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kfree(dn); |
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ClearPageUptodate(page); |
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SetPageError(page); |
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flush_dcache_page(page); |
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kunmap(page); |
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return err; |
|
} |
|
|
|
/** |
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* release_new_page_budget - release budget of a new page. |
|
* @c: UBIFS file-system description object |
|
* |
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* This is a helper function which releases budget corresponding to the budget |
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* of one new page of data. |
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*/ |
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static void release_new_page_budget(struct ubifs_info *c) |
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{ |
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struct ubifs_budget_req req = { .recalculate = 1, .new_page = 1 }; |
|
|
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ubifs_release_budget(c, &req); |
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} |
|
|
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/** |
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* release_existing_page_budget - release budget of an existing page. |
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* @c: UBIFS file-system description object |
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* |
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* This is a helper function which releases budget corresponding to the budget |
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* of changing one page of data which already exists on the flash media. |
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*/ |
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static void release_existing_page_budget(struct ubifs_info *c) |
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{ |
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struct ubifs_budget_req req = { .dd_growth = c->bi.page_budget}; |
|
|
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ubifs_release_budget(c, &req); |
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} |
|
|
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static int write_begin_slow(struct address_space *mapping, |
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loff_t pos, unsigned len, struct page **pagep) |
|
{ |
|
struct inode *inode = mapping->host; |
|
struct ubifs_info *c = inode->i_sb->s_fs_info; |
|
pgoff_t index = pos >> PAGE_SHIFT; |
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struct ubifs_budget_req req = { .new_page = 1 }; |
|
int err, appending = !!(pos + len > inode->i_size); |
|
struct page *page; |
|
|
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dbg_gen("ino %lu, pos %llu, len %u, i_size %lld", |
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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 |
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* written to a hole. This corresponds to largest budget. Later the |
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* budget will be amended if this is not true. |
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*/ |
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if (appending) |
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/* We are appending data, budget for inode change */ |
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req.dirtied_ino = 1; |
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|
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err = ubifs_budget_space(c, &req); |
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if (unlikely(err)) |
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return err; |
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|
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page = grab_cache_page_write_begin(mapping, index); |
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if (unlikely(!page)) { |
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ubifs_release_budget(c, &req); |
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return -ENOMEM; |
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} |
|
|
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if (!PageUptodate(page)) { |
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if (!(pos & ~PAGE_MASK) && len == PAGE_SIZE) |
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SetPageChecked(page); |
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else { |
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err = do_readpage(page); |
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if (err) { |
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unlock_page(page); |
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put_page(page); |
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ubifs_release_budget(c, &req); |
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return err; |
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} |
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} |
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|
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SetPageUptodate(page); |
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ClearPageError(page); |
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} |
|
|
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if (PagePrivate(page)) |
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/* |
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* The page is dirty, which means it was budgeted twice: |
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* o first time the budget was allocated by the task which |
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* made the page dirty and set the PG_private flag; |
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* o and then we budgeted for it for the second time at the |
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* very beginning of this function. |
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* |
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* So what we have to do is to release the page budget we |
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* allocated. |
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*/ |
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release_new_page_budget(c); |
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else if (!PageChecked(page)) |
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/* |
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* We are changing a page which already exists on the media. |
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* This means that changing the page does not make the amount |
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* of indexing information larger, and this part of the budget |
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* which we have already acquired may be released. |
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*/ |
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ubifs_convert_page_budget(c); |
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|
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if (appending) { |
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struct ubifs_inode *ui = ubifs_inode(inode); |
|
|
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/* |
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* 'ubifs_write_end()' is optimized from the fast-path part of |
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* 'ubifs_write_begin()' and expects the @ui_mutex to be locked |
|
* if data is appended. |
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*/ |
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mutex_lock(&ui->ui_mutex); |
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if (ui->dirty) |
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/* |
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* The inode is dirty already, so we may free the |
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* budget we allocated. |
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*/ |
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ubifs_release_dirty_inode_budget(c, ui); |
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} |
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|
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*pagep = page; |
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return 0; |
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} |
|
|
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/** |
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* allocate_budget - allocate budget for 'ubifs_write_begin()'. |
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* @c: UBIFS file-system description object |
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* @page: page to allocate budget for |
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* @ui: UBIFS inode object the page belongs to |
|
* @appending: non-zero if the page is appended |
|
* |
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* This is a helper function for 'ubifs_write_begin()' which allocates budget |
|
* for the operation. The budget is allocated differently depending on whether |
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* this is appending, whether the page is dirty or not, and so on. This |
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* function leaves the @ui->ui_mutex locked in case of appending. Returns zero |
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* in case of success and %-ENOSPC in case of failure. |
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*/ |
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static int allocate_budget(struct ubifs_info *c, struct page *page, |
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struct ubifs_inode *ui, int appending) |
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{ |
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struct ubifs_budget_req req = { .fast = 1 }; |
|
|
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if (PagePrivate(page)) { |
|
if (!appending) |
|
/* |
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* 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, |
|
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_SHIFT; |
|
int err, appending = !!(pos + len > inode->i_size); |
|
int skipped_read = 0; |
|
struct page *page; |
|
|
|
ubifs_assert(c, ubifs_inode(inode)->ui_size == inode->i_size); |
|
ubifs_assert(c, !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); |
|
if (unlikely(!page)) |
|
return -ENOMEM; |
|
|
|
if (!PageUptodate(page)) { |
|
/* The page is not loaded from the flash */ |
|
if (!(pos & ~PAGE_MASK) && len == PAGE_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); |
|
put_page(page); |
|
return err; |
|
} |
|
} |
|
|
|
SetPageUptodate(page); |
|
ClearPageError(page); |
|
} |
|
|
|
err = allocate_budget(c, page, ui, appending); |
|
if (unlikely(err)) { |
|
ubifs_assert(c, 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(c, mutex_is_locked(&ui->ui_mutex)); |
|
mutex_unlock(&ui->ui_mutex); |
|
} |
|
unlock_page(page); |
|
put_page(page); |
|
|
|
return write_begin_slow(mapping, pos, len, pagep); |
|
} |
|
|
|
/* |
|
* 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_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_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)) { |
|
attach_page_private(page, (void *)1); |
|
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(c, mutex_is_locked(&ui->ui_mutex)); |
|
mutex_unlock(&ui->ui_mutex); |
|
} |
|
|
|
out: |
|
unlock_page(page); |
|
put_page(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_SHIFT; |
|
if (!i_size || page->index > end_index) { |
|
hole = 1; |
|
memset(addr, 0, PAGE_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(c, 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; |
|
|
|
if (IS_ENCRYPTED(inode)) { |
|
err = ubifs_decrypt(inode, dn, &dlen, page_block); |
|
if (err) |
|
goto out_err; |
|
} |
|
|
|
err = ubifs_decompress(c, &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_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(c, "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; |
|
gfp_t ra_gfp_mask = readahead_gfp_mask(mapping) & ~__GFP_FS; |
|
|
|
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(c, bu->buf_len > 0); |
|
ubifs_assert(c, 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_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 = pagecache_get_page(mapping, page_offset, |
|
FGP_LOCK|FGP_ACCESSED|FGP_CREAT|FGP_NOWAIT, |
|
ra_gfp_mask); |
|
if (!page) |
|
break; |
|
if (!PageUptodate(page)) |
|
err = populate_page(c, page, bu, &n); |
|
unlock_page(page); |
|
put_page(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(c, "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_read_folio(struct file *file, struct folio *folio) |
|
{ |
|
struct page *page = &folio->page; |
|
|
|
if (ubifs_bulk_read(page)) |
|
return 0; |
|
do_readpage(page); |
|
folio_unlock(folio); |
|
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 |
|
struct ubifs_inode *ui = ubifs_inode(inode); |
|
spin_lock(&ui->ui_lock); |
|
ubifs_assert(c, page->index <= ui->synced_i_size >> PAGE_SHIFT); |
|
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(c, "cannot write page %lu of inode %lu, error %d", |
|
page->index, inode->i_ino, err); |
|
ubifs_ro_mode(c, err); |
|
} |
|
|
|
ubifs_assert(c, PagePrivate(page)); |
|
if (PageChecked(page)) |
|
release_new_page_budget(c); |
|
else |
|
release_existing_page_budget(c); |
|
|
|
atomic_long_dec(&c->dirty_pg_cnt); |
|
detach_page_private(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_info *c = inode->i_sb->s_fs_info; |
|
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_SHIFT; |
|
int err, len = i_size & (PAGE_SIZE - 1); |
|
void *kaddr; |
|
|
|
dbg_gen("ino %lu, pg %lu, pg flags %#lx", |
|
inode->i_ino, page->index, page->flags); |
|
ubifs_assert(c, 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_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_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); |
|
memset(kaddr + len, 0, PAGE_SIZE - len); |
|
flush_dcache_page(page); |
|
kunmap_atomic(kaddr); |
|
|
|
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 = attr->ia_atime; |
|
if (attr->ia_valid & ATTR_MTIME) |
|
inode->i_mtime = attr->ia_mtime; |
|
if (attr->ia_valid & ATTR_CTIME) |
|
inode->i_ctime = attr->ia_ctime; |
|
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_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(c, PagePrivate(page)); |
|
|
|
clear_page_dirty_for_io(page); |
|
if (UBIFS_BLOCKS_PER_PAGE_SHIFT) |
|
offset = new_size & |
|
(PAGE_SIZE - 1); |
|
err = do_writepage(page, offset); |
|
put_page(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); |
|
put_page(page); |
|
} |
|
} |
|
} |
|
|
|
mutex_lock(&ui->ui_mutex); |
|
ui->ui_size = inode->i_size; |
|
/* Truncation changes inode [mc]time */ |
|
inode->i_mtime = inode->i_ctime = 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 = 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_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 user_namespace *mnt_userns, struct dentry *dentry, |
|
struct iattr *attr) |
|
{ |
|
int err; |
|
struct inode *inode = d_inode(dentry); |
|
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 = setattr_prepare(&init_user_ns, dentry, attr); |
|
if (err) |
|
return err; |
|
|
|
err = dbg_check_synced_i_size(c, inode); |
|
if (err) |
|
return err; |
|
|
|
err = fscrypt_prepare_setattr(dentry, attr); |
|
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_invalidate_folio(struct folio *folio, size_t offset, |
|
size_t length) |
|
{ |
|
struct inode *inode = folio->mapping->host; |
|
struct ubifs_info *c = inode->i_sb->s_fs_info; |
|
|
|
ubifs_assert(c, folio_test_private(folio)); |
|
if (offset || length < folio_size(folio)) |
|
/* Partial folio remains dirty */ |
|
return; |
|
|
|
if (folio_test_checked(folio)) |
|
release_new_page_budget(c); |
|
else |
|
release_existing_page_budget(c); |
|
|
|
atomic_long_dec(&c->dirty_pg_cnt); |
|
folio_detach_private(folio); |
|
folio_clear_checked(folio); |
|
} |
|
|
|
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 = file_write_and_wait_range(file, start, end); |
|
if (err) |
|
return err; |
|
inode_lock(inode); |
|
|
|
/* 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: |
|
inode_unlock(inode); |
|
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 timespec64 *now) |
|
{ |
|
if (!timespec64_equal(&inode->i_mtime, now) || |
|
!timespec64_equal(&inode->i_ctime, now)) |
|
return 1; |
|
return 0; |
|
} |
|
|
|
/** |
|
* ubifs_update_time - update time of inode. |
|
* @inode: inode to update |
|
* |
|
* This function updates time of the inode. |
|
*/ |
|
int ubifs_update_time(struct inode *inode, struct timespec64 *time, |
|
int flags) |
|
{ |
|
struct ubifs_inode *ui = ubifs_inode(inode); |
|
struct ubifs_info *c = inode->i_sb->s_fs_info; |
|
struct ubifs_budget_req req = { .dirtied_ino = 1, |
|
.dirtied_ino_d = ALIGN(ui->data_len, 8) }; |
|
int err, release; |
|
|
|
if (!IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT)) |
|
return generic_update_time(inode, time, flags); |
|
|
|
err = ubifs_budget_space(c, &req); |
|
if (err) |
|
return err; |
|
|
|
mutex_lock(&ui->ui_mutex); |
|
if (flags & S_ATIME) |
|
inode->i_atime = *time; |
|
if (flags & S_CTIME) |
|
inode->i_ctime = *time; |
|
if (flags & S_MTIME) |
|
inode->i_mtime = *time; |
|
|
|
release = ui->dirty; |
|
__mark_inode_dirty(inode, I_DIRTY_SYNC); |
|
mutex_unlock(&ui->ui_mutex); |
|
if (release) |
|
ubifs_release_budget(c, &req); |
|
return 0; |
|
} |
|
|
|
/** |
|
* update_mctime - update mtime and ctime of an inode. |
|
* @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 inode *inode) |
|
{ |
|
struct timespec64 now = current_time(inode); |
|
struct ubifs_inode *ui = ubifs_inode(inode); |
|
struct ubifs_info *c = inode->i_sb->s_fs_info; |
|
|
|
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 = 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_write_iter(struct kiocb *iocb, struct iov_iter *from) |
|
{ |
|
int err = update_mctime(file_inode(iocb->ki_filp)); |
|
if (err) |
|
return err; |
|
|
|
return generic_file_write_iter(iocb, from); |
|
} |
|
|
|
static bool ubifs_dirty_folio(struct address_space *mapping, |
|
struct folio *folio) |
|
{ |
|
bool ret; |
|
struct ubifs_info *c = mapping->host->i_sb->s_fs_info; |
|
|
|
ret = filemap_dirty_folio(mapping, folio); |
|
/* |
|
* An attempt to dirty a page without budgeting for it - should not |
|
* happen. |
|
*/ |
|
ubifs_assert(c, ret == false); |
|
return ret; |
|
} |
|
|
|
static bool ubifs_release_folio(struct folio *folio, gfp_t unused_gfp_flags) |
|
{ |
|
struct inode *inode = folio->mapping->host; |
|
struct ubifs_info *c = inode->i_sb->s_fs_info; |
|
|
|
/* |
|
* An attempt to release a dirty page without budgeting for it - should |
|
* not happen. |
|
*/ |
|
if (folio_test_writeback(folio)) |
|
return false; |
|
ubifs_assert(c, folio_test_private(folio)); |
|
ubifs_assert(c, 0); |
|
folio_detach_private(folio); |
|
folio_clear_checked(folio); |
|
return true; |
|
} |
|
|
|
/* |
|
* mmap()d file has taken write protection fault and is being made writable. |
|
* UBIFS must ensure page is budgeted for. |
|
*/ |
|
static vm_fault_t ubifs_vm_page_mkwrite(struct vm_fault *vmf) |
|
{ |
|
struct page *page = vmf->page; |
|
struct inode *inode = file_inode(vmf->vma->vm_file); |
|
struct ubifs_info *c = inode->i_sb->s_fs_info; |
|
struct timespec64 now = 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, !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(c, "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 */ |
|
goto sigbus; |
|
} |
|
|
|
if (PagePrivate(page)) |
|
release_new_page_budget(c); |
|
else { |
|
if (!PageChecked(page)) |
|
ubifs_convert_page_budget(c); |
|
attach_page_private(page, (void *)1); |
|
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 = 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); |
|
} |
|
|
|
wait_for_stable_page(page); |
|
return VM_FAULT_LOCKED; |
|
|
|
sigbus: |
|
unlock_page(page); |
|
ubifs_release_budget(c, &req); |
|
return VM_FAULT_SIGBUS; |
|
} |
|
|
|
static const struct vm_operations_struct ubifs_file_vm_ops = { |
|
.fault = filemap_fault, |
|
.map_pages = filemap_map_pages, |
|
.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; |
|
|
|
if (IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT)) |
|
file_accessed(file); |
|
|
|
return 0; |
|
} |
|
|
|
static const char *ubifs_get_link(struct dentry *dentry, |
|
struct inode *inode, |
|
struct delayed_call *done) |
|
{ |
|
struct ubifs_inode *ui = ubifs_inode(inode); |
|
|
|
if (!IS_ENCRYPTED(inode)) |
|
return ui->data; |
|
|
|
if (!dentry) |
|
return ERR_PTR(-ECHILD); |
|
|
|
return fscrypt_get_symlink(inode, ui->data, ui->data_len, done); |
|
} |
|
|
|
static int ubifs_symlink_getattr(struct user_namespace *mnt_userns, |
|
const struct path *path, struct kstat *stat, |
|
u32 request_mask, unsigned int query_flags) |
|
{ |
|
ubifs_getattr(mnt_userns, path, stat, request_mask, query_flags); |
|
|
|
if (IS_ENCRYPTED(d_inode(path->dentry))) |
|
return fscrypt_symlink_getattr(path, stat); |
|
return 0; |
|
} |
|
|
|
const struct address_space_operations ubifs_file_address_operations = { |
|
.read_folio = ubifs_read_folio, |
|
.writepage = ubifs_writepage, |
|
.write_begin = ubifs_write_begin, |
|
.write_end = ubifs_write_end, |
|
.invalidate_folio = ubifs_invalidate_folio, |
|
.dirty_folio = ubifs_dirty_folio, |
|
.migrate_folio = filemap_migrate_folio, |
|
.release_folio = ubifs_release_folio, |
|
}; |
|
|
|
const struct inode_operations ubifs_file_inode_operations = { |
|
.setattr = ubifs_setattr, |
|
.getattr = ubifs_getattr, |
|
.listxattr = ubifs_listxattr, |
|
.update_time = ubifs_update_time, |
|
.fileattr_get = ubifs_fileattr_get, |
|
.fileattr_set = ubifs_fileattr_set, |
|
}; |
|
|
|
const struct inode_operations ubifs_symlink_inode_operations = { |
|
.get_link = ubifs_get_link, |
|
.setattr = ubifs_setattr, |
|
.getattr = ubifs_symlink_getattr, |
|
.listxattr = ubifs_listxattr, |
|
.update_time = ubifs_update_time, |
|
}; |
|
|
|
const struct file_operations ubifs_file_operations = { |
|
.llseek = generic_file_llseek, |
|
.read_iter = generic_file_read_iter, |
|
.write_iter = ubifs_write_iter, |
|
.mmap = ubifs_file_mmap, |
|
.fsync = ubifs_fsync, |
|
.unlocked_ioctl = ubifs_ioctl, |
|
.splice_read = generic_file_splice_read, |
|
.splice_write = iter_file_splice_write, |
|
.open = fscrypt_file_open, |
|
#ifdef CONFIG_COMPAT |
|
.compat_ioctl = ubifs_compat_ioctl, |
|
#endif |
|
};
|
|
|