kernel.git/fs/jffs2/file.c, branch linux-5.4.y

jffs2: correct logic when creating a hole in jffs2_write_begin

2023-03-22T12:28:07Z

[ Upstream commit 23892d383bee15b64f5463bd7195615734bb2415 ] Bug description and fix: 1. Write data to a file, say all 1s from offset 0 to 16. 2. Truncate the file to a smaller size, say 8 bytes. 3. Write new bytes (say 2s) from an offset past the original size of the file, say at offset 20, for 4 bytes. This is supposed to create a "hole" in the file, meaning that the bytes from offset 8 (where it was truncated above) up to the new write at offset 20, should all be 0s (zeros). 4. Flush all caches using "echo 3 > /proc/sys/vm/drop_caches" (or unmount and remount) the f/s. 5. Check the content of the file. It is wrong. The 1s that used to be between bytes 9 and 16, before the truncation, have REAPPEARED (they should be 0s). We wrote a script and helper C program to reproduce the bug (reproduce_jffs2_write_begin_issue.sh, write_file.c, and Makefile). We can make them available to anyone. The above example is shown when writing a small file within the same first page. But the bug happens for larger files, as long as steps 1, 2, and 3 above all happen within the same page. The problem was traced to the jffs2_write_begin code, where it goes into an 'if' statement intended to handle writes past the current EOF (i.e., writes that may create a hole). The code computes a 'pageofs' that is the floor of the write position (pos), aligned to the page size boundary. In other words, 'pageofs' will never be larger than 'pos'. The code then sets the internal jffs2_raw_inode->isize to the size of max(current inode size, pageofs) but that is wrong: the new file size should be the 'pos', which is larger than both the current inode size and pageofs. Similarly, the code incorrectly sets the internal jffs2_raw_inode->dsize to the difference between the pageofs minus current inode size; instead it should be the current pos minus the current inode size. Finally, inode->i_size was also set incorrectly. The patch below fixes this bug. The bug was discovered using a new tool for finding f/s bugs using model checking, called MCFS (Model Checking File Systems). Signed-off-by: Yifei Liu Signed-off-by: Erez Zadok Signed-off-by: Manish Adkar Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

jffs2: GC deadlock reading a page that is used in jffs2_write_begin()

2022-01-27T08:19:45Z

[ Upstream commit aa39cc675799bc92da153af9a13d6f969c348e82 ] GC task can deadlock in read_cache_page() because it may attempt to release a page that is actually allocated by another task in jffs2_write_begin(). The reason is that in jffs2_write_begin() there is a small window a cache page is allocated for use but not set Uptodate yet. This ends up with a deadlock between two tasks: 1) A task (e.g. file copy) - jffs2_write_begin() locks a cache page - jffs2_write_end() tries to lock "alloc_sem" from jffs2_reserve_space() <-- STUCK 2) GC task (jffs2_gcd_mtd3) - jffs2_garbage_collect_pass() locks "alloc_sem" - try to lock the same cache page in read_cache_page() <-- STUCK So to avoid this deadlock, hold "alloc_sem" in jffs2_write_begin() while reading data in a cache page. Signed-off-by: Kyeong Yoo Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

jffs2: pass the correct prototype to read_cache_page

2019-07-12T18:05:43Z

Fix the callback jffs2 passes to read_cache_page to actually have the proper type expected. Casting around function pointers can easily hide typing bugs, and defeats control flow protection. Link: http://lkml.kernel.org/r/20190520055731.24538-4-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Kees Cook Cc: Nick Desaulniers Cc: Sami Tolvanen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

jffs2: use 64-bit intermediate timestamps

2018-07-18T14:43:58Z

The VFS now uses timespec64 timestamps consistently, but jffs2 still converts them to 32-bit numbers on the storage medium. As the helper functions for the conversion (get_seconds() and timespec_to_timespec64()) are now deprecated, let's change them over to the more modern replacements. This keeps the traditional interpretation of those values, where the on-disk 32-bit numbers are taken to be negative numbers, i.e. dates before 1970, on 32-bit machines, but future numbers past 2038 on 64-bit machines. Signed-off-by: Arnd Bergmann Signed-off-by: Boris Brezillon

vfs: change inode times to use struct timespec64

2018-06-05T23:57:31Z

struct timespec is not y2038 safe. Transition vfs to use y2038 safe struct timespec64 instead. The change was made with the help of the following cocinelle script. This catches about 80% of the changes. All the header file and logic changes are included in the first 5 rules. The rest are trivial substitutions. I avoid changing any of the function signatures or any other filesystem specific data structures to keep the patch simple for review. The script can be a little shorter by combining different cases. But, this version was sufficient for my usecase. virtual patch @ depends on patch @ identifier now; @@ - struct timespec + struct timespec64 current_time ( ... ) { - struct timespec now = current_kernel_time(); + struct timespec64 now = current_kernel_time64(); ... - return timespec_trunc( + return timespec64_trunc( ... ); } @ depends on patch @ identifier xtime; @@ struct $ iattr \| inode \| kstat $ { ... - struct timespec xtime; + struct timespec64 xtime; ... } @ depends on patch @ identifier t; @@ struct inode_operations { ... int (*update_time) (..., - struct timespec t, + struct timespec64 t, ...); ... } @ depends on patch @ identifier t; identifier fn_update_time =~ "update_time$"; @@ fn_update_time (..., - struct timespec *t, + struct timespec64 *t, ...) { ... } @ depends on patch @ identifier t; @@ lease_get_mtime( ... , - struct timespec *t + struct timespec64 *t ) { ... } @te depends on patch forall@ identifier ts; local idexpression struct inode *inode_node; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; identifier fn_update_time =~ "update_time$"; identifier fn; expression e, E3; local idexpression struct inode *node1; local idexpression struct inode *node2; local idexpression struct iattr *attr1; local idexpression struct iattr *attr2; local idexpression struct iattr attr; identifier i_xtime1 =~ "^i_[acm]time$"; identifier i_xtime2 =~ "^i_[acm]time$"; identifier ia_xtime1 =~ "^ia_[acm]time$"; identifier ia_xtime2 =~ "^ia_[acm]time$"; @@ ( ( - struct timespec ts; + struct timespec64 ts; | - struct timespec ts = current_time(inode_node); + struct timespec64 ts = current_time(inode_node); ) <+... when != ts ( - timespec_equal(&inode_node->i_xtime, &ts) + timespec64_equal(&inode_node->i_xtime, &ts) | - timespec_equal(&ts, &inode_node->i_xtime) + timespec64_equal(&ts, &inode_node->i_xtime) | - timespec_compare(&inode_node->i_xtime, &ts) + timespec64_compare(&inode_node->i_xtime, &ts) | - timespec_compare(&ts, &inode_node->i_xtime) + timespec64_compare(&ts, &inode_node->i_xtime) | ts = current_time(e) | fn_update_time(..., &ts,...) | inode_node->i_xtime = ts | node1->i_xtime = ts | ts = inode_node->i_xtime | <+... attr1->ia_xtime ...+> = ts | ts = attr1->ia_xtime | ts.tv_sec | ts.tv_nsec | btrfs_set_stack_timespec_sec(..., ts.tv_sec) | btrfs_set_stack_timespec_nsec(..., ts.tv_nsec) | - ts = timespec64_to_timespec( + ts = ... -) | - ts = ktime_to_timespec( + ts = ktime_to_timespec64( ...) | - ts = E3 + ts = timespec_to_timespec64(E3) | - ktime_get_real_ts(&ts) + ktime_get_real_ts64(&ts) | fn(..., - ts + timespec64_to_timespec(ts) ,...) ) ...+> ( <... when != ts - return ts; + return timespec64_to_timespec(ts); ...> ) | - timespec_equal(&node1->i_xtime1, &node2->i_xtime2) + timespec64_equal(&node1->i_xtime2, &node2->i_xtime2) | - timespec_equal(&node1->i_xtime1, &attr2->ia_xtime2) + timespec64_equal(&node1->i_xtime2, &attr2->ia_xtime2) | - timespec_compare(&node1->i_xtime1, &node2->i_xtime2) + timespec64_compare(&node1->i_xtime1, &node2->i_xtime2) | node1->i_xtime1 = - timespec_trunc(attr1->ia_xtime1, + timespec64_trunc(attr1->ia_xtime1, ...) | - attr1->ia_xtime1 = timespec_trunc(attr2->ia_xtime2, + attr1->ia_xtime1 = timespec64_trunc(attr2->ia_xtime2, ...) | - ktime_get_real_ts(&attr1->ia_xtime1) + ktime_get_real_ts64(&attr1->ia_xtime1) | - ktime_get_real_ts(&attr.ia_xtime1) + ktime_get_real_ts64(&attr.ia_xtime1) ) @ depends on patch @ struct inode *node; struct iattr *attr; identifier fn; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; expression e; @@ ( - fn(node->i_xtime); + fn(timespec64_to_timespec(node->i_xtime)); | fn(..., - node->i_xtime); + timespec64_to_timespec(node->i_xtime)); | - e = fn(attr->ia_xtime); + e = fn(timespec64_to_timespec(attr->ia_xtime)); ) @ depends on patch forall @ struct inode *node; struct iattr *attr; identifier i_xtime =~ "^i_[acm]time$"; identifier ia_xtime =~ "^ia_[acm]time$"; identifier fn; @@ { + struct timespec ts; <+... ( + ts = timespec64_to_timespec(node->i_xtime); fn (..., - &node->i_xtime, + &ts, ...); | + ts = timespec64_to_timespec(attr->ia_xtime); fn (..., - &attr->ia_xtime, + &ts, ...); ) ...+> } @ depends on patch forall @ struct inode *node; struct iattr *attr; struct kstat *stat; identifier ia_xtime =~ "^ia_[acm]time$"; identifier i_xtime =~ "^i_[acm]time$"; identifier xtime =~ "^[acm]time$"; identifier fn, ret; @@ { + struct timespec ts; <+... ( + ts = timespec64_to_timespec(node->i_xtime); ret = fn (..., - &node->i_xtime, + &ts, ...); | + ts = timespec64_to_timespec(node->i_xtime); ret = fn (..., - &node->i_xtime); + &ts); | + ts = timespec64_to_timespec(attr->ia_xtime); ret = fn (..., - &attr->ia_xtime, + &ts, ...); | + ts = timespec64_to_timespec(attr->ia_xtime); ret = fn (..., - &attr->ia_xtime); + &ts); | + ts = timespec64_to_timespec(stat->xtime); ret = fn (..., - &stat->xtime); + &ts); ) ...+> } @ depends on patch @ struct inode *node; struct inode *node2; identifier i_xtime1 =~ "^i_[acm]time$"; identifier i_xtime2 =~ "^i_[acm]time$"; identifier i_xtime3 =~ "^i_[acm]time$"; struct iattr *attrp; struct iattr *attrp2; struct iattr attr ; identifier ia_xtime1 =~ "^ia_[acm]time$"; identifier ia_xtime2 =~ "^ia_[acm]time$"; struct kstat *stat; struct kstat stat1; struct timespec64 ts; identifier xtime =~ "^[acmb]time$"; expression e; @@ ( ( node->i_xtime2 \| attrp->ia_xtime2 \| attr.ia_xtime2 \) = node->i_xtime1 ; | node->i_xtime2 = $ node2->i_xtime1 \| timespec64_trunc(...) $; | node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = $ts \| current_time(...) $; | node->i_xtime1 = node->i_xtime3 = $ts \| current_time(...) $; | stat->xtime = node2->i_xtime1; | stat1.xtime = node2->i_xtime1; | ( node->i_xtime2 \| attrp->ia_xtime2 \) = attrp->ia_xtime1 ; | ( attrp->ia_xtime1 \| attr.ia_xtime1 \) = attrp2->ia_xtime2; | - e = node->i_xtime1; + e = timespec64_to_timespec( node->i_xtime1 ); | - e = attrp->ia_xtime1; + e = timespec64_to_timespec( attrp->ia_xtime1 ); | node->i_xtime1 = current_time(...); | node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = - e; + timespec_to_timespec64(e); | node->i_xtime1 = node->i_xtime3 = - e; + timespec_to_timespec64(e); | - node->i_xtime1 = e; + node->i_xtime1 = timespec_to_timespec64(e); ) Signed-off-by: Deepa Dinamani Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc:

fs: convert a pile of fsync routines to errseq_t based reporting

2017-08-01T12:39:29Z

This patch converts most of the in-kernel filesystems that do writeback out of the pagecache to report errors using the errseq_t-based infrastructure that was recently added. This allows them to report errors once for each open file description. Most filesystems have a fairly straightforward fsync operation. They call filemap_write_and_wait_range to write back all of the data and wait on it, and then (sometimes) sync out the metadata. For those filesystems this is a straightforward conversion from calling filemap_write_and_wait_range in their fsync operation to calling file_write_and_wait_range. Acked-by: Jan Kara Acked-by: Dave Kleikamp Signed-off-by: Jeff Layton

vfs: Remove {get,set,remove}xattr inode operations

2016-10-08T01:48:36Z

These inode operations are no longer used; remove them. Signed-off-by: Andreas Gruenbacher Signed-off-by: Al Viro

jffs2: Remove jffs2_{get,set,remove}xattr macros

2016-10-07T02:17:38Z

When CONFIG_JFFS2_FS_XATTR is off, jffs2_xattr_handlers is defined as NULL. With sb->s_xattr == NULL, the generic_{get,set,remove}xattr functions produce the same result as setting the {get,set,remove}xattr inode operations to NULL, so there is no need for these macros. Signed-off-by: Andreas Gruenbacher Signed-off-by: Al Viro

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08Z

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds

Revert "jffs2: Fix lock acquisition order bug in jffs2_write_begin"

2016-02-25T11:11:25Z

This reverts commit 5ffd3412ae55 ("jffs2: Fix lock acquisition order bug in jffs2_write_begin"). The commit modified jffs2_write_begin() to remove a deadlock with jffs2_garbage_collect_live(), but this introduced new deadlocks found by multiple users. page_lock() actually has to be called before mutex_lock(&c->alloc_sem) or mutex_lock(&f->sem) because jffs2_write_end() and jffs2_readpage() are called with the page locked, and they acquire c->alloc_sem and f->sem, resp. In other words, the lock order in jffs2_write_begin() was correct, and it is the jffs2_garbage_collect_live() path that has to be changed. Revert the commit to get rid of the new deadlocks, and to clear the way for a better fix of the original deadlock. Reported-by: Deng Chao Reported-by: Ming Liu Reported-by: wangzaiwei Signed-off-by: Thomas Betker Signed-off-by: David Woodhouse Cc: stable@vger.kernel.org