- 15 Feb, 2019 13 commits
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Ming Lei authored
This patch introduces one extra iterator variable to bio_for_each_segment_all(), then we can allow bio_for_each_segment_all() to iterate over multi-page bvec. Given it is just one mechannical & simple change on all bio_for_each_segment_all() users, this patch does tree-wide change in one single patch, so that we can avoid to use a temporary helper for this conversion. Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
bch_bio_alloc_pages() is always called on one new bio, so it is safe to access the bvec table directly. Given it is the only kind of this case, open code the bvec table access since bio_for_each_segment_all() will be changed to support for iterating over multipage bvec. Acked-by: Coly Li <colyli@suse.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
iov_iter is implemented on bvec itererator helpers, so it is safe to pass multi-page bvec to it, and this way is much more efficient than passing one page in each bvec. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
Preparing for supporting multi-page bvec. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
Once multi-page bvec is enabled, the last bvec may include more than one page, this patch use mp_bvec_last_segment() to truncate the bio. Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
BTRFS and guard_bio_eod() need to get the last singlepage segment from one multipage bvec, so introduce this helper to make them happy. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
It is more efficient to use bio_for_each_bvec() to map sg, meantime we have to consider splitting multipage bvec as done in blk_bio_segment_split(). Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
First it is more efficient to use bio_for_each_bvec() in both blk_bio_segment_split() and __blk_recalc_rq_segments() to compute how many multi-page bvecs there are in the bio. Secondly once bio_for_each_bvec() is used, the bvec may need to be splitted because its length can be very longer than max segment size, so we have to split the big bvec into several segments. Thirdly when splitting multi-page bvec into segments, the max segment limit may be reached, so the bio split need to be considered under this situation too. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
bio_for_each_bvec() is used for iterating over multi-page bvec for bio split & merge code. rq_for_each_bvec() can be used for drivers which may handle the multi-page bvec directly, so far loop is one perfect use case. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
This patch introduces helpers of 'mp_bvec_iter_*' for multi-page bvec support. The introduced helpers treate one bvec as real multi-page segment, which may include more than one pages. The existed helpers of bvec_iter_* are interfaces for supporting current bvec iterator which is thought as single-page by drivers, fs, dm and etc. These introduced helpers will build single-page bvec in flight, so this way won't break current bio/bvec users, which needn't any change. Follows some multi-page bvec background: - bvecs stored in bio->bi_io_vec is always multi-page style - bvec(struct bio_vec) represents one physically contiguous I/O buffer, now the buffer may include more than one page after multi-page bvec is supported, and all these pages represented by one bvec is physically contiguous. Before multi-page bvec support, at most one page is included in one bvec, we call it single-page bvec. - .bv_page of the bvec points to the 1st page in the multi-page bvec - .bv_offset of the bvec is the offset of the buffer in the bvec The effect on the current drivers/filesystem/dm/bcache/...: - almost everyone supposes that one bvec only includes one single page, so we keep the sp interface not changed, for example, bio_for_each_segment() still returns single-page bvec - bio_for_each_segment_all() will return single-page bvec too - during iterating, iterator variable(struct bvec_iter) is always updated in multi-page bvec style, and bvec_iter_advance() is kept not changed - returned(copied) single-page bvec is built in flight by bvec helpers from the stored multi-page bvec Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
Commit 7759eb23 ("block: remove bio_rewind_iter()") removes bio_rewind_iter(), then no one uses bvec_iter_rewind() any more, so remove it. Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
It is wrong to use bio->bi_vcnt to figure out how many segments there are in the bio even though CLONED flag isn't set on this bio, because this bio may be splitted or advanced. So always use bio_segments() in blk_recount_segments(), and it shouldn't cause any performance loss now because the physical segment number is figured out in blk_queue_split() and BIO_SEG_VALID is set meantime since bdced438 ("block: setup bi_phys_segments after splitting"). Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Fixes: 76d8137a ("blk-merge: recaculate segment if it isn't less than max segments") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Hellwig authored
bio_readpage_error currently uses bi_vcnt to decide if it is worth retrying an I/O. But the vector count is mostly an implementation artifact - it really should figure out if there is more than a single sector worth retrying. Use bi_size for that and shift by PAGE_SHIFT. This really should be blocks/sectors, but given that btrfs doesn't support a sector size different from the PAGE_SIZE using the page size keeps the changes to a minimum. Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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- 11 Feb, 2019 10 commits
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Aleksei Zakharov authored
There's no reason to freeze queue and remove scheduler if there's no scheduler already. Signed-off-by: Aleksei Zakharov <zakharov.a.g@yandex.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Aleksei Zakharov authored
There's no reason to set wbt min lat and freeze request queue if current value is the same. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Aleksei Zakharov <zakharov.a.g@yandex.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Heiner Litz authored
This patch fixes a race condition where a write is mapped to the last sectors of a line. The write is synced to the device but the L2P is not updated yet. When the line is garbage collected before the L2P update is performed, the sectors are ignored by the GC logic and the line is freed before all sectors are moved. When the L2P is finally updated, it contains a mapping to a freed line, subsequent reads of the corresponding LBAs fail. This patch introduces a per line counter specifying the number of sectors that are synced to the device but have not been updated in the L2P. Lines with a counter of greater than zero will not be selected for GC. Signed-off-by: Heiner Litz <hlitz@ucsc.edu> Reviewed-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Javier González authored
In order to respect mw_cuinits, pblk's write buffer maintains a backpointer to protect data not yet persisted; when writing to the write buffer, this backpointer defines a threshold that pblk's rate-limiter enforces. On small PU configurations, the following scenarios might take place: (i) the threshold is larger than the write buffer and (ii) the threshold is smaller than the write buffer, but larger than the maximun allowed split bio - 256KB at this moment (Note that writes are not always split - we only do this when we the size of the buffer is smaller than the buffer). In both cases, pblk's rate-limiter prevents the I/O to be written to the buffer, thus stalling. This patch fixes the original backpointer implementation by considering the threshold both on buffer creation and on the rate-limiters path, when bio_split is triggered (case (ii) above). Fixes: 766c8ceb ("lightnvm: pblk: guarantee that backpointer is respected on writer stall") Signed-off-by: Javier González <javier@javigon.com> Reviewed-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Hans Holmberg authored
pblk stripes writes of minimal write size across all non-offline chunks in a line, which means that the maximum write pointer delta should not exceed the minimal write size. Extend the line write pointer balance check to cover this case, and ignore the offline chunk wps. This will render us a warning during recovery if something unexpected has happened to the chunk write pointers (i.e. powerloss, a spurious chunk reset, ..). Reported-by: Zhoujie Wu <zjwu@marvell.com> Tested-by: Zhoujie Wu <zjwu@marvell.com> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Masahiro Yamada authored
As the comment block in include/trace/define_trace.h says, TRACE_INCLUDE_PATH should be a relative path to the define_trace.h ../../drivers/lightnvm is the correct relative path. ../../../drivers/lightnvm is working by coincidence because the top Makefile adds -I$(srctree)/arch/$(SRCARCH)/include as a header search path, but we should not rely on it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Andy Shevchenko authored
There are new types and helpers that are supposed to be used in new code. As a preparation to get rid of legacy types and API functions do the conversion here. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Andy Shevchenko authored
Sparse complains about using strict data types: drivers/lightnvm/pblk-read.c:254:43: warning: incorrect type in assignment (different base types) drivers/lightnvm/pblk-read.c:254:43: expected restricted __le64 <noident> drivers/lightnvm/pblk-read.c:254:43: got unsigned long long [unsigned] [usertype] <noident> drivers/lightnvm/pblk-read.c:255:29: warning: cast from restricted __le64 drivers/lightnvm/pblk-read.c:268:29: warning: cast from restricted __le64 drivers/lightnvm/pblk-read.c:328:41: warning: incorrect type in assignment (different base types) drivers/lightnvm/pblk-read.c:328:41: expected restricted __le64 <noident> drivers/lightnvm/pblk-read.c:328:41: got unsigned long long [unsigned] [usertype] <noident> In the code it seems explicit that lba_list_mem and lba_list_media members of struct pblk_pr_ctx are used on CPU side, which means they should not be of strict types. Change types of lba_list_mem and lba_list_media members to be u64. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Hans Holmberg authored
As chunk metadata is allocated using vmalloc, we need to free it using vfree. Fixes: 090ee26f ("lightnvm: use internal allocation for chunk log page") Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Hans Holmberg authored
pblk_line_meta_free might sleep (it can end up calling vfree, depending on how we allocate lba lists), and this can lead to a BUG() if we wake up on a different cpu and release the lock. As there is no point of grabbing the free lock when pblk has shut down, remove the lock. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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- 10 Feb, 2019 2 commits
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Marcos Paulo de Souza authored
The Notes section of the comment was removed, because now blk_release_queue can only be executed from blk_cleanup_queue (being called when the q->kobj reaches zero), and also blk_init_queue was removed in a1ce35fa. Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Marcos Paulo de Souza authored
Since 4cf6324b, a portion of function blk_cleanup_queue was moved to a newly created function called blk_exit_queue, including the call of blkcg_exit_queue. So, adjust the documenation according. Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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- 09 Feb, 2019 15 commits
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Jens Axboe authored
We have QUEUE_FLAG_DEFAULT defined, but it's not used anymore since the legacy IO stack is gone. Kill it. Sanitize the queue flags in general, they use spaces (for some reason), and the space is pretty sparse. With the flags renumbered, we can more clearly see how many we have available. Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Jens Axboe authored
We have various helpers for setting/clearing this flag, and also a helper to check if the queue supports queueable flushes or not. But nobody uses them anymore, kill it with fire. Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
In 'commit 752f66a7 ("bcache: use REQ_PRIO to indicate bio for metadata")' REQ_META is replaced by REQ_PRIO to indicate metadata bio. This assumption is not always correct, e.g. XFS uses REQ_META to mark metadata bio other than REQ_PRIO. This is why Nix noticed that bcache does not cache metadata for XFS after the above commit. Thanks to Dave Chinner, he explains the difference between REQ_META and REQ_PRIO from view of file system developer. Here I quote part of his explanation from mailing list, REQ_META is used for metadata. REQ_PRIO is used to communicate to the lower layers that the submitter considers this IO to be more important that non REQ_PRIO IO and so dispatch should be expedited. IOWs, if the filesystem considers metadata IO to be more important that user data IO, then it will use REQ_PRIO | REQ_META rather than just REQ_META. Then it seems bios with REQ_META or REQ_PRIO should both be cached for performance optimation, because they are all probably low I/O latency demand by upper layer (e.g. file system). So in this patch, when we want to decide whether to bypass the cache, REQ_META and REQ_PRIO are both checked. Then both metadata and high priority I/O requests will be handled properly. Reported-by: Nix <nix@esperi.org.uk> Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Andre Noll <maan@tuebingen.mpg.de> Tested-by: Nix <nix@esperi.org.uk> Cc: stable@vger.kernel.org Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
Cache set sysfs entry io_error_halflife is used to set c->error_decay. c->error_decay is in type unsigned int, and it is converted by strtoul_or_return(), therefore overflow to c->error_decay is possible for a large input value. This patch fixes the overflow by using strtoul_safe_clamp() to convert input string to an unsigned long value in range [0, UINT_MAX], then divides by 88 and set it to c->error_decay. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
c->error_limit is in type unsigned int, it is set via cache set sysfs file io_error_limit. Inside the bcache code, input string is converted by strtoul_or_return() and set the converted value to c->error_limit. Because the converted value is unsigned long, and c->error_limit is unsigned int, if the input is large enought, overflow will happen to c->error_limit. This patch uses sysfs_strtoul_clamp() to convert input string, and set the range in [0, UINT_MAX] to avoid the potential overflow. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
c->journal_delay_ms is in type unsigned short, it is set via sysfs interface and converted by sysfs_strtoul() from input string to unsigned short value. Therefore overflow to unsigned short might be happen when the converted value exceed USHRT_MAX. e.g. writing 65536 into sysfs file journal_delay_ms, c->journal_delay_ms is set to 0. This patch uses sysfs_strtoul_clamp() to convert the input string and limit value range in [0, USHRT_MAX], to avoid the input overflow. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
dc->writeback_rate_minimum is type unsigned integer variable, it is set via sysfs interface, and converte from input string to unsigned integer by d_strtoul_nonzero(). When the converted input value is larger than UINT_MAX, overflow to unsigned integer happens. This patch fixes the overflow by using sysfs_strotoul_clamp() to convert input string and limit the value in range [1, UINT_MAX], then the overflow can be avoided. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
Current code already uses d_strtoul_nonzero() to convert input string to an unsigned integer, to make sure writeback_rate_p_term_inverse won't be zero value. But overflow may happen when converting input string to an unsigned integer value by d_strtoul_nonzero(), then dc->writeback_rate_p_term_inverse can still be set to 0 even if the sysfs file input value is not zero, e.g. 4294967296 (a.k.a UINT_MAX+1). If dc->writeback_rate_p_term_inverse is set to 0, it might cause a dev-zero error in following code from __update_writeback_rate(), int64_t proportional_scaled = div_s64(error, dc->writeback_rate_p_term_inverse); This patch replaces d_strtoul_nonzero() by sysfs_strtoul_clamp() and limit the value range in [1, UINT_MAX]. Then the unsigned integer overflow and dev-zero error can be avoided. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
dc->writeback_rate_i_term_inverse can be set via sysfs interface. It is in type unsigned int, and convert from input string by d_strtoul(). The problem is d_strtoul() does not check valid range of the input, if 4294967296 is written into sysfs file writeback_rate_i_term_inverse, an overflow of unsigned integer will happen and value 0 is set to dc->writeback_rate_i_term_inverse. In writeback.c:__update_writeback_rate(), there are following lines of code, integral_scaled = div_s64(dc->writeback_rate_integral, dc->writeback_rate_i_term_inverse); If dc->writeback_rate_i_term_inverse is set to 0 via sysfs interface, a div-zero error might be triggered in the above code. Therefore we need to add a range limitation in the sysfs interface, this is what this patch does, use sysfs_stroul_clamp() to replace d_strtoul() and restrict the input range in [1, UINT_MAX]. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
Sysfs file writeback_delay is used to configure dc->writeback_delay which is type unsigned int. But bcache code uses sysfs_strtoul() to convert the input string, therefore it might be overflowed if the input value is too large. E.g. input value is 4294967296 but indeed 0 is set to dc->writeback_delay. This patch uses sysfs_strtoul_clamp() to convert the input string and set the result value range in [0, UINT_MAX] to avoid such unsigned integer overflow. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
When setting bcache parameters via sysfs, there are some variables are defined as bit-field value. Current bcache code in sysfs.c uses either d_strtoul() or sysfs_strtoul() to convert the input string to unsigned integer value and set it to the corresponded bit-field value. The problem is, the bit-field value only takes the lowest bit of the converted value. If input is 2, the expected value (like bool value) of the bit-field value should be 1, but indeed it is 0. The following sysfs files for bit-field variables have such problem, bypass_torture_test, for dc->bypass_torture_test writeback_metadata, for dc->writeback_metadata writeback_running, for dc->writeback_running verify, for c->verify key_merging_disabled, for c->key_merging_disabled gc_always_rewrite, for c->gc_always_rewrite btree_shrinker_disabled,for c->shrinker_disabled copy_gc_enabled, for c->copy_gc_enabled This patch uses sysfs_strtoul_bool() to set such bit-field variables, then if the converted value is non-zero, the bit-field variables will be set to 1, like setting a bool value like expensive_debug_checks. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
When setting bool values via sysfs interface, e.g. writeback_metadata, if writing 1 into writeback_metadata file, dc->writeback_metadata is set to 1, but if writing 2 into the file, dc->writeback_metadata is 0. This is misleading, a better result should be 1 for all non-zero input value. It is because dc->writeback_metadata is a bit-field variable, and current code simply use d_strtoul() to convert a string into integer and takes the lowest bit value. To fix such error, we need a routine to convert the input string into unsigned integer, and set target variable to 1 if the converted integer is non-zero. This patch introduces a new macro called sysfs_strtoul_bool(), it can be used to convert input string into bool value, we can use it to set bool value for bit-field vairables. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
People may set sequential_cutoff of a cached device via sysfs file, but current code does not check input value overflow. E.g. if value 4294967295 (UINT_MAX) is written to file sequential_cutoff, its value is 4GB, but if 4294967296 (UINT_MAX + 1) is written into, its value will be 0. This is an unexpected behavior. This patch replaces d_strtoi_h() by sysfs_strtoul_clamp() to convert input string to unsigned integer value, and limit its range in [0, UINT_MAX]. Then the input overflow can be fixed. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
Cache set congested threshold values congested_read_threshold_us and congested_write_threshold_us can be set via sysfs interface. These two values are 'unsigned int' type, but sysfs interface uses strtoul to convert input string. So if people input a large number like 9999999999, the value indeed set is 1410065407, which is not expected behavior. This patch replaces sysfs_strtoul() by sysfs_strtoul_clamp() when convert input string to unsigned int value, and set value range in [0, UINT_MAX], to avoid the above integer overflow errors. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Coly Li authored
Currently sysfs_strtoul_clamp() is defined as, 82 #define sysfs_strtoul_clamp(file, var, min, max) \ 83 do { \ 84 if (attr == &sysfs_ ## file) \ 85 return strtoul_safe_clamp(buf, var, min, max) \ 86 ?: (ssize_t) size; \ 87 } while (0) The problem is, if bit width of var is less then unsigned long, min and max may not protect var from integer overflow, because overflow happens in strtoul_safe_clamp() before checking min and max. To fix such overflow in sysfs_strtoul_clamp(), to make min and max take effect, this patch adds an unsigned long variable, and uses it to macro strtoul_safe_clamp() to convert an unsigned long value in range defined by [min, max]. Then assign this value to var. By this method, if bit width of var is less than unsigned long, integer overflow won't happen before min and max are checking. Now sysfs_strtoul_clamp() can properly handle smaller data type like unsigned int, of cause min and max should be defined in range of unsigned int too. Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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