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2013-11-20Squashfs: Generalise paging handling in the decompressorsPhillip Lougher
Further generalise the decompressors by adding a page handler abstraction. This adds helpers to allow the decompressors to access and process the output buffers in an implementation independant manner. This allows different types of output buffer to be passed to the decompressors, with the implementation specific aspects handled at decompression time, but without the knowledge being held in the decompressor wrapper code. This will allow the decompressors to handle Squashfs cache buffers, and page cache pages. This patch adds the abstraction and an implementation for the caches. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reviewed-by: Minchan Kim <minchan@kernel.org>
2013-11-20Squashfs: Refactor decompressor interface and codePhillip Lougher
The decompressor interface and code was written from the point of view of single-threaded operation. In doing so it mixed a lot of single-threaded implementation specific aspects into the decompressor code and elsewhere which makes it difficult to seamlessly support multiple different decompressor implementations. This patch does the following: 1. It removes compressor_options parsing from the decompressor init() function. This allows the decompressor init() function to be dynamically called to instantiate multiple decompressors, without the compressor options needing to be read and parsed each time. 2. It moves threading and all sleeping operations out of the decompressors. In doing so, it makes the decompressors non-blocking wrappers which only deal with interfacing with the decompressor implementation. 3. It splits decompressor.[ch] into decompressor generic functions in decompressor.[ch], and moves the single threaded decompressor implementation into decompressor_single.c. The result of this patch is Squashfs should now be able to support multiple decompressors by adding new decompressor_xxx.c files with specialised implementations of the functions in decompressor_single.c Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reviewed-by: Minchan Kim <minchan@kernel.org>
2013-09-05Squashfs: Optimized uncompressed buffer loopManish Sharma
Merged the two for loops. We might get a little gain by overlapping wait_on_bh and the memcpy operations. Signed-off-by: Manish Sharma <manishrma@gmail.com> Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
2012-03-10Squashfs: update comment removing reference to zlib onlyPhillip Lougher
Comment was written when Squashfs only supported zlib compression. This comment is now misleading given Squashfs supports other compression algorithms. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
2011-05-26Squashfs: update email addressPhillip Lougher
My existing email address may stop working in a month or two, so update email to one that will continue working. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2011-01-26squashfs: fix use of uninitialised variable in zlib & xz decompressorsPhillip Lougher
Fix potential use of uninitialised variable caused by recent decompressor code optimisations. In zlib_uncompress (zlib_wrapper.c) we have int zlib_err, zlib_init = 0; ... do { ... if (avail == 0) { offset = 0; put_bh(bh[k++]); continue; } ... zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH); ... } while (zlib_err == Z_OK); If continue is executed (avail == 0) then the while condition will be evaluated testing zlib_err, which is uninitialised first time around the loop. Fix this by getting rid of the 'if (avail == 0)' condition test, this edge condition should not be being handled in the decompressor code, and instead handle it generically in the caller code. Similarly for xz_wrapper.c. Incidentally, on most architectures (bar Mips and Parisc), no uninitialised variable warning is generated by gcc, this is because the while condition test on continue is optimised out and not performed (when executing continue zlib_err has not been changed since entering the loop, and logically if the while condition was true previously, then it's still true). Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk> Reported-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13Squashfs: move squashfs_i() definition from squashfs.hPhillip Lougher
Move squashfs_i() definition out of squashfs.h, this eliminates the need to #include squashfs_fs_i.h from numerous files. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2010-04-25squashfs: fix potential buffer over-run on 4K block file systemsPhillip Lougher
Sizing the buffer based on block size is incorrect, leading to a potential buffer over-run on 4K block size file systems (because the metadata block size is always 8K). This bug doesn't seem have triggered because 4K block size file systems are not default, and also because metadata blocks after compression tend to be less than 4K. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2010-01-20Squashfs: add a decompressor frameworkPhillip Lougher
This adds a decompressor framework which allows multiple compression algorithms to be cleanly supported. Also update zlib wrapper and other code to use the new framework. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2010-01-20Squashfs: factor out remaining zlib dependencies into separate wrapper filePhillip Lougher
Move zlib buffer init/destroy code into separate wrapper file. Also make zlib z_stream field a void * removing the need to include zlib.h for most files. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2010-01-20Squashfs: move zlib decompression wrapper code into a separate filePhillip Lougher
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2009-03-12Squashfs: Valid filesystems are flagged as bad by the corrupted fs patchPhillip Lougher
The corrupted filesystem patch added a check against zlib trying to output too much data in the presence of data corruption. This check triggered if zlib_inflate asked to be called again (Z_OK) with avail_out == 0 and no more output buffers available. This check proves to be rather dumb, as it incorrectly catches the case where zlib has generated all the output, but there are still input bytes to be processed. This patch does a number of things. It removes the original check and replaces it with code to not move to the next output buffer if there are no more output buffers available, relying on zlib to error if it wants an extra output buffer in the case of data corruption. It also replaces the Z_NO_FLUSH flag with the more correct Z_SYNC_FLUSH flag, and makes the error messages more understandable to non-technical users. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk> Reported-by: Stefan Lippers-Hollmann <s.L-H@gmx.de>
2009-03-05Squashfs: Fix oops when reading fsfuzzer corrupted filesystemsPhillip Lougher
This fixes a code regression caused by the recent mainlining changes. The recent code changes call zlib_inflate repeatedly, decompressing into separate 4K buffers, this code didn't check for the possibility that zlib_inflate might ask for too many buffers when decompressing corrupted data. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
2009-01-05Squashfs: block operationsPhillip Lougher
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>