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4 dayserofs: fix large fragment handlingGao Xiang
[ Upstream commit b44686c8391b427fb1c85a31c35077e6947c6d90 ] Fragments aren't limited by Z_EROFS_PCLUSTER_MAX_DSIZE. However, if a fragment's logical length is larger than Z_EROFS_PCLUSTER_MAX_DSIZE but the fragment is not the whole inode, it currently returns -EOPNOTSUPP because m_flags has the wrong EROFS_MAP_ENCODED flag set. It is not intended by design but should be rare, as it can only be reproduced by mkfs with `-Eall-fragments` in a specific case. Let's normalize fragment m_flags using the new EROFS_MAP_FRAGMENT. Reported-by: Axel Fontaine <axel@axelfontaine.com> Closes: https://github.com/erofs/erofs-utils/issues/23 Fixes: 7c3ca1838a78 ("erofs: restrict pcluster size limitations") Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250711195826.3601157-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
4 dayserofs: clean up header parsing for ztailpacking and fragmentsGao Xiang
[ Upstream commit 540787d38b10dbc16a7d2bc2845752ab1605403a ] Simplify the logic in z_erofs_fill_inode_lazy() by combining the handling of ztailpacking and fragments, as they are mutually exclusive. Note that `h->h_clusterbits >> Z_EROFS_FRAGMENT_INODE_BIT` is handled above, so no need to duplicate the check. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250224123747.1387122-2-hsiangkao@linux.alibaba.com Stable-dep-of: b44686c8391b ("erofs: fix large fragment handling") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
4 dayserofs: simplify tail inline pcluster handlingGao Xiang
[ Upstream commit b7710262d743aca112877d12abed61ce8a5d0d98 ] Use `z_idata_size != 0` to indicate that ztailpacking is enabled. `Z_EROFS_ADVISE_INLINE_PCLUSTER` cannot be ignored, as `h_idata_size` could be non-zero prior to erofs-utils 1.6 [1]. Additionally, merge `z_idataoff` and `z_fragmentoff` since these two features are mutually exclusive for a given inode. [1] https://git.kernel.org/xiang/erofs-utils/c/547bea3cb71a Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250225114038.3259726-1-hsiangkao@linux.alibaba.com Stable-dep-of: b44686c8391b ("erofs: fix large fragment handling") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
4 dayserofs: use Z_EROFS_LCLUSTER_TYPE_MAX to simplify switchesHongzhen Luo
[ Upstream commit 3b7781aeaefb627d4e07c1af9be923f9e8047d8b ] There's no need to enumerate each type. No logic changes. Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20250210032923.3382136-1-hongzhen@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Stable-dep-of: b44686c8391b ("erofs: fix large fragment handling") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
4 dayserofs: refine z_erofs_get_extent_compressedlen()Gao Xiang
[ Upstream commit 8f9530aeeb4f756bdfa70510b40e5d28ea3c742e ] - Set `compressedblks = 1` directly for non-bigpcluster cases. This simplifies the logic a bit since lcluster sizes larger than one block are unsupported and the details remain unclear. - For Z_EROFS_LCLUSTER_TYPE_PLAIN pclusters, avoid assuming `compressedblks = 1` by default. Instead, check if Z_EROFS_ADVISE_BIG_PCLUSTER_2 is set. It basically has no impact to existing valid images, but it's useful to find the gap to prepare for large PLAIN pclusters. Link: https://lore.kernel.org/r/20250123090109.973463-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Stable-dep-of: b44686c8391b ("erofs: fix large fragment handling") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
4 dayserofs: simplify z_erofs_load_compact_lcluster()Gao Xiang
[ Upstream commit 2a810ea79cd7a6d5f134ea69ca2ba726e600cbc4 ] - Get rid of unpack_compacted_index() and fold it into z_erofs_load_compact_lcluster(); - Avoid a goto. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250114034429.431408-1-hsiangkao@linux.alibaba.com Stable-dep-of: b44686c8391b ("erofs: fix large fragment handling") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17erofs: fix rare pcluster memory leak after unmountingGao Xiang
commit b10a1e5643e505c367c7e16aa6d8a9a0dc07354b upstream. There may still exist some pcluster with valid reference counts during unmounting. Instead of introducing another synchronization primitive, just try again as unmounting is relatively rare. This approach is similar to z_erofs_cache_invalidate_folio(). It was also reported by syzbot as a UAF due to commit f5ad9f9a603f ("erofs: free pclusters if no cached folio is attached"): BUG: KASAN: slab-use-after-free in do_raw_spin_trylock+0x72/0x1f0 kernel/locking/spinlock_debug.c:123 .. queued_spin_trylock include/asm-generic/qspinlock.h:92 [inline] do_raw_spin_trylock+0x72/0x1f0 kernel/locking/spinlock_debug.c:123 __raw_spin_trylock include/linux/spinlock_api_smp.h:89 [inline] _raw_spin_trylock+0x20/0x80 kernel/locking/spinlock.c:138 spin_trylock include/linux/spinlock.h:361 [inline] z_erofs_put_pcluster fs/erofs/zdata.c:959 [inline] z_erofs_decompress_pcluster fs/erofs/zdata.c:1403 [inline] z_erofs_decompress_queue+0x3798/0x3ef0 fs/erofs/zdata.c:1425 z_erofs_decompressqueue_work+0x99/0xe0 fs/erofs/zdata.c:1437 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> However, it seems a long outstanding memory leak. Fix it now. Fixes: f5ad9f9a603f ("erofs: free pclusters if no cached folio is attached") Reported-by: syzbot+7ff87b095e7ca0c5ac39@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/674c1235.050a0220.ad585.0032.GAE@google.com Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241203072821.1885740-1-hsiangkao@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17erofs: fix to add missing tracepoint in erofs_readahead()Chao Yu
[ Upstream commit d53238b614e01266a3d36b417b60a502e0698504 ] Commit 771c994ea51f ("erofs: convert all uncompressed cases to iomap") converts to use iomap interface, it removed trace_erofs_readahead() tracepoint in the meantime, let's add it back. Fixes: 771c994ea51f ("erofs: convert all uncompressed cases to iomap") Signed-off-by: Chao Yu <chao@kernel.org> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250707084832.2725677-1-chao@kernel.org Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17erofs: refine readahead tracepointGao Xiang
[ Upstream commit 4eb56b0761e75034dd35067a81da4c280c178262 ] - trace_erofs_readpages => trace_erofs_readahead; - Rename a redundant statement `nrpages = readahead_count(rac);`; - Move the tracepoint to the beginning of z_erofs_readahead(). Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Hongbo Li <lihongbo22@huawei.com> Link: https://lore.kernel.org/r/20250514120820.2739288-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Stable-dep-of: d53238b614e0 ("erofs: fix to add missing tracepoint in erofs_readahead()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17erofs: tidy up zdata.cGao Xiang
[ Upstream commit 6f435e94a19ad25b372bc61443afd0839b8a521c ] All small code style adjustments, no logic changes: - z_erofs_decompress_frontend => z_erofs_frontend; - z_erofs_decompress_backend => z_erofs_backend; - Use Z_EROFS_DEFINE_FRONTEND() to replace DECOMPRESS_FRONTEND_INIT(); - `nr_folios` should be `nrpages` in z_erofs_readahead(); - Refine in-line comments. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250114034429.431408-3-hsiangkao@linux.alibaba.com Stable-dep-of: d53238b614e0 ("erofs: fix to add missing tracepoint in erofs_readahead()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17erofs: get rid of `z_erofs_next_pcluster_t`Gao Xiang
[ Upstream commit 5514d8478b8ef3f0ba1b77beaa65f05c12825143 ] It was originally intended for tagged pointer reservation. Now all encoded data can be represented uniformally with `struct z_erofs_pcluster` as described in commit bf1aa03980f4 ("erofs: sunset `struct erofs_workgroup`"), let's drop it too. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250114034429.431408-2-hsiangkao@linux.alibaba.com Stable-dep-of: d53238b614e0 ("erofs: fix to add missing tracepoint in erofs_readahead()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17erofs: free pclusters if no cached folio is attachedChunhai Guo
[ Upstream commit f5ad9f9a603f829d11ca31a0a4049e16091e8c13 ] Once a pcluster is fully decompressed and there are no attached cached folios, its corresponding `struct z_erofs_pcluster` will be freed. This will significantly reduce the frequency of calls to erofs_shrink_scan() and the memory allocated for `struct z_erofs_pcluster`. The tables below show approximately a 96% reduction in the calls to erofs_shrink_scan() and in the memory allocated for `struct z_erofs_pcluster` after applying this patch. The results were obtained by performing a test to copy a 4.1GB partition on ARM64 Android devices running the 6.6 kernel with an 8-core CPU and 12GB of memory. 1. The reduction in calls to erofs_shrink_scan(): +-----------------+-----------+----------+---------+ | | w/o patch | w/ patch | diff | +-----------------+-----------+----------+---------+ | Average (times) | 11390 | 390 | -96.57% | +-----------------+-----------+----------+---------+ 2. The reduction in memory released by erofs_shrink_scan(): +-----------------+-----------+----------+---------+ | | w/o patch | w/ patch | diff | +-----------------+-----------+----------+---------+ | Average (Byte) | 133612656 | 4434552 | -96.68% | +-----------------+-----------+----------+---------+ Signed-off-by: Chunhai Guo <guochunhai@vivo.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241112043235.546164-1-guochunhai@vivo.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Stable-dep-of: d53238b614e0 ("erofs: fix to add missing tracepoint in erofs_readahead()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-07-17erofs: address D-cache aliasingGao Xiang
commit 27917e8194f91dffd8b4825350c63cb68e98ce58 upstream. Flush the D-cache before unlocking folios for compressed inodes, as they are dirtied during decompression. Avoid calling flush_dcache_folio() on every CPU write, since it's more like playing whack-a-mole without real benefit. It has no impact on x86 and arm64/risc-v: on x86, flush_dcache_folio() is a no-op, and on arm64/risc-v, PG_dcache_clean (PG_arch_1) is clear for new page cache folios. However, certain ARM boards are affected, as reported. Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support") Closes: https://lore.kernel.org/r/c1e51e16-6cc6-49d0-a63e-4e9ff6c4dd53@pengutronix.de Closes: https://lore.kernel.org/r/38d43fae-1182-4155-9c5b-ffc7382d9917@siemens.com Tested-by: Jan Kiszka <jan.kiszka@siemens.com> Tested-by: Stefan Kerkmann <s.kerkmann@pengutronix.de> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250709034614.2780117-2-hsiangkao@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-17erofs: fix to add missing tracepoint in erofs_read_folio()Chao Yu
commit 99f7619a77a0a2e3e2bcae676d0f301769167754 upstream. Commit 771c994ea51f ("erofs: convert all uncompressed cases to iomap") converts to use iomap interface, it removed trace_erofs_readpage() tracepoint in the meantime, let's add it back. Fixes: 771c994ea51f ("erofs: convert all uncompressed cases to iomap") Signed-off-by: Chao Yu <chao@kernel.org> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250708111942.3120926-1-chao@kernel.org Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-07-10add a string-to-qstr constructorAl Viro
[ Upstream commit c1feab95e0b2e9fce7e4f4b2739baf40d84543af ] Quite a few places want to build a struct qstr by given string; it would be convenient to have a primitive doing that, rather than open-coding it via QSTR_INIT(). The closest approximation was in bcachefs, but that expands to initializer list - {.len = strlen(string), .name = string}. It would be more useful to have it as compound literal - (struct qstr){.len = strlen(string), .name = string}. Unlike initializer list it's a valid expression. What's more, it's a valid lvalue - it's an equivalent of anonymous local variable with such initializer, so the things like path->dentry = d_alloc_pseudo(mnt->mnt_sb, &QSTR(name)); are valid. It can also be used as initializer, with identical effect - struct qstr x = (struct qstr){.name = s, .len = strlen(s)}; is equivalent to struct qstr anon_variable = {.name = s, .len = strlen(s)}; struct qstr x = anon_variable; // anon_variable is never used after that point and any even remotely sane compiler will manage to collapse that into struct qstr x = {.name = s, .len = strlen(s)}; What compound literals can't be used for is initialization of global variables, but those are covered by QSTR_INIT(). This commit lifts definition(s) of QSTR() into linux/dcache.h, converts it to compound literal (all bcachefs users are fine with that) and converts assorted open-coded instances to using that. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Stable-dep-of: cbe4134ea4bc ("fs: export anon_inode_make_secure_inode() and fix secretmem LSM bypass") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19erofs: avoid using multiple devices with different typeSheng Yong
[ Upstream commit 9748f2f54f66743ac77275c34886a9f890e18409 ] For multiple devices, both primary and extra devices should be the same type. `erofs_init_device` has already guaranteed that if the primary is a file-backed device, extra devices should also be regular files. However, if the primary is a block device while the extra device is a file-backed device, `erofs_init_device` will get an ENOTBLK, which is not treated as an error in `erofs_fc_get_tree`, and that leads to an UAF: erofs_fc_get_tree get_tree_bdev_flags(erofs_fc_fill_super) erofs_read_superblock erofs_init_device // sbi->dif0 is not inited yet, // return -ENOTBLK deactivate_locked_super free(sbi) if (err is -ENOTBLK) sbi->dif0.file = filp_open() // sbi UAF So if -ENOTBLK is hitted in `erofs_init_device`, it means the primary device must be a block device, and the extra device is not a block device. The error can be converted to -EINVAL. Fixes: fb176750266a ("erofs: add file-backed mount support") Signed-off-by: Sheng Yong <shengyong1@xiaomi.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Hongbo Li <lihongbo22@huawei.com> Link: https://lore.kernel.org/r/20250515014837.3315886-1-shengyong1@xiaomi.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-19erofs: fix file handle encoding for 64-bit NIDsHongbo Li
[ Upstream commit 510de8363f2c3d8e67fa9dfb2366e821382036e0 ] EROFS uses NID to indicate the on-disk inode offset, which can exceed 32 bits. However, the default encode_fh uses the ino32, thus it doesn't work if the image is larger than 128GiB. Let's introduce our own helpers to encode file handles. It's easy to reproduce: 1. prepare an erofs image with nid bigger than U32_MAX 2. mount -t erofs foo.img /mnt/erofs 3. set exportfs with configuration: /mnt/erofs *(rw,sync, no_root_squash) 4. mount -t nfs $IP:/mnt/erofs /mnt/nfs 5. md5sum /mnt/nfs/foo # foo is the file which nid bigger than U32_MAX. # you will get ESTALE error. In the case of overlayfs, the underlying filesystem's file handle is encoded in ovl_fb.fid, which is similar to NFS's case. If the NID of file is larger than U32_MAX, the overlay will get -ESTALE error when calls exportfs_decode_fh. Fixes: 3e917cc305c6 ("erofs: make filesystem exportable") Signed-off-by: Hongbo Li <lihongbo22@huawei.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250507094015.14007-1-lihongbo22@huawei.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29erofs: initialize decompression earlyGao Xiang
[ Upstream commit fe1e57d44d7f106df9048e815e4862cf63921220 ] - Rename erofs_init_managed_cache() to z_erofs_init_super(); - Move the initialization of managed_pslots into z_erofs_init_super() too; - Move z_erofs_init_super() and packed inode preparation upwards, before the root inode initialization. Therefore, the root directory can also be compressible. Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Acked-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20250317054840.3483000-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-18erofs: ensure the extra temporary copy is valid for shortened bvecsGao Xiang
[ Upstream commit 35076d2223c731f7be75af61e67f90807384d030 ] When compressed data deduplication is enabled, multiple logical extents may reference the same compressed physical cluster. The previous commit 94c43de73521 ("erofs: fix wrong primary bvec selection on deduplicated extents") already avoids using shortened bvecs. However, in such cases, the extra temporary buffers also need to be preserved for later use in z_erofs_fill_other_copies() to to prevent data corruption. IOWs, extra temporary buffers have to be retained not only due to varying start relative offsets (`pageofs_out`, as indicated by `pcl->multibases`) but also because of shortened bvecs. android.hardware.graphics.composer@2.1.so : 270696 bytes 0: 0.. 204185 | 204185 : 628019200.. 628084736 | 65536 -> 1: 204185.. 225536 | 21351 : 544063488.. 544129024 | 65536 2: 225536.. 270696 | 45160 : 0.. 0 | 0 com.android.vndk.v28.apex : 93814897 bytes ... 364: 53869896..54095257 | 225361 : 543997952.. 544063488 | 65536 -> 365: 54095257..54309344 | 214087 : 544063488.. 544129024 | 65536 366: 54309344..54514557 | 205213 : 544129024.. 544194560 | 65536 ... Both 204185 and 54095257 have the same start relative offset of 3481, but the logical page 55 of `android.hardware.graphics.composer@2.1.so` ranges from 225280 to 229632, forming a shortened bvec [225280, 225536) that cannot be used for decompressing the range from 54095257 to 54309344 of `com.android.vndk.v28.apex`. Since `pcl->multibases` is already meaningless, just mark `be->keepxcpy` on demand for simplicity. Again, this issue can only lead to data corruption if `-Ededupe` is on. Fixes: 94c43de73521 ("erofs: fix wrong primary bvec selection on deduplicated extents") Reviewed-by: Hongbo Li <lihongbo22@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250506101850.191506-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-18fs/erofs/fileio: call erofs_onlinefolio_split() after bio_add_folio()Max Kellermann
commit bbfe756dc3062c1e934f06e5ba39c239aa953b92 upstream. If bio_add_folio() fails (because it is full), erofs_fileio_scan_folio() needs to submit the I/O request via erofs_fileio_rq_submit() and allocate a new I/O request with an empty `struct bio`. Then it retries the bio_add_folio() call. However, at this point, erofs_onlinefolio_split() has already been called which increments `folio->private`; the retry will call erofs_onlinefolio_split() again, but there will never be a matching erofs_onlinefolio_end() call. This leaves the folio locked forever and all waiters will be stuck in folio_wait_bit_common(). This bug has been added by commit ce63cb62d794 ("erofs: support unencoded inodes for fileio"), but was practically unreachable because there was room for 256 folios in the `struct bio` - until commit 9f74ae8c9ac9 ("erofs: shorten bvecs[] for file-backed mounts") which reduced the array capacity to 16 folios. It was now trivial to trigger the bug by manually invoking readahead from userspace, e.g.: posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED); This should be fixed by invoking erofs_onlinefolio_split() only after bio_add_folio() has succeeded. This is safe: asynchronous completions invoking erofs_onlinefolio_end() will not unlock the folio because erofs_fileio_scan_folio() is still holding a reference to be released by erofs_onlinefolio_end() at the end. Fixes: ce63cb62d794 ("erofs: support unencoded inodes for fileio") Fixes: 9f74ae8c9ac9 ("erofs: shorten bvecs[] for file-backed mounts") Cc: stable@vger.kernel.org Signed-off-by: Max Kellermann <max.kellermann@ionos.com> Reviewed-by: Gao Xiang <xiang@kernel.org> Tested-by: Hongbo Li <lihongbo22@huawei.com> Link: https://lore.kernel.org/r/20250428230933.3422273-1-max.kellermann@ionos.com Signed-off-by: Gao Xiang <xiang@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-20erofs: set error to bio if file-backed IO failsSheng Yong
[ Upstream commit 1595f15391b81815e4ef91c339991913d556c1b6 ] If a file-backed IO fails before submitting the bio to the lower filesystem, an error is returned, but the bio->bi_status is not marked as an error. However, the error information should be passed to the end_io handler. Otherwise, the IO request will be treated as successful. Fixes: 283213718f5d ("erofs: support compressed inodes for fileio") Signed-off-by: Sheng Yong <shengyong1@xiaomi.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250408122351.2104507-1-shengyong1@xiaomi.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08erofs: fix potential return value overflow of z_erofs_shrink_scan()Gao Xiang
[ Upstream commit db902986dee453bfb5835cbc8efa67154ab34caf ] z_erofs_shrink_scan() could return small numbers due to the mistyped `freed`. Although I don't think it has any visible impact. Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support") Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20250114040058.459981-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08erofs: sunset `struct erofs_workgroup`Gao Xiang
[ Upstream commit bf1aa03980f4eb1599b866ccd2c4ac577ef56a8a ] `struct erofs_workgroup` was introduced to provide a unique header for all physically indexed objects. However, after big pclusters and shared pclusters are implemented upstream, it seems that all EROFS encoded data (which requires transformation) can be represented with `struct z_erofs_pcluster` directly. Move all members into `struct z_erofs_pcluster` for simplicity. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241021035323.3280682-3-hsiangkao@linux.alibaba.com Stable-dep-of: db902986dee4 ("erofs: fix potential return value overflow of z_erofs_shrink_scan()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08erofs: move erofs_workgroup operations into zdata.cGao Xiang
[ Upstream commit 9c91f959626e6d9f460b8906e27c37fca1b6456a ] Move related helpers into zdata.c as an intermediate step of getting rid of `struct erofs_workgroup`, and rename: erofs_workgroup_put => z_erofs_put_pcluster erofs_workgroup_get => z_erofs_get_pcluster erofs_try_to_release_workgroup => erofs_try_to_release_pcluster erofs_shrink_workstation => z_erofs_shrink_scan Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241021035323.3280682-2-hsiangkao@linux.alibaba.com Stable-dep-of: db902986dee4 ("erofs: fix potential return value overflow of z_erofs_shrink_scan()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08erofs: get rid of erofs_{find,insert}_workgroupGao Xiang
[ Upstream commit b091e8ed24b7965953147a389bac1dc7c3e8a11c ] Just fold them into the only two callers since they are simple enough. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241021035323.3280682-1-hsiangkao@linux.alibaba.com Stable-dep-of: db902986dee4 ("erofs: fix potential return value overflow of z_erofs_shrink_scan()") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-27erofs: use buffered I/O for file-backed mounts by defaultGao Xiang
[ Upstream commit 6422cde1b0d5a31b206b263417c1c2b3c80fe82c ] For many use cases (e.g. container images are just fetched from remote), performance will be impacted if underlay page cache is up-to-date but direct i/o flushes dirty pages first. Instead, let's use buffered I/O by default to keep in sync with loop devices and add a (re)mount option to explicitly give a try to use direct I/O if supported by the underlying files. The container startup time is improved as below: [workload] docker.io/library/workpress:latest unpack 1st run non-1st runs EROFS snapshotter buffered I/O file 4.586404265s 0.308s 0.198s EROFS snapshotter direct I/O file 4.581742849s 2.238s 0.222s EROFS snapshotter loop 4.596023152s 0.346s 0.201s Overlayfs snapshotter 5.382851037s 0.206s 0.214s Fixes: fb176750266a ("erofs: add file-backed mount support") Cc: Derek McGowan <derek@mcg.dev> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241212134336.2059899-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-27erofs: reference `struct erofs_device_info` for erofs_map_devGao Xiang
[ Upstream commit f8d920a402aec3482931cb5f1539ed438740fc49 ] Record `m_sb` and `m_dif` to replace `m_fscache`, `m_daxdev`, `m_fp` and `m_dax_part_off` in order to simplify the codebase. Note that `m_bdev` is still left since it can be assigned from `sb->s_bdev` directly. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241212235401.2857246-1-hsiangkao@linux.alibaba.com Stable-dep-of: 6422cde1b0d5 ("erofs: use buffered I/O for file-backed mounts by default") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-27erofs: use `struct erofs_device_info` for the primary deviceGao Xiang
[ Upstream commit 7b00af2c5414dc01e0718deef7ead81102867636 ] Instead of just listing each one directly in `struct erofs_sb_info` except that we still use `sb->s_bdev` for the primary block device. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241216125310.930933-2-hsiangkao@linux.alibaba.com Stable-dep-of: 6422cde1b0d5 ("erofs: use buffered I/O for file-backed mounts by default") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-27erofs: add erofs_sb_free() helperGao Xiang
[ Upstream commit e2de3c1bf6a0c99b089bd706a62da8f988918858 ] Unify the common parts of erofs_fc_free() and erofs_kill_sb() as erofs_sb_free(). Thus, fput() in erofs_fc_get_tree() is no longer needed, too. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241212133504.2047178-1-hsiangkao@linux.alibaba.com Stable-dep-of: 6422cde1b0d5 ("erofs: use buffered I/O for file-backed mounts by default") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-27erofs: fix PSI memstall accountingGao Xiang
[ Upstream commit 1a2180f6859c73c674809f9f82e36c94084682ba ] Max Kellermann recently reported psi_group_cpu.tasks[NR_MEMSTALL] is incorrect in the 6.11.9 kernel. The root cause appears to be that, since the problematic commit, bio can be NULL, causing psi_memstall_leave() to be skipped in z_erofs_submit_queue(). Reported-by: Max Kellermann <max.kellermann@ionos.com> Closes: https://lore.kernel.org/r/CAKPOu+8tvSowiJADW2RuKyofL_CSkm_SuyZA7ME5vMLWmL6pqw@mail.gmail.com Fixes: 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of crafted images properly") Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241127085236.3538334-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05erofs: handle NONHEAD !delta[1] lclusters gracefullyGao Xiang
[ Upstream commit 0bc8061ffc733a0a246b8689b2d32a3e9204f43c ] syzbot reported a WARNING in iomap_iter_done: iomap_fiemap+0x73b/0x9b0 fs/iomap/fiemap.c:80 ioctl_fiemap fs/ioctl.c:220 [inline] Generally, NONHEAD lclusters won't have delta[1]==0, except for crafted images and filesystems created by pre-1.0 mkfs versions. Previously, it would immediately bail out if delta[1]==0, which led to inadequate decompressed lengths (thus FIEMAP is impacted). Treat it as delta[1]=1 to work around these legacy mkfs versions. `lclusterbits > 14` is illegal for compact indexes, error out too. Reported-by: syzbot+6c0b301317aa0156f9eb@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/67373c0c.050a0220.2a2fcc.0079.GAE@google.com Tested-by: syzbot+6c0b301317aa0156f9eb@syzkaller.appspotmail.com Fixes: d95ae5e25326 ("erofs: add support for the full decompressed length") Fixes: 001b8ccd0650 ("erofs: fix compact 4B support for 16k block size") Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241115173651.3339514-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05erofs: fix blksize < PAGE_SIZE for file-backed mountsHongzhen Luo
[ Upstream commit bae0854160939a64a092516ff1b2f221402b843b ] Adjust sb->s_blocksize{,_bits} directly for file-backed mounts when the fs block size is smaller than PAGE_SIZE. Previously, EROFS used sb_set_blocksize(), which caused a panic if bdev-backed mounts is not used. Fixes: fb176750266a ("erofs: add file-backed mount support") Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com> Link: https://lore.kernel.org/r/20241015103836.3757438-1-hongzhen@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05erofs: fix file-backed mounts over FUSEGao Xiang
[ Upstream commit 3a23787ca8756920d65fda39f41353a4be1d1642 ] syzbot reported a null-ptr-deref in fuse_read_args_fill: fuse_read_folio+0xb0/0x100 fs/fuse/file.c:905 filemap_read_folio+0xc6/0x2a0 mm/filemap.c:2367 do_read_cache_folio+0x263/0x5c0 mm/filemap.c:3825 read_mapping_folio include/linux/pagemap.h:1011 [inline] erofs_bread+0x34d/0x7e0 fs/erofs/data.c:41 erofs_read_superblock fs/erofs/super.c:281 [inline] erofs_fc_fill_super+0x2b9/0x2500 fs/erofs/super.c:625 Unlike most filesystems, some network filesystems and FUSE need unavoidable valid `file` pointers for their read I/Os [1]. Anyway, those use cases need to be supported too. [1] https://docs.kernel.org/filesystems/vfs.html Reported-by: syzbot+0b1279812c46e48bb0c1@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/6727bbdf.050a0220.3c8d68.0a7e.GAE@google.com Fixes: fb176750266a ("erofs: add file-backed mount support") Tested-by: syzbot+0b1279812c46e48bb0c1@syzkaller.appspotmail.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241114234905.1873723-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-21erofs: use get_tree_bdev_flags() to avoid misleading messagesGao Xiang
Users can pass in an arbitrary source path for the proper type of a mount then without "Can't lookup blockdev" error message. Reported-by: Allison Karlitskaya <allison.karlitskaya@redhat.com> Closes: https://lore.kernel.org/r/CAOYeF9VQ8jKVmpy5Zy9DNhO6xmWSKMB-DO8yvBB0XvBE7=3Ugg@mail.gmail.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241009033151.2334888-2-hsiangkao@linux.alibaba.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-14Merge tag 'erofs-for-6.12-rc4-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs Pull erofs fixes from Gao Xiang: "The main one fixes a syzbot issue due to the invalid inode type out of file-backed mounts. The others are minor cleanups without actual logic changes. Summary: - Make sure only regular inodes can be used for file-backed mounts - Two minor codebase cleanups" * tag 'erofs-for-6.12-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs: erofs: get rid of kaddr in `struct z_erofs_maprecorder` erofs: get rid of z_erofs_try_to_claim_pcluster() erofs: ensure regular inodes for file-backed mounts
2024-10-11erofs: get rid of kaddr in `struct z_erofs_maprecorder`Gao Xiang
`kaddr` becomes useless after switching to metabuf. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241010235830.1535616-1-hsiangkao@linux.alibaba.com
2024-10-11erofs: get rid of z_erofs_try_to_claim_pcluster()Gao Xiang
Just fold it into the caller for simplicity. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20241010090420.405871-1-hsiangkao@linux.alibaba.com
2024-10-11erofs: ensure regular inodes for file-backed mountsGao Xiang
Only regular inodes are allowed for file-backed mounts, not directories (as seen in the original syzbot case) or special inodes. Also ensure that .read_folio() is implemented on the underlying fs for the primary device. Fixes: fb176750266a ("erofs: add file-backed mount support") Reported-by: syzbot+001306cd9c92ce0df23f@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/00000000000011bdde0622498ee3@google.com Tested-by: syzbot+001306cd9c92ce0df23f@syzkaller.appspotmail.com Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240917130803.32418-1-hsiangkao@linux.alibaba.com
2024-10-02move asm/unaligned.h to linux/unaligned.hAl Viro
asm/unaligned.h is always an include of asm-generic/unaligned.h; might as well move that thing to linux/unaligned.h and include that - there's nothing arch-specific in that header. auto-generated by the following: for i in `git grep -l -w asm/unaligned.h`; do sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i done for i in `git grep -l -w asm-generic/unaligned.h`; do sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i done git mv include/asm-generic/unaligned.h include/linux/unaligned.h git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h
2024-09-12erofs: reject inodes with negative i_sizeGao Xiang
Negative i_size is never supported, although crafted images with inodes having negative i_size will NOT lead to security issues in our current codebase: The following image can verify this (gzip+base64 encoded): H4sICCmk4mYAA3Rlc3QuaW1nAGNgGAWjYBSMVPDo4dcH3jP2aTED2TwMKgxMUHHNJY/SQDQX LxcDIw3tZwXit44MDNpQ/n8gQJZ/vxjijosPuSyZ0DUDgQqcZoKzVYFsDShbHeh6PT29ktTi Eqz2g/y2pBFiLxDMh4lhs5+W4TAKRsEoGAWjYBSMglEwCkYBPQAAS2DbowAQAAA= Mark as bad inodes for such corrupted inodes explicitly. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240912083538.3011860-1-hsiangkao@linux.alibaba.com
2024-09-12erofs: restrict pcluster size limitationsGao Xiang
Error out if {en,de}encoded size of a pcluster is unsupported: Maximum supported encoded size (of a pcluster): 1 MiB Maximum supported decoded size (of a pcluster): 12 MiB Users can still choose to use supported large configurations (e.g., for archival purposes), but there may be performance penalties in low-memory scenarios compared to smaller pclusters. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240912074156.2925394-1-hsiangkao@linux.alibaba.com
2024-09-12erofs: allocate more short-lived pages from reserved pool firstChunhai Guo
This patch aims to allocate bvpages and short-lived compressed pages from the reserved pool first. After applying this patch, there are three benefits. 1. It reduces the page allocation time. The bvpages and short-lived compressed pages account for about 4% of the pages allocated from the system in the multi-app launch benchmarks [1]. It reduces the page allocation time accordingly and lowers the likelihood of blockage by page allocation in low memory scenarios. 2. The pages in the reserved pool will be allocated on demand. Currently, bvpages and short-lived compressed pages are short-lived pages allocated from the system, and the pages in the reserved pool all originate from short-lived pages. Consequently, the number of reserved pool pages will increase to z_erofs_rsv_nrpages over time. With this patch, all short-lived pages are allocated from the reserved pool first, so the number of reserved pool pages will only increase when there are not enough pages. Thus, even if z_erofs_rsv_nrpages is set to a large number for specific reasons, the actual number of reserved pool pages may remain low as per demand. In the multi-app launch benchmarks [1], z_erofs_rsv_nrpages is set at 256, while the number of reserved pool pages remains below 64. 3. When erofs cache decompression is disabled (EROFS_ZIP_CACHE_DISABLED), all pages will *only* be allocated from the reserved pool for erofs. This will significantly reduce the memory pressure from erofs. [1] For additional details on the multi-app launch benchmarks, please refer to commit 0f6273ab4637 ("erofs: add a reserved buffer pool for lz4 decompression"). Signed-off-by: Chunhai Guo <guochunhai@vivo.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20240906121110.3701889-1-guochunhai@vivo.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-09-12erofs: sunset unneeded NOFAILsGao Xiang
With iterative development, our codebase can now deal with compressed buffer misses properly if both in-place I/O and compressed buffer allocation fail. Note that if readahead fails (with non-uptodate folios), the original request will then fall back to synchronous read, and `.read_folio()` should return appropriate errnos; otherwise -EIO will be passed to user space, which is unexpected. To simplify rarely encountered failure paths, a mimic decompression will be just used. Before that, failure reasons are recorded in compressed_bvecs[] and they also act as placeholders to avoid in-place pages. They will be parsed just before decompression and then pass back to `.read_folio()`. Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240905084732.2684515-1-hsiangkao@linux.alibaba.com
2024-09-10erofs: simplify erofs_map_blocks_flatmode()Hongzhen Luo
Get rid of redundant variables (nblocks, offset) and a dead branch (!tailendpacking). Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20240905030339.1474396-1-hongzhen@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-09-10erofs: refactor read_inode calling conventionYiyang Wu
Refactor out the iop binding behavior out of the erofs_fill_symlink and move erofs_buf into the erofs_read_inode, so that erofs_fill_inode can only deal with inode operation bindings and can be decoupled from metabuf operations. This results in better calling conventions. Note that after this patch, we do not need erofs_buf and ofs as parameters any more when calling erofs_read_inode as all the data operations are now included in itself. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Link: https://lore.kernel.org/all/20240425222847.GN2118490@ZenIV/ Signed-off-by: Yiyang Wu <toolmanp@tlmp.cc> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20240902093412.509083-1-toolmanp@tlmp.cc Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-09-10erofs: use kmemdup_nul in erofs_fill_symlinkYiyang Wu
Remove open coding in erofs_fill_symlink. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Link: https://lore.kernel.org/all/20240425222847.GN2118490@ZenIV Signed-off-by: Yiyang Wu <toolmanp@tlmp.cc> Link: https://lore.kernel.org/r/20240902083147.450558-2-toolmanp@tlmp.cc Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-09-10erofs: mark experimental fscache backend deprecatedGao Xiang
Although fscache is still described as "General Filesystem Caching" for network filesystems and other things such as ISO9660 filesystems, it has actually become a part of netfslib recently, which was unexpected at the time when "EROFS over fscache" proposed (2021) since EROFS is entirely a disk filesystem and the dependency is redundant. Mark it deprecated and it will be removed after "fanotify pre-content hooks" lands, which will provide the same functionality for EROFS. Reviewed-by: Sandeep Dhavale <dhavale@google.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240830032840.3783206-4-hsiangkao@linux.alibaba.com
2024-09-10erofs: support compressed inodes for fileioGao Xiang
Use pseudo bios just like the previous fscache approach since merged bio_vecs can be filled properly with unique interfaces. Reviewed-by: Sandeep Dhavale <dhavale@google.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240830032840.3783206-3-hsiangkao@linux.alibaba.com
2024-09-10erofs: support unencoded inodes for fileioGao Xiang
Since EROFS only needs to handle read requests in simple contexts, Just directly use vfs_iocb_iter_read() for data I/Os. Reviewed-by: Sandeep Dhavale <dhavale@google.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240905093031.2745929-1-hsiangkao@linux.alibaba.com
2024-09-10erofs: add file-backed mount supportGao Xiang
It actually has been around for years: For containers and other sandbox use cases, there will be thousands (and even more) of authenticated (sub)images running on the same host, unlike OS images. Of course, all scenarios can use the same EROFS on-disk format, but bdev-backed mounts just work well for OS images since golden data is dumped into real block devices. However, it's somewhat hard for container runtimes to manage and isolate so many unnecessary virtual block devices safely and efficiently [1]: they just look like a burden to orchestrators and file-backed mounts are preferred indeed. There were already enough attempts such as Incremental FS, the original ComposeFS and PuzzleFS acting in the same way for immutable fses. As for current EROFS users, ComposeFS, containerd and Android APEXs will be directly benefited from it. On the other hand, previous experimental feature "erofs over fscache" was once also intended to provide a similar solution (inspired by Incremental FS discussion [2]), but the following facts show file-backed mounts will be a better approach: - Fscache infrastructure has recently been moved into new Netfslib which is an unexpected dependency to EROFS really, although it originally claims "it could be used for caching other things such as ISO9660 filesystems too." [3] - It takes an unexpectedly long time to upstream Fscache/Cachefiles enhancements. For example, the failover feature took more than one year, and the deamonless feature is still far behind now; - Ongoing HSM "fanotify pre-content hooks" [4] together with this will perfectly supersede "erofs over fscache" in a simpler way since developers (mainly containerd folks) could leverage their existing caching mechanism entirely in userspace instead of strictly following the predefined in-kernel caching tree hierarchy. After "fanotify pre-content hooks" lands upstream to provide the same functionality, "erofs over fscache" will be removed then (as an EROFS internal improvement and EROFS will not have to bother with on-demand fetching and/or caching improvements anymore.) [1] https://github.com/containers/storage/pull/2039 [2] https://lore.kernel.org/r/CAOQ4uxjbVxnubaPjVaGYiSwoGDTdpWbB=w_AeM6YM=zVixsUfQ@mail.gmail.com [3] https://docs.kernel.org/filesystems/caching/fscache.html [4] https://lore.kernel.org/r/cover.1723670362.git.josef@toxicpanda.com Closes: https://github.com/containers/composefs/issues/144 Reviewed-by: Sandeep Dhavale <dhavale@google.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> Link: https://lore.kernel.org/r/20240830032840.3783206-1-hsiangkao@linux.alibaba.com
generated by cgit v1.2.3 (git 2.39.1) at 2025-08-05 06:36:12 +0000