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* Merge tag 'vfs-6.8.rw' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfsLinus Torvalds2024-01-0822-510/+759
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull vfs rw updates from Christian Brauner: "This contains updates from Amir for read-write backing file helpers for stacking filesystems such as overlayfs: - Fanotify is currently in the process of introducing pre content events. Roughly, a new permission event will be added indicating that it is safe to write to the file being accessed. These events are used by hierarchical storage managers to e.g., fill the content of files on first access. During that work we noticed that our current permission checking is inconsistent in rw_verify_area() and remap_verify_area(). Especially in the splice code permission checking is done multiple times. For example, one time for the whole range and then again for partial ranges inside the iterator. In addition, we mostly do permission checking before we call file_start_write() except for a few places where we call it after. For pre-content events we need such permission checking to be done before file_start_write(). So this is a nice reason to clean this all up. After this series, all permission checking is done before file_start_write(). As part of this cleanup we also massaged the splice code a bit. We got rid of a few helpers because we are alredy drowning in special read-write helpers. We also cleaned up the return types for splice helpers. - Introduce generic read-write helpers for backing files. This lifts some overlayfs code to common code so it can be used by the FUSE passthrough work coming in over the next cycles. Make Amir and Miklos the maintainers for this new subsystem of the vfs" * tag 'vfs-6.8.rw' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits) fs: fix __sb_write_started() kerneldoc formatting fs: factor out backing_file_mmap() helper fs: factor out backing_file_splice_{read,write}() helpers fs: factor out backing_file_{read,write}_iter() helpers fs: prepare for stackable filesystems backing file helpers fsnotify: optionally pass access range in file permission hooks fsnotify: assert that file_start_write() is not held in permission hooks fsnotify: split fsnotify_perm() into two hooks fs: use splice_copy_file_range() inline helper splice: return type ssize_t from all helpers fs: use do_splice_direct() for nfsd/ksmbd server-side-copy fs: move file_start_write() into direct_splice_actor() fs: fork splice_file_range() from do_splice_direct() fs: create {sb,file}_write_not_started() helpers fs: create file_write_started() helper fs: create __sb_write_started() helper fs: move kiocb_start_write() into vfs_iocb_iter_write() fs: move permission hook out of do_iter_read() fs: move permission hook out of do_iter_write() fs: move file_start_write() into vfs_iter_write() ...
| * fs: factor out backing_file_mmap() helperAmir Goldstein2023-12-232-17/+33
| | | | | | | | | | | | | | | | Assert that the file object is allocated in a backing_file container so that file_user_path() could be used to display the user path and not the backing file's path in /proc/<pid>/maps. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
| * fs: factor out backing_file_splice_{read,write}() helpersAmir Goldstein2023-12-232-20/+64
| | | | | | | | | | | | | | | | There is not much in those helpers, but it makes sense to have them logically next to the backing_file_{read,write}_iter() helpers as they may grow more common logic in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
| * fs: factor out backing_file_{read,write}_iter() helpersAmir Goldstein2023-12-234-185/+232
| | | | | | | | | | | | | | | | | | | | Overlayfs submits files io to backing files on other filesystems. Factor out some common helpers to perform io to backing files, into fs/backing-file.c. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Link: https://lore.kernel.org/r/CAJfpeguhmZbjP3JLqtUy0AdWaHOkAPWeP827BBWwRFEAUgnUcQ@mail.gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com>
| * fs: prepare for stackable filesystems backing file helpersAmir Goldstein2023-12-236-38/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation for factoring out some backing file io helpers from overlayfs, move backing_file_open() into a new file fs/backing-file.c and header. Add a MAINTAINERS entry for stackable filesystems and add a Kconfig FS_STACK which stackable filesystems need to select. For now, the backing_file struct, the backing_file alloc/free functions and the backing_file_real_path() accessor remain internal to file_table.c. We may change that in the future. Signed-off-by: Amir Goldstein <amir73il@gmail.com>
| * fsnotify: optionally pass access range in file permission hooksAmir Goldstein2023-12-124-3/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation for pre-content permission events with file access range, move fsnotify_file_perm() hook out of security_file_permission() and into the callers. Callers that have the access range information call the new hook fsnotify_file_area_perm() with the access range. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231212094440.250945-6-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: use splice_copy_file_range() inline helperAmir Goldstein2023-12-126-45/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | generic_copy_file_range() is just a wrapper around splice_file_range(), which caps the maximum copy length. The only caller of splice_file_range(), namely __ceph_copy_file_range() is already ready to cope with short copy. Move the length capping into splice_file_range() and replace the exported symbol generic_copy_file_range() with a simple inline helper. Suggested-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/linux-fsdevel/20231204083849.GC32438@lst.de/ Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231212094440.250945-3-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
| * splice: return type ssize_t from all helpersAmir Goldstein2023-12-124-57/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | Not sure why some splice helpers return long, maybe historic reasons. Change them all to return ssize_t to conform to the splice methods and to the rest of the helpers. Suggested-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20231208-horchen-helium-d3ec1535ede5@brauner/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231212094440.250945-2-amir73il@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: use do_splice_direct() for nfsd/ksmbd server-side-copyAmir Goldstein2023-12-051-13/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nfsd/ksmbd call vfs_copy_file_range() with flag COPY_FILE_SPLICE to perform kernel copy between two files on any two filesystems. Splicing input file, while holding file_start_write() on the output file which is on a different sb, posses a risk for fanotify related deadlocks. We only need to call splice_file_range() from within the context of ->copy_file_range() filesystem methods with file_start_write() held. To avoid the possible deadlocks, always use do_splice_direct() instead of splice_file_range() for the kernel copy fallback in vfs_copy_file_range() without holding file_start_write(). Reported-and-tested-by: Bert Karwatzki <spasswolf@web.de> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231130141624.3338942-4-amir73il@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: move file_start_write() into direct_splice_actor()Amir Goldstein2023-12-013-7/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The callers of do_splice_direct() hold file_start_write() on the output file. This may cause file permission hooks to be called indirectly on an overlayfs lower layer, which is on the same filesystem of the output file and could lead to deadlock with fanotify permission events. To fix this potential deadlock, move file_start_write() from the callers into the direct_splice_actor(), so file_start_write() will not be held while splicing from the input file. Suggested-by: Josef Bacik <josef@toxicpanda.com> Link: https://lore.kernel.org/r/20231128214258.GA2398475@perftesting/ Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231130141624.3338942-3-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: fork splice_file_range() from do_splice_direct()Amir Goldstein2023-12-013-28/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation of calling do_splice_direct() without file_start_write() held, create a new helper splice_file_range(), to be called from context of ->copy_file_range() methods instead of do_splice_direct(). Currently, the only difference is that splice_file_range() does not take flags argument and that it asserts that file_start_write() is held, but we factor out a common helper do_splice_direct_actor() that will be used later. Use the new helper from __ceph_copy_file_range(), that was incorrectly passing to do_splice_direct() the copy flags argument as splice flags. The value of copy flags in ceph is always 0, so it is a smenatic bug fix. Move the declaration of both helpers to linux/splice.h. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231130141624.3338942-2-amir73il@gmail.com Acked-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: create file_write_started() helperAmir Goldstein2023-11-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Convenience wrapper for sb_write_started(file_inode(inode)->i_sb)), which has a single occurrence in the code right now. Document the false negatives of those helpers, which makes them unusable to assert that sb_start_write() is not held. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-16-amir73il@gmail.com Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: move kiocb_start_write() into vfs_iocb_iter_write()Amir Goldstein2023-11-243-7/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In vfs code, sb_start_write() is usually called after the permission hook in rw_verify_area(). vfs_iocb_iter_write() is an exception to this rule, where kiocb_start_write() is called by its callers. Move kiocb_start_write() from the callers into vfs_iocb_iter_write() after the rw_verify_area() checks, to make them "start-write-safe". The semantics of vfs_iocb_iter_write() is changed, so that the caller is responsible for calling kiocb_end_write() on completion only if async iocb was queued. The completion handlers of both callers were adapted to this semantic change. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara <jack@suse.cz> Suggested-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-14-amir73il@gmail.com Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: move permission hook out of do_iter_read()Amir Goldstein2023-11-241-27/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We recently moved fsnotify hook, rw_verify_area() and other checks from do_iter_write() out to its two callers. for consistency, do the same thing for do_iter_read() - move the rw_verify_area() checks and fsnotify hook to the callers vfs_iter_read() and vfs_readv(). This aligns those vfs helpers with the pattern used in vfs_read() and vfs_iocb_iter_read() and the vfs write helpers, where all the checks are in the vfs helpers and the do_* or call_* helpers do the work. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-13-amir73il@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: move permission hook out of do_iter_write()Amir Goldstein2023-11-241-38/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In many of the vfs helpers, the rw_verity_area() checks are called before taking sb_start_write(), making them "start-write-safe". do_iter_write() is an exception to this rule. do_iter_write() has two callers - vfs_iter_write() and vfs_writev(). Move rw_verify_area() and other checks from do_iter_write() out to its callers to make them "start-write-safe". Move also the fsnotify_modify() hook to align with similar pattern used in vfs_write() and other vfs helpers. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-12-amir73il@gmail.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * fs: move file_start_write() into vfs_iter_write()Amir Goldstein2023-11-244-9/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All the callers of vfs_iter_write() call file_start_write() just before calling vfs_iter_write() except for target_core_file's fd_do_rw(). Move file_start_write() from the callers into vfs_iter_write(). fd_do_rw() calls vfs_iter_write() with a non-regular file, so file_start_write() is a no-op. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-11-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
| * coda: change locking order in coda_file_write_iter()Amir Goldstein2023-11-241-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The coda host file is a backing file for the coda inode on a different filesystem than the coda inode. Change the locking order to take the coda inode lock before taking the backing host file freeze protection, same as in ovl_write_iter() and in network filesystems that use cachefiles. Link: https://lore.kernel.org/r/CAOQ4uxjcnwuF1gMxe64WLODGA_MyAy8x-DtqkCUxqVQKk3Xbng@mail.gmail.com/ Acked-by: Jan Harkes <jaharkes@cs.cmu.edu> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-10-amir73il@gmail.com Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * btrfs: move file_start_write() to after permission hookAmir Goldstein2023-11-241-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In vfs code, file_start_write() is usually called after the permission hook in rw_verify_area(). btrfs_ioctl_encoded_write() in an exception to this rule. Move file_start_write() to after the rw_verify_area() check in encoded write to make the permission hook "start-write-safe". This is needed for fanotify "pre content" events. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-9-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * remap_range: move file_start_write() to after permission hookAmir Goldstein2023-11-241-8/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In vfs code, file_start_write() is usually called after the permission hook in rw_verify_area(). vfs_dedupe_file_range_one() is an exception to this rule. In vfs_dedupe_file_range_one(), move file_start_write() to after the the rw_verify_area() checks to make them "start-write-safe". This is needed for fanotify "pre content" events. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-8-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * remap_range: move permission hooks out of do_clone_file_range()Amir Goldstein2023-11-241-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In many of the vfs helpers, file permission hook is called before taking sb_start_write(), making them "start-write-safe". do_clone_file_range() is an exception to this rule. do_clone_file_range() has two callers - vfs_clone_file_range() and overlayfs. Move remap_verify_area() checks from do_clone_file_range() out to vfs_clone_file_range() to make them "start-write-safe". Overlayfs already has calls to rw_verify_area() with the same security permission hooks as remap_verify_area() has. The rest of the checks in remap_verify_area() are irrelevant for overlayfs that calls do_clone_file_range() offset 0 and positive length. This is needed for fanotify "pre content" events. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-7-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * splice: remove permission hook from iter_file_splice_write()Amir Goldstein2023-11-241-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All the callers of ->splice_write(), (e.g. do_splice_direct() and do_splice()) already check rw_verify_area() for the entire range and perform all the other checks that are in vfs_write_iter(). Instead of creating another tiny helper for special caller, just open-code it. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-6-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
| * splice: move permission hook out of splice_file_to_pipe()Amir Goldstein2023-11-241-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vfs_splice_read() has a permission hook inside rw_verify_area() and it is called from splice_file_to_pipe(), which is called from do_splice() and do_sendfile(). do_sendfile() already has a rw_verify_area() check for the entire range. do_splice() has a rw_verify_check() for the splice to file case, not for the splice from file case. Add the rw_verify_area() check for splice from file case in do_splice() and use a variant of vfs_splice_read() without rw_verify_area() check in splice_file_to_pipe() to avoid the redundant rw_verify_area() checks. This is needed for fanotify "pre content" events. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-5-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * splice: move permission hook out of splice_direct_to_actor()Amir Goldstein2023-11-242-24/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vfs_splice_read() has a permission hook inside rw_verify_area() and it is called from do_splice_direct() -> splice_direct_to_actor(). The callers of do_splice_direct() (e.g. vfs_copy_file_range()) already call rw_verify_area() for the entire range, but the other caller of splice_direct_to_actor() (nfsd) does not. Add the rw_verify_area() checks in nfsd_splice_read() and use a variant of vfs_splice_read() without rw_verify_area() check in splice_direct_to_actor() to avoid the redundant rw_verify_area() checks. This is needed for fanotify "pre content" events. Acked-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-4-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * splice: remove permission hook from do_splice_direct()Amir Goldstein2023-11-241-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All callers of do_splice_direct() have a call to rw_verify_area() for the entire range that is being copied, e.g. by vfs_copy_file_range() or do_sendfile() before calling do_splice_direct(). The rw_verify_area() check inside do_splice_direct() is redundant and is called after sb_start_write(), so it is not "start-write-safe". Remove this redundant check. This is needed for fanotify "pre content" events. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-3-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * ovl: add permission hooks outside of do_splice_direct()Amir Goldstein2023-11-241-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The main callers of do_splice_direct() also call rw_verify_area() for the entire range that is being copied, e.g. by vfs_copy_file_range() or do_sendfile() before calling do_splice_direct(). The only caller that does not have those checks for entire range is ovl_copy_up_file(). In preparation for removing the checks inside do_splice_direct(), add rw_verify_area() call in ovl_copy_up_file(). For extra safety, perform minimal sanity checks from rw_verify_area() for non negative offsets also in the copy up do_splice_direct() loop without calling the file permission hooks. This is needed for fanotify "pre content" events. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-2-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
* | Merge tag 'vfs-6.8.mount' of ↵Linus Torvalds2024-01-086-125/+555
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs mount updates from Christian Brauner: "This contains the work to retrieve detailed information about mounts via two new system calls. This is hopefully the beginning of the end of the saga that started with fsinfo() years ago. The LWN articles in [1] and [2] can serve as a summary so we can avoid rehashing everything here. At LSFMM in May 2022 we got into a room and agreed on what we want to do about fsinfo(). Basically, split it into pieces. This is the first part of that agreement. Specifically, it is concerned with retrieving information about mounts. So this only concerns the mount information retrieval, not the mount table change notification, or the extended filesystem specific mount option work. That is separate work. Currently mounts have a 32bit id. Mount ids are already in heavy use by libmount and other low-level userspace but they can't be relied upon because they're recycled very quickly. We agreed that mounts should carry a unique 64bit id by which they can be referenced directly. This is now implemented as part of this work. The new 64bit mount id is exposed in statx() through the new STATX_MNT_ID_UNIQUE flag. If the flag isn't raised the old mount id is returned. If it is raised and the kernel supports the new 64bit mount id the flag is raised in the result mask and the new 64bit mount id is returned. New and old mount ids do not overlap so they cannot be conflated. Two new system calls are introduced that operate on the 64bit mount id: statmount() and listmount(). A summary of the api and usage can be found on LWN as well (cf. [3]) but of course, I'll provide a summary here as well. Both system calls rely on struct mnt_id_req. Which is the request struct used to pass the 64bit mount id identifying the mount to operate on. It is extensible to allow for the addition of new parameters and for future use in other apis that make use of mount ids. statmount() mimicks the semantics of statx() and exposes a set flags that userspace may raise in mnt_id_req to request specific information to be retrieved. A statmount() call returns a struct statmount filled in with information about the requested mount. Supported requests are indicated by raising the request flag passed in struct mnt_id_req in the @mask argument in struct statmount. Currently we do support: - STATMOUNT_SB_BASIC: Basic filesystem info - STATMOUNT_MNT_BASIC Mount information (mount id, parent mount id, mount attributes etc) - STATMOUNT_PROPAGATE_FROM Propagation from what mount in current namespace - STATMOUNT_MNT_ROOT Path of the root of the mount (e.g., mount --bind /bla /mnt returns /bla) - STATMOUNT_MNT_POINT Path of the mount point (e.g., mount --bind /bla /mnt returns /mnt) - STATMOUNT_FS_TYPE Name of the filesystem type as the magic number isn't enough due to submounts The string options STATMOUNT_MNT_{ROOT,POINT} and STATMOUNT_FS_TYPE are appended to the end of the struct. Userspace can use the offsets in @fs_type, @mnt_root, and @mnt_point to reference those strings easily. The struct statmount reserves quite a bit of space currently for future extensibility. This isn't really a problem and if this bothers us we can just send a follow-up pull request during this cycle. listmount() is given a 64bit mount id via mnt_id_req just as statmount(). It takes a buffer and a size to return an array of the 64bit ids of the child mounts of the requested mount. Userspace can thus choose to either retrieve child mounts for a mount in batches or iterate through the child mounts. For most use-cases it will be sufficient to just leave space for a few child mounts. But for big mount tables having an iterator is really helpful. Iterating through a mount table works by setting @param in mnt_id_req to the mount id of the last child mount retrieved in the previous listmount() call" Link: https://lwn.net/Articles/934469 [1] Link: https://lwn.net/Articles/829212 [2] Link: https://lwn.net/Articles/950569 [3] * tag 'vfs-6.8.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: add selftest for statmount/listmount fs: keep struct mnt_id_req extensible wire up syscalls for statmount/listmount add listmount(2) syscall statmount: simplify string option retrieval statmount: simplify numeric option retrieval add statmount(2) syscall namespace: extract show_path() helper mounts: keep list of mounts in an rbtree add unique mount ID
| * | fs: keep struct mnt_id_req extensibleChristian Brauner2023-12-141-4/+30
| | | | | | | | | | | | | | | | | | | | | Make it extensible so that we have the liberty to reuse it in future mount-id based apis. Treat zero size as the first published struct. Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | add listmount(2) syscallMiklos Szeredi2023-12-141-2/+84
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add way to query the children of a particular mount. This is a more flexible way to iterate the mount tree than having to parse /proc/self/mountinfo. Lookup the mount by the new 64bit mount ID. If a mount needs to be queried based on path, then statx(2) can be used to first query the mount ID belonging to the path. Return an array of new (64bit) mount ID's. Without privileges only mounts are listed which are reachable from the task's root. Folded into this patch are several later improvements. Keeping them separate would make the history pointlessly confusing: * Recursive listing of mounts is the default now (cf. [1]). * Remove explicit LISTMOUNT_UNREACHABLE flag (cf. [1]) and fail if mount is unreachable from current root. This also makes permission checking consistent with statmount() (cf. [3]). * Start listing mounts in unique mount ID order (cf. [2]) to allow continuing listmount() from a midpoint. * Allow to continue listmount(). The @request_mask parameter is renamed and to @param to be usable by both statmount() and listmount(). If @param is set to a mount id then listmount() will continue listing mounts from that id on. This allows listing mounts in multiple listmount invocations without having to resize the buffer. If @param is zero then the listing starts from the beginning (cf. [4]). * Don't return EOVERFLOW, instead return the buffer size which allows to detect a full buffer as well (cf. [4]). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20231025140205.3586473-6-mszeredi@redhat.com Reviewed-by: Ian Kent <raven@themaw.net> Link: https://lore.kernel.org/r/20231128160337.29094-2-mszeredi@redhat.com [1] (folded) Link: https://lore.kernel.org/r/20231128160337.29094-3-mszeredi@redhat.com [2] (folded) Link: https://lore.kernel.org/r/20231128160337.29094-4-mszeredi@redhat.com [3] (folded) Link: https://lore.kernel.org/r/20231128160337.29094-5-mszeredi@redhat.com [4] (folded) [Christian Brauner <brauner@kernel.org>: various smaller fixes] Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | statmount: simplify string option retrievalChristian Brauner2023-12-141-102/+145
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous code was a bit too clever for what we currently support. A few minor changes: * Avoid indirect function calls and use a simple switch statement. We really only have three cases to handle so it's not like it's massively complex. We can switch to something more elaborate should we introduce more complex options. * Defer all copy_to_user() calls until after we've given up namespace semaphore. On kernels with userfaultfd it's possible to abuse copy_from/to_user() calls to indefinitely block on page faults. That's usually a privileged operation but may be made available to unprivileged users. Independent of userfaultfd it's better to not do all the copy_to_user() work while holding namespace semaphore. Instead collect the information and then copy it out after we've given up all locks. * This also folds a change from Arnd to reduce the stack size in prepare_kstatmount() to avoid warning such as: fs/namespace.c:4995:1: error: stack frame size (1536) exceeds limit (1024) in '__se_sys_statmount' [-Werror,-Wframe-larger-than] 4995 | SYSCALL_DEFINE4(statmount, const struct mnt_id_req __user *, req, Reviewed-by: Ian Kent <raven@themaw.net> Link: https://lore.kernel.org/r/20231213090015.518044-1-arnd@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | statmount: simplify numeric option retrievalChristian Brauner2023-12-111-25/+17
| | | | | | | | | | | | | | | | | | | | | | | | Don't use all of this indirection which makes it really hard to follow the code which is very basic. Error handling is also not really neede here at all. Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | add statmount(2) syscallMiklos Szeredi2023-12-111-0/+281
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a way to query attributes of a single mount instead of having to parse the complete /proc/$PID/mountinfo, which might be huge. Lookup the mount the new 64bit mount ID. If a mount needs to be queried based on path, then statx(2) can be used to first query the mount ID belonging to the path. Design is based on a suggestion by Linus: "So I'd suggest something that is very much like "statfsat()", which gets a buffer and a length, and returns an extended "struct statfs" *AND* just a string description at the end." The interface closely mimics that of statx. Handle ASCII attributes by appending after the end of the structure (as per above suggestion). Pointers to strings are stored in u64 members to make the structure the same regardless of pointer size. Strings are nul terminated. Link: https://lore.kernel.org/all/CAHk-=wh5YifP7hzKSbwJj94+DZ2czjrZsczy6GBimiogZws=rg@mail.gmail.com/ Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20231025140205.3586473-5-mszeredi@redhat.com Reviewed-by: Ian Kent <raven@themaw.net> [Christian Brauner <brauner@kernel.org>: various minor changes] Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | namespace: extract show_path() helperMiklos Szeredi2023-11-183-7/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | To be used by the statmount(2) syscall as well. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20231025140205.3586473-4-mszeredi@redhat.com Reviewed-by: Ian Kent <raven@themaw.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | mounts: keep list of mounts in an rbtreeMiklos Szeredi2023-11-184-115/+104
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When adding a mount to a namespace insert it into an rbtree rooted in the mnt_namespace instead of a linear list. The mnt.mnt_list is still used to set up the mount tree and for propagation, but not after the mount has been added to a namespace. Hence mnt_list can live in union with rb_node. Use MNT_ONRB mount flag to validate that the mount is on the correct list. This allows removing the cursor used for reading /proc/$PID/mountinfo. The mnt_id_unique of the next mount can be used as an index into the seq file. Tested by inserting 100k bind mounts, unsharing the mount namespace, and unmounting. No performance regressions have been observed. For the last mount in the 100k list the statmount() call was more than 100x faster due to the mount ID lookup not having to do a linear search. This patch makes the overhead of mount ID lookup non-observable in this range. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20231025140205.3586473-3-mszeredi@redhat.com Reviewed-by: Ian Kent <raven@themaw.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | add unique mount IDMiklos Szeredi2023-11-183-3/+13
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a mount is released then its mnt_id can immediately be reused. This is bad news for user interfaces that want to uniquely identify a mount. Implementing a unique mount ID is trivial (use a 64bit counter). Unfortunately userspace assumes 32bit size and would overflow after the counter reaches 2^32. Introduce a new 64bit ID alongside the old one. Initialize the counter to 2^32, this guarantees that the old and new IDs are never mixed up. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20231025140205.3586473-2-mszeredi@redhat.com Reviewed-by: Ian Kent <raven@themaw.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
* | Merge tag 'vfs-6.8.super' of ↵Linus Torvalds2024-01-0811-271/+305
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs super updates from Christian Brauner: "This contains the super work for this cycle including the long-awaited series by Jan to make it possible to prevent writing to mounted block devices: - Writing to mounted devices is dangerous and can lead to filesystem corruption as well as crashes. Furthermore syzbot comes with more and more involved examples how to corrupt block device under a mounted filesystem leading to kernel crashes and reports we can do nothing about. Add tracking of writers to each block device and a kernel cmdline argument which controls whether other writeable opens to block devices open with BLK_OPEN_RESTRICT_WRITES flag are allowed. Note that this effectively only prevents modification of the particular block device's page cache by other writers. The actual device content can still be modified by other means - e.g. by issuing direct scsi commands, by doing writes through devices lower in the storage stack (e.g. in case loop devices, DM, or MD are involved) etc. But blocking direct modifications of the block device page cache is enough to give filesystems a chance to perform data validation when loading data from the underlying storage and thus prevent kernel crashes. Syzbot can use this cmdline argument option to avoid uninteresting crashes. Also users whose userspace setup does not need writing to mounted block devices can set this option for hardening. We expect that this will be interesting to quite a few workloads. Btrfs is currently opted out of this because they still haven't merged patches we require for this to work from three kernel releases ago. - Reimplement block device freezing and thawing as holder operations on the block device. This allows us to extend block device freezing to all devices associated with a superblock and not just the main device. It also allows us to remove get_active_super() and thus another function that scans the global list of superblocks. Freezing via additional block devices only works if the filesystem chooses to use @fs_holder_ops for these additional devices as well. That currently only includes ext4 and xfs. Earlier releases switched get_tree_bdev() and mount_bdev() to use @fs_holder_ops. The remaining nilfs2 open-coded version of mount_bdev() has been converted to rely on @fs_holder_ops as well. So block device freezing for the main block device will continue to work as before. There should be no regressions in functionality. The only special case is btrfs where block device freezing for the main block device never worked because sb->s_bdev isn't set. Block device freezing for btrfs can be fixed once they can switch to @fs_holder_ops but that can happen whenever they're ready" * tag 'vfs-6.8.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits) block: Fix a memory leak in bdev_open_by_dev() super: don't bother with WARN_ON_ONCE() super: massage wait event mechanism ext4: Block writes to journal device xfs: Block writes to log device fs: Block writes to mounted block devices btrfs: Do not restrict writes to btrfs devices block: Add config option to not allow writing to mounted devices block: Remove blkdev_get_by_*() functions bcachefs: Convert to bdev_open_by_path() fs: handle freezing from multiple devices fs: remove dead check nilfs2: simplify device handling fs: streamline thaw_super_locked ext4: simplify device handling xfs: simplify device handling fs: simplify setup_bdev_super() calls blkdev: comment fs_holder_ops porting: document block device freeze and thaw changes fs: remove unused helper ...
| * | super: don't bother with WARN_ON_ONCE()Christian Brauner2023-11-281-4/+1
| | | | | | | | | | | | | | | | | | | | | We hold our own active reference and we've checked it above. Link: https://lore.kernel.org/r/20231127-vfs-super-massage-wait-v1-2-9ab277bfd01a@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | super: massage wait event mechanismChristian Brauner2023-11-281-37/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We're currently using two separate helpers wait_born() and wait_dead() when we can just all do it in a single helper super_load_flags(). We're also acquiring the lock before we check whether this superblock is even a viable candidate. If it's already dying we don't even need to bother with the lock. Link: https://lore.kernel.org/r/20231127-vfs-super-massage-wait-v1-1-9ab277bfd01a@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | ext4: Block writes to journal deviceJan Kara2023-11-181-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ask block layer to not allow other writers to open block device used for ext4 journal. Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20231101174325.10596-7-jack@suse.cz Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | xfs: Block writes to log deviceJan Kara2023-11-181-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ask block layer to not allow other writers to open block devices used for xfs log and realtime devices. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20231101174325.10596-6-jack@suse.cz Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | btrfs: Do not restrict writes to btrfs devicesJan Kara2023-11-181-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Btrfs device probing code needs adaptation so that it works when writes are restricted to its mounted devices. Since btrfs maintainer wants to merge these changes through btrfs tree and there are review bandwidth issues with that, let's not block all other filesystems and just not restrict writes to btrfs devices for now. CC: <linux-btrfs@vger.kernel.org> CC: David Sterba <dsterba@suse.com> CC: Josef Bacik <josef@toxicpanda.com> CC: Chris Mason <clm@fb.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20231101174325.10596-4-jack@suse.cz Acked-by: David Sterba <dsterba@suse.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | bcachefs: Convert to bdev_open_by_path()Jan Kara2023-11-182-9/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert bcachefs to use bdev_open_by_path() and pass the handle around. CC: Kent Overstreet <kent.overstreet@linux.dev> CC: Brian Foster <bfoster@redhat.com> CC: <linux-bcachefs@vger.kernel.org> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20231101174325.10596-1-jack@suse.cz Acked-by: Kent Overstreet <kent.overstreet@linux.dev> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | fs: handle freezing from multiple devicesChristian Brauner2023-11-181-32/+112
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before [1] freezing a filesystems through the block layer only worked for the main block device as the owning superblock of additional block devices could not be found. Any filesystem that made use of multiple block devices would only be freezable via it's main block device. For example, consider xfs over device mapper with /dev/dm-0 as main block device and /dev/dm-1 as external log device. Two freeze requests before [1]: (1) dmsetup suspend /dev/dm-0 on the main block device bdev_freeze(dm-0) -> dm-0->bd_fsfreeze_count++ -> freeze_super(xfs-sb) The owning superblock is found and the filesystem gets frozen. Returns 0. (2) dmsetup suspend /dev/dm-1 on the log device bdev_freeze(dm-1) -> dm-1->bd_fsfreeze_count++ The owning superblock isn't found and only the block device freeze count is incremented. Returns 0. Two freeze requests after [1]: (1') dmsetup suspend /dev/dm-0 on the main block device bdev_freeze(dm-0) -> dm-0->bd_fsfreeze_count++ -> freeze_super(xfs-sb) The owning superblock is found and the filesystem gets frozen. Returns 0. (2') dmsetup suspend /dev/dm-1 on the log device bdev_freeze(dm-0) -> dm-0->bd_fsfreeze_count++ -> freeze_super(xfs-sb) The owning superblock is found and the filesystem gets frozen. Returns -EBUSY. When (2') is called we initiate a freeze from another block device of the same superblock. So we increment the bd_fsfreeze_count for that additional block device. But we now also find the owning superblock for additional block devices and call freeze_super() again which reports -EBUSY. This can be reproduced through xfstests via: mkfs.xfs -f -m crc=1,reflink=1,rmapbt=1, -i sparse=1 -lsize=1g,logdev=/dev/nvme1n1p4 /dev/nvme1n1p3 mkfs.xfs -f -m crc=1,reflink=1,rmapbt=1, -i sparse=1 -lsize=1g,logdev=/dev/nvme1n1p6 /dev/nvme1n1p5 FSTYP=xfs export TEST_DEV=/dev/nvme1n1p3 export TEST_DIR=/mnt/test export TEST_LOGDEV=/dev/nvme1n1p4 export SCRATCH_DEV=/dev/nvme1n1p5 export SCRATCH_MNT=/mnt/scratch export SCRATCH_LOGDEV=/dev/nvme1n1p6 export USE_EXTERNAL=yes sudo ./check generic/311 Current semantics allow two concurrent freezers: one initiated from userspace via FREEZE_HOLDER_USERSPACE and one initiated from the kernel via FREEZE_HOLDER_KERNEL. If there are multiple concurrent freeze requests from either FREEZE_HOLDER_USERSPACE or FREEZE_HOLDER_KERNEL -EBUSY is returned. We need to preserve these semantics because as they are uapi via FIFREEZE and FITHAW ioctl()s. IOW, freezes don't nest for FIFREEZE and FITHAW. Other kernels consumers rely on non-nesting freezes as well. With freezes initiated from the block layer freezes need to nest if the same superblock is frozen via multiple devices. So we need to start counting the number of freeze requests. If FREEZE_MAY_NEST is passed alongside FREEZE_HOLDER_KERNEL or FREEZE_HOLDER_USERSPACE we allow the caller to nest freeze calls. To accommodate the old semantics we split the freeze counter into two counting kernel initiated and userspace initiated freezes separately. We can then also stop recording FREEZE_HOLDER_* in struct sb_writers. We also simplify freezing by making all concurrent freezers share a single active superblock reference count instead of having separate references for kernel and userspace. I don't see why we would need two active reference counts. Neither FREEZE_HOLDER_KERNEL nor FREEZE_HOLDER_USERSPACE can put the active reference as long as they are concurrent freezers anwyay. That was already true before we allowed nesting freezes. Survives various fstests runs with different options including the reproducer, online scrub, and online repair, fsfreze, and so on. Also survives blktests. Link: https://lore.kernel.org/linux-block/87bkccnwxc.fsf@debian-BULLSEYE-live-builder-AMD64 Link: https://lore.kernel.org/r/20231104-vfs-multi-device-freeze-v2-2-5b5b69626eac@kernel.org Fixes: 288d8706abfc ("bdev: implement freeze and thaw holder operations") [1] # no backport needed Tested-by: Chandan Babu R <chandanbabu@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Reported-by: Chandan Babu R <chandanbabu@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | fs: remove dead checkChristian Brauner2023-11-181-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Above we call super_lock_excl() which waits until the superblock is SB_BORN and since SB_BORN is never unset once set this check can never fire. Plus, we also hold an active reference at this point already so this superblock can't even be shutdown. Link: https://lore.kernel.org/r/20231104-vfs-multi-device-freeze-v2-1-5b5b69626eac@kernel.org Tested-by: Chandan Babu R <chandanbabu@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | nilfs2: simplify device handlingJan Kara2023-11-181-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We removed all codepaths where s_umount is taken beneath open_mutex and bd_holder_lock so don't make things more complicated than they need to be and hold s_umount over block device opening. CC: Ryusuke Konishi <konishi.ryusuke@gmail.com> CC: <linux-nilfs@vger.kernel.org> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20231101172739.8676-1-jack@suse.cz Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | fs: streamline thaw_super_lockedChristoph Hellwig2023-11-181-23/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a new out_unlock label to share code that just releases s_umount and returns an error, and rename and reuse the out label that deactivates the sb for one more case. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231027064001.GA9469@lst.de Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | ext4: simplify device handlingChristian Brauner2023-11-181-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We removed all codepaths where s_umount is taken beneath open_mutex and bd_holder_lock so don't make things more complicated than they need to be and hold s_umount over block device opening. Link: https://lore.kernel.org/r/20231024-vfs-super-rework-v1-3-37a8aa697148@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | xfs: simplify device handlingChristian Brauner2023-11-181-16/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We removed all codepaths where s_umount is taken beneath open_mutex and bd_holder_lock so don't make things more complicated than they need to be and hold s_umount over block device opening. Link: https://lore.kernel.org/r/20231024-vfs-super-rework-v1-2-37a8aa697148@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | fs: simplify setup_bdev_super() callsChristian Brauner2023-11-181-16/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | There's no need to drop s_umount anymore now that we removed all sources where s_umount is taken beneath open_mutex or bd_holder_lock. Link: https://lore.kernel.org/r/20231024-vfs-super-rework-v1-1-37a8aa697148@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | fs: remove unused helperChristian Brauner2023-11-181-40/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The grab_super() helper is now only used by grab_super_dead(). Merge the two helpers into one. Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-8-599c19f4faac@kernel.org Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
| * | fs: remove get_active_super()Christian Brauner2023-11-181-28/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function is now unused so remove it. One less function that uses the global superblock list. Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-6-599c19f4faac@kernel.org Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
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