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authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-26 19:50:21 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-26 19:50:21 +0300
commit64bf6ae93e08787f4a6db8dddf671fd3a9c43916 (patch)
tree120d7fe35d953aeb31b1fd6bdcceeab223f89c92 /fs/super.c
parent5c1c88cddb79d3ed3fb1d02a3eaf529eded76f05 (diff)
parent2507135e4ff231a368eae38000a501da0b96c662 (diff)
downloadlinux-64bf6ae93e08787f4a6db8dddf671fd3a9c43916.tar.xz
Merge tag 'v6.5/vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner: "Miscellaneous features, cleanups, and fixes for vfs and individual fs Features: - Use mode 0600 for file created by cachefilesd so it can be run by unprivileged users. This aligns them with directories which are already created with mode 0700 by cachefilesd - Reorder a few members in struct file to prevent some false sharing scenarios - Indicate that an eventfd is used a semaphore in the eventfd's fdinfo procfs file - Add a missing uapi header for eventfd exposing relevant uapi defines - Let the VFS protect transitions of a superblock from read-only to read-write in addition to the protection it already provides for transitions from read-write to read-only. Protecting read-only to read-write transitions allows filesystems such as ext4 to perform internal writes, keeping writers away until the transition is completed Cleanups: - Arnd removed the architecture specific arch_report_meminfo() prototypes and added a generic one into procfs.h. Note, we got a report about a warning in amdpgpu codepaths that suggested this was bisectable to this change but we concluded it was a false positive - Remove unused parameters from split_fs_names() - Rename put_and_unmap_page() to unmap_and_put_page() to let the name reflect the order of the cleanup operation that has to unmap before the actual put - Unexport buffer_check_dirty_writeback() as it is not used outside of block device aops - Stop allocating aio rings from highmem - Protecting read-{only,write} transitions in the VFS used open-coded barriers in various places. Replace them with proper little helpers and document both the helpers and all barrier interactions involved when transitioning between read-{only,write} states - Use flexible array members in old readdir codepaths Fixes: - Use the correct type __poll_t for epoll and eventfd - Replace all deprecated strlcpy() invocations, whose return value isn't checked with an equivalent strscpy() call - Fix some kernel-doc warnings in fs/open.c - Reduce the stack usage in jffs2's xattr codepaths finally getting rid of this: fs/jffs2/xattr.c:887:1: error: the frame size of 1088 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] royally annoying compilation warning - Use __FMODE_NONOTIFY instead of FMODE_NONOTIFY where an int and not fmode_t is required to avoid fmode_t to integer degradation warnings - Create coredumps with O_WRONLY instead of O_RDWR. There's a long explanation in that commit how O_RDWR is actually a bug which we found out with the help of Linus and git archeology - Fix "no previous prototype" warnings in the pipe codepaths - Add overflow calculations for remap_verify_area() as a signed addition overflow could be triggered in xfstests - Fix a null pointer dereference in sysv - Use an unsigned variable for length calculations in jfs avoiding compilation warnings with gcc 13 - Fix a dangling pipe pointer in the watch queue codepath - The legacy mount option parser provided as a fallback by the VFS for filesystems not yet converted to the new mount api did prefix the generated mount option string with a leading ',' causing issues for some filesystems - Fix a repeated word in a comment in fs.h - autofs: Update the ctime when mtime is updated as mandated by POSIX" * tag 'v6.5/vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits) readdir: Replace one-element arrays with flexible-array members fs: Provide helpers for manipulating sb->s_readonly_remount fs: Protect reconfiguration of sb read-write from racing writes eventfd: add a uapi header for eventfd userspace APIs autofs: set ctime as well when mtime changes on a dir eventfd: show the EFD_SEMAPHORE flag in fdinfo fs/aio: Stop allocating aio rings from HIGHMEM fs: Fix comment typo fs: unexport buffer_check_dirty_writeback fs: avoid empty option when generating legacy mount string watch_queue: prevent dangling pipe pointer fs.h: Optimize file struct to prevent false sharing highmem: Rename put_and_unmap_page() to unmap_and_put_page() cachefiles: Allow the cache to be non-root init: remove unused names parameter in split_fs_names() jfs: Use unsigned variable for length calculations fs/sysv: Null check to prevent null-ptr-deref bug fs: use UB-safe check for signed addition overflow in remap_verify_area procfs: consolidate arch_report_meminfo declaration fs: pipe: reveal missing function protoypes ...
Diffstat (limited to 'fs/super.c')
-rw-r--r--fs/super.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/fs/super.c b/fs/super.c
index 04bc62ab7dfe..48c29954d487 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -595,7 +595,7 @@ retry:
fc->s_fs_info = NULL;
s->s_type = fc->fs_type;
s->s_iflags |= fc->s_iflags;
- strlcpy(s->s_id, s->s_type->name, sizeof(s->s_id));
+ strscpy(s->s_id, s->s_type->name, sizeof(s->s_id));
list_add_tail(&s->s_list, &super_blocks);
hlist_add_head(&s->s_instances, &s->s_type->fs_supers);
spin_unlock(&sb_lock);
@@ -674,7 +674,7 @@ retry:
return ERR_PTR(err);
}
s->s_type = type;
- strlcpy(s->s_id, type->name, sizeof(s->s_id));
+ strscpy(s->s_id, type->name, sizeof(s->s_id));
list_add_tail(&s->s_list, &super_blocks);
hlist_add_head(&s->s_instances, &type->fs_supers);
spin_unlock(&sb_lock);
@@ -903,6 +903,7 @@ int reconfigure_super(struct fs_context *fc)
struct super_block *sb = fc->root->d_sb;
int retval;
bool remount_ro = false;
+ bool remount_rw = false;
bool force = fc->sb_flags & SB_FORCE;
if (fc->sb_flags_mask & ~MS_RMT_MASK)
@@ -920,7 +921,7 @@ int reconfigure_super(struct fs_context *fc)
bdev_read_only(sb->s_bdev))
return -EACCES;
#endif
-
+ remount_rw = !(fc->sb_flags & SB_RDONLY) && sb_rdonly(sb);
remount_ro = (fc->sb_flags & SB_RDONLY) && !sb_rdonly(sb);
}
@@ -943,13 +944,18 @@ int reconfigure_super(struct fs_context *fc)
*/
if (remount_ro) {
if (force) {
- sb->s_readonly_remount = 1;
- smp_wmb();
+ sb_start_ro_state_change(sb);
} else {
retval = sb_prepare_remount_readonly(sb);
if (retval)
return retval;
}
+ } else if (remount_rw) {
+ /*
+ * Protect filesystem's reconfigure code from writes from
+ * userspace until reconfigure finishes.
+ */
+ sb_start_ro_state_change(sb);
}
if (fc->ops->reconfigure) {
@@ -965,9 +971,7 @@ int reconfigure_super(struct fs_context *fc)
WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) |
(fc->sb_flags & fc->sb_flags_mask)));
- /* Needs to be ordered wrt mnt_is_readonly() */
- smp_wmb();
- sb->s_readonly_remount = 0;
+ sb_end_ro_state_change(sb);
/*
* Some filesystems modify their metadata via some other path than the
@@ -982,7 +986,7 @@ int reconfigure_super(struct fs_context *fc)
return 0;
cancel_readonly:
- sb->s_readonly_remount = 0;
+ sb_end_ro_state_change(sb);
return retval;
}