Amir Goldstein writes:
+config TMPFS_INODE64
+ bool "Use 64-bit ino_t by default in tmpfs"
+ depends on TMPFS && 64BIT
+ default n
+ help
+ tmpfs has historically used only inode numbers as wide as an unsigned
+ int. In some cases this can cause wraparound, potentially resulting in
+ multiple files with the same inode number on a single device. This option
+ makes tmpfs use the full width of ino_t by default, similarly to the
+ inode64 mount option.
+
+ tmpfs mounts that are used privately by the kernel and are not visible to
+ users are unaffected.
Admins won't know what the line above means and they shouldn't care.
It adds no information, so better remove it.
Sure thing.
+
+ /*
+ * Showing inode{64,32} might be useful even if it's the system default,
+ * since then people don't have to resort to checking both here and
+ * /proc/config.gz to confirm 64-bit inums were successfully applied
+ * (which may not even exist if IKCONFIG_PROC isn't enabled).
+ *
+ * We hide it when inode64 isn't the default and we are using 32-bit
+ * inodes, since that probably just means the feature isn't even under
+ * consideration.
+ *
+ * As such:
+ *
+ * +-----------------+-----------------+
+ * | TMPFS_INODE64=y | TMPFS_INODE64=n |
+ * +------------------+-----------------+-----------------+
+ * | full_inums=true | show | show |
+ * | full_inums=false | show | hide |
+ * +------------------+-----------------+-----------------+
+ *
+ */
+ if (IS_ENABLED(CONFIG_TMPFS_INODE64) || !sbinfo->full_inums)
Condition does not match comment - should be || sbinfo->full_inums)
Good catch! Thanks.
@@ -3915,6 +3969,7 @@ int shmem_init_fs_context(struct fs_context *fc)
ctx->mode = 0777 | S_ISVTX;
ctx->uid = current_fsuid();
ctx->gid = current_fsgid();
+ ctx->full_inums = IS_ENABLED(CONFIG_TMPFS_INODE64);
This is the wrong place for this - it is also being set for the kern_mount.
Follow the lead of shmem_default_max_inodes.
Hmm, full_inums is intended to be simply ignored for SB_KERNMOUNT though, so it
seems harmless, but I agree maybe it makes the intent of the code clearer to
move it to a more specific place.
Thanks! I'll fix these up for v3.
