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authorEric Biggers <ebiggers@google.com>2022-08-26 23:58:47 -0700
committerEric Biggers <ebiggers@google.com>2022-09-11 19:47:12 -0500
commit8434ef1d8aafc523443525bbc6237a07d7ec5606 (patch)
tree2c8427584a44a65de901210f2389826e386052db /fs/ext4/inode.c
parent53dd3f802a6e269868cb599609287a841e65a996 (diff)
ext4: support STATX_DIOALIGN
Add support for STATX_DIOALIGN to ext4, so that direct I/O alignment restrictions are exposed to userspace in a generic way. Acked-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20220827065851.135710-5-ebiggers@kernel.org
Diffstat (limited to 'fs/ext4/inode.c')
-rw-r--r--fs/ext4/inode.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 601214453c3a..364774230d87 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5550,6 +5550,22 @@ err_out:
return error;
}
+u32 ext4_dio_alignment(struct inode *inode)
+{
+ if (fsverity_active(inode))
+ return 0;
+ if (ext4_should_journal_data(inode))
+ return 0;
+ if (ext4_has_inline_data(inode))
+ return 0;
+ if (IS_ENCRYPTED(inode)) {
+ if (!fscrypt_dio_supported(inode))
+ return 0;
+ return i_blocksize(inode);
+ }
+ return 1; /* use the iomap defaults */
+}
+
int ext4_getattr(struct user_namespace *mnt_userns, const struct path *path,
struct kstat *stat, u32 request_mask, unsigned int query_flags)
{
@@ -5565,6 +5581,27 @@ int ext4_getattr(struct user_namespace *mnt_userns, const struct path *path,
stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
}
+ /*
+ * Return the DIO alignment restrictions if requested. We only return
+ * this information when requested, since on encrypted files it might
+ * take a fair bit of work to get if the file wasn't opened recently.
+ */
+ if ((request_mask & STATX_DIOALIGN) && S_ISREG(inode->i_mode)) {
+ u32 dio_align = ext4_dio_alignment(inode);
+
+ stat->result_mask |= STATX_DIOALIGN;
+ if (dio_align == 1) {
+ struct block_device *bdev = inode->i_sb->s_bdev;
+
+ /* iomap defaults */
+ stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
+ stat->dio_offset_align = bdev_logical_block_size(bdev);
+ } else {
+ stat->dio_mem_align = dio_align;
+ stat->dio_offset_align = dio_align;
+ }
+ }
+
flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
if (flags & EXT4_APPEND_FL)
stat->attributes |= STATX_ATTR_APPEND;