tmpfs: support for file creation time

Various filesystems (including ext4) now support file creation time.
This adds such support for tmpfs-based filesystems.

Note that using shmem_getattr() on other file types than regular
requires that shmem_is_huge() check type, to stop incorrect
HPAGE_PMD_SIZE blksize.

[hughd@google.com: three tweaks to creation time patch]
Link: https://lkml.kernel.org/r/b954973a-b8d1-cab8-63bd-6ea8063de3@google.com
Link: https://lkml.kernel.org/r/20220314211150.GA123458@xavier-xps
Link: https://lkml.kernel.org/r/b954973a-b8d1-cab8-63bd-6ea8063de3@google.com
Link: https://lkml.kernel.org/r/20220211213628.GA1919658@xavier-xps
Signed-off-by: Xavier Roche <xavier.roche@algolia.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Tested-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Sylvain Bellone <sylvain.bellone@algolia.com>
Reported-by: Xavier Grand <xavier.grand@algolia.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index e65b80e..ab51d3c 100644 (file)
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -24,6 +24,7 @@ struct shmem_inode_info {
        struct shared_policy    policy;         /* NUMA memory alloc policy */
        struct simple_xattrs    xattrs;         /* list of xattrs */
        atomic_t                stop_eviction;  /* hold when working on inode */
+       struct timespec64       i_crtime;       /* file creation time */
        struct inode            vfs_inode;
 };
 

diff --git a/mm/shmem.c b/mm/shmem.c
index a09b29e..f8205b2 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -476,6 +476,8 @@ bool shmem_is_huge(struct vm_area_struct *vma,
 {
        loff_t i_size;
 
+       if (!S_ISREG(inode->i_mode))
+               return false;
        if (shmem_huge == SHMEM_HUGE_DENY)
                return false;
        if (vma && ((vma->vm_flags & VM_NOHUGEPAGE) ||
@@ -1061,6 +1063,12 @@ static int shmem_getattr(struct user_namespace *mnt_userns,
        if (shmem_is_huge(NULL, inode, 0))
                stat->blksize = HPAGE_PMD_SIZE;
 
+       if (request_mask & STATX_BTIME) {
+               stat->result_mask |= STATX_BTIME;
+               stat->btime.tv_sec = info->i_crtime.tv_sec;
+               stat->btime.tv_nsec = info->i_crtime.tv_nsec;
+       }
+
        return 0;
 }
 
@@ -1854,9 +1862,6 @@ repeat:
                return 0;
        }
 
-       /* Never use a huge page for shmem_symlink() */
-       if (S_ISLNK(inode->i_mode))
-               goto alloc_nohuge;
        if (!shmem_is_huge(vma, inode, index))
                goto alloc_nohuge;
 
@@ -2265,6 +2270,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
                atomic_set(&info->stop_eviction, 0);
                info->seals = F_SEAL_SEAL;
                info->flags = flags & VM_NORESERVE;
+               info->i_crtime = inode->i_mtime;
                INIT_LIST_HEAD(&info->shrinklist);
                INIT_LIST_HEAD(&info->swaplist);
                simple_xattrs_init(&info->xattrs);
@@ -3196,6 +3202,7 @@ static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
 #endif /* CONFIG_TMPFS_XATTR */
 
 static const struct inode_operations shmem_short_symlink_operations = {
+       .getattr        = shmem_getattr,
        .get_link       = simple_get_link,
 #ifdef CONFIG_TMPFS_XATTR
        .listxattr      = shmem_listxattr,
@@ -3203,6 +3210,7 @@ static const struct inode_operations shmem_short_symlink_operations = {
 };
 
 static const struct inode_operations shmem_symlink_inode_operations = {
+       .getattr        = shmem_getattr,
        .get_link       = shmem_get_link,
 #ifdef CONFIG_TMPFS_XATTR
        .listxattr      = shmem_listxattr,
@@ -3790,6 +3798,7 @@ static const struct inode_operations shmem_inode_operations = {
 
 static const struct inode_operations shmem_dir_inode_operations = {
 #ifdef CONFIG_TMPFS
+       .getattr        = shmem_getattr,
        .create         = shmem_create,
        .lookup         = simple_lookup,
        .link           = shmem_link,
@@ -3811,6 +3820,7 @@ static const struct inode_operations shmem_dir_inode_operations = {
 };
 
 static const struct inode_operations shmem_special_inode_operations = {
+       .getattr        = shmem_getattr,
 #ifdef CONFIG_TMPFS_XATTR
        .listxattr      = shmem_listxattr,
 #endif