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author | 2022-09-09 09:00:31 -0400 | |
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committer | 2022-10-03 14:03:06 -0700 | |
commit | 36f05cab0a2c97bda288c3b6a557ec5fb8d9bba6 (patch) | |
tree | 5822bc43904c43dbce00d7dfe1aab83dd02e6633 /mm | |
parent | mm/damon/vaddr: add a comment for 'default' case in damon_va_apply_scheme() (diff) | |
download | linux-36f05cab0a2c97bda288c3b6a557ec5fb8d9bba6.tar.gz linux-36f05cab0a2c97bda288c3b6a557ec5fb8d9bba6.tar.bz2 linux-36f05cab0a2c97bda288c3b6a557ec5fb8d9bba6.zip |
tmpfs: add support for an i_version counter
NFSv4 mandates a change attribute to avoid problems with timestamp
granularity, which Linux implements using the i_version counter. This is
particularly important when the underlying filesystem is fast.
Give tmpfs an i_version counter. Since it doesn't have to be persistent,
we can just turn on SB_I_VERSION and sprinkle some inode_inc_iversion
calls in the right places.
Also, while there is no formal spec for xattrs, most implementations
update the ctime on setxattr. Fix shmem_xattr_handler_set to update the
ctime and bump the i_version appropriately.
Link: https://lkml.kernel.org/r/20220909130031.15477-1-jlayton@kernel.org
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/shmem.c | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 3d0b729fcc5e..275899bacbea 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -38,6 +38,7 @@ #include <linux/hugetlb.h> #include <linux/fs_parser.h> #include <linux/swapfile.h> +#include <linux/iversion.h> #include "swap.h" static struct vfsmount *shm_mnt; @@ -1030,6 +1031,7 @@ void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) { shmem_undo_range(inode, lstart, lend, false); inode->i_ctime = inode->i_mtime = current_time(inode); + inode_inc_iversion(inode); } EXPORT_SYMBOL_GPL(shmem_truncate_range); @@ -1074,6 +1076,8 @@ static int shmem_setattr(struct user_namespace *mnt_userns, struct inode *inode = d_inode(dentry); struct shmem_inode_info *info = SHMEM_I(inode); int error; + bool update_mtime = false; + bool update_ctime = true; error = setattr_prepare(&init_user_ns, dentry, attr); if (error) @@ -1094,7 +1098,9 @@ static int shmem_setattr(struct user_namespace *mnt_userns, if (error) return error; i_size_write(inode, newsize); - inode->i_ctime = inode->i_mtime = current_time(inode); + update_mtime = true; + } else { + update_ctime = false; } if (newsize <= oldsize) { loff_t holebegin = round_up(newsize, PAGE_SIZE); @@ -1114,6 +1120,12 @@ static int shmem_setattr(struct user_namespace *mnt_userns, setattr_copy(&init_user_ns, inode, attr); if (attr->ia_valid & ATTR_MODE) error = posix_acl_chmod(&init_user_ns, inode, inode->i_mode); + if (!error && update_ctime) { + inode->i_ctime = current_time(inode); + if (update_mtime) + inode->i_mtime = inode->i_ctime; + inode_inc_iversion(inode); + } return error; } @@ -2890,6 +2902,7 @@ shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir, error = 0; dir->i_size += BOGO_DIRENT_SIZE; dir->i_ctime = dir->i_mtime = current_time(dir); + inode_inc_iversion(dir); d_instantiate(dentry, inode); dget(dentry); /* Extra count - pin the dentry in core */ } @@ -2965,6 +2978,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr dir->i_size += BOGO_DIRENT_SIZE; inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); + inode_inc_iversion(dir); inc_nlink(inode); ihold(inode); /* New dentry reference */ dget(dentry); /* Extra pinning count for the created dentry */ @@ -2982,6 +2996,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry) dir->i_size -= BOGO_DIRENT_SIZE; inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); + inode_inc_iversion(dir); drop_nlink(inode); dput(dentry); /* Undo the count from "create" - this does all the work */ return 0; @@ -3071,6 +3086,8 @@ static int shmem_rename2(struct user_namespace *mnt_userns, old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = new_dir->i_mtime = inode->i_ctime = current_time(old_dir); + inode_inc_iversion(old_dir); + inode_inc_iversion(new_dir); return 0; } @@ -3123,6 +3140,7 @@ static int shmem_symlink(struct user_namespace *mnt_userns, struct inode *dir, } dir->i_size += BOGO_DIRENT_SIZE; dir->i_ctime = dir->i_mtime = current_time(dir); + inode_inc_iversion(dir); d_instantiate(dentry, inode); dget(dentry); return 0; @@ -3194,6 +3212,7 @@ static int shmem_fileattr_set(struct user_namespace *mnt_userns, shmem_set_inode_flags(inode, info->fsflags); inode->i_ctime = current_time(inode); + inode_inc_iversion(inode); return 0; } @@ -3257,9 +3276,15 @@ static int shmem_xattr_handler_set(const struct xattr_handler *handler, size_t size, int flags) { struct shmem_inode_info *info = SHMEM_I(inode); + int err; name = xattr_full_name(handler, name); - return simple_xattr_set(&info->xattrs, name, value, size, flags, NULL); + err = simple_xattr_set(&info->xattrs, name, value, size, flags, NULL); + if (!err) { + inode->i_ctime = current_time(inode); + inode_inc_iversion(inode); + } + return err; } static const struct xattr_handler shmem_security_xattr_handler = { @@ -3722,7 +3747,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_flags |= SB_NOUSER; } sb->s_export_op = &shmem_export_ops; - sb->s_flags |= SB_NOSEC; + sb->s_flags |= SB_NOSEC | SB_I_VERSION; #else sb->s_flags |= SB_NOUSER; #endif |