ubifs: introduce UBIFS_ATIME_SUPPORT to ubifs

To make ubifs support atime flexily, this commit introduces
a Kconfig option named as UBIFS_ATIME_SUPPORT.

With UBIFS_ATIME_SUPPORT=n:
	ubifs keeps the full compatibility to no_atime from
the start of ubifs.

=================UBIFS_ATIME_SUPPORT=n=======================
-o - no atime
-o atime - no atime
-o noatime - no atime
-o relatime - no atime
-o strictatime - no atime
-o lazyatime - no atime

With UBIFS_ATIME_SUPPORT=y:
	ubifs supports the atime same with other main stream
file systems.
=================UBIFS_ATIME_SUPPORT=y=======================
-o - default behavior (relatime currently)
-o atime - atime support
-o noatime - no atime support
-o relatime - relative atime support
-o strictatime - strict atime support
-o lazyatime - lazy atime support

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/fs/ubifs/Kconfig b/fs/ubifs/Kconfig
index ba66d508006afe3acb2716a7da021ff484c436c0..7ff7712f284e030baf4e90a268c0577429497574 100644 (file)
--- a/fs/ubifs/Kconfig
+++ b/fs/ubifs/Kconfig
@@ -35,3 +35,18 @@ config UBIFS_FS_ZLIB
        default y
        help
          Zlib compresses better than LZO but it is slower. Say 'Y' if unsure.
+
+config UBIFS_ATIME_SUPPORT
+       bool "Access time support" if UBIFS_FS
+       depends on UBIFS_FS
+       default n
+       help
+         Originally UBIFS did not support atime, because it looked like a bad idea due
+         increased flash wear. This option adds atime support and it is disabled by default
+         to preserve the old behavior. If you enable this option, UBIFS starts updating atime,
+         which means that file-system read operations will cause writes (inode atime
+         updates). This may affect file-system performance and increase flash device wear,
+         so be careful. How often atime is updated depends on the selected strategy:
+         strictatime is the "heavy", relatime is "lighter", etc.
+
+         If unsure, say 'N'

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index a2f9d978b1101e9d08c3aea2da031d76f5351a96..e49bd2808bf3e397b9b499fe4d6036ad7600a71b 100644 (file)
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -1186,6 +1186,9 @@ const struct inode_operations ubifs_dir_inode_operations = {
        .getxattr    = ubifs_getxattr,
        .listxattr   = ubifs_listxattr,
        .removexattr = ubifs_removexattr,
+#ifdef CONFIG_UBIFS_ATIME_SUPPORT
+       .update_time = ubifs_update_time,
+#endif
 };
 
 const struct file_operations ubifs_dir_operations = {

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index a3dfe2ae79f28592a0ba01feb6d0b1889345957c..0edc128561476a804656fba068810cf47a76fa32 100644 (file)
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1354,6 +1354,47 @@ static inline int mctime_update_needed(const struct inode *inode,
        return 0;
 }
 
+#ifdef CONFIG_UBIFS_ATIME_SUPPORT
+/**
+ * ubifs_update_time - update time of inode.
+ * @inode: inode to update
+ *
+ * This function updates time of the inode.
+ */
+int ubifs_update_time(struct inode *inode, struct timespec *time,
+                            int flags)
+{
+       struct ubifs_inode *ui = ubifs_inode(inode);
+       struct ubifs_info *c = inode->i_sb->s_fs_info;
+       struct ubifs_budget_req req = { .dirtied_ino = 1,
+                       .dirtied_ino_d = ALIGN(ui->data_len, 8) };
+       int iflags = I_DIRTY_TIME;
+       int err, release;
+
+       err = ubifs_budget_space(c, &req);
+       if (err)
+               return err;
+
+       mutex_lock(&ui->ui_mutex);
+       if (flags & S_ATIME)
+               inode->i_atime = *time;
+       if (flags & S_CTIME)
+               inode->i_ctime = *time;
+       if (flags & S_MTIME)
+               inode->i_mtime = *time;
+
+       if (!(inode->i_sb->s_flags & MS_LAZYTIME))
+               iflags |= I_DIRTY_SYNC;
+
+       release = ui->dirty;
+       __mark_inode_dirty(inode, iflags);
+       mutex_unlock(&ui->ui_mutex);
+       if (release)
+               ubifs_release_budget(c, &req);
+       return 0;
+}
+#endif
+
 /**
  * update_ctime - update mtime and ctime of an inode.
  * @inode: inode to update
@@ -1537,6 +1578,9 @@ static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
        if (err)
                return err;
        vma->vm_ops = &ubifs_file_vm_ops;
+#ifdef CONFIG_UBIFS_ATIME_SUPPORT
+       file_accessed(file);
+#endif
        return 0;
 }
 
@@ -1557,6 +1601,9 @@ const struct inode_operations ubifs_file_inode_operations = {
        .getxattr    = ubifs_getxattr,
        .listxattr   = ubifs_listxattr,
        .removexattr = ubifs_removexattr,
+#ifdef CONFIG_UBIFS_ATIME_SUPPORT
+       .update_time = ubifs_update_time,
+#endif
 };
 
 const struct inode_operations ubifs_symlink_inode_operations = {
@@ -1568,6 +1615,9 @@ const struct inode_operations ubifs_symlink_inode_operations = {
        .getxattr    = ubifs_getxattr,
        .listxattr   = ubifs_listxattr,
        .removexattr = ubifs_removexattr,
+#ifdef CONFIG_UBIFS_ATIME_SUPPORT
+       .update_time = ubifs_update_time,
+#endif
 };
 
 const struct file_operations ubifs_file_operations = {

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 9547a27868ad49e11151c324c8f60a7db2bc92f6..8ee3133dd8e49af9f413025683236cf464a62f12 100644 (file)
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -128,7 +128,10 @@ struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
        if (err)
                goto out_ino;
 
-       inode->i_flags |= (S_NOCMTIME | S_NOATIME);
+       inode->i_flags |= S_NOCMTIME;
+#ifndef CONFIG_UBIFS_ATIME_SUPPORT
+       inode->i_flags |= S_NOATIME;
+#endif
        set_nlink(inode, le32_to_cpu(ino->nlink));
        i_uid_write(inode, le32_to_cpu(ino->uid));
        i_gid_write(inode, le32_to_cpu(ino->gid));
@@ -2139,7 +2142,12 @@ static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
                if (err)
                        goto out_deact;
                /* We do not support atime */
-               sb->s_flags |= MS_ACTIVE | MS_NOATIME;
+               sb->s_flags |= MS_ACTIVE;
+#ifndef CONFIG_UBIFS_ATIME_SUPPORT
+               sb->s_flags |= MS_NOATIME;
+#else
+               ubifs_msg(c, "full atime support is enabled.");
+#endif
        }
 
        /* 'fill_super()' opens ubi again so we must close it here */

diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 6ef2415aad9dd4fe452321d0e0ff231733e806c1..01142e129d168ccba3139992ce50df56c9acea3a 100644 (file)
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1746,6 +1746,9 @@ int ubifs_calc_dark(const struct ubifs_info *c, int spc);
 /* file.c */
 int ubifs_fsync(struct file *file, loff_t start, loff_t end, int datasync);
 int ubifs_setattr(struct dentry *dentry, struct iattr *attr);
+#ifdef CONFIG_UBIFS_ATIME_SUPPORT
+int ubifs_update_time(struct inode *inode, struct timespec *time, int flags);
+#endif
 
 /* dir.c */
 struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,