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Message-Id: <1336734608-15157-2-git-send-email-ludwig.nussel@suse.de>
Date: Fri, 11 May 2012 13:10:06 +0200
From: Ludwig Nussel <ludwig.nussel@...e.de>
To: linux-kernel@...r.kernel.org
Cc: Ludwig Nussel <ludwig.nussel@...e.de>,
linux-fsdevel@...r.kernel.org,
Jan Kara <jack@...e.cz> (maintainer:EXT2 FILE SYSTEM),
Rob Landley <rob@...dley.net> (maintainer:DOCUMENTATION),
Andrew Morton <akpm@...ux-foundation.org> (maintainer:EXT3 FILE
SYSTEM),
Andreas Dilger <adilger.kernel@...ger.ca> (maintainer:EXT3 FILE
SYSTEM),
"Theodore Ts'o" <tytso@....edu> (maintainer:EXT4 FILE SYSTEM),
linux-ext4@...r.kernel.org (open list:EXT2 FILE SYSTEM),
linux-doc@...r.kernel.org (open list:DOCUMENTATION)
Subject: [PATCH 1/3] implement uid and gid mount options for ext2
Signed-off-by: Ludwig Nussel <ludwig.nussel@...e.de>
---
Documentation/filesystems/ext2.txt | 9 ++++++
fs/ext2/ext2.h | 8 +++++
fs/ext2/inode.c | 42 ++++++++++++++++++++------
fs/ext2/super.c | 57 +++++++++++++++++++++++++++++++++++-
4 files changed, 105 insertions(+), 11 deletions(-)
diff --git a/Documentation/filesystems/ext2.txt b/Documentation/filesystems/ext2.txt
index 67639f9..fcc1002 100644
--- a/Documentation/filesystems/ext2.txt
+++ b/Documentation/filesystems/ext2.txt
@@ -42,6 +42,15 @@ orlov (*) Use the Orlov block allocator.
resuid=n The user ID which may use the reserved blocks.
resgid=n The group ID which may use the reserved blocks.
+uid=n[:m] Make all files appear to belong to uid n.
+ Useful for e.g. removable media with fstab
+ options 'user,uid=useruid'. The optional second
+ uid m is actually written to the file system.
+
+gid=n[:m] Make all files appear to belong to gid n.
+ The optional second gid m is actually written to
+ the file system.
+
sb=n Use alternate superblock at this location.
user_xattr Enable "user." POSIX Extended Attributes
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 0b2b4db..b584e45 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -84,6 +84,10 @@ struct ext2_sb_info {
unsigned long s_sb_block;
uid_t s_resuid;
gid_t s_resgid;
+ uid_t s_uid; /* make all files appear to belong to this uid */
+ uid_t s_diskuid; /* write this uid to disk (if s_uid != 0) */
+ gid_t s_gid; /* make all files appear to belong to this gid */
+ gid_t s_diskgid; /* write this gid to disk (if s_gid != 0) */
unsigned short s_mount_state;
unsigned short s_pad;
int s_addr_per_block_bits;
@@ -639,6 +643,10 @@ struct ext2_mount_options {
unsigned long s_mount_opt;
uid_t s_resuid;
gid_t s_resgid;
+ uid_t s_uid;
+ uid_t s_diskuid;
+ gid_t s_gid;
+ gid_t s_diskgid;
};
/*
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 740cad8..aabcb38 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1316,6 +1316,10 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
}
+ if (EXT2_SB(sb)->s_uid)
+ inode->i_uid = EXT2_SB(sb)->s_uid;
+ if (EXT2_SB(sb)->s_gid)
+ inode->i_gid = EXT2_SB(sb)->s_gid;
set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
inode->i_size = le32_to_cpu(raw_inode->i_size);
inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
@@ -1419,6 +1423,10 @@ static int __ext2_write_inode(struct inode *inode, int do_sync)
struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
int n;
int err = 0;
+ __le16 uid_low;
+ __le16 gid_low;
+ __le16 uid_high;
+ __le16 gid_high;
if (IS_ERR(raw_inode))
return -EIO;
@@ -1430,26 +1438,40 @@ static int __ext2_write_inode(struct inode *inode, int do_sync)
ext2_get_inode_flags(ei);
raw_inode->i_mode = cpu_to_le16(inode->i_mode);
+ if (EXT2_SB(sb)->s_uid)
+ uid = EXT2_SB(sb)->s_diskuid;
+ if (EXT2_SB(sb)->s_gid)
+ gid = EXT2_SB(sb)->s_diskgid;
if (!(test_opt(sb, NO_UID32))) {
- raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
- raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
+ uid_low = cpu_to_le16(low_16_bits(uid));
+ gid_low = cpu_to_le16(low_16_bits(gid));
/*
* Fix up interoperability with old kernels. Otherwise, old inodes get
* re-used with the upper 16 bits of the uid/gid intact
*/
if (!ei->i_dtime) {
- raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
- raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
+ uid_high = cpu_to_le16(high_16_bits(uid));
+ gid_high = cpu_to_le16(high_16_bits(gid));
} else {
- raw_inode->i_uid_high = 0;
- raw_inode->i_gid_high = 0;
+ uid_high = 0;
+ gid_high = 0;
}
} else {
- raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
- raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
- raw_inode->i_uid_high = 0;
- raw_inode->i_gid_high = 0;
+ uid_low = cpu_to_le16(fs_high2lowuid(uid));
+ gid_low = cpu_to_le16(fs_high2lowgid(gid));
+ uid_high = 0;
+ gid_high = 0;
}
+ /* don't mangle uid/gid of existing files if override is active */
+ if (!EXT2_SB(sb)->s_uid || ei->i_state & EXT2_STATE_NEW) {
+ raw_inode->i_uid_high = uid_high;
+ raw_inode->i_uid_low = uid_low;
+ }
+ if (!EXT2_SB(sb)->s_gid || ei->i_state & EXT2_STATE_NEW) {
+ raw_inode->i_gid_high = gid_high;
+ raw_inode->i_gid_low = gid_low;
+ }
+
raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
raw_inode->i_size = cpu_to_le32(inode->i_size);
raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index e1025c7..0661574 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -236,6 +236,20 @@ static int ext2_show_options(struct seq_file *seq, struct dentry *root)
le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
seq_printf(seq, ",resgid=%u", sbi->s_resgid);
}
+ if (sbi->s_uid) {
+ if (sbi->s_uid != sbi->s_diskuid)
+ seq_printf(seq, ",uid=%u:%u",
+ sbi->s_uid, sbi->s_diskuid);
+ else
+ seq_printf(seq, ",uid=%u", sbi->s_uid);
+ }
+ if (sbi->s_gid) {
+ if (sbi->s_gid != sbi->s_diskgid)
+ seq_printf(seq, ",gid=%u:%u",
+ sbi->s_gid, sbi->s_diskgid);
+ else
+ seq_printf(seq, ",gid=%u", sbi->s_gid);
+ }
if (test_opt(sb, ERRORS_RO)) {
int def_errors = le16_to_cpu(es->s_errors);
@@ -393,7 +407,8 @@ enum {
Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
- Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
+ Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation,
+ Opt_uid, Opt_diskuid, Opt_gid, Opt_diskgid
};
static const match_table_t tokens = {
@@ -427,6 +442,10 @@ static const match_table_t tokens = {
{Opt_usrquota, "usrquota"},
{Opt_reservation, "reservation"},
{Opt_noreservation, "noreservation"},
+ {Opt_uid, "uid=%u"},
+ {Opt_diskuid, "uid=%u:%u"},
+ {Opt_gid, "gid=%u"},
+ {Opt_diskgid, "gid=%u:%u"},
{Opt_err, NULL}
};
@@ -568,6 +587,34 @@ static int parse_options(char *options, struct super_block *sb)
clear_opt(sbi->s_mount_opt, RESERVATION);
ext2_msg(sb, KERN_INFO, "reservations OFF");
break;
+ case Opt_uid:
+ if (match_int(&args[0], &option))
+ return 0;
+ sbi->s_uid = sbi->s_diskuid = option;
+ break;
+ case Opt_diskuid:
+ if (match_int(&args[0], &option))
+ return 0;
+ sbi->s_uid = option;
+
+ if (match_int(&args[1], &option))
+ return 0;
+ sbi->s_diskuid = option;
+ break;
+ case Opt_gid:
+ if (match_int(&args[0], &option))
+ return 0;
+ sbi->s_gid = sbi->s_diskgid = option;
+ break;
+ case Opt_diskgid:
+ if (match_int(&args[0], &option))
+ return 0;
+ sbi->s_gid = option;
+
+ if (match_int(&args[1], &option))
+ return 0;
+ sbi->s_diskgid = option;
+ break;
case Opt_ignore:
break;
default:
@@ -1214,6 +1261,10 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
old_opts.s_mount_opt = sbi->s_mount_opt;
old_opts.s_resuid = sbi->s_resuid;
old_opts.s_resgid = sbi->s_resgid;
+ old_opts.s_uid = sbi->s_uid;
+ old_opts.s_diskuid = sbi->s_diskuid;
+ old_opts.s_gid = sbi->s_gid;
+ old_opts.s_diskgid = sbi->s_diskgid;
/*
* Allow the "check" option to be passed as a remount option.
@@ -1300,6 +1351,10 @@ restore_opts:
sbi->s_mount_opt = old_opts.s_mount_opt;
sbi->s_resuid = old_opts.s_resuid;
sbi->s_resgid = old_opts.s_resgid;
+ sbi->s_uid = old_opts.s_uid;
+ sbi->s_diskuid = old_opts.s_diskuid;
+ sbi->s_gid = old_opts.s_gid;
+ sbi->s_diskgid = old_opts.s_diskgid;
sb->s_flags = old_sb_flags;
spin_unlock(&sbi->s_lock);
return err;
--
1.7.7
--
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