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authorSascha Hauer <s.hauer@pengutronix.de>2021-03-04 13:35:39 +0100
committerJan Kara <jack@suse.cz>2021-03-16 12:28:22 +0100
commit9dfa23c8de925041b7b45637a1a80a98a22f19dd (patch)
tree8626111ab082053fedac5e0e7d3f82a41aa2e889 /fs/quota
parent1e28eed17697bcf343c6743f0028cc3b5dd88bf0 (diff)
downloadlwn-9dfa23c8de925041b7b45637a1a80a98a22f19dd.tar.gz
lwn-9dfa23c8de925041b7b45637a1a80a98a22f19dd.zip
quota: Add mountpath based quota support
Add syscall quotactl_path, a variant of quotactl which allows to specify the mountpath instead of a path of to a block device. The quotactl syscall expects a path to the mounted block device to specify the filesystem to work on. This limits usage to filesystems which actually have a block device. quotactl_path replaces the path to the block device with a path where the filesystem is mounted at. The global Q_SYNC command to sync all filesystems is not supported for this new syscall, otherwise quotactl_path behaves like quotactl. Link: https://lore.kernel.org/r/20210304123541.30749-2-s.hauer@pengutronix.de Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/quota')
-rw-r--r--fs/quota/quota.c49
1 files changed, 46 insertions, 3 deletions
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 6d16b2be5ac4..f7b4b66491fc 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -17,6 +17,7 @@
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>
+#include <linux/mount.h>
#include <linux/writeback.h>
#include <linux/nospec.h>
#include "compat.h"
@@ -827,8 +828,6 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
}
}
-#ifdef CONFIG_BLOCK
-
/* Return 1 if 'cmd' will block on frozen filesystem */
static int quotactl_cmd_write(int cmd)
{
@@ -850,7 +849,6 @@ static int quotactl_cmd_write(int cmd)
}
return 1;
}
-#endif /* CONFIG_BLOCK */
/* Return true if quotactl command is manipulating quota on/off state */
static bool quotactl_cmd_onoff(int cmd)
@@ -968,3 +966,48 @@ out:
path_put(pathp);
return ret;
}
+
+SYSCALL_DEFINE4(quotactl_path, unsigned int, cmd, const char __user *,
+ mountpoint, qid_t, id, void __user *, addr)
+{
+ struct super_block *sb;
+ struct path mountpath;
+ unsigned int cmds = cmd >> SUBCMDSHIFT;
+ unsigned int type = cmd & SUBCMDMASK;
+ int ret;
+
+ if (type >= MAXQUOTAS)
+ return -EINVAL;
+
+ ret = user_path_at(AT_FDCWD, mountpoint,
+ LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
+ if (ret)
+ return ret;
+
+ sb = mountpath.mnt->mnt_sb;
+
+ if (quotactl_cmd_write(cmds)) {
+ ret = mnt_want_write(mountpath.mnt);
+ if (ret)
+ goto out;
+ }
+
+ if (quotactl_cmd_onoff(cmds))
+ down_write(&sb->s_umount);
+ else
+ down_read(&sb->s_umount);
+
+ ret = do_quotactl(sb, type, cmds, id, addr, ERR_PTR(-EINVAL));
+
+ if (quotactl_cmd_onoff(cmds))
+ up_write(&sb->s_umount);
+ else
+ up_read(&sb->s_umount);
+
+ if (quotactl_cmd_write(cmds))
+ mnt_drop_write(mountpath.mnt);
+out:
+ path_put(&mountpath);
+
+ return ret;
+}