From e89a5a43b95cdc4305b7c8e8121a380f02476636 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Fri, 31 Aug 2007 10:45:17 -0400 Subject: NFS: Fix the mount regression This avoids the recent NFS mount regression (returning EBUSY when mounting the same filesystem twice with different parameters). The best I can do given the constraints appears to be to have the kernel first look for a superblock that matches both the fsid and the user-specified mount options, and then spawn off a new superblock if that search fails. Note that this is not the same as specifying nosharecache everywhere since nosharecache will never attempt to match an existing superblock. Signed-off-by: Trond Myklebust Tested-by: Hua Zhong Signed-off-by: Linus Torvalds --- fs/nfs/super.c | 110 +++++++++++++++++++++++++++++++++------------------------ 1 file changed, 64 insertions(+), 46 deletions(-) diff --git a/fs/nfs/super.c b/fs/nfs/super.c index b2a851c..4613900 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -1303,34 +1303,6 @@ static void nfs_clone_super(struct super_block *sb, nfs_initialise_sb(sb); } -static int nfs_set_super(struct super_block *s, void *_server) -{ - struct nfs_server *server = _server; - int ret; - - s->s_fs_info = server; - ret = set_anon_super(s, server); - if (ret == 0) - server->s_dev = s->s_dev; - return ret; -} - -static int nfs_compare_super(struct super_block *sb, void *data) -{ - struct nfs_server *server = data, *old = NFS_SB(sb); - - if (memcmp(&old->nfs_client->cl_addr, - &server->nfs_client->cl_addr, - sizeof(old->nfs_client->cl_addr)) != 0) - return 0; - /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */ - if (old->flags & NFS_MOUNT_UNSHARED) - return 0; - if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0) - return 0; - return 1; -} - #define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS) static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags) @@ -1359,9 +1331,46 @@ static int nfs_compare_mount_options(const struct super_block *s, const struct n goto Ebusy; if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor) goto Ebusy; - return 0; + return 1; Ebusy: - return -EBUSY; + return 0; +} + +struct nfs_sb_mountdata { + struct nfs_server *server; + int mntflags; +}; + +static int nfs_set_super(struct super_block *s, void *data) +{ + struct nfs_sb_mountdata *sb_mntdata = data; + struct nfs_server *server = sb_mntdata->server; + int ret; + + s->s_flags = sb_mntdata->mntflags; + s->s_fs_info = server; + ret = set_anon_super(s, server); + if (ret == 0) + server->s_dev = s->s_dev; + return ret; +} + +static int nfs_compare_super(struct super_block *sb, void *data) +{ + struct nfs_sb_mountdata *sb_mntdata = data; + struct nfs_server *server = sb_mntdata->server, *old = NFS_SB(sb); + int mntflags = sb_mntdata->mntflags; + + if (memcmp(&old->nfs_client->cl_addr, + &server->nfs_client->cl_addr, + sizeof(old->nfs_client->cl_addr)) != 0) + return 0; + /* Note: NFS_MOUNT_UNSHARED == NFS4_MOUNT_UNSHARED */ + if (old->flags & NFS_MOUNT_UNSHARED) + return 0; + if (memcmp(&old->fsid, &server->fsid, sizeof(old->fsid)) != 0) + return 0; + return nfs_compare_mount_options(sb, server, mntflags); } static int nfs_get_sb(struct file_system_type *fs_type, @@ -1373,6 +1382,9 @@ static int nfs_get_sb(struct file_system_type *fs_type, struct nfs_mount_data *data = raw_data; struct dentry *mntroot; int (*compare_super)(struct super_block *, void *) = nfs_compare_super; + struct nfs_sb_mountdata sb_mntdata = { + .mntflags = flags, + }; int error; /* Validate the mount data */ @@ -1386,28 +1398,25 @@ static int nfs_get_sb(struct file_system_type *fs_type, error = PTR_ERR(server); goto out; } + sb_mntdata.server = server; if (server->flags & NFS_MOUNT_UNSHARED) compare_super = NULL; /* Get a superblock - note that we may end up sharing one that already exists */ - s = sget(fs_type, compare_super, nfs_set_super, server); + s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata); if (IS_ERR(s)) { error = PTR_ERR(s); goto out_err_nosb; } if (s->s_fs_info != server) { - error = nfs_compare_mount_options(s, server, flags); nfs_free_server(server); server = NULL; - if (error < 0) - goto error_splat_super; } if (!s->s_root) { /* initial superblock/root creation */ - s->s_flags = flags; nfs_fill_super(s, data); } @@ -1460,6 +1469,9 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags, struct nfs_server *server; struct dentry *mntroot; int (*compare_super)(struct super_block *, void *) = nfs_compare_super; + struct nfs_sb_mountdata sb_mntdata = { + .mntflags = flags, + }; int error; dprintk("--> nfs_xdev_get_sb()\n"); @@ -1470,28 +1482,25 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags, error = PTR_ERR(server); goto out_err_noserver; } + sb_mntdata.server = server; if (server->flags & NFS_MOUNT_UNSHARED) compare_super = NULL; /* Get a superblock - note that we may end up sharing one that already exists */ - s = sget(&nfs_fs_type, compare_super, nfs_set_super, server); + s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata); if (IS_ERR(s)) { error = PTR_ERR(s); goto out_err_nosb; } if (s->s_fs_info != server) { - error = nfs_compare_mount_options(s, server, flags); nfs_free_server(server); server = NULL; - if (error < 0) - goto error_splat_super; } if (!s->s_root) { /* initial superblock/root creation */ - s->s_flags = flags; nfs_clone_super(s, data->sb); } @@ -1729,6 +1738,9 @@ static int nfs4_get_sb(struct file_system_type *fs_type, struct dentry *mntroot; char *mntpath = NULL, *hostname = NULL, *ip_addr = NULL; int (*compare_super)(struct super_block *, void *) = nfs_compare_super; + struct nfs_sb_mountdata sb_mntdata = { + .mntflags = flags, + }; int error; /* Validate the mount data */ @@ -1744,12 +1756,13 @@ static int nfs4_get_sb(struct file_system_type *fs_type, error = PTR_ERR(server); goto out; } + sb_mntdata.server = server; if (server->flags & NFS4_MOUNT_UNSHARED) compare_super = NULL; /* Get a superblock - note that we may end up sharing one that already exists */ - s = sget(fs_type, compare_super, nfs_set_super, server); + s = sget(fs_type, compare_super, nfs_set_super, &sb_mntdata); if (IS_ERR(s)) { error = PTR_ERR(s); goto out_free; @@ -1762,7 +1775,6 @@ static int nfs4_get_sb(struct file_system_type *fs_type, if (!s->s_root) { /* initial superblock/root creation */ - s->s_flags = flags; nfs4_fill_super(s); } @@ -1816,6 +1828,9 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags, struct nfs_server *server; struct dentry *mntroot; int (*compare_super)(struct super_block *, void *) = nfs_compare_super; + struct nfs_sb_mountdata sb_mntdata = { + .mntflags = flags, + }; int error; dprintk("--> nfs4_xdev_get_sb()\n"); @@ -1826,12 +1841,13 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags, error = PTR_ERR(server); goto out_err_noserver; } + sb_mntdata.server = server; if (server->flags & NFS4_MOUNT_UNSHARED) compare_super = NULL; /* Get a superblock - note that we may end up sharing one that already exists */ - s = sget(&nfs_fs_type, compare_super, nfs_set_super, server); + s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata); if (IS_ERR(s)) { error = PTR_ERR(s); goto out_err_nosb; @@ -1844,7 +1860,6 @@ static int nfs4_xdev_get_sb(struct file_system_type *fs_type, int flags, if (!s->s_root) { /* initial superblock/root creation */ - s->s_flags = flags; nfs4_clone_super(s, data->sb); } @@ -1887,6 +1902,9 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags, struct dentry *mntroot; struct nfs_fh mntfh; int (*compare_super)(struct super_block *, void *) = nfs_compare_super; + struct nfs_sb_mountdata sb_mntdata = { + .mntflags = flags, + }; int error; dprintk("--> nfs4_referral_get_sb()\n"); @@ -1897,12 +1915,13 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags, error = PTR_ERR(server); goto out_err_noserver; } + sb_mntdata.server = server; if (server->flags & NFS4_MOUNT_UNSHARED) compare_super = NULL; /* Get a superblock - note that we may end up sharing one that already exists */ - s = sget(&nfs_fs_type, compare_super, nfs_set_super, server); + s = sget(&nfs_fs_type, compare_super, nfs_set_super, &sb_mntdata); if (IS_ERR(s)) { error = PTR_ERR(s); goto out_err_nosb; @@ -1915,7 +1934,6 @@ static int nfs4_referral_get_sb(struct file_system_type *fs_type, int flags, if (!s->s_root) { /* initial superblock/root creation */ - s->s_flags = flags; nfs4_fill_super(s); } -- cgit v1.1