ovl: constant st_ino for non-samefs with xino (e487d889) · Commits · 戴 / test

fs/overlayfs/inode.c

+29 −2

Original line number	Diff line number	Diff line
		@@ -63,6 +63,7 @@ static int ovl_map_dev_ino(struct dentry dentry, struct kstat stat,
		struct ovl_layer *lower_layer)
		{
		bool samefs = ovl_same_sb(dentry->d_sb);
		unsigned int xinobits = ovl_xino_bits(dentry->d_sb);

		if (samefs) {
		/*
		@@ -71,7 +72,31 @@ static int ovl_map_dev_ino(struct dentry dentry, struct kstat stat,
		* which is friendly to du -x.
		*/
		stat->dev = dentry->d_sb->s_dev;
		} else if (S_ISDIR(dentry->d_inode->i_mode)) {
		return 0;
		} else if (xinobits) {
		unsigned int shift = 64 - xinobits;
		/*
		* All inode numbers of underlying fs should not be using the
		* high xinobits, so we use high xinobits to partition the
		* overlay st_ino address space. The high bits holds the fsid
		* (upper fsid is 0). This way overlay inode numbers are unique
		* and all inodes use overlay st_dev. Inode numbers are also
		* persistent for a given layer configuration.
		*/
		if (stat->ino >> shift) {
		pr_warn_ratelimited("overlayfs: inode number too big (%pd2, ino=%llu, xinobits=%d)\n",
		dentry, stat->ino, xinobits);
		} else {
		if (lower_layer)
		stat->ino \|= ((u64)lower_layer->fsid) << shift;

		stat->dev = dentry->d_sb->s_dev;
		return 0;
		}
		}

		/* The inode could not be mapped to a unified st_ino address space */
		if (S_ISDIR(dentry->d_inode->i_mode)) {
		/*
		* Always use the overlay st_dev for directories, so 'find
		* -xdev' will scan the entire overlay mount and won't cross the
		@@ -118,11 +143,13 @@ int ovl_getattr(const struct path path, struct kstat stat,
		/*
		* For non-dir or same fs, we use st_ino of the copy up origin.
		* This guaranties constant st_dev/st_ino across copy up.
		* With xino feature and non-samefs, we use st_ino of the copy up
		* origin masked with high bits that represent the layer id.
		*
		* If lower filesystem supports NFS file handles, this also guaranties
		* persistent st_ino across mount cycle.
		*/
		if (!is_dir \|\| samefs) {
		if (!is_dir \|\| samefs \|\| ovl_xino_bits(dentry->d_sb)) {
		if (!OVL_TYPE_UPPER(type)) {
		lower_layer = ovl_layer_lower(dentry);
		} else if (OVL_TYPE_ORIGIN(type)) {

fs/overlayfs/overlayfs.h

+8 −1

Original line number	Diff line number	Diff line
		@@ -202,7 +202,7 @@ void ovl_drop_write(struct dentry *dentry);
		struct dentry ovl_workdir(struct dentry dentry);
		const struct cred ovl_override_creds(struct super_block sb);
		struct super_block ovl_same_sb(struct super_block sb);
		bool ovl_can_decode_fh(struct super_block *sb);
		int ovl_can_decode_fh(struct super_block *sb);
		struct dentry ovl_indexdir(struct super_block sb);
		bool ovl_index_all(struct super_block *sb);
		bool ovl_verify_lower(struct super_block *sb);
		@@ -264,6 +264,13 @@ static inline bool ovl_is_impuredir(struct dentry *dentry)
		return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
		}

		static inline unsigned int ovl_xino_bits(struct super_block *sb)
		{
		struct ovl_fs *ofs = sb->s_fs_info;

		return ofs->xino_bits;
		}


		/* namei.c */
		int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);

fs/overlayfs/ovl_entry.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -63,6 +63,8 @@ struct ovl_fs {
		/* Did we take the inuse lock? */
		bool upperdir_locked;
		bool workdir_locked;
		/* Inode numbers in all layers do not use the high xino_bits */
		unsigned int xino_bits;
		};

		/* private information held for every overlayfs dentry */

fs/overlayfs/super.c

+22 −4

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@
		#include <linux/statfs.h>
		#include <linux/seq_file.h>
		#include <linux/posix_acl_xattr.h>
		#include <linux/exportfs.h>
		#include "overlayfs.h"

		MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
		@@ -701,6 +702,7 @@ static int ovl_check_namelen(struct path path, struct ovl_fs ofs,
		static int ovl_lower_dir(const char name, struct path path,
		struct ovl_fs ofs, int stack_depth, bool *remote)
		{
		int fh_type;
		int err;

		err = ovl_mount_dir_noesc(name, path);
		@@ -720,15 +722,19 @@ static int ovl_lower_dir(const char name, struct path path,
		* The inodes index feature and NFS export need to encode and decode
		* file handles, so they require that all layers support them.
		*/
		fh_type = ovl_can_decode_fh(path->dentry->d_sb);
		if ((ofs->config.nfs_export \|\|
		(ofs->config.index && ofs->config.upperdir)) &&
		!ovl_can_decode_fh(path->dentry->d_sb)) {
		(ofs->config.index && ofs->config.upperdir)) && !fh_type) {
		ofs->config.index = false;
		ofs->config.nfs_export = false;
		pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n",
		name);
		}

		/* Check if lower fs has 32bit inode numbers */
		if (fh_type != FILEID_INO32_GEN)
		ofs->xino_bits = 0;

		return 0;

		out_put:
		@@ -952,6 +958,7 @@ static int ovl_make_workdir(struct ovl_fs ofs, struct path workpath)
		{
		struct vfsmount *mnt = ofs->upper_mnt;
		struct dentry *temp;
		int fh_type;
		int err;

		err = mnt_want_write(mnt);
		@@ -1001,12 +1008,16 @@ static int ovl_make_workdir(struct ovl_fs ofs, struct path workpath)
		}

		/* Check if upper/work fs supports file handles */
		if (ofs->config.index &&
		!ovl_can_decode_fh(ofs->workdir->d_sb)) {
		fh_type = ovl_can_decode_fh(ofs->workdir->d_sb);
		if (ofs->config.index && !fh_type) {
		ofs->config.index = false;
		pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n");
		}

		/* Check if upper fs has 32bit inode numbers */
		if (fh_type != FILEID_INO32_GEN)
		ofs->xino_bits = 0;

		/* NFS export of r/w mount depends on index */
		if (ofs->config.nfs_export && !ofs->config.index) {
		pr_warn("overlayfs: NFS export requires \"index=on\", falling back to nfs_export=off.\n");
		@@ -1185,6 +1196,11 @@ static int ovl_get_lower_layers(struct ovl_fs ofs, struct path stack,
		}
		ofs->numlower++;
		}

		/* When all layers on same fs, overlay can use real inode numbers */
		if (!ofs->numlowerfs \|\| (ofs->numlowerfs == 1 && !ofs->upper_mnt))
		ofs->xino_bits = 0;

		err = 0;
		out:
		return err;
		@@ -1308,6 +1324,8 @@ static int ovl_fill_super(struct super_block sb, void data, int silent)

		sb->s_stack_depth = 0;
		sb->s_maxbytes = MAX_LFS_FILESIZE;
		/* Assume underlaying fs uses 32bit inodes unless proven otherwise */
		ofs->xino_bits = BITS_PER_LONG - 32;
		if (ofs->config.upperdir) {
		if (!ofs->config.workdir) {
		pr_err("overlayfs: missing 'workdir'\n");

fs/overlayfs/util.c

+14 −3

Original line number	Diff line number	Diff line
		@@ -55,10 +55,21 @@ struct super_block ovl_same_sb(struct super_block sb)
		return NULL;
		}

		bool ovl_can_decode_fh(struct super_block *sb)
		/*
		* Check if underlying fs supports file handles and try to determine encoding
		* type, in order to deduce maximum inode number used by fs.
		*
		* Return 0 if file handles are not supported.
		* Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding.
		* Return -1 if fs uses a non default encoding with unknown inode size.
		*/
		int ovl_can_decode_fh(struct super_block *sb)
		{
		return (sb->s_export_op && sb->s_export_op->fh_to_dentry &&
		!uuid_is_null(&sb->s_uuid));
		if (!sb->s_export_op \|\| !sb->s_export_op->fh_to_dentry \|\|
		uuid_is_null(&sb->s_uuid))
		return 0;

		return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN;
		}

		struct dentry ovl_indexdir(struct super_block sb)

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