diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-11-07 11:46:31 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-11-07 11:46:31 -0800 |
commit | 7f851936a0ca4b231224ee296cba28f9b1bc555e (patch) | |
tree | 474b2147829e3cef0f5bfc157554c7f446e064c5 /fs/overlayfs | |
parent | c9d01179e185f72b20af7e37aa4308f4c7ca7eeb (diff) | |
parent | 24e16e385f2272b1a9df51337a5c32d28a29c7ad (diff) |
Merge tag 'ovl-update-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs
Pull overlayfs updates from Amir Goldstein:
- Overlayfs aio cleanups and fixes
Cleanups and minor fixes in preparation for factoring out of
read/write passthrough code.
- Overlayfs lock ordering changes
Hold mnt_writers only throughout copy up instead of a long lived
elevated refcount.
- Add support for nesting overlayfs private xattrs
There are cases where you want to use an overlayfs mount as a
lowerdir for another overlayfs mount. For example, if the system
rootfs is on overlayfs due to composefs, or to make it volatile (via
tmpfs), then you cannot currently store a lowerdir on the rootfs,
because the inner overlayfs will eat all the whiteouts and overlay
xattrs. This means you can't e.g. store on the rootfs a prepared
container image for use with overlayfs.
This adds support for nesting of overlayfs mounts by escaping the
problematic features and unescaping them when exposing to the
overlayfs user.
- Add new mount options for appending lowerdirs
* tag 'ovl-update-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
ovl: add support for appending lowerdirs one by one
ovl: refactor layer parsing helpers
ovl: store and show the user provided lowerdir mount option
ovl: remove unused code in lowerdir param parsing
ovl: Add documentation on nesting of overlayfs mounts
ovl: Add an alternative type of whiteout
ovl: Support escaped overlay.* xattrs
ovl: Add OVL_XATTR_TRUSTED/USER_PREFIX_LEN macros
ovl: Move xattr support to new xattrs.c file
ovl: do not encode lower fh with upper sb_writers held
ovl: do not open/llseek lower file with upper sb_writers held
ovl: reorder ovl_want_write() after ovl_inode_lock()
ovl: split ovl_want_write() into two helpers
ovl: add helper ovl_file_modified()
ovl: protect copying of realinode attributes to ovl inode
ovl: punt write aio completion to workqueue
ovl: propagate IOCB_APPEND flag on writes to realfile
ovl: use simpler function to convert iocb to rw flags
Diffstat (limited to 'fs/overlayfs')
-rw-r--r-- | fs/overlayfs/Makefile | 2 | ||||
-rw-r--r-- | fs/overlayfs/copy_up.c | 142 | ||||
-rw-r--r-- | fs/overlayfs/dir.c | 64 | ||||
-rw-r--r-- | fs/overlayfs/export.c | 7 | ||||
-rw-r--r-- | fs/overlayfs/file.c | 88 | ||||
-rw-r--r-- | fs/overlayfs/inode.c | 165 | ||||
-rw-r--r-- | fs/overlayfs/namei.c | 52 | ||||
-rw-r--r-- | fs/overlayfs/overlayfs.h | 72 | ||||
-rw-r--r-- | fs/overlayfs/params.c | 322 | ||||
-rw-r--r-- | fs/overlayfs/params.h | 1 | ||||
-rw-r--r-- | fs/overlayfs/readdir.c | 27 | ||||
-rw-r--r-- | fs/overlayfs/super.c | 92 | ||||
-rw-r--r-- | fs/overlayfs/util.c | 115 | ||||
-rw-r--r-- | fs/overlayfs/xattrs.c | 271 |
14 files changed, 891 insertions, 529 deletions
diff --git a/fs/overlayfs/Makefile b/fs/overlayfs/Makefile index 4e173d56b11f..5648954f8588 100644 --- a/fs/overlayfs/Makefile +++ b/fs/overlayfs/Makefile @@ -6,4 +6,4 @@ obj-$(CONFIG_OVERLAY_FS) += overlay.o overlay-objs := super.o namei.o util.o inode.o file.o dir.o readdir.o \ - copy_up.o export.o params.o + copy_up.o export.o params.o xattrs.o diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index ada3fcc9c6d5..4382881b0709 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -252,7 +252,9 @@ static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, return PTR_ERR(old_file); /* Try to use clone_file_range to clone up within the same fs */ + ovl_start_write(dentry); cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0); + ovl_end_write(dentry); if (cloned == len) goto out_fput; /* Couldn't clone, so now we try to copy the data */ @@ -287,8 +289,12 @@ static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, * it may not recognize all kind of holes and sometimes * only skips partial of hole area. However, it will be * enough for most of the use cases. + * + * We do not hold upper sb_writers throughout the loop to avert + * lockdep warning with llseek of lower file in nested overlay: + * - upper sb_writers + * -- lower ovl_inode_lock (ovl_llseek) */ - if (skip_hole && data_pos < old_pos) { data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA); if (data_pos > old_pos) { @@ -303,9 +309,11 @@ static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, } } + ovl_start_write(dentry); bytes = do_splice_direct(old_file, &old_pos, new_file, &new_pos, this_len, SPLICE_F_MOVE); + ovl_end_write(dentry); if (bytes <= 0) { error = bytes; break; @@ -426,29 +434,29 @@ out_err: return ERR_PTR(err); } -int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower, - struct dentry *upper) +struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin) { - const struct ovl_fh *fh = NULL; - int err; - /* * When lower layer doesn't support export operations store a 'null' fh, * so we can use the overlay.origin xattr to distignuish between a copy * up and a pure upper inode. */ - if (ovl_can_decode_fh(lower->d_sb)) { - fh = ovl_encode_real_fh(ofs, lower, false); - if (IS_ERR(fh)) - return PTR_ERR(fh); - } + if (!ovl_can_decode_fh(origin->d_sb)) + return NULL; + + return ovl_encode_real_fh(ofs, origin, false); +} + +int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh, + struct dentry *upper) +{ + int err; /* * Do not fail when upper doesn't support xattrs. */ err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf, fh ? fh->fb.len : 0, 0); - kfree(fh); /* Ignore -EPERM from setting "user.*" on symlink/special */ return err == -EPERM ? 0 : err; @@ -476,7 +484,7 @@ static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper, * * Caller must hold i_mutex on indexdir. */ -static int ovl_create_index(struct dentry *dentry, struct dentry *origin, +static int ovl_create_index(struct dentry *dentry, const struct ovl_fh *fh, struct dentry *upper) { struct ovl_fs *ofs = OVL_FS(dentry->d_sb); @@ -502,7 +510,7 @@ static int ovl_create_index(struct dentry *dentry, struct dentry *origin, if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry)))) return -EIO; - err = ovl_get_index_name(ofs, origin, &name); + err = ovl_get_index_name_fh(fh, &name); if (err) return err; @@ -541,6 +549,7 @@ struct ovl_copy_up_ctx { struct dentry *destdir; struct qstr destname; struct dentry *workdir; + const struct ovl_fh *origin_fh; bool origin; bool indexed; bool metacopy; @@ -555,14 +564,16 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c) struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); struct inode *udir = d_inode(upperdir); + ovl_start_write(c->dentry); + /* Mark parent "impure" because it may now contain non-pure upper */ err = ovl_set_impure(c->parent, upperdir); if (err) - return err; + goto out; err = ovl_set_nlink_lower(c->dentry); if (err) - return err; + goto out; inode_lock_nested(udir, I_MUTEX_PARENT); upper = ovl_lookup_upper(ofs, c->dentry->d_name.name, upperdir, @@ -581,10 +592,12 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c) } inode_unlock(udir); if (err) - return err; + goto out; err = ovl_set_nlink_upper(c->dentry); +out: + ovl_end_write(c->dentry); return err; } @@ -637,7 +650,7 @@ static int ovl_copy_up_metadata(struct ovl_copy_up_ctx *c, struct dentry *temp) * hard link. */ if (c->origin) { - err = ovl_set_origin(ofs, c->lowerpath.dentry, temp); + err = ovl_set_origin_fh(ofs, c->origin_fh, temp); if (err) return err; } @@ -719,21 +732,19 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c) .link = c->link }; - /* workdir and destdir could be the same when copying up to indexdir */ - err = -EIO; - if (lock_rename(c->workdir, c->destdir) != NULL) - goto unlock; - err = ovl_prep_cu_creds(c->dentry, &cc); if (err) - goto unlock; + return err; + ovl_start_write(c->dentry); + inode_lock(wdir); temp = ovl_create_temp(ofs, c->workdir, &cattr); + inode_unlock(wdir); + ovl_end_write(c->dentry); ovl_revert_cu_creds(&cc); - err = PTR_ERR(temp); if (IS_ERR(temp)) - goto unlock; + return PTR_ERR(temp); /* * Copy up data first and then xattrs. Writing data after @@ -741,15 +752,28 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c) */ path.dentry = temp; err = ovl_copy_up_data(c, &path); - if (err) + /* + * We cannot hold lock_rename() throughout this helper, because or + * lock ordering with sb_writers, which shouldn't be held when calling + * ovl_copy_up_data(), so lock workdir and destdir and make sure that + * temp wasn't moved before copy up completion or cleanup. + * If temp was moved, abort without the cleanup. + */ + ovl_start_write(c->dentry); + if (lock_rename(c->workdir, c->destdir) != NULL || + temp->d_parent != c->workdir) { + err = -EIO; + goto unlock; + } else if (err) { goto cleanup; + } err = ovl_copy_up_metadata(c, temp); if (err) goto cleanup; if (S_ISDIR(c->stat.mode) && c->indexed) { - err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp); + err = ovl_create_index(c->dentry, c->origin_fh, temp); if (err) goto cleanup; } @@ -779,6 +803,7 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c) ovl_set_flag(OVL_WHITEOUTS, inode); unlock: unlock_rename(c->workdir, c->destdir); + ovl_end_write(c->dentry); return err; @@ -802,9 +827,10 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) if (err) return err; + ovl_start_write(c->dentry); tmpfile = ovl_do_tmpfile(ofs, c->workdir, c->stat.mode); + ovl_end_write(c->dentry); ovl_revert_cu_creds(&cc); - if (IS_ERR(tmpfile)) return PTR_ERR(tmpfile); @@ -815,9 +841,11 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) goto out_fput; } + ovl_start_write(c->dentry); + err = ovl_copy_up_metadata(c, temp); if (err) - goto out_fput; + goto out; inode_lock_nested(udir, I_MUTEX_PARENT); @@ -831,7 +859,7 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) inode_unlock(udir); if (err) - goto out_fput; + goto out; if (c->metacopy_digest) ovl_set_flag(OVL_HAS_DIGEST, d_inode(c->dentry)); @@ -843,6 +871,8 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) ovl_set_upperdata(d_inode(c->dentry)); ovl_inode_update(d_inode(c->dentry), dget(temp)); +out: + ovl_end_write(c->dentry); out_fput: fput(tmpfile); return err; @@ -861,6 +891,8 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) { int err; struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); + struct dentry *origin = c->lowerpath.dentry; + struct ovl_fh *fh = NULL; bool to_index = false; /* @@ -877,25 +909,35 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) to_index = true; } - if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index) + if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index) { + fh = ovl_get_origin_fh(ofs, origin); + if (IS_ERR(fh)) + return PTR_ERR(fh); + + /* origin_fh may be NULL */ + c->origin_fh = fh; c->origin = true; + } if (to_index) { c->destdir = ovl_indexdir(c->dentry->d_sb); - err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname); + err = ovl_get_index_name(ofs, origin, &c->destname); if (err) - return err; + goto out_free_fh; } else if (WARN_ON(!c->parent)) { /* Disconnected dentry must be copied up to index dir */ - return -EIO; + err = -EIO; + goto out_free_fh; } else { /* * Mark parent "impure" because it may now contain non-pure * upper */ + ovl_start_write(c->dentry); err = ovl_set_impure(c->parent, c->destdir); + ovl_end_write(c->dentry); if (err) - return err; + goto out_free_fh; } /* Should we copyup with O_TMPFILE or with workdir? */ @@ -909,6 +951,7 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) if (c->indexed) ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); + ovl_start_write(c->dentry); if (to_index) { /* Initialize nlink for copy up of disconnected dentry */ err = ovl_set_nlink_upper(c->dentry); @@ -923,10 +966,13 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) ovl_dentry_set_upper_alias(c->dentry); ovl_dentry_update_reval(c->dentry, ovl_dentry_upper(c->dentry)); } + ovl_end_write(c->dentry); out: if (to_index) kfree(c->destname.name); +out_free_fh: + kfree(fh); return err; } @@ -1011,15 +1057,16 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c) * Writing to upper file will clear security.capability xattr. We * don't want that to happen for normal copy-up operation. */ + ovl_start_write(c->dentry); if (capability) { err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS, capability, cap_size, 0); - if (err) - goto out_free; } - - - err = ovl_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY); + if (!err) { + err = ovl_removexattr(ofs, upperpath.dentry, + OVL_XATTR_METACOPY); + } + ovl_end_write(c->dentry); if (err) goto out_free; @@ -1170,17 +1217,10 @@ static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) int ovl_maybe_copy_up(struct dentry *dentry, int flags) { - int err = 0; - - if (ovl_open_need_copy_up(dentry, flags)) { - err = ovl_want_write(dentry); - if (!err) { - err = ovl_copy_up_flags(dentry, flags); - ovl_drop_write(dentry); - } - } + if (!ovl_open_need_copy_up(dentry, flags)) + return 0; - return err; + return ovl_copy_up_flags(dentry, flags); } int ovl_copy_up_with_data(struct dentry *dentry) diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 033fc0458a3d..aab3f5d93556 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -477,7 +477,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, goto out_unlock; err = -ESTALE; - if (d_is_negative(upper) || !IS_WHITEOUT(d_inode(upper))) + if (d_is_negative(upper) || !ovl_upper_is_whiteout(ofs, upper)) goto out_dput; newdentry = ovl_create_temp(ofs, workdir, cattr); @@ -559,10 +559,6 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, struct cred *override_cred; struct dentry *parent = dentry->d_parent; - err = ovl_copy_up(parent); - if (err) - return err; - old_cred = ovl_override_creds(dentry->d_sb); /* @@ -626,6 +622,10 @@ static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, .link = link, }; + err = ovl_copy_up(dentry->d_parent); + if (err) + return err; + err = ovl_want_write(dentry); if (err) goto out; @@ -700,28 +700,24 @@ static int ovl_link(struct dentry *old, struct inode *newdir, int err; struct inode *inode; - err = ovl_want_write(old); + err = ovl_copy_up(old); if (err) goto out; - err = ovl_copy_up(old); + err = ovl_copy_up(new->d_parent); if (err) - goto out_drop_write; + goto out; - err = ovl_copy_up(new->d_parent); + err = ovl_nlink_start(old); if (err) - goto out_drop_write; + goto out; if (ovl_is_metacopy_dentry(old)) { err = ovl_set_link_redirect(old); if (err) - goto out_drop_write; + goto out_nlink_end; } - err = ovl_nlink_start(old); - if (err) - goto out_drop_write; - inode = d_inode(old); ihold(inode); @@ -731,9 +727,8 @@ static int ovl_link(struct dentry *old, struct inode *newdir, if (err) iput(inode); +out_nlink_end: ovl_nlink_end(old); -out_drop_write: - ovl_drop_write(old); out: return err; } @@ -891,17 +886,13 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir) goto out; } - err = ovl_want_write(dentry); - if (err) - goto out; - err = ovl_copy_up(dentry->d_parent); if (err) - goto out_drop_write; + goto out; err = ovl_nlink_start(dentry); if (err) - goto out_drop_write; + goto out; old_cred = ovl_override_creds(dentry->d_sb); if (!lower_positive) @@ -926,8 +917,6 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir) if (ovl_dentry_upper(dentry)) ovl_copyattr(d_inode(dentry)); -out_drop_write: - ovl_drop_write(dentry); out: ovl_cache_free(&list); return err; @@ -1131,29 +1120,32 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, } } - err = ovl_want_write(old); - if (err) - goto out; - err = ovl_copy_up(old); if (err) - goto out_drop_write; + goto out; err = ovl_copy_up(new->d_parent); if (err) - goto out_drop_write; + goto out; if (!overwrite) { err = ovl_copy_up(new); if (err) - goto out_drop_write; + goto out; } else if (d_inode(new)) { err = ovl_nlink_start(new); if (err) - goto out_drop_write; + goto out; update_nlink = true; } + if (!update_nlink) { + /* ovl_nlink_start() took ovl_want_write() */ + err = ovl_want_write(old); + if (err) + goto out; + } + old_cred = ovl_override_creds(old->d_sb); if (!list_empty(&list)) { @@ -1219,7 +1211,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, } } else { if (!d_is_negative(newdentry)) { - if (!new_opaque || !ovl_is_whiteout(newdentry)) + if (!new_opaque || !ovl_upper_is_whiteout(ofs, newdentry)) goto out_dput; } else { if (flags & RENAME_EXCHANGE) @@ -1286,8 +1278,8 @@ out_revert_creds: revert_creds(old_cred); if (update_nlink) ovl_nlink_end(new); -out_drop_write: - ovl_drop_write(old); + else + ovl_drop_write(old); out: dput(opaquedir); ovl_cache_free(&list); diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 26b782c53910..7e16bbcad95e 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -23,12 +23,7 @@ static int ovl_encode_maybe_copy_up(struct dentry *dentry) if (ovl_dentry_upper(dentry)) return 0; - err = ovl_want_write(dentry); - if (!err) { - err = ovl_copy_up(dentry); - ovl_drop_write(dentry); - } - + err = ovl_copy_up(dentry); if (err) { pr_warn_ratelimited("failed to copy up on encode (%pd2, err=%i)\n", dentry, err); diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index ec3671ca140c..131621daeb13 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -15,10 +15,15 @@ #include <linux/fs.h> #include "overlayfs.h" +#include "../internal.h" /* for sb_init_dio_done_wq */ + struct ovl_aio_req { struct kiocb iocb; refcount_t ref; struct kiocb *orig_iocb; + /* used for aio completion */ + struct work_struct work; + long res; }; static struct kmem_cache *ovl_aio_request_cachep; @@ -235,6 +240,12 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence) return ret; } +static void ovl_file_modified(struct file *file) +{ + /* Update size/mtime */ + ovl_copyattr(file_inode(file)); +} + static void ovl_file_accessed(struct file *file) { struct inode *inode, *upperinode; @@ -263,20 +274,12 @@ static void ovl_file_accessed(struct file *file) touch_atime(&file->f_path); } -static rwf_t ovl_iocb_to_rwf(int ifl) +#define OVL_IOCB_MASK \ + (IOCB_NOWAIT | IOCB_HIPRI | IOCB_DSYNC | IOCB_SYNC | IOCB_APPEND) + +static rwf_t iocb_to_rw_flags(int flags) { - rwf_t flags = 0; - - if (ifl & IOCB_NOWAIT) - flags |= RWF_NOWAIT; - if (ifl & IOCB_HIPRI) - flags |= RWF_HIPRI; - if (ifl & IOCB_DSYNC) - flags |= RWF_DSYNC; - if (ifl & IOCB_SYNC) - flags |= RWF_SYNC; - - return flags; + return (__force rwf_t)(flags & OVL_IOCB_MASK); } static inline void ovl_aio_put(struct ovl_aio_req *aio_req) @@ -293,10 +296,8 @@ static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req) struct kiocb *orig_iocb = aio_req->orig_iocb; if (iocb->ki_flags & IOCB_WRITE) { - struct inode *inode = file_inode(orig_iocb->ki_filp); - kiocb_end_write(iocb); - ovl_copyattr(inode); + ovl_file_modified(orig_iocb->ki_filp); } orig_iocb->ki_pos = iocb->ki_pos; @@ -313,6 +314,37 @@ static void ovl_aio_rw_complete(struct kiocb *iocb, long res) orig_iocb->ki_complete(orig_iocb, res); } +static void ovl_aio_complete_work(struct work_struct *work) +{ + struct ovl_aio_req *aio_req = container_of(work, + struct ovl_aio_req, work); + + ovl_aio_rw_complete(&aio_req->iocb, aio_req->res); +} + +static void ovl_aio_queue_completion(struct kiocb *iocb, long res) +{ + struct ovl_aio_req *aio_req = container_of(iocb, + struct ovl_aio_req, iocb); + struct kiocb *orig_iocb = aio_req->orig_iocb; + + /* + * Punt to a work queue to serialize updates of mtime/size. + */ + aio_req->res = res; + INIT_WORK(&aio_req->work, ovl_aio_complete_work); + queue_work(file_inode(orig_iocb->ki_filp)->i_sb->s_dio_done_wq, + &aio_req->work); +} + +static int ovl_init_aio_done_wq(struct super_block *sb) +{ + if (sb->s_dio_done_wq) + return 0; + + return sb_init_dio_done_wq(sb); +} + static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter) { struct file *file = iocb->ki_filp; @@ -334,8 +366,9 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter) old_cred = ovl_override_creds(file_inode(file)->i_sb); if (is_sync_kiocb(iocb)) { - ret = vfs_iter_read(real.file, iter, &iocb->ki_pos, - ovl_iocb_to_rwf(iocb->ki_flags)); + rwf_t rwf = iocb_to_rw_flags(iocb->ki_flags); + + ret = vfs_iter_read(real.file, iter, &iocb->ki_pos, rwf); } else { struct ovl_aio_req *aio_req; @@ -401,15 +434,20 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) old_cred = ovl_override_creds(file_inode(file)->i_sb); if (is_sync_kiocb(iocb)) { + rwf_t rwf = iocb_to_rw_flags(ifl); + file_start_write(real.file); - ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, - ovl_iocb_to_rwf(ifl)); + ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, rwf); file_end_write(real.file); /* Update size */ - ovl_copyattr(inode); + ovl_file_modified(file); } else { struct ovl_aio_req *aio_req; + ret = ovl_init_aio_done_wq(inode->i_sb); + if (ret) + goto out; + ret = -ENOMEM; aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL); if (!aio_req) @@ -418,7 +456,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) aio_req->orig_iocb = iocb; kiocb_clone(&aio_req->iocb, iocb, get_file(real.file)); aio_req->iocb.ki_flags = ifl; - aio_req->iocb.ki_complete = ovl_aio_rw_complete; + aio_req->iocb.ki_complete = ovl_aio_queue_completion; refcount_set(&aio_req->ref, 2); kiocb_start_write(&aio_req->iocb); ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter); @@ -492,7 +530,7 @@ static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out, file_end_write(real.file); /* Update size */ - ovl_copyattr(inode); + ovl_file_modified(out); revert_creds(old_cred); fdput(real); @@ -573,7 +611,7 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len revert_creds(old_cred); /* Update size */ - ovl_copyattr(inode); + ovl_file_modified(file); fdput(real); @@ -657,7 +695,7 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in, revert_creds(old_cred); /* Update size */ - ovl_copyattr(inode_out); + ovl_file_modified(file_out); fdput(real_in); fdput(real_out); diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index b6e98a7d36ce..345b8f161ca4 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -32,10 +32,6 @@ int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, if (err) return err; - err = ovl_want_write(dentry); - if (err) - goto out; - if (attr->ia_valid & ATTR_SIZE) { /* Truncate should trigger data copy up as well */ full_copy_up = true; @@ -54,7 +50,7 @@ int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, winode = d_inode(upperdentry); err = get_write_access(winode); if (err) - goto out_drop_write; + goto out; } if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) @@ -78,6 +74,10 @@ int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, */ attr->ia_valid &= ~ATTR_OPEN; + err = ovl_want_write(dentry); + if (err) + goto out_put_write; + inode_lock(upperdentry->d_inode); old_cred = ovl_override_creds(dentry->d_sb); err = ovl_do_notify_change(ofs, upperdentry, attr); @@ -85,12 +85,12 @@ int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, if (!err) ovl_copyattr(dentry->d_inode); inode_unlock(upperdentry->d_inode); + ovl_drop_write(dentry); +out_put_write: if (winode) put_write_access(winode); } -out_drop_write: - ovl_drop_write(dentry); out: return err; } @@ -339,130 +339,6 @@ static const char *ovl_get_link(struct dentry *dentry, return p; } -bool ovl_is_private_xattr(struct super_block *sb, const char *name) -{ - struct ovl_fs *ofs = OVL_FS(sb); - - if (ofs->config.userxattr) - return strncmp(name, OVL_XATTR_USER_PREFIX, - sizeof(OVL_XATTR_USER_PREFIX) - 1) == 0; - else - return strncmp(name, OVL_XATTR_TRUSTED_PREFIX, - sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) == 0; -} - -int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, - const void *value, size_t size, int flags) -{ - int err; - struct ovl_fs *ofs = OVL_FS(dentry->d_sb); - struct dentry *upperdentry = ovl_i_dentry_upper(inode); - struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); - struct path realpath; - const struct cred *old_cred; - - err = ovl_want_write(dentry); - if (err) - goto out; - - if (!value && !upperdentry) { - ovl_path_lower(dentry, &realpath); - old_cred = ovl_override_creds(dentry->d_sb); - err = vfs_getxattr(mnt_idmap(realpath.mnt), realdentry, name, NULL, 0); - revert_creds(old_cred); - if (err < 0) - goto out_drop_write; - } - - if (!upperdentry) { - err = ovl_copy_up(dentry); - if (err) - goto out_drop_write; - - realdentry = ovl_dentry_upper(dentry); - } - - old_cred = ovl_override_creds(dentry->d_sb); - if (value) { - err = ovl_do_setxattr(ofs, realdentry, name, value, size, - flags); - } else { - WARN_ON(flags != XATTR_REPLACE); - err = ovl_do_removexattr(ofs, realdentry, name); - } - revert_creds(old_cred); - - /* copy c/mtime */ - ovl_copyattr(inode); - -out_drop_write: - ovl_drop_write(dentry); -out: - return err; -} - -int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, - void *value, size_t size) -{ - ssize_t res; - const struct cred *old_cred; - struct path realpath; - - ovl_i_path_real(inode, &realpath); - old_cred = ovl_override_creds(dentry->d_sb); - res = vfs_getxattr(mnt_idmap(realpath.mnt), realpath.dentry, name, value, size); - revert_creds(old_cred); - return res; -} - -static bool ovl_can_list(struct super_block *sb, const char *s) -{ - /* Never list private (.overlay) */ - if (ovl_is_private_xattr(sb, s)) - return false; - - /* List all non-trusted xattrs */ - if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) - return true; - - /* list other trusted for superuser only */ - return ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN); -} - -ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) -{ - struct dentry *realdentry = ovl_dentry_real(dentry); - ssize_t res; - size_t len; - char *s; - const struct cred *old_cred; - - old_cred = ovl_override_creds(dentry->d_sb); - res = vfs_listxattr(realdentry, list, size); - revert_creds(old_cred); - if (res <= 0 || size == 0) - return res; - - /* filter out private xattrs */ - for (s = list, len = res; len;) { - size_t slen = strnlen(s, len) + 1; - - /* underlying fs providing us with an broken xattr list? */ - if (WARN_ON(slen > len)) - return -EIO; - - len -= slen; - if (!ovl_can_list(dentry->d_sb, s)) { - res -= slen; - memmove(s, s + slen, len); - } else { - s += slen; - } - } - - return res; -} - #ifdef CONFIG_FS_POSIX_ACL /* * Apply the idmapping of the layer to POSIX ACLs. The caller must pass a clone @@ -611,10 +487,6 @@ static int ovl_set_or_remove_acl(struct dentry *dentry, struct inode *inode, struct dentry *upperdentry = ovl_dentry_upper(dentry); struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); - err = ovl_want_write(dentry); - if (err) - return err; - /* * If ACL is to be removed from a lower file, check if it exists in * the first place before copying it up. @@ -630,7 +502,7 @@ static int ovl_set_or_remove_acl(struct dentry *dentry, struct inode *inode, revert_creds(old_cred); if (IS_ERR(real_acl)) { err = PTR_ERR(real_acl); - goto out_drop_write; + goto out; } posix_acl_release(real_acl); } @@ -638,23 +510,26 @@ static int ovl_set_or_remove_acl(struct dentry *dentry, struct inode *inode, if (!upperdentry) { err = ovl_copy_up(dentry); if (err) - goto out_drop_write; + goto out; realdentry = ovl_dentry_upper(dentry); } + err = ovl_want_write(dentry); + if (err) + goto out; + old_cred = ovl_override_creds(dentry->d_sb); if (acl) err = ovl_do_set_acl(ofs, realdentry, acl_name, acl); else err = ovl_do_remove_acl(ofs, realdentry, acl_name); revert_creds(old_cred); + ovl_drop_write(dentry); /* copy c/mtime */ ovl_copyattr(inode); - -out_drop_write: - ovl_drop_write(dentry); +out: return err; } @@ -778,14 +653,14 @@ int ovl_fileattr_set(struct mnt_idmap *idmap, unsigned int flags; int err; - err = ovl_want_write(dentry); - if (err) - goto out; - err = ovl_copy_up(dentry); if (!err) { ovl_path_real(dentry, &upperpath); + err = ovl_want_write(dentry); + if (err) + goto out; + old_cred = ovl_override_creds(inode->i_sb); /* * Store immutable/append-only flags in xattr and clear them @@ -798,6 +673,7 @@ int ovl_fileattr_set(struct mnt_idmap *idmap, if (!err) err = ovl_real_fileattr_set(&upperpath, fa); revert_creds(old_cred); + ovl_drop_write(dentry); /* * Merge real inode flags with inode flags read from @@ -812,7 +688,6 @@ int ovl_fileattr_set(struct mnt_idmap *idmap, /* Update ctime */ ovl_copyattr(inode); } - ovl_drop_write(dentry); out: return err; } diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 80391c687c2a..03bc8d5dfa31 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -251,7 +251,10 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d, err = -EREMOTE; goto out_err; } - if (ovl_is_whiteout(this)) { + + path.dentry = this; + path.mnt = d->mnt; + if (ovl_path_is_whiteout(OVL_FS(d->sb), &path)) { d->stop = d->opaque = true; goto put_and_out; } @@ -264,8 +267,6 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d, goto put_and_out; } - path.dentry = this; - path.mnt = d->mnt; if (!d_can_lookup(this)) { if (d->is_dir || !last_element) { d->stop = true; @@ -438,7 +439,7 @@ int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, else if (IS_ERR(origin)) return PTR_ERR(origin); - if (upperdentry && !ovl_is_whiteout(upperdentry) && + if (upperdentry && !ovl_upper_is_whiteout(ofs, upperdentry) && inode_wrong_type(d_inode(upperdentry), d_inode(origin)->i_mode)) goto invalid; @@ -507,6 +508,19 @@ static int ovl_verify_fh(struct ovl_fs *ofs, struct dentry *dentry, return err; } +int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, + enum ovl_xattr ox, const struct ovl_fh *fh, + bool is_upper, bool set) +{ + int err; + + err = ovl_verify_fh(ofs, dentry, ox, fh); + if (set && err == -ENODATA) + err = ovl_setxattr(ofs, dentry, ox, fh->buf, fh->fb.len); + + return err; +} + /* * Verify that @real dentry matches the file handle stored in xattr @name. * @@ -515,9 +529,9 @@ static int ovl_verify_fh(struct ovl_fs *ofs, struct dentry *dentry, * * Return 0 on match, -ESTALE on mismatch, -ENODATA on no xattr, < 0 on error. */ -int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, - enum ovl_xattr ox, struct dentry *real, bool is_upper, - bool set) +int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry, + enum ovl_xattr ox, struct dentry *real, + bool is_upper, bool set) { struct inode *inode; struct ovl_fh *fh; @@ -530,9 +544,7 @@ int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, goto fail; } - err = ovl_verify_fh(ofs, dentry, ox, fh); - if (set && err == -ENODATA) - err = ovl_setxattr(ofs, dentry, ox, fh->buf, fh->fb.len); + err = ovl_verify_set_fh(ofs, dentry, ox, fh, is_upper, set); if (err) goto fail; @@ -548,6 +560,7 @@ fail: goto out; } + /* Get upper dentry from index */ struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index, bool connected) @@ -684,7 +697,7 @@ orphan: goto out; } -static int ovl_get_index_name_fh(struct ovl_fh *fh, struct qstr *name) +int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name) { char *n, *s; @@ -873,20 +886,27 @@ int ovl_path_next(int idx, struct dentry *dentry, struct path *path) static int ovl_fix_origin(struct ovl_fs *ofs, struct dentry *dentry, struct dentry *lower, struct dentry *upper) { + const struct ovl_fh *fh; int err; if (ovl_check_origin_xattr(ofs, upper)) return 0; + fh = ovl_get_origin_fh(ofs, lower); + if (IS_ERR(fh)) + return PTR_ERR(fh); + err = ovl_want_write(dentry); if (err) - return err; + goto out; - err = ovl_set_origin(ofs, lower, upper); + err = ovl_set_origin_fh(ofs, fh, upper); if (!err) err = ovl_set_impure(dentry->d_parent, upper->d_parent); ovl_drop_write(dentry); +out: + kfree(fh); return err; } @@ -1383,7 +1403,11 @@ bool ovl_lower_positive(struct dentry *dentry) break; } } else { - positive = !ovl_is_whiteout(this); + struct path path = { + .dentry = this, + .mnt = parentpath->layer->mnt, + }; + positive = !ovl_path_is_whiteout(OVL_FS(dentry->d_sb), &path); done = true; dput(this); } diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 9817b2dcb132..ca88b2636a57 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -28,7 +28,16 @@ enum ovl_path_type { #define OVL_XATTR_NAMESPACE "overlay." #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE +#define OVL_XATTR_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE +#define OVL_XATTR_USER_PREFIX_LEN (sizeof(OVL_XATTR_USER_PREFIX) - 1) + +#define OVL_XATTR_ESCAPE_PREFIX OVL_XATTR_NAMESPACE +#define OVL_XATTR_ESCAPE_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_PREFIX) - 1) +#define OVL_XATTR_ESCAPE_TRUSTED_PREFIX OVL_XATTR_TRUSTED_PREFIX OVL_XATTR_ESCAPE_PREFIX +#define OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_TRUSTED_PREFIX) - 1) +#define OVL_XATTR_ESCAPE_USER_PREFIX OVL_XATTR_USER_PREFIX OVL_XATTR_ESCAPE_PREFIX +#define OVL_XATTR_ESCAPE_USER_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_USER_PREFIX) - 1) enum ovl_xattr { OVL_XATTR_OPAQUE, @@ -40,6 +49,8 @@ enum ovl_xattr { OVL_XATTR_UUID, OVL_XATTR_METACOPY, OVL_XATTR_PROTATTR, + OVL_XATTR_XWHITEOUT, + OVL_XATTR_XWHITEOUTS, }; enum ovl_inode_flag { @@ -398,6 +409,10 @@ static inline bool ovl_open_flags_need_copy_up(int flags) } /* util.c */ +int ovl_get_write_access(struct dentry *dentry); +void ovl_put_write_access(struct dentry *dentry); +void ovl_start_write(struct dentry *dentry); +void ovl_end_write(struct dentry *dentry); int ovl_want_write(struct dentry *dentry); void ovl_drop_write(struct dentry *dentry); struct dentry *ovl_workdir(struct dentry *dentry); @@ -460,6 +475,7 @@ void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); void ovl_dir_modified(struct dentry *dentry, bool impurity); u64 ovl_inode_version_get(struct inode *inode); bool ovl_is_whiteout(struct dentry *dentry); +bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path); struct file *ovl_path_open(const struct path *path, int flags); int ovl_copy_up_start(struct dentry *dentry, int flags); void ovl_copy_up_end(struct dentry *dentry); @@ -467,9 +483,21 @@ bool ovl_already_copied_up(struct dentry *dentry, int flags); bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path, enum ovl_xattr ox); bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path); +bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path); +bool ovl_path_check_xwhiteouts_xattr(struct ovl_fs *ofs, const struct path *path); bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs, const struct path *upperpath); +static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs, + struct dentry *upperdentry) +{ + struct path upperpath = { + .dentry = upperdentry, + .mnt = ovl_upper_mnt(ofs), + }; + return ovl_path_is_whiteout(ofs, &upperpath); +} + static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *upperdentry) { @@ -624,11 +652,15 @@ struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh, int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, struct dentry *upperdentry, struct ovl_path **stackp); int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, - enum ovl_xattr ox, struct dentry *real, bool is_upper, - bool set); + enum ovl_xattr ox, const struct ovl_fh *fh, + bool is_upper, bool set); +int ovl_verify_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry, + enum ovl_xattr ox, struct dentry *real, + bool is_upper, bool set); struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index, bool connected); int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); +int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name); int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin, struct qstr *name); struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); @@ -640,17 +672,24 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags); bool ovl_lower_positive(struct dentry *dentry); +static inline int ovl_verify_origin_fh(struct ovl_fs *ofs, struct dentry *upper, + const struct ovl_fh *fh, bool set) +{ + return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, fh, false, set); +} + static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, struct dentry *origin, bool set) { - return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin, - false, set); + return ovl_verify_origin_xattr(ofs, upper, OVL_XATTR_ORIGIN, origin, + false, set); } static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, struct dentry *upper, bool set) { - return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set); + return ovl_verify_origin_xattr(ofs, index, OVL_XATTR_UPPER, upper, + true, set); } /* readdir.c */ @@ -684,17 +723,8 @@ int ovl_set_nlink_lower(struct dentry *dentry); unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, struct dentry *upperdentry, unsigned int fallback); -int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, - struct iattr *attr); -int ovl_getattr(struct mnt_idmap *idmap, const struct path *path, - struct kstat *stat, u32 request_mask, unsigned int flags); int ovl_permission(struct mnt_idmap *idmap, struct inode *inode, int mask); -int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, - const void *value, size_t size, int flags); -int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, - void *value, size_t size); -ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); #ifdef CONFIG_FS_POSIX_ACL struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap, @@ -815,8 +845,9 @@ int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentr int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat); struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real, bool is_upper); -int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower, - struct dentry *upper); +struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin); +int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh, + struct dentry *upper); /* export.c */ extern const struct export_operations ovl_export_operations; @@ -830,3 +861,12 @@ static inline bool ovl_force_readonly(struct ovl_fs *ofs) { return (!ovl_upper_mnt(ofs) || !ofs->workdir); } + +/* xattr.c */ + +const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs); +int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *attr); +int ovl_getattr(struct mnt_idmap *idmap, const struct path *path, + struct kstat *stat, u32 request_mask, unsigned int flags); +ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index f6ff23fd101c..ddab9ea267d1 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -43,8 +43,10 @@ module_param_named(metacopy, ovl_metacopy_def, bool, 0644); MODULE_PARM_DESC(metacopy, "Default to on or off for the metadata only copy up feature"); -enum { +enum ovl_opt { Opt_lowerdir, + Opt_lowerdir_add, + Opt_datadir_add, Opt_upperdir, Opt_workdir, Opt_default_permissions, @@ -140,8 +142,11 @@ static int ovl_verity_mode_def(void) #define fsparam_string_empty(NAME, OPT) \ __fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL) + const struct fs_parameter_spec ovl_parameter_spec[] = { fsparam_string_empty("lowerdir", Opt_lowerdir), + fsparam_string("lowerdir+", Opt_lowerdir_add), + fsparam_string("datadir+", Opt_datadir_add), fsparam_string("upperdir", Opt_upperdir), fsparam_string("workdir", Opt_workdir), fsparam_flag("default_permissions", Opt_default_permissions), @@ -238,19 +243,8 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) pr_err("failed to resolve '%s': %i\n", name, err); goto out; } - err = -EINVAL; - if (ovl_dentry_weird(path->dentry)) { - pr_err("filesystem on '%s' not supported\n", name); - goto out_put; - } - if (!d_is_dir(path->dentry)) { - pr_err("'%s' not a directory\n", name); - goto out_put; - } return 0; -out_put: - path_put_init(path); out: return err; } @@ -268,7 +262,7 @@ static void ovl_unescape(char *s) } } -static int ovl_mount_dir(const char *name, struct path *path, bool upper) +static int ovl_mount_dir(const char *name, struct path *path) { int err = -ENOMEM; char *tmp = kstrdup(name, GFP_KERNEL); @@ -276,68 +270,147 @@ static int ovl_mount_dir(const char *name, struct path *path, bool upper) if (tmp) { ovl_unescape(tmp); err = ovl_mount_dir_noesc(tmp, path); - - if (!err && upper && path->dentry->d_flags & DCACHE_OP_REAL) { - pr_err("filesystem on '%s' not supported as upperdir\n", - tmp); - path_put_init(path); - err = -EINVAL; - } kfree(tmp); } return err; } -static int ovl_parse_param_upperdir(const char *name, struct fs_context *fc, - bool workdir) +static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path, + enum ovl_opt layer, const char *name, bool upper) { - int err; - struct ovl_fs *ofs = fc->s_fs_info; - struct ovl_config *config = &ofs->config; struct ovl_fs_context *ctx = fc->fs_private; - struct path path; - char *dup; - err = ovl_mount_dir(name, &path, true); - if (err) - return err; + if (ovl_dentry_weird(path->dentry)) + return invalfc(fc, "filesystem on %s not supported", name); + + if (!d_is_dir(path->dentry)) + return invalfc(fc, "%s is not a directory", name); + /* * Check whether upper path is read-only here to report failures * early. Don't forget to recheck when the superblock is created * as the mount attributes could change. */ - if (__mnt_is_readonly(path.mnt)) { - path_put(&path); - return -EINVAL; + if (upper) { + if (path->dentry->d_flags & DCACHE_OP_REAL) + return invalfc(fc, "filesystem on %s not supported as upperdir", name); + if (__mnt_is_readonly(path->mnt)) + return invalfc(fc, "filesystem on %s is read-only", name); + } else { + if (ctx->lowerdir_all && layer != Opt_lowerdir) + return invalfc(fc, "lowerdir+ and datadir+ cannot follow lowerdir"); + if (ctx->nr_data && layer == Opt_lowerdir_add) + return invalfc(fc, "regular lower layers cannot follow data layers"); + if (ctx->nr == OVL_MAX_STACK) + return invalfc(fc, "too many lower directories, limit is %d", + OVL_MAX_STACK); } + return 0; +} - dup = kstrdup(name, GFP_KERNEL); - if (!dup) { - path_put(&path); +static int ovl_ctx_realloc_lower(struct fs_context *fc) +{ + struct ovl_fs_context *ctx = fc->fs_private; + struct ovl_fs_context_layer *l; + size_t nr; + + if (ctx->nr < ctx->capacity) + return 0; + + nr = min_t(size_t, max(4096 / sizeof(*l), ctx->capacity * 2), + OVL_MAX_STACK); + l = krealloc_array(ctx->lower, nr, sizeof(*l), GFP_KERNEL_ACCOUNT); + if (!l) return -ENOMEM; + + ctx->lower = l; + ctx->capacity = nr; + return 0; +} + +static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer, + struct path *path, char **pname) +{ + struct ovl_fs *ofs = fc->s_fs_info; + struct ovl_config *config = &ofs->config; + struct ovl_fs_context *ctx = fc->fs_private; + struct ovl_fs_context_layer *l; + + switch (layer) { + case Opt_workdir: + swap(config->workdir, *pname); + swap(ctx->work, *path); + break; + case Opt_upperdir: + swap(config->upperdir, *pname); + swap(ctx->upper, *path); + break; + case Opt_datadir_add: + ctx->nr_data++; + fallthrough; + case Opt_lowerdir_add: + WARN_ON(ctx->nr >= ctx->capacity); + l = &ctx->lower[ctx->nr++]; + memset(l, 0, sizeof(*l)); + swap(l->name, *pname); + swap(l->path, *path); + break; + default: + WARN_ON(1); } +} - if (workdir) { - kfree(config->workdir); - config->workdir = dup; - path_put(&ctx->work); - ctx->work = path; - } else { - kfree(config->upperdir); - config->upperdir = dup; - path_put(&ctx->upper); - ctx->upper = path; +static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param, + enum ovl_opt layer) +{ + char *name = kstrdup(param->string, GFP_KERNEL); + bool upper = (layer == Opt_upperdir || layer == Opt_workdir); + struct path path; + int err; + + if (!name) + return -ENOMEM; + + if (upper) + err = ovl_mount_dir(name, &path); + else + err = ovl_mount_dir_noesc(name, &path); + if (err) + goto out_free; + + err = ovl_mount_dir_check(fc, &path, layer, name, upper); + if (err) + goto out_put; + + if (!upper) { + err = ovl_ctx_realloc_lower(fc); + if (err) + goto out_put; } - return 0; + + /* Store the user provided path string in ctx to show in mountinfo */ + ovl_add_layer(fc, layer, &path, &name); + +out_put: + path_put(&path); +out_free: + kfree(name); + return err; } -static void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx) +static void ovl_reset_lowerdirs(struct ovl_fs_context *ctx) { - for (size_t nr = 0; nr < ctx->nr; nr++) { - path_put(&ctx->lower[nr].path); - kfree(ctx->lower[nr].name); - ctx->lower[nr].name = NULL; + struct ovl_fs_context_layer *l = ctx->lower; + + // Reset old user provided lowerdir string + kfree(ctx->lowerdir_all); + ctx->lowerdir_all = NULL; + + for (size_t nr = 0; nr < ctx->nr; nr++, l++) { + path_put(&l->path); + kfree(l->name); + l->name = NULL; } ctx->nr = 0; ctx->nr_data = 0; @@ -346,7 +419,7 @@ static void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx) /* * Parse lowerdir= mount option: * - * (1) lowerdir=/lower1:/lower2:/lower3::/data1::/data2 + * e.g.: lowerdir=/lower1:/lower2:/lower3::/data1::/data2 * Set "/lower1", "/lower2", and "/lower3" as lower layers and * "/data1" and "/data2" as data lower layers. Any existing lower * layers are replaced. @@ -356,9 +429,9 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) int err; struct ovl_fs_context *ctx = fc->fs_private; struct ovl_fs_context_layer *l; - char *dup = NULL, *dup_iter; + char *dup = NULL, *iter; ssize_t nr_lower = 0, nr = 0, nr_data = 0; - bool append = false, data_layer = false; + bool data_layer = false; /* * Ensure we're backwards compatible with mount(2) @@ -366,16 +439,21 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) */ /* drop all existing lower layers */ - if (!*name) { - ovl_parse_param_drop_lowerdir(ctx); + ovl_reset_lowerdirs(ctx); + + if (!*name) return 0; - } if (*name == ':') { pr_err("cannot append lower layer"); return -EINVAL; } + // Store user provided lowerdir string to show in mount options + ctx->lowerdir_all = kstrdup(name, GFP_KERNEL); + if (!ctx->lowerdir_all) + return -ENOMEM; + dup = kstrdup(name, GFP_KERNEL); if (!dup) return -ENOMEM; @@ -385,36 +463,11 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) if (nr_lower < 0) goto out_err; - if ((nr_lower > OVL_MAX_STACK) || - (append && (size_add(ctx->nr, nr_lower) > OVL_MAX_STACK))) { + if (nr_lower > OVL_MAX_STACK) { pr_err("too many lower directories, limit is %d\n", OVL_MAX_STACK); goto out_err; } - if (!append) - ovl_parse_param_drop_lowerdir(ctx); - - /* - * (1) append - * - * We want nr <= nr_lower <= capacity We know nr > 0 and nr <= - * capacity. If nr == 0 this wouldn't be append. If nr + - * nr_lower is <= capacity then nr <= nr_lower <= capacity - * already holds. If nr + nr_lower exceeds capacity, we realloc. - * - * (2) replace - * - * Ensure we're backwards compatible with mount(2) which allows - * "lowerdir=/a:/b:/c,lowerdir=/d:/e:/f" causing the last - * specified lowerdir mount option to win. - * - * We want nr <= nr_lower <= capacity We know either (i) nr == 0 - * or (ii) nr > 0. We also know nr_lower > 0. The capacity - * could've been changed multiple times already so we only know - * nr <= capacity. If nr + nr_lower > capacity we realloc, - * otherwise nr <= nr_lower <= capacity holds already. - */ - nr_lower += ctx->nr; if (nr_lower > ctx->capacity) { err = -ENOMEM; l = krealloc_array(ctx->lower, nr_lower, sizeof(*ctx->lower), @@ -426,41 +479,21 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) ctx->capacity = nr_lower; } - /* - * (3) By (1) and (2) we know nr <= nr_lower <= capacity. - * (4) If ctx->nr == 0 => replace - * We have verified above that the lowerdir mount option - * isn't an append, i.e., the lowerdir mount option - * doesn't start with ":" or "::". - * (4.1) The lowerdir mount options only contains regular lower - * layers ":". - * => Nothing to verify. - * (4.2) The lowerdir mount options contains regular ":" and - * data "::" layers. - * => We need to verify that data lower layers "::" aren't - * followed by regular ":" lower layers - * (5) If ctx->nr > 0 => append - * We know that there's at least one regular layer - * otherwise we would've failed when parsing the previous - * lowerdir mount option. - * (5.1) The lowerdir mount option is a regular layer ":" append - * => We need to verify that no data layers have been - * specified before. - * (5.2) The lowerdir mount option is a data layer "::" append - * We know that there's at least one regular layer or - * other data layers. => There's nothing to verify. - */ - dup_iter = dup; - for (nr = ctx->nr; nr < nr_lower; nr++) { - l = &ctx->lower[nr]; + iter = dup; + l = ctx->lower; + for (nr = 0; nr < nr_lower; nr++, l++) { memset(l, 0, sizeof(*l)); - err = ovl_mount_dir(dup_iter, &l->path, false); + err = ovl_mount_dir(iter, &l->path); + if (err) + goto out_put; + + err = ovl_mount_dir_check(fc, &l->path, Opt_lowerdir, iter, false); if (err) goto out_put; err = -ENOMEM; - l->name = kstrdup(dup_iter, GFP_KERNEL_ACCOUNT); + l->name = kstrdup(iter, GFP_KERNEL_ACCOUNT); if (!l->name) goto out_put; @@ -472,8 +505,8 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) break; err = -EINVAL; - dup_iter = strchr(dup_iter, '\0') + 1; - if (*dup_iter) { + iter = strchr(iter, '\0') + 1; + if (*iter) { /* * This is a regular layer so we require that * there are no data layers. @@ -489,7 +522,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) /* This is a data lower layer. */ data_layer = true; - dup_iter++; + iter++; } ctx->nr = nr_lower; ctx->nr_data += nr_data; @@ -497,21 +530,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) return 0; out_put: - /* - * We know nr >= ctx->nr < nr_lower. If we failed somewhere - * we want to undo until nr == ctx->nr. This is correct for - * both ctx->nr == 0 and ctx->nr > 0. - */ - for (; nr >= ctx->nr; nr--) { - l = &ctx->lower[nr]; - kfree(l->name); - l->name = NULL; - path_put(&l->path); - - /* don't overflow */ - if (nr == 0) - break; - } + ovl_reset_lowerdirs(ctx); out_err: kfree(dup); @@ -556,11 +575,11 @@ static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param) case Opt_lowerdir: err = ovl_parse_param_lowerdir(param->string, fc); break; + case Opt_lowerdir_add: + case Opt_datadir_add: case Opt_upperdir: - fallthrough; case Opt_workdir: - err = ovl_parse_param_upperdir(param->string, fc, - (Opt_workdir == opt)); + err = ovl_parse_layer(fc, param, opt); break; case Opt_default_permissions: config->default_permissions = true; @@ -617,7 +636,7 @@ static int ovl_get_tree(struct fs_context *fc) static inline void ovl_fs_context_free(struct ovl_fs_context *ctx) { - ovl_parse_param_drop_lowerdir(ctx); + ovl_reset_lowerdirs(ctx); path_put(&ctx->upper); path_put(&ctx->work); kfree(ctx->lower); @@ -933,23 +952,28 @@ int ovl_show_options(struct seq_file *m, struct dentry *dentry) { struct super_block *sb = dentry->d_sb; struct ovl_fs *ofs = OVL_FS(sb); - size_t nr, nr_merged_lower = ofs->numlayer - ofs->numdatalayer; + size_t nr, nr_merged_lower, nr_lower = 0; + char **lowerdirs = ofs->config.lowerdirs; /* - * lowerdirs[] starts from offset 1, then - * >= 0 regular lower layers prefixed with : and - * >= 0 data-only lower layers prefixed with :: - * - * we need to escase comma and space like seq_show_option() does and - * we also need to escape the colon separator from lowerdir paths. + * lowerdirs[0] holds the colon separated list that user provided + * with lowerdir mount option. + * lowerdirs[1..numlayer] hold the lowerdir paths that were added + * using the lowerdir+ and datadir+ mount options. + * For now, we do not allow mixing the legacy lowerdir mount option + * with the new lowerdir+ and datadir+ mount options. */ - seq_puts(m, ",lowerdir="); - for (nr = 1; nr < ofs->numlayer; nr++) { - if (nr > 1) - seq_putc(m, ':'); - if (nr >= nr_merged_lower) - seq_putc(m, ':'); - seq_escape(m, ofs->config.lowerdirs[nr], ":, \t\n\\"); + if (lowerdirs[0]) { + seq_show_option(m, "lowerdir", lowerdirs[0]); + } else { + nr_lower = ofs->numlayer; + nr_merged_lower = nr_lower - ofs->numdatalayer; + } + for (nr = 1; nr < nr_lower; nr++) { + if (nr < nr_merged_lower) + seq_show_option(m, "lowerdir+", lowerdirs[nr]); + else + seq_show_option(m, "datadir+", lowerdirs[nr]); } if (ofs->config.upperdir) { seq_show_option(m, "upperdir", ofs->config.upperdir); diff --git a/fs/overlayfs/params.h b/fs/overlayfs/params.h index 8750da68ab2a..c96d93982021 100644 --- a/fs/overlayfs/params.h +++ b/fs/overlayfs/params.h @@ -32,6 +32,7 @@ struct ovl_fs_context { size_t nr_data; struct ovl_opt_set set; struct ovl_fs_context_layer *lower; + char *lowerdir_all; /* user provided lowerdir string */ }; int ovl_init_fs_context(struct fs_context *fc); diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index de39e067ae65..a490fc47c3e7 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -25,6 +25,7 @@ struct ovl_cache_entry { struct ovl_cache_entry *next_maybe_whiteout; bool is_upper; bool is_whiteout; + bool check_xwhiteout; char name[]; }; @@ -47,6 +48,7 @@ struct ovl_readdir_data { int err; bool is_upper; bool d_type_supported; + bool in_xwhiteouts_dir; }; struct ovl_dir_file { @@ -162,6 +164,8 @@ static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd, p->ino = 0; p->is_upper = rdd->is_upper; p->is_whiteout = false; + /* Defer check for overlay.whiteout to ovl_iterate() */ + p->check_xwhiteout = rdd->in_xwhiteouts_dir && d_type == DT_REG; if (d_type == DT_CHR) { p->next_maybe_whiteout = rdd->first_maybe_whiteout; @@ -301,6 +305,8 @@ static inline int ovl_dir_read(const struct path *realpath, if (IS_ERR(realfile)) return PTR_ERR(realfile); + rdd->in_xwhiteouts_dir = rdd->dentry && + ovl_path_check_xwhiteouts_xattr(OVL_FS(rdd->dentry->d_sb), realpath); rdd->first_maybe_whiteout = NULL; rdd->ctx.pos = 0; do { @@ -447,7 +453,7 @@ static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid, } /* - * Set d_ino for upper entries. Non-upper entries should always report + * Set d_ino for upper entries if needed. Non-upper entries should always report * the uppermost real inode ino and should not call this function. * * When not all layer are on same fs, report real ino also for upper. @@ -455,8 +461,11 @@ static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid, * When all layers are on the same fs, and upper has a reference to * copy up origin, call vfs_getattr() on the overlay entry to make * sure that d_ino will be consistent with st_ino from stat(2). + * + * Also checks the overlay.whiteout xattr by doing a full lookup which will return + * negative in this case. */ -static int ovl_cache_update_ino(const struct path *path, struct ovl_cache_entry *p) +static int ovl_cache_update(const struct path *path, struct ovl_cache_entry *p, bool update_ino) { struct dentry *dir = path->dentry; @@ -467,7 +476,7 @@ static int ovl_cache_update_ino(const struct path *path, struct ovl_cache_entry int xinobits = ovl_xino_bits(ofs); int err = 0; - if (!ovl_same_dev(ofs)) + if (!ovl_same_dev(ofs) && !p->check_xwhiteout) goto out; if (p->name[0] == '.') { @@ -481,6 +490,7 @@ static int ovl_cache_update_ino(const struct path *path, struct ovl_cache_entry goto get; } } + /* This checks also for xwhiteouts */ this = lookup_one(mnt_idmap(path->mnt), p->name, dir, p->len); if (IS_ERR_OR_NULL(this) || !this->d_inode) { /* Mark a stale entry */ @@ -494,6 +504,9 @@ static int ovl_cache_update_ino(const struct path *path, struct ovl_cache_entry } get: + if (!ovl_same_dev(ofs) || !update_ino) + goto out; + type = ovl_path_type(this); if (OVL_TYPE_ORIGIN(type)) { struct kstat stat; @@ -572,7 +585,7 @@ static int ovl_dir_read_impure(const struct path *path, struct list_head *list, list_for_each_entry_safe(p, n, list, l_node) { if (strcmp(p->name, ".") != 0 && strcmp(p->name, "..") != 0) { - err = ovl_cache_update_ino(path, p); + err = ovl_cache_update(path, p, true); if (err) return err; } @@ -778,13 +791,13 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) while (od->cursor != &od->cache->entries) { p = list_entry(od->cursor, struct ovl_cache_entry, l_node); if (!p->is_whiteout) { - if (!p->ino) { - err = ovl_cache_update_ino(&file->f_path, p); + if (!p->ino || p->check_xwhiteout) { + err = ovl_cache_update(&file->f_path, p, !p->ino); if (err) goto out; } } - /* ovl_cache_update_ino() sets is_whiteout on stale entry */ + /* ovl_cache_update() sets is_whiteout on stale entry */ if (!p->is_whiteout) { if (!dir_emit(ctx, p->name, p->len, p->ino, p->type)) break; diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 17864a8d2b85..a0967bb25003 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -445,68 +445,6 @@ static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) return ok; } -static int ovl_own_xattr_get(const struct xattr_handler *handler, - struct dentry *dentry, struct inode *inode, - const char *name, void *buffer, size_t size) -{ - return -EOPNOTSUPP; -} - -static int ovl_own_xattr_set(const struct xattr_handler *handler, - struct mnt_idmap *idmap, - struct dentry *dentry, struct inode *inode, - const char *name, const void *value, - size_t size, int flags) -{ - return -EOPNOTSUPP; -} - -static int ovl_other_xattr_get(const struct xattr_handler *handler, - struct dentry *dentry, struct inode *inode, - const char *name, void *buffer, size_t size) -{ - return ovl_xattr_get(dentry, inode, name, buffer, size); -} - -static int ovl_other_xattr_set(const struct xattr_handler *handler, - struct mnt_idmap *idmap, - struct dentry *dentry, struct inode *inode, - const char *name, const void *value, - size_t size, int flags) -{ - return ovl_xattr_set(dentry, inode, name, value, size, flags); -} - -static const struct xattr_handler ovl_own_trusted_xattr_handler = { - .prefix = OVL_XATTR_TRUSTED_PREFIX, - .get = ovl_own_xattr_get, - .set = ovl_own_xattr_set, -}; - -static const struct xattr_handler ovl_own_user_xattr_handler = { - .prefix = OVL_XATTR_USER_PREFIX, - .get = ovl_own_xattr_get, - .set = ovl_own_xattr_set, -}; - -static const struct xattr_handler ovl_other_xattr_handler = { - .prefix = "", /* catch all */ - .get = ovl_other_xattr_get, - .set = ovl_other_xattr_set, -}; - -static const struct xattr_handler * const ovl_trusted_xattr_handlers[] = { - &ovl_own_trusted_xattr_handler, - &ovl_other_xattr_handler, - NULL -}; - -static const struct xattr_handler * const ovl_user_xattr_handlers[] = { - &ovl_own_user_xattr_handler, - &ovl_other_xattr_handler, - NULL -}; - static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, struct inode **ptrap, const char *name) { @@ -647,7 +585,7 @@ static int ovl_check_rename_whiteout(struct ovl_fs *ofs) if (IS_ERR(whiteout)) goto cleanup_temp; - err = ovl_is_whiteout(whiteout); + err = ovl_upper_is_whiteout(ofs, whiteout); /* Best effort cleanup of whiteout and temp file */ if (err) @@ -887,15 +825,20 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, { struct vfsmount *mnt = ovl_upper_mnt(ofs); struct dentry *indexdir; + struct dentry *origin = ovl_lowerstack(oe)->dentry; + const struct ovl_fh *fh; int err; + fh = ovl_get_origin_fh(ofs, origin); + if (IS_ERR(fh)) + return PTR_ERR(fh); + err = mnt_want_write(mnt); if (err) - return err; + goto out_free_fh; /* Verify lower root is upper root origin */ - err = ovl_verify_origin(ofs, upperpath->dentry, - ovl_lowerstack(oe)->dentry, true); + err = ovl_verify_origin_fh(ofs, upperpath->dentry, fh, true); if (err) { pr_err("failed to verify upper root origin\n"); goto out; @@ -927,9 +870,10 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, * directory entries. */ if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { - err = ovl_verify_set_fh(ofs, ofs->indexdir, - OVL_XATTR_ORIGIN, - upperpath->dentry, true, false); + err = ovl_verify_origin_xattr(ofs, ofs->indexdir, + OVL_XATTR_ORIGIN, + upperpath->dentry, true, + false); if (err) pr_err("failed to verify index dir 'origin' xattr\n"); } @@ -947,6 +891,8 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, out: mnt_drop_write(mnt); +out_free_fh: + kfree(fh); return err; } @@ -1382,8 +1328,11 @@ int ovl_fill_super(struct super_block *sb, struct fs_context *fc) ofs->layers = layers; /* * Layer 0 is reserved for upper even if there's no upper. - * For consistency, config.lowerdirs[0] is NULL. + * config.lowerdirs[0] is used for storing the user provided colon + * separated lowerdir string. */ + ofs->config.lowerdirs[0] = ctx->lowerdir_all; + ctx->lowerdir_all = NULL; ofs->numlayer = 1; sb->s_stack_depth = 0; @@ -1493,8 +1442,7 @@ int ovl_fill_super(struct super_block *sb, struct fs_context *fc) cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); sb->s_magic = OVERLAYFS_SUPER_MAGIC; - sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : - ovl_trusted_xattr_handlers; + sb->s_xattr = ovl_xattr_handlers(ofs); sb->s_fs_info = ofs; #ifdef CONFIG_FS_POSIX_ACL sb->s_flags |= SB_POSIXACL; diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 868afd8834c3..73ac47b49218 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -17,12 +17,38 @@ #include <linux/ratelimit.h> #include "overlayfs.h" +/* Get write access to upper mnt - may fail if upper sb was remounted ro */ +int ovl_get_write_access(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + return mnt_get_write_access(ovl_upper_mnt(ofs)); +} + +/* Get write access to upper sb - may block if upper sb is frozen */ +void ovl_start_write(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + sb_start_write(ovl_upper_mnt(ofs)->mnt_sb); +} + int ovl_want_write(struct dentry *dentry) { struct ovl_fs *ofs = OVL_FS(dentry->d_sb); return mnt_want_write(ovl_upper_mnt(ofs)); } +void ovl_put_write_access(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + mnt_put_write_access(ovl_upper_mnt(ofs)); +} + +void ovl_end_write(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + sb_end_write(ovl_upper_mnt(ofs)->mnt_sb); +} + void ovl_drop_write(struct dentry *dentry) { struct ovl_fs *ofs = OVL_FS(dentry->d_sb); @@ -575,6 +601,16 @@ bool ovl_is_whiteout(struct dentry *dentry) return inode && IS_WHITEOUT(inode); } +/* + * Use this over ovl_is_whiteout for upper and lower files, as it also + * handles overlay.whiteout xattr whiteout files. + */ +bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path) +{ + return ovl_is_whiteout(path->dentry) || + ovl_path_check_xwhiteout_xattr(ofs, path); +} + struct file *ovl_path_open(const struct path *path, int flags) { struct inode *inode = d_inode(path->dentry); @@ -644,22 +680,36 @@ bool ovl_already_copied_up(struct dentry *dentry, int flags) return false; } +/* + * The copy up "transaction" keeps an elevated mnt write count on upper mnt, + * but leaves taking freeze protection on upper sb to lower level helpers. + */ int ovl_copy_up_start(struct dentry *dentry, int flags) { struct inode *inode = d_inode(dentry); int err; err = ovl_inode_lock_interruptible(inode); - if (!err && ovl_already_copied_up_locked(dentry, flags)) { + if (err) + return err; + + if (ovl_already_copied_up_locked(dentry, flags)) err = 1; /* Already copied up */ - ovl_inode_unlock(inode); - } + else + err = ovl_get_write_access(dentry); + if (err) + goto out_unlock; + + return 0; +out_unlock: + ovl_inode_unlock(inode); return err; } void ovl_copy_up_end(struct dentry *dentry) { + ovl_put_write_access(dentry); ovl_inode_unlock(d_inode(dentry)); } @@ -676,6 +726,32 @@ bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path) return false; } +bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path) +{ + struct dentry *dentry = path->dentry; + int res; + + /* xattr.whiteout must be a zero size regular file */ + if (!d_is_reg(dentry) || i_size_read(d_inode(dentry)) != 0) + return false; + + res = ovl_path_getxattr(ofs, path, OVL_XATTR_XWHITEOUT, NULL, 0); + return res >= 0; +} + +bool ovl_path_check_xwhiteouts_xattr(struct ovl_fs *ofs, const struct path *path) +{ + struct dentry *dentry = path->dentry; + int res; + + /* xattr.whiteouts must be a directory */ + if (!d_is_dir(dentry)) + return false; + + res = ovl_path_getxattr(ofs, path, OVL_XATTR_XWHITEOUTS, NULL, 0); + return res >= 0; +} + /* * Load persistent uuid from xattr into s_uuid if found, or store a new * random generated value in s_uuid and in xattr. @@ -760,6 +836,8 @@ bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path, #define OVL_XATTR_UUID_POSTFIX "uuid" #define OVL_XATTR_METACOPY_POSTFIX "metacopy" #define OVL_XATTR_PROTATTR_POSTFIX "protattr" +#define OVL_XATTR_XWHITEOUT_POSTFIX "whiteout" +#define OVL_XATTR_XWHITEOUTS_POSTFIX "whiteouts" #define OVL_XATTR_TAB_ENTRY(x) \ [x] = { [false] = OVL_XATTR_TRUSTED_PREFIX x ## _POSTFIX, \ @@ -775,6 +853,8 @@ const char *const ovl_xattr_table[][2] = { OVL_XATTR_TAB_ENTRY(OVL_XATTR_UUID), OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY), OVL_XATTR_TAB_ENTRY(OVL_XATTR_PROTATTR), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_XWHITEOUT), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_XWHITEOUTS), }; int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry, @@ -973,12 +1053,18 @@ static void ovl_cleanup_index(struct dentry *dentry) struct dentry *index = NULL; struct inode *inode; struct qstr name = { }; + bool got_write = false; int err; err = ovl_get_index_name(ofs, lowerdentry, &name); if (err) goto fail; + err = ovl_want_write(dentry); + if (err) + goto fail; + + got_write = true; inode = d_inode(upperdentry); if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) { pr_warn_ratelimited("cleanup linked index (%pd2, ino=%lu, nlink=%u)\n", @@ -1016,6 +1102,8 @@ static void ovl_cleanup_index(struct dentry *dentry) goto fail; out: + if (got_write) + ovl_drop_write(dentry); kfree(name.name); dput(index); return; @@ -1062,8 +1150,12 @@ int ovl_nlink_start(struct dentry *dentry) if (err) return err; + err = ovl_want_write(dentry); + if (err) + goto out_unlock; + if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode)) - goto out; + return 0; old_cred = ovl_override_creds(dentry->d_sb); /* @@ -1074,10 +1166,15 @@ int ovl_nlink_start(struct dentry *dentry) */ err = ovl_set_nlink_upper(dentry); revert_creds(old_cred); - -out: if (err) - ovl_inode_unlock(inode); + goto out_drop_write; + + return 0; + +out_drop_write: + ovl_drop_write(dentry); +out_unlock: + ovl_inode_unlock(inode); return err; } @@ -1086,6 +1183,8 @@ void ovl_nlink_end(struct dentry *dentry) { struct inode *inode = d_inode(dentry); + ovl_drop_write(dentry); + if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) { const struct cred *old_cred; @@ -1403,6 +1502,7 @@ void ovl_copyattr(struct inode *inode) realinode = ovl_i_path_real(inode, &realpath); real_idmap = mnt_idmap(realpath.mnt); + spin_lock(&inode->i_lock); vfsuid = i_uid_into_vfsuid(real_idmap, realinode); vfsgid = i_gid_into_vfsgid(real_idmap, realinode); @@ -1413,4 +1513,5 @@ void ovl_copyattr(struct inode *inode) inode_set_mtime_to_ts(inode, inode_get_mtime(realinode)); inode_set_ctime_to_ts(inode, inode_get_ctime(realinode)); i_size_write(inode, i_size_read(realinode)); + spin_unlock(&inode->i_lock); } diff --git a/fs/overlayfs/xattrs.c b/fs/overlayfs/xattrs.c new file mode 100644 index 000000000000..383978e4663c --- /dev/null +++ b/fs/overlayfs/xattrs.c @@ -0,0 +1,271 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <linux/fs.h> +#include <linux/xattr.h> +#include "overlayfs.h" + +static bool ovl_is_escaped_xattr(struct super_block *sb, const char *name) +{ + struct ovl_fs *ofs = sb->s_fs_info; + + if (ofs->config.userxattr) + return strncmp(name, OVL_XATTR_ESCAPE_USER_PREFIX, + OVL_XATTR_ESCAPE_USER_PREFIX_LEN) == 0; + else + return strncmp(name, OVL_XATTR_ESCAPE_TRUSTED_PREFIX, + OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN - 1) == 0; +} + +static bool ovl_is_own_xattr(struct super_block *sb, const char *name) +{ + struct ovl_fs *ofs = OVL_FS(sb); + + if (ofs->config.userxattr) + return strncmp(name, OVL_XATTR_USER_PREFIX, + OVL_XATTR_USER_PREFIX_LEN) == 0; + else + return strncmp(name, OVL_XATTR_TRUSTED_PREFIX, + OVL_XATTR_TRUSTED_PREFIX_LEN) == 0; +} + +bool ovl_is_private_xattr(struct super_block *sb, const char *name) +{ + return ovl_is_own_xattr(sb, name) && !ovl_is_escaped_xattr(sb, name); +} + +static int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, + const void *value, size_t size, int flags) +{ + int err; + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + struct dentry *upperdentry = ovl_i_dentry_upper(inode); + struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); + struct path realpath; + const struct cred *old_cred; + + if (!value && !upperdentry) { + ovl_path_lower(dentry, &realpath); + old_cred = ovl_override_creds(dentry->d_sb); + err = vfs_getxattr(mnt_idmap(realpath.mnt), realdentry, name, NULL, 0); + revert_creds(old_cred); + if (err < 0) + goto out; + } + + if (!upperdentry) { + err = ovl_copy_up(dentry); + if (err) + goto out; + + realdentry = ovl_dentry_upper(dentry); + } + + err = ovl_want_write(dentry); + if (err) + goto out; + + old_cred = ovl_override_creds(dentry->d_sb); + if (value) { + err = ovl_do_setxattr(ofs, realdentry, name, value, size, + flags); + } else { + WARN_ON(flags != XATTR_REPLACE); + err = ovl_do_removexattr(ofs, realdentry, name); + } + revert_creds(old_cred); + ovl_drop_write(dentry); + + /* copy c/mtime */ + ovl_copyattr(inode); +out: + return err; +} + +static int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, + void *value, size_t size) +{ + ssize_t res; + const struct cred *old_cred; + struct path realpath; + + ovl_i_path_real(inode, &realpath); + old_cred = ovl_override_creds(dentry->d_sb); + res = vfs_getxattr(mnt_idmap(realpath.mnt), realpath.dentry, name, value, size); + revert_creds(old_cred); + return res; +} + +static bool ovl_can_list(struct super_block *sb, const char *s) +{ + /* Never list private (.overlay) */ + if (ovl_is_private_xattr(sb, s)) + return false; + + /* List all non-trusted xattrs */ + if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) + return true; + + /* list other trusted for superuser only */ + return ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN); +} + +ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) +{ + struct dentry *realdentry = ovl_dentry_real(dentry); + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + ssize_t res; + size_t len; + char *s; + const struct cred *old_cred; + size_t prefix_len, name_len; + + old_cred = ovl_override_creds(dentry->d_sb); + res = vfs_listxattr(realdentry, list, size); + revert_creds(old_cred); + if (res <= 0 || size == 0) + return res; + + prefix_len = ofs->config.userxattr ? + OVL_XATTR_USER_PREFIX_LEN : OVL_XATTR_TRUSTED_PREFIX_LEN; + + /* filter out private xattrs */ + for (s = list, len = res; len;) { + size_t slen = strnlen(s, len) + 1; + + /* underlying fs providing us with an broken xattr list? */ + if (WARN_ON(slen > len)) + return -EIO; + + len -= slen; + if (!ovl_can_list(dentry->d_sb, s)) { + res -= slen; + memmove(s, s + slen, len); + } else if (ovl_is_escaped_xattr(dentry->d_sb, s)) { + res -= OVL_XATTR_ESCAPE_PREFIX_LEN; + name_len = slen - prefix_len - OVL_XATTR_ESCAPE_PREFIX_LEN; + s += prefix_len; + memmove(s, s + OVL_XATTR_ESCAPE_PREFIX_LEN, name_len + len); + s += name_len; + } else { + s += slen; + } + } + + return res; +} + +static char *ovl_xattr_escape_name(const char *prefix, const char *name) +{ + size_t prefix_len = strlen(prefix); + size_t name_len = strlen(name); + size_t escaped_len; + char *escaped, *s; + + escaped_len = prefix_len + OVL_XATTR_ESCAPE_PREFIX_LEN + name_len; + if (escaped_len > XATTR_NAME_MAX) + return ERR_PTR(-EOPNOTSUPP); + + escaped = kmalloc(escaped_len + 1, GFP_KERNEL); + if (escaped == NULL) + return ERR_PTR(-ENOMEM); + + s = escaped; + memcpy(s, prefix, prefix_len); + s += prefix_len; + memcpy(s, OVL_XATTR_ESCAPE_PREFIX, OVL_XATTR_ESCAPE_PREFIX_LEN); + s += OVL_XATTR_ESCAPE_PREFIX_LEN; + memcpy(s, name, name_len + 1); + + return escaped; +} + +static int ovl_own_xattr_get(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, void *buffer, size_t size) +{ + char *escaped; + int r; + + escaped = ovl_xattr_escape_name(handler->prefix, name); + if (IS_ERR(escaped)) + return PTR_ERR(escaped); + + r = ovl_xattr_get(dentry, inode, escaped, buffer, size); + + kfree(escaped); + + return r; +} + +static int ovl_own_xattr_set(const struct xattr_handler *handler, + struct mnt_idmap *idmap, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + char *escaped; + int r; + + escaped = ovl_xattr_escape_name(handler->prefix, name); + if (IS_ERR(escaped)) + return PTR_ERR(escaped); + + r = ovl_xattr_set(dentry, inode, escaped, value, size, flags); + + kfree(escaped); + + return r; +} + +static int ovl_other_xattr_get(const struct xattr_handler *handler, + struct dentry *dentry, struct inode *inode, + const char *name, void *buffer, size_t size) +{ + return ovl_xattr_get(dentry, inode, name, buffer, size); +} + +static int ovl_other_xattr_set(const struct xattr_handler *handler, + struct mnt_idmap *idmap, + struct dentry *dentry, struct inode *inode, + const char *name, const void *value, + size_t size, int flags) +{ + return ovl_xattr_set(dentry, inode, name, value, size, flags); +} + +static const struct xattr_handler ovl_own_trusted_xattr_handler = { + .prefix = OVL_XATTR_TRUSTED_PREFIX, + .get = ovl_own_xattr_get, + .set = ovl_own_xattr_set, +}; + +static const struct xattr_handler ovl_own_user_xattr_handler = { + .prefix = OVL_XATTR_USER_PREFIX, + .get = ovl_own_xattr_get, + .set = ovl_own_xattr_set, +}; + +static const struct xattr_handler ovl_other_xattr_handler = { + .prefix = "", /* catch all */ + .get = ovl_other_xattr_get, + .set = ovl_other_xattr_set, +}; + +static const struct xattr_handler * const ovl_trusted_xattr_handlers[] = { + &ovl_own_trusted_xattr_handler, + &ovl_other_xattr_handler, + NULL +}; + +static const struct xattr_handler * const ovl_user_xattr_handlers[] = { + &ovl_own_user_xattr_handler, + &ovl_other_xattr_handler, + NULL +}; + +const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs) +{ + return ofs->config.userxattr ? ovl_user_xattr_handlers : + ovl_trusted_xattr_handlers; +} + |