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author | Chandan Rajendra <chandan@linux.vnet.ibm.com> | 2017-07-24 01:57:54 -0500 |
---|---|---|
committer | Miklos Szeredi <mszeredi@redhat.com> | 2017-11-09 10:23:27 +0100 |
commit | b93436320c1e9089a055941523571cd7c037f7cb (patch) | |
tree | c97ece67e4499dd7b184b728272786b597aed681 /fs/overlayfs/namei.c | |
parent | ee023c30d7d6bc21d3a85f3625a30209bdcc41e6 (diff) | |
download | linux-stable-b93436320c1e9089a055941523571cd7c037f7cb.tar.gz linux-stable-b93436320c1e9089a055941523571cd7c037f7cb.tar.bz2 linux-stable-b93436320c1e9089a055941523571cd7c037f7cb.zip |
ovl: re-structure overlay lower layers in-memory
Define new structures to represent overlay instance lower layers and
overlay merge dir lower layers to make room for storing more per layer
information in-memory.
Instead of keeping the fs instance lower layers in an array of struct
vfsmount, keep them in an array of new struct ovl_layer, that has a
pointer to struct vfsmount.
Instead of keeping the dentry lower layers in an array of struct path,
keep them in an array of new struct ovl_path, that has a pointer to
struct dentry and to struct ovl_layer.
Add a small helper to find the fs layer id that correspopnds to a lower
struct ovl_path and use it in ovl_lookup().
[amir: split re-structure from anonymous bdev patch]
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs/namei.c')
-rw-r--r-- | fs/overlayfs/namei.c | 52 |
1 files changed, 31 insertions, 21 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 505a4b8902fc..6cc3ece3417d 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -285,16 +285,15 @@ static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d, static int ovl_check_origin(struct dentry *upperdentry, - struct path *lowerstack, unsigned int numlower, - struct path **stackp, unsigned int *ctrp) + struct ovl_path *lower, unsigned int numlower, + struct ovl_path **stackp, unsigned int *ctrp) { struct vfsmount *mnt; struct dentry *origin = NULL; int i; - for (i = 0; i < numlower; i++) { - mnt = lowerstack[i].mnt; + mnt = lower[i].layer->mnt; origin = ovl_get_origin(upperdentry, mnt); if (IS_ERR(origin)) return PTR_ERR(origin); @@ -308,12 +307,12 @@ static int ovl_check_origin(struct dentry *upperdentry, BUG_ON(*ctrp); if (!*stackp) - *stackp = kmalloc(sizeof(struct path), GFP_KERNEL); + *stackp = kmalloc(sizeof(struct ovl_path), GFP_KERNEL); if (!*stackp) { dput(origin); return -ENOMEM; } - **stackp = (struct path) { .dentry = origin, .mnt = mnt }; + **stackp = (struct ovl_path){.dentry = origin, .layer = lower[i].layer}; *ctrp = 1; return 0; @@ -383,13 +382,13 @@ fail: * OVL_XATTR_ORIGIN and that origin file handle can be decoded to lower path. * Return 0 on match, -ESTALE on mismatch or stale origin, < 0 on error. */ -int ovl_verify_index(struct dentry *index, struct path *lowerstack, +int ovl_verify_index(struct dentry *index, struct ovl_path *lower, unsigned int numlower) { struct ovl_fh *fh = NULL; size_t len; - struct path origin = { }; - struct path *stack = &origin; + struct ovl_path origin = { }; + struct ovl_path *stack = &origin; unsigned int ctr = 0; int err; @@ -428,7 +427,7 @@ int ovl_verify_index(struct dentry *index, struct path *lowerstack, if (err) goto fail; - err = ovl_check_origin(index, lowerstack, numlower, &stack, &ctr); + err = ovl_check_origin(index, lower, numlower, &stack, &ctr); if (!err && !ctr) err = -ESTALE; if (err) @@ -567,11 +566,24 @@ int ovl_path_next(int idx, struct dentry *dentry, struct path *path) idx++; } BUG_ON(idx > oe->numlower); - *path = oe->lowerstack[idx - 1]; + path->dentry = oe->lowerstack[idx - 1].dentry; + path->mnt = oe->lowerstack[idx - 1].layer->mnt; return (idx < oe->numlower) ? idx + 1 : -1; } +static int ovl_find_layer(struct ovl_fs *ofs, struct ovl_path *path) +{ + int i; + + for (i = 0; i < ofs->numlower; i++) { + if (ofs->lower_layers[i].mnt == path->layer->mnt) + break; + } + + return i; +} + struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { @@ -580,7 +592,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, struct ovl_fs *ofs = dentry->d_sb->s_fs_info; struct ovl_entry *poe = dentry->d_parent->d_fsdata; struct ovl_entry *roe = dentry->d_sb->s_root->d_fsdata; - struct path *stack = NULL; + struct ovl_path *stack = NULL; struct dentry *upperdir, *upperdentry = NULL; struct dentry *index = NULL; unsigned int ctr = 0; @@ -645,17 +657,17 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, if (!d.stop && poe->numlower) { err = -ENOMEM; - stack = kcalloc(ofs->numlower, sizeof(struct path), + stack = kcalloc(ofs->numlower, sizeof(struct ovl_path), GFP_KERNEL); if (!stack) goto out_put_upper; } for (i = 0; !d.stop && i < poe->numlower; i++) { - struct path lowerpath = poe->lowerstack[i]; + struct ovl_path lower = poe->lowerstack[i]; d.last = i == poe->numlower - 1; - err = ovl_lookup_layer(lowerpath.dentry, &d, &this); + err = ovl_lookup_layer(lower.dentry, &d, &this); if (err) goto out_put; @@ -663,7 +675,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, continue; stack[ctr].dentry = this; - stack[ctr].mnt = lowerpath.mnt; + stack[ctr].layer = lower.layer; ctr++; if (d.stop) @@ -673,10 +685,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, poe = roe; /* Find the current layer on the root dentry */ - for (i = 0; i < poe->numlower; i++) - if (poe->lowerstack[i].mnt == lowerpath.mnt) - break; - if (WARN_ON(i == poe->numlower)) + i = ovl_find_layer(ofs, &lower); + if (WARN_ON(i == ofs->numlower)) break; } } @@ -699,7 +709,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, goto out_put; oe->opaque = upperopaque; - memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr); + memcpy(oe->lowerstack, stack, sizeof(struct ovl_path) * ctr); dentry->d_fsdata = oe; if (upperdentry) |