[PATCH 4.19 1/5] staging: erofs: add error handling for xattr submodule

commit cadf1ccf1b0021d0b7a9347e102ac5258f9f98c8 upstream.

This patch enhances the missing error handling code for xattr submodule, which improves the stability for the rare cases.

Reviewed-by: Chao Yu yuchao0@huawei.com Signed-off-by: Chao Yu yuchao0@huawei.com Signed-off-by: Gao Xiang gaoxiang25@huawei.com ---

This series resolves the following conflicts: FAILED: patch "[PATCH] staging: erofs: fix fast symlink w/o xattr when fs xattr is" failed to apply to 4.19-stable tree FAILED: patch "[PATCH] staging: erofs: fix memleak of inode's shared xattr array" failed to apply to 4.19-stable tree FAILED: patch "[PATCH] staging: erofs: fix race of initializing xattrs of a inode at" failed to apply to 4.19-stable tree FAILED: patch "[PATCH] staging: erofs: keep corrupted fs from crashing kernel in" failed to apply to 4.19-stable tree

In addition, there is another patch called staging: erofs: add error handling for xattr submodule that needs to be backported to 4.19 as well (4.20+ already has this patch.)

drivers/staging/erofs/internal.h | 5 +- drivers/staging/erofs/xattr.c | 112 +++++++++++++++++++++++++++------------ 2 files changed, 81 insertions(+), 36 deletions(-)

diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h index 9f44ed8f0023..1c048c412fb2 100644 --- a/drivers/staging/erofs/internal.h +++ b/drivers/staging/erofs/internal.h @@ -485,8 +485,9 @@ struct erofs_map_blocks_iter { };

-static inline struct page *erofs_get_inline_page(struct inode *inode, - erofs_blk_t blkaddr) +static inline struct page * +erofs_get_inline_page(struct inode *inode, + erofs_blk_t blkaddr) { return erofs_get_meta_page(inode->i_sb, blkaddr, S_ISDIR(inode->i_mode)); diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c index 0e9cfeccdf99..d4bccb57e7c3 100644 --- a/drivers/staging/erofs/xattr.c +++ b/drivers/staging/erofs/xattr.c @@ -24,16 +24,25 @@ struct xattr_iter {

static inline void xattr_iter_end(struct xattr_iter *it, bool atomic) { - /* only init_inode_xattrs use non-atomic once */ + /* the only user of kunmap() is 'init_inode_xattrs' */ if (unlikely(!atomic)) kunmap(it->page); else kunmap_atomic(it->kaddr); + unlock_page(it->page); put_page(it->page); }

-static void init_inode_xattrs(struct inode *inode) +static inline void xattr_iter_end_final(struct xattr_iter *it) +{ + if (!it->page) + return; + + xattr_iter_end(it, true); +} + +static int init_inode_xattrs(struct inode *inode) { struct xattr_iter it; unsigned i; @@ -43,7 +52,7 @@ static void init_inode_xattrs(struct inode *inode) bool atomic_map;

if (likely(inode_has_inited_xattr(inode))) - return; + return 0;

vi = EROFS_V(inode); BUG_ON(!vi->xattr_isize); @@ -53,7 +62,8 @@ static void init_inode_xattrs(struct inode *inode) it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);

it.page = erofs_get_inline_page(inode, it.blkaddr); - BUG_ON(IS_ERR(it.page)); + if (IS_ERR(it.page)) + return PTR_ERR(it.page);

/* read in shared xattr array (non-atomic, see kmalloc below) */ it.kaddr = kmap(it.page); @@ -62,9 +72,12 @@ static void init_inode_xattrs(struct inode *inode) ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);

vi->xattr_shared_count = ih->h_shared_count; - vi->xattr_shared_xattrs = (unsigned *)kmalloc_array( - vi->xattr_shared_count, sizeof(unsigned), - GFP_KERNEL | __GFP_NOFAIL); + vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count, + sizeof(uint), GFP_KERNEL); + if (!vi->xattr_shared_xattrs) { + xattr_iter_end(&it, atomic_map); + return -ENOMEM; + }

/* let's skip ibody header */ it.ofs += sizeof(struct erofs_xattr_ibody_header); @@ -77,7 +90,8 @@ static void init_inode_xattrs(struct inode *inode)

it.page = erofs_get_meta_page(inode->i_sb, ++it.blkaddr, S_ISDIR(inode->i_mode)); - BUG_ON(IS_ERR(it.page)); + if (IS_ERR(it.page)) + return PTR_ERR(it.page);

it.kaddr = kmap_atomic(it.page); atomic_map = true; @@ -90,6 +104,7 @@ static void init_inode_xattrs(struct inode *inode) xattr_iter_end(&it, atomic_map);

inode_set_inited_xattr(inode); + return 0; }

struct xattr_iter_handlers { @@ -99,18 +114,25 @@ struct xattr_iter_handlers { void (*value)(struct xattr_iter *, unsigned, char *, unsigned); };

-static void xattr_iter_fixup(struct xattr_iter *it) +static inline int xattr_iter_fixup(struct xattr_iter *it) { - if (unlikely(it->ofs >= EROFS_BLKSIZ)) { - xattr_iter_end(it, true); + if (it->ofs < EROFS_BLKSIZ) + return 0;

- it->blkaddr += erofs_blknr(it->ofs); - it->page = erofs_get_meta_page(it->sb, it->blkaddr, false); - BUG_ON(IS_ERR(it->page)); + xattr_iter_end(it, true);

- it->kaddr = kmap_atomic(it->page); - it->ofs = erofs_blkoff(it->ofs); + it->blkaddr += erofs_blknr(it->ofs); + it->page = erofs_get_meta_page(it->sb, it->blkaddr, false); + if (IS_ERR(it->page)) { + int err = PTR_ERR(it->page); + + it->page = NULL; + return err; } + + it->kaddr = kmap_atomic(it->page); + it->ofs = erofs_blkoff(it->ofs); + return 0; }

static int inline_xattr_iter_begin(struct xattr_iter *it, @@ -132,21 +154,24 @@ static int inline_xattr_iter_begin(struct xattr_iter *it, it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);

it->page = erofs_get_inline_page(inode, it->blkaddr); - BUG_ON(IS_ERR(it->page)); - it->kaddr = kmap_atomic(it->page); + if (IS_ERR(it->page)) + return PTR_ERR(it->page);

+ it->kaddr = kmap_atomic(it->page); return vi->xattr_isize - xattr_header_sz; }

static int xattr_foreach(struct xattr_iter *it, - struct xattr_iter_handlers *op, unsigned *tlimit) + const struct xattr_iter_handlers *op, unsigned int *tlimit) { struct erofs_xattr_entry entry; unsigned value_sz, processed, slice; int err;

/* 0. fixup blkaddr, ofs, ipage */ - xattr_iter_fixup(it); + err = xattr_iter_fixup(it); + if (err) + return err;

/* * 1. read xattr entry to the memory, @@ -178,7 +203,9 @@ static int xattr_foreach(struct xattr_iter *it, if (it->ofs >= EROFS_BLKSIZ) { BUG_ON(it->ofs > EROFS_BLKSIZ);

- xattr_iter_fixup(it); + err = xattr_iter_fixup(it); + if (err) + goto out; it->ofs = 0; }

@@ -210,7 +237,10 @@ static int xattr_foreach(struct xattr_iter *it, while (processed < value_sz) { if (it->ofs >= EROFS_BLKSIZ) { BUG_ON(it->ofs > EROFS_BLKSIZ); - xattr_iter_fixup(it); + + err = xattr_iter_fixup(it); + if (err) + goto out; it->ofs = 0; }

@@ -270,7 +300,7 @@ static void xattr_copyvalue(struct xattr_iter *_it, memcpy(it->buffer + processed, buf, len); }

-static struct xattr_iter_handlers find_xattr_handlers = { +static const struct xattr_iter_handlers find_xattr_handlers = { .entry = xattr_entrymatch, .name = xattr_namematch, .alloc_buffer = xattr_checkbuffer, @@ -291,8 +321,11 @@ static int inline_getxattr(struct inode *inode, struct getxattr_iter *it) ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining); if (ret >= 0) break; + + if (ret != -ENOATTR) /* -ENOMEM, -EIO, etc. */ + break; } - xattr_iter_end(&it->it, true); + xattr_iter_end_final(&it->it);

return ret < 0 ? ret : it->buffer_size; } @@ -315,8 +348,10 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it) xattr_iter_end(&it->it, true);

it->it.page = erofs_get_meta_page(inode->i_sb, - blkaddr, false); - BUG_ON(IS_ERR(it->it.page)); + blkaddr, false); + if (IS_ERR(it->it.page)) + return PTR_ERR(it->it.page); + it->it.kaddr = kmap_atomic(it->it.page); it->it.blkaddr = blkaddr; } @@ -324,9 +359,12 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it) ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL); if (ret >= 0) break; + + if (ret != -ENOATTR) /* -ENOMEM, -EIO, etc. */ + break; } if (vi->xattr_shared_count) - xattr_iter_end(&it->it, true); + xattr_iter_end_final(&it->it);

return ret < 0 ? ret : it->buffer_size; } @@ -351,7 +389,9 @@ int erofs_getxattr(struct inode *inode, int index, if (unlikely(name == NULL)) return -EINVAL;

- init_inode_xattrs(inode); + ret = init_inode_xattrs(inode); + if (ret) + return ret;

it.index = index;

@@ -494,7 +534,7 @@ static int xattr_skipvalue(struct xattr_iter *_it, return 1; }

-static struct xattr_iter_handlers list_xattr_handlers = { +static const struct xattr_iter_handlers list_xattr_handlers = { .entry = xattr_entrylist, .name = xattr_namelist, .alloc_buffer = xattr_skipvalue, @@ -516,7 +556,7 @@ static int inline_listxattr(struct listxattr_iter *it) if (ret < 0) break; } - xattr_iter_end(&it->it, true); + xattr_iter_end_final(&it->it); return ret < 0 ? ret : it->buffer_ofs; }

@@ -538,8 +578,10 @@ static int shared_listxattr(struct listxattr_iter *it) xattr_iter_end(&it->it, true);

it->it.page = erofs_get_meta_page(inode->i_sb, - blkaddr, false); - BUG_ON(IS_ERR(it->it.page)); + blkaddr, false); + if (IS_ERR(it->it.page)) + return PTR_ERR(it->it.page); + it->it.kaddr = kmap_atomic(it->it.page); it->it.blkaddr = blkaddr; } @@ -549,7 +591,7 @@ static int shared_listxattr(struct listxattr_iter *it) break; } if (vi->xattr_shared_count) - xattr_iter_end(&it->it, true); + xattr_iter_end_final(&it->it);

return ret < 0 ? ret : it->buffer_ofs; } @@ -560,7 +602,9 @@ ssize_t erofs_listxattr(struct dentry *dentry, int ret; struct listxattr_iter it;

- init_inode_xattrs(d_inode(dentry)); + ret = init_inode_xattrs(d_inode(dentry)); + if (ret) + return ret;

it.dentry = dentry; it.buffer = buffer;