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Commit a2c75c81 authored by Gao Xiang's avatar Gao Xiang Committed by Greg Kroah-Hartman
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erofs: better erofs symlink stuffs 

Fix as Christoph suggested [1] [2], "remove is_inode_fast_symlink
and just opencode it in the few places using it"

and
"Please just set the ops directly instead of obsfucating that in
a single caller, single line inline function.  And please set it
instead of the normal symlink iops in the same place where you
also set those."

[1] https://lore.kernel.org/r/20190830163910.GB29603@infradead.org/
[2] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/


Reported-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarGao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190904020912.63925-13-gaoxiang25@huawei.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2d78c209

fs/erofs/inode.c

+27 −41
Original line number Diff line number Diff line
@@ -127,35 +127,25 @@ static int read_inode(struct inode *inode, void *data) 
	return -EFSCORRUPTED;

}



/*

 * try_lock can be required since locking order is:

 *   file data(fs_inode)

 *        meta(bd_inode)

 * but the majority of the callers is "iget",

 * in that case we are pretty sure no deadlock since

 * no data operations exist. However I tend to

 * try_lock since it takes no much overhead and

 * will success immediately.

 */

static int fill_inline_data(struct inode *inode, void *data,

static int erofs_fill_symlink(struct inode *inode, void *data,

			      unsigned int m_pofs)

{

	struct erofs_inode *vi = EROFS_I(inode);

	struct erofs_sb_info *sbi = EROFS_I_SB(inode);

	char *lnk;



	/* should be tail-packing data inline */

	if (vi->datalayout != EROFS_INODE_FLAT_INLINE)

	/* if it cannot be handled with fast symlink scheme */

	if (vi->datalayout != EROFS_INODE_FLAT_INLINE ||

	    inode->i_size >= PAGE_SIZE) {

		inode->i_op = &erofs_symlink_iops;

		return 0;

	}



	/* fast symlink */

	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {

		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);



	lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);

	if (!lnk)

		return -ENOMEM;



	m_pofs += vi->inode_isize + vi->xattr_isize;



	/* inline symlink data shouldn't cross page boundary as well */

	if (m_pofs + inode->i_size > PAGE_SIZE) {

		kfree(lnk);
@@ -169,8 +159,7 @@ static int fill_inline_data(struct inode *inode, void *data, 
	lnk[inode->i_size] = '\0';



	inode->i_link = lnk;

		set_inode_fast_symlink(inode);

	}

	inode->i_op = &erofs_fast_symlink_iops;

	return 0;

}
@@ -217,8 +206,9 @@ static int fill_inode(struct inode *inode, int isdir) 
			inode->i_fop = &erofs_dir_fops;

			break;

		case S_IFLNK:

			/* by default, page_get_link is used for symlink */

			inode->i_op = &erofs_symlink_iops;

			err = erofs_fill_symlink(inode, data, ofs);

			if (err)

				goto out_unlock;

			inode_nohighmem(inode);

			break;

		case S_IFCHR:
@@ -237,11 +227,7 @@ static int fill_inode(struct inode *inode, int isdir) 
			err = z_erofs_fill_inode(inode);

			goto out_unlock;

		}



		inode->i_mapping->a_ops = &erofs_raw_access_aops;



		/* fill last page if inline data is available */

		err = fill_inline_data(inode, data, ofs);

	}



out_unlock:

fs/erofs/internal.h

+0 −10
Original line number Diff line number Diff line
@@ -479,16 +479,6 @@ extern const struct inode_operations erofs_generic_iops; 
extern const struct inode_operations erofs_symlink_iops;

extern const struct inode_operations erofs_fast_symlink_iops;



static inline void set_inode_fast_symlink(struct inode *inode)

{

	inode->i_op = &erofs_fast_symlink_iops;

}



static inline bool is_inode_fast_symlink(struct inode *inode)

{

	return inode->i_op == &erofs_fast_symlink_iops;

}



struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid, bool dir);

int erofs_getattr(const struct path *path, struct kstat *stat,

		  u32 request_mask, unsigned int query_flags);

fs/erofs/super.c

+2 −3
Original line number Diff line number Diff line
@@ -40,10 +40,9 @@ static void free_inode(struct inode *inode) 
{

	struct erofs_inode *vi = EROFS_I(inode);



	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */

	if (is_inode_fast_symlink(inode))

	/* be careful of RCU symlink path */

	if (inode->i_op == &erofs_fast_symlink_iops)

		kfree(inode->i_link);



	kfree(vi->xattr_shared_xattrs);



	kmem_cache_free(erofs_inode_cachep, vi);