truncate: new helpers (25d9e2d1) · Commits · 戴 / test

Documentation/vm/locking

+1 −1

Original line number	Diff line number	Diff line
		@@ -80,7 +80,7 @@ Note: PTL can also be used to guarantee that no new clones using the
		mm start up ... this is a loose form of stability on mm_users. For
		example, it is used in copy_mm to protect against a racing tlb_gather_mmu
		single address space optimization, so that the zap_page_range (from
		vmtruncate) does not lose sending ipi's to cloned threads that might
		truncate) does not lose sending ipi's to cloned threads that might
		be spawned underneath it and go to user mode to drag in pte's into tlbs.

		swap_lock

fs/attr.c

+44 −2

Original line number	Diff line number	Diff line
		@@ -18,7 +18,7 @@
		/* Taken over from the old code... */

		/* POSIX UID/GID verification for setting inode attributes. */
		int inode_change_ok(struct inode inode, struct iattr attr)
		int inode_change_ok(const struct inode inode, struct iattr attr)
		{
		int retval = -EPERM;
		unsigned int ia_valid = attr->ia_valid;
		@@ -60,9 +60,51 @@ fine:
		error:
		return retval;
		}

		EXPORT_SYMBOL(inode_change_ok);

		/**
		* inode_newsize_ok - may this inode be truncated to a given size
		* @inode: the inode to be truncated
		* @offset: the new size to assign to the inode
		* @Returns: 0 on success, -ve errno on failure
		*
		* inode_newsize_ok will check filesystem limits and ulimits to check that the
		* new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
		* when necessary. Caller must not proceed with inode size change if failure is
		* returned. @inode must be a file (not directory), with appropriate
		* permissions to allow truncate (inode_newsize_ok does NOT check these
		* conditions).
		*
		* inode_newsize_ok must be called with i_mutex held.
		*/
		int inode_newsize_ok(const struct inode *inode, loff_t offset)
		{
		if (inode->i_size < offset) {
		unsigned long limit;

		limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
		if (limit != RLIM_INFINITY && offset > limit)
		goto out_sig;
		if (offset > inode->i_sb->s_maxbytes)
		goto out_big;
		} else {
		/*
		* truncation of in-use swapfiles is disallowed - it would
		* cause subsequent swapout to scribble on the now-freed
		* blocks.
		*/
		if (IS_SWAPFILE(inode))
		return -ETXTBSY;
		}

		return 0;
		out_sig:
		send_sig(SIGXFSZ, current, 0);
		out_big:
		return -EFBIG;
		}
		EXPORT_SYMBOL(inode_newsize_ok);

		int inode_setattr(struct inode * inode, struct iattr * attr)
		{
		unsigned int ia_valid = attr->ia_valid;

include/linux/fs.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -2382,7 +2382,8 @@ extern int buffer_migrate_page(struct address_space *,
		#define buffer_migrate_page NULL
		#endif

		extern int inode_change_ok(struct inode , struct iattr );
		extern int inode_change_ok(const struct inode , struct iattr );
		extern int inode_newsize_ok(const struct inode *, loff_t offset);
		extern int __must_check inode_setattr(struct inode , struct iattr );

		extern void file_update_time(struct file *file);

include/linux/mm.h

+3 −2

Original line number	Diff line number	Diff line
		@@ -791,6 +791,7 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
		unmap_mapping_range(mapping, holebegin, holelen, 0);
		}

		extern void truncate_pagecache(struct inode *inode, loff_t old, loff_t new);
		extern int vmtruncate(struct inode *inode, loff_t offset);
		extern int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end);

mm/filemap.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -58,7 +58,7 @@
		/*
		* Lock ordering:
		*
		* ->i_mmap_lock (vmtruncate)
		* ->i_mmap_lock (truncate_pagecache)
		* ->private_lock (__free_pte->__set_page_dirty_buffers)
		* ->swap_lock (exclusive_swap_page, others)
		* ->mapping->tree_lock

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